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Clinical and genetic study of Japanese patients with type 3 Gaucher disease
Molecular Genetics and Metabolism 97 (2009) 272–277
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Clinical and genetic study of Japanese patients with type 3 Gaucher disease Asako Tajima a,*, Takayuki Yokoi a, Masamichi Ariga a, Takeru Ito a, Eiko Kaneshiro a, Yoshikatsu Eto b, Hiroyuki Ida a a b
Department of Pediatrics, Jikei University School of Medicine, Japan Lysosomal Disease Research Center/Institute for Genetic Disease, Jikei University School of Medicine, Japan
a r t i c l e
i n f o
Article history: Received 7 March 2009 Received in revised form 1 May 2009 Accepted 2 May 2009 Available online 10 May 2009 Keywords: Type 3 Gaucher disease Gene mutation Outcome Enzyme replacement therapy Phenotype
a b s t r a c t Information on the phenotypic variations seen in patients with type 3 (chronic neuronopathic) Gaucher disease (GD) is still limited compared with type 1 GD. We retrospectively investigated the clinical features of 42 Japanese patients with type 3 GD. The 42 patients classified as type 3 fell into two groups: those diagnosed as having type 3 GD at diagnosis (group A; n = 24) and those thought to have type 1 at diagnosis but who later developed neurological symptoms (group B; n = 18). The genotype of group A patients varied widely; however, L444P/L444P and L444P/F213I genotypes accounted for 83% in group B. All the patients who did not receive enzyme replacement with alglucerase or imiglucerase (4 in group A, 2 in group B) died. Nineteen patients received enzyme replacement in group A; however, 7 of these died despite the therapy. On the other hand, 14 patients received enzyme replacement alone in group B and 13 of them survived. Among the ERT-treated patients who survived, only one of 12 in group A and 12 out of 13 in group B can walk unaided. In conclusion, some Japanese GD patients who are thought to have type 1 at diagnosis develop neurological symptoms during their clinical course, and careful observation is essential for patients with characteristic genotypes. Moreover, enzyme replacement alone might not have a sufficient effect on the early onset neurological symptoms in type 3 patients. A different treatment strategy is needed to improve the prognosis of these patients. Ó 2009 Elsevier Inc. All rights reserved.
Introduction Gaucher disease (GD) is the most prevalent sphingolipid storage disease caused by deposition of glucocerebroside in cells of the macrophage–monocyte system. It is an autosomal recessively inherited disorder of metabolism, and more than 180 mutations have been detected since the first report of the causative gene [1]. Clinical phenotypes are classified mainly into three groups according to the absence or presence of neurological involvement and its progression: type 1, non-neuronopathic form; type 2, acute neuronopathic form; type 3, subacute neuronopathic form. Type 1 is the most common form and may be diagnosed at any age. The diagnosis can be made only by hematological, visceral, and bone manifestations and, with treatment, the prognosis is good. Type 2 disease is characterized by severe and progressive neurological deterioration and is either fatal at birth or within 2–3 years of life. Type 3 GD includes patients with any form of neurological involvement who have survived the first few years of their lives.
* Corresponding author. Address: Department of Pediatrics, Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan. Fax: +81 3 3435 8665. E-mail address: [email protected] (A. Tajima). 1096-7192/$ - see front matter Ó 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.ymgme.2009.05.001
Since type 1 is prevalent worldwide, its clinical course and treatment outcome have often been reported, mainly from Western countries, indicating a good prognosis and effectiveness of enzyme replacement therapy (ERT) with imiglucerase or alglucerase [2,3]. Strategies such as bone marrow transplantation (BMT) and substrate reduction therapy (SRT) have also been reported to be effective in certain cases [4,5], although BMT carries a high risk of mortality and is not commonly used in type 1 patients and SRT is currently only approved for use in patients in whom enzyme replacement is not an option. In contrast, information on type 3 GD patients is still limited. The prevalence of mutations and phenotypes in Japanese GD patients differs from that in the non-Asian population [6–8]. Namely, type 1 GD patients were found to have more severe and progressive disease compared to Caucasians; the disease is characterized by earlier onset of symptoms with more severe bone involvement and hepatosplenomegaly. Moreover, because the N370S mutation, which is a neuroprotective factor for GD, is absent in Japanese patients, it is possible that there could be more individuals with the neuronopathic form in Japan but their disease follows a different course compared to patients in other populations. The current study, therefore, aim to investigate the clinical features of Japanese individuals with type 3 GD with regard to the genetic and phenotypic perspectives. Furthermore, the appropriate therapeutic strategy for this disorder is discussed.
A. Tajima et al. / Molecular Genetics and Metabolism 97 (2009) 272–277
Patients and methods Patients A total of 124 individuals who were clinically diagnosed as having GD by the attending physicians have been referred to our institution for diagnostic confirmation from all over Japan since 1990. Their diagnoses were confirmed by the assay of beta-glucosidase (EC 3.2.1.45) enzyme activity and/or genetic analysis. Since this procedure is not commercially available in Japan, institutions where enzyme activity can be measured are limited. Our institution is one of them, and because of this situation, our data covers the majority of Japanese Gaucher patients. According to the clinical features of these 124 cases, 54 (43.5%), 28 (22.6%), and 42 (33.9%) were classified as type 1, 2, and 3 at final evaluation, respectively. In general, making a clear distinction between type 2 and 3 is difficult because of the overlap of age at onset. In this study, we classified patients with onset of any neurological symptom at the age of 1 and older as type 3 (mean age at onset of the type 2 patient group was 7 months). However, during the time course we became aware of patients who had been diagnosed as having type 1 GD at diagnosis but later developed symptoms related to central nervous system (CNS) involvement. The phenotypic diagnosis for this group of patients was corrected to type 3. We have distinguished former type 3 patients as group A (‘‘original” type 3) and the latter as group B (‘‘transitioned” type 3). As for clinical features, we have analyzed age at diagnosis, major clinical findings at diagnosis, other clinical manifestation or neurological manifestation at final evaluation, types of treatment if received, age at treatment initiation, age at present or age of death, and activities of daily living (ADL) if the patient was alive. Methods Diagnosis of GD was confirmed by beta-glucosidase enzyme assay using 4-methylumbelliferyl beta-glucoside, and by genetic analysis according to previously described methods [9]. Genomic DNA was extracted from skin fibroblasts using DNA Midi Kit (QIAGEN, Valencia, CA). DNA was first amplified by polymerase chain reaction (PCR) avoiding the pseudo genes, and 8 common mutations (L444P, F213I, R463C, N370S, 84insG, IVS2+1, RecNciI, and D409H) were detected by enzyme digestion or mismatched PCR fragments. When no common mutation was detected, single strand conformation polymorphism (SSCP) and direct sequencing of the beta-glucosidase gene were performed. The mutations detected through these procedures included N188S, R120W, and G202R. PCR fragments were digested with TspRI, NciI, and MspI, to confirm each mutation. Results Forty-two patients were diagnosed as having type 3 GD among the 124 Japanese GD patients at final evaluation. They were clinically distinguished into two groups. Their characteristics are summarized in Tables 1 and 2. Of 42 type 3 patients, 24 patients (57.1%) presented neurological symptoms such as developmental delay, oculomotor apraxia, and seizures at their diagnosis and were classified as type 3 GD; the other 18 patients (42.9%) whose diagnosis was type 1 GD developed neurological symptoms and their diagnosis was ultimately changed to type 3. Table 1 summarizes the characteristics of group A patients. There were 13 males and 11 females. Their age at diagnosis ranged from 11 months to 51 years. Thirteen patients survived and are now between 6 and 61 years old; the other 11 patients died due to deterioration of CNS involvements and their complications ex-
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cept 1 case (patient no. D20) who had died of progressive heart failure. The genotypes of group A patients were diverse, including F213I/F213I or heterozygotes with L444P, F213I, and D409H. RecNciI carriers were found only in group A, and there were no L444P homozygotes or L444P/F213I heterozygotes. Mutation prevalence was the highest for F213I (29.2%), followed by D409H (18.8%), RecNciI (6.3%), R120W (4.2%) and L444P (2.1%). Group B consisted of 13 males and 5 females, including 2 pairs of identical twins (patient no. 3 and 4, patient no. 11 and 12) and 1 pair of siblings (patient no. 6 and 7) (Table 2). Age at diagnosis was from 8 months to 20 years old. When the subjects were evaluated, 14 patients (77.8%) had survived, the youngest was 10 years old and the oldest was 47. L444P/L444P accounted for 61% of all genotypes in group B, followed by L444P/F213I and F213I/F213I. There were no D409H carriers in this group of patients. Twenty-six L444P mutations and eight F213I mutations were detected in this group. All patients both in group A and B presented hepatosplenomegaly at diagnosis. Neurological symptom at diagnosis varied in group A. Developmental delay was seen in 14 patients, seizures in 5, oculomotor apraxia in 4, laryngeal spasms in 4, and myoclonus in 3. Strabismus was also found. In group B, oculomotor apraxia and mental retardation were the most frequent neurological symptoms that had developed (found in 9 patients each). Other neurological symptoms included laryngeal spasms (3 patients), seizures (3 patients), ataxia (3 patients), strabismus (2 patients), and nystagmus (1 patient). In this study we have defined ‘‘developmental delay” as a manifestation seen in patients younger than 6 years of age at diagnosis. ‘‘Mental retardation” was used when a patient of 6 years old and older showed regression of psychomotor function at the time of final evaluation. Those who had received enzyme replacement therapy (ERT) took 50–60 U/kg/2 weeks of imiglucerase, which is the limit dose in Japan. In group A, 19 patients received enzyme replacement; age at first infusion ranged from 1 year to 56 years old. One patient received BMT and 4 patients were not treated at all due to financial problems or unavailability of ERT. The 11 deceased patients included all 4 patients without any treatment, but the other 7 patients had been on ERT and died despite the therapy. Overall ADL of the patients who are alive was severely affected. Ten of the 12 patients receiving ERT who survived are bedridden, 1 patient is able to crawl, and 1 patient can walk unaided. The patient who had undergone BMT is alive and is able to roll over. In group B, 14 patients received ERT alone, 1 patient underwent BMT after ERT because the latter was not effective, and 3 patients did not receive any treatment (Table 2). The age at which ERT was started ranged from 1 to 40 years. Two of the 4 deceased patients were not treated. One patient had died of suffocation due to laryngeal spasms (patient no. D15), and the other 2 patients had died due to regression of neurological symptoms (patient no. D16 and D17). The patient who had received BMT after ERT (patient no. D18) had died due to a severe graft versus host disease after BMT. We were able to evaluate the ADL of 13 patients, and only one patient was bedridden. Gross motor function for the other 12 patients was relatively good; they could walk without help. Visceral involvements and hematological disorders were noted in all the patients. Those symptoms were effectively treated in patients who had received ERT (data not shown). Discussion In this study we analyzed 42 patients with type 3, which accounted for a relatively large number in Japanese GD patients. Our data covers the majority of the patients in Japan, therefore, the patients are not biased for selection. We found that quite a large number of Japanese type 3 GD patients (43%) had initially
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Table 1 Characteristics of group A patients. Gender
Age at diagnosis
Genotype
Major clinical findings at diagnosis
Other clinical manifestation at final evaluation
Treatment
Age at treatment initiation
Age at present/age of death
ADL
1
M
2y8m
F213I/F213I
Seizures, myoclonus, mental retardation
ERT
5y3m
18y2m
4
2 3
M F
2y3m 1y7m
F213I/F213I F213I/RecNciI
Seizures Seizures
ERT ERT
2y4m 1y7m
9y11m 11y8m
2 4
4 5 6 7 8 9
F M F F M F
1y1m 1y8m 1y1m 1y7m 51y 1y9m
Seizures, oculomotor abnormality ND ND ND Tremors Hydrocephalus, corneal opacity
ERT ERT ERT ERT ERT ERT
1y1m 1y8m 1y1m 1y8m 52y 1y10m
10y 6y4m 8y3m 7y2m 61y5m 7y8m
4 4 4 4 1 4
10
F
3y8m
Oculomotor apraxia
BMT
4y
20y8m
3
11
M
3y1m
F213I/RecNciI F213I/R120W F213I/? F213I/? F213I/D409H D409H/ R120W D409H/ IVS10-1 D409H/?
Hepatosplenomegaly, oculomotor abnormality Developmental delay, walking disorder Oculomotor apraxia, laryngeal spasms, hepatosplenomegaly, anemia Developmental delay, hepatosplenomegaly Developmental delay, seizures Developmental delay, hepatosplenomegaly Developmental delay, laryngeal spasms, Myoclonus Developmental delay, laryngeal spasms, hepatosplenomegaly Hepatosplenomegaly, laryngeal spasms
3y2m
13y3m
4
M F
12y 1y7m
?/? ?/?
Hydrocephalus, heart valve calcification, corneal opacity ND Seizures
ERT
12 13
ERT ERT
18y6m 1y8m
28y7m 6y4m
4 4
D14 D15 D16
M M M
1y2m 1y1m ND
Oculomotor apraxia, laryngeal spasms Seizures, oculomotor abnormality ND
ERT ERT ERT
1y2m 1y1m 1y8m
7y2m 2y 4y2m
NA NA NA
D17
M
1y5m
L444P/G202R F213I/RecNciI F213I/ del20insTG F213I/?
Oculomotor apraxia, developmental delay, hepatosplenomegaly Myoclonus, seizures Developmental delay, strabismus, hepatosplenomegaly Seizures, splenomegaly Developmental delay, hepatosplenomegaly, ND
ND
None
NA
3y
NA
D18
F
43y
F213I/D409H
Developmental delay, hepatosplenomegaly, seizures Myoclonus, hepatosplenomegaly
Seizures
ERT
56y
NA
D19
F
31y
Oculomotor apraxia, mental retardation
NA
F
1y3m
Hydrocephalus, heart valve calcification, corneal opacity Heart valve calcification
None
D20
D409H/ D409H D409H/?
Age of death not known 31y
ERT
3y4m
7y
NA
D21
M
1y7m
D409H/?
ERT
8y1m
15y
NA
D22
F
14y
None
NA
25y
NA
D23 D24
M M
4y4m 11m
N188S/ 55 bp del ?/? ?/?
Seizures, oculomotor abnormality, hydrocephalus, heart valve calcification Myoclonus, oculomotor abnormality Oculomotor abnormality ND
None ERT
NA 1y
8y 3y3m
NA NA
Oculomotor apraxia, developmental delay, hepatosplenomegaly Developmental delay, hepatosplenomegaly Seizures Developmental delay, splenomegaly Developmental delay, hepatosplenomegaly, tonic posture
D, deceased; ADL, activities of daily living; ERT, enzyme replacement therapy; BMT, bone marrow transplantation; ?, not identified; NA, not applicable; ND, no data. 1, walks; 2, crawls; 3, rolls over; 4, bedridden.
NA
A. Tajima et al. / Molecular Genetics and Metabolism 97 (2009) 272–277
No.
NA NA NA Hepatosplenomegaly Hepatosplenomegaly Hepatosplenomegaly 1y4m 7y 2y3m F M F D16 D17 D18
L444P/F213I L444P/F213I ?/?
Hepatosplenomegaly L444P/L444P 1y4m M D15
, à, identical twins; , siblings; D, deceased; ADL, activities of daily living; ERT, enzyme replacement therapy; BMT, bone marrow transplantation; ?, not identified. NA, not applicable; ND, no data; 1, walks; 2, crawls; 3, rolls over; 4, bedridden.
7y 44y 9y3m NA 40y 3y10m None ERT ERT ? BMT
NA 3y2m NA None
4 12y 1y ERT F213I/F213I M 14
1y
1y 4y 20y 16y 1y11m 1y4m 5y3m 2y1m 2y1m 2y3m M F M M M F F M M M 4 5 *6 *7 8 9 10 à11 à12 13
L444P/L444P L444P/L444P L444P/L444P L444P/L444P L444P/L444P L444P/L444P L444P/L444P L444P/F213I L444P/F213I F213I/F213I
Hepatosplenomegaly Splenomegaly Splenomegaly, arthralgia Splenomegaly, bone fracture Hepatosplenomegaly Hepatosplenomegaly Hepatosplenomegaly Hepatosplenomegaly Hepatosplenomegaly Hepatosplenomegaly, bone crisis Hepatosplenomegaly
Oculomotor apraxia, mental retardation, ataxia Laryngeal spasms, oculomotor abnormality Oculomotor apraxia, seizures, myoclonus Seizures Ataxia, nystagmus
1 1 1 1 1 1 ND 1 1 1 16y4m 40y1m 47y5m 43y8m 11y7m 10y7m 37y11m 15y7m 15y7m 12y8m 3y 28y4m 36y 32y 2y 1y4m NA 3y10m 3y10m 2y ERT ERT ERT ERT ERT ERT None ERT ERT ERT
1 1 1 23y2m 31y1m 16y4m 7y 19y 3y ERT ERT ERT
Strabismus Oculomotor apraxia, ataxia Mental retardation, laryngeal spasms, seizures Mental retardation, laryngeal spasms Oculomotor apraxia, hearing loss Seizures Strabismus Oculomotor apraxia, mental retardation Oculomotor apraxia, mental retardation Mental retardation Oculomotor apraxia, mental retardation Oculomotor apraxia, mental retardation Oculomotor apraxia, mental retardation Hepatosplenomegaly Hepatosplenomegaly Hepatosplenomegaly L444P/L444P L444P/L444P L444P/L444P 2y11m 8m 1y M M M 1 2 3
Age at diagnosis Gender No.
Table 2 Characteristics of group B patients.
Genotype
Major clinical findings at diagnosis
Neurological manifestation at final evaluation
Treatment
Age at treatment initiation
Age at present/age of death
ADL
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been diagnosed as having type 1 GD, but had later developed symptoms indicative of CNS involvement and thus were reclassified as type 3 GD. Ida et al. [7] and Goker-Alpan et al. [10] also observed that some of the patients diagnosed as having type 1 GD developed neurological symptoms despite treatment. Our transitioned type 3 GD patients were unique, L444P/L444P being the most frequent genotype (11 cases, 61.1%), followed by L444P/ F213I (4 cases) and F213I/F213I (2 cases). These results matched the findings of Ida et al., in that delayed onset of neurologic symptoms is often seen in L444P homoallelism. On the other hand, the genotypes of the original type 3 GD group varied. We have distinguished these two groups, and in addition to the difference of the genotypes, we have shown that their clinical courses and prognoses were clearly distinctive. The linkage of L444P/L444P genotype to neuronopathic form of GD has already been reported in Caucasians and in patients from the Norrbotten region of Sweden [11,12]. However, there is a study by Masuno et al. suggesting that L444P homoallelism is associated with non-neurological form in Japan and that that there may be a genetic heterogeneity between different ethnic groups [13]. In Ida et al.’s first report on the Japanese L444P homozygotes, the patients did not have neurological abnormalities at diagnosis [7]. The authors proposed that the patients were still young thus neurological signs may have not yet developed, and that early initiation of enzyme replacement therapy (ERT) may contribute in preventing those symptoms. After following the patients from the same cohort for 8 years, we found that some of them did develop neurological symptoms even though they had been on ERT from the time of the diagnosis. Therefore, neurological symptoms in Japanese GD patients with L444P homoallelism seem to be unique in that they are often very mild and difficult to detect clinically. As for the various manifestations of a same genotype, Goker-Alpan et al. have suggested the influence of modifier loci for L444P, although other mechanisms such as promoter mutations, environment, and other causes may influence the occurrence of symptoms [10]. Although this is still an unknown field, finding modifier genes might lead to a more clear explanation for the complex phenotypes of GD. L444P homozygous patients diagnosed as having type 1 are still alive, and they should be carefully monitored for the possibility of neurological involvement. Another finding in this report is the existence of F213I, which is a unique mutation among the GD patients from Asia. Understanding the phenotype of patients carrying F213I is significant, because it is still unknown worldwide. There were F213I homozygotes in both group A and B. It is not yet clear how the F213I mutation affects the clinical course, however, it is possible that neurologic symptoms might have not been noticed at the time of diagnosis in the patients in group B. Four L444P/F213I patients were found in group B, and 2 are alive and 2 are deceased. Of the deceased, 1 patient was not treated at all (patient no. D16) and one patient had not been treated for 33 years (patient no. D17). On the other hand, the two living patients had started ERT at an early age. The interval between onset of the disease and the initiation of the treatment might have affected their prognosis. In our study, L444P homozygotes, F213I homozygotes and L444P/F213I compound heterozygotes presented neurologic symptoms subsequently. Since oculomotor apraxia and mental retardation were often detected in these groups of patients, we suggest that ophthalmological investigation by a specialist and neuropsychometrical assessment of intelligence quotient are particularly important. GD patients are mainly diagnosed and followed by a pediatrician in Japan. There is a possibility that neurological symptoms in some patients included in this study might have been detected if examined by a neurologist at onset. We should be aware that there are many cases with a very mild
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neurological impairment that could not be detected without a thorough assessment at onset and a regular follow up. Moreover, a comprehensive care comprised of pediatrician, neurologist, and ophthalmologist in the least is essential in the care and management of GD. It is important to refer to the recombinant allele because in our patients RecNciI mutation was associated with a very poor outcome. RecNciI is sometimes mistaken as L444P depending on the methodology of genetic analysis. In our study F213I/RecNciI was detected only in group A patients (Table 1, patients no. 3, 4, and 15). All of them were very young at the onset of symptoms and despite the initiation of ERT as soon as they were diagnosed, their clinical courses were severe. This shows that F213I/RecNciI carriers present the initial symptoms while they are relatively young, and detecting this specific mutation is essential in predicting their prognosis. If we focus on the efficacy of enzyme replacement for the neurological aspects of GD, we might say that the onset of neurological symptoms may not be totally prevented by enzyme replacement alone in transitioned type 3 GD patients. ERT may slow the progression of the disease, but the already acquired symptoms will not disappear. Our results were not exactly the same as previously reported studies on the efficacy of enzyme replacement in type 3 GD patients [14–16]. For example, although ERT was not effective in patients with myoclonus in the study by Altarescu et al. cognitive improvement and amelioration of saccadic eye movement abnormalities were seen. Moreover, Erikson et al. reported that ERT might have contributed in slowing down or stabilizing neurological signs. The reason may be the relatively high doses of enzyme they used, which is not currently available in Japan. Another aspect we would like to point out is that the patients in the study by Altarescu et al. seem to have had a milder form of type 3 GD, since most of them were L444P homozygotes. As we have shown, all L444P homozygotes in our study were classified as transitioned type 3 GD, showed slow progression of neurological symptoms and their gross motor function was much better than that of the original type 3 GD group. This may explain the difference in the outcome between our report and the previous ones. In our study, all patients not treated with enzyme replacement died, while many of the patients treated with ERT survived. Hematological impairment and hepatosplenomegaly were improved in all ERT-treated patients. This fact suggests that ERT is effective for the life-threatening hematologic, visceral, and skeletal symptoms of the disease and improves mortality and modality. However, since Japanese GD patients are more neurologically affected compared to Caucasian patients, ERT itself may not be enough to improve their prognosis. In this regard, novel strategies are being considered to deal with CNS involvement. In 2004, Lin et al. introduced a potential therapy using N-octyl-b-valienamine, which works as a pharmacologic chaperone to move mutant beta-glucosidase into the lysosome [17]. The activity of beta-glucosidase was successfully enhanced in in vitro studies, and the results suggested a promising future for GD patients with specific mutations, including F213I. Since F213I is the second most frequent mutation among the Japanese GD patients and we found F213I carriers among our type 3 GD patients, N-octyl-b-valienamine might eventually become a promising therapy, although it has not yet been successfully tested in vivo. Other reports came from Capablo et al., who described positive results obtained with high-dose imiglucerase combined with miglustat in an adult type 3 GD patient, and from Cox-Brinkman et al., who reported a pediatric patient with stabilized CNS symptom whose treatment was started at the age of 5 months with a similar combination therapy [18,19]. This combination of imiglucerase and miglustat once seemed to be hopeful, however, in a recent report, miglustat did not appear to be effective in improving the neurological symptoms of type 3
patients [20]. This study evaluated the efficacy of the treatment using the vertical saccadic eye movement as the primary endpoint, which is an essential examination in assessing the neurological involvement in Gaucher disease [21]. This study was done in a larger cohort, however, we could not ignore the results from the first two reports regarding several points. Seizures, myoclonus, and other general neurological status such as walking, speech, and sleep improved in the report from Capablo et al., and the patients described by Cox-Brinkman et al. showed stabilized oculomotor apraxia and epileptic symptoms had not occurred despite the abnormality in their electroencephalogram. Therefore, we speculate that the efficacy of imiglucerase and miglustat might be enhanced through interaction and may be beneficial for the major neurological symptoms such as seizures and deterioration of motor function. Although currently available therapies are limited, other new techniques are being developed, such as the convection-enhanced delivery for distribution of beta-glucosidase to the brain, which has been successful in rodents [22]. Combination of ERT with one of these potential therapies will be needed in the future to improve the outcome of Japanese type 3 GD patients. Acknowledgments The authors thank all patients, their families, and the physicians who have participated in our research. This research was supported by the Jikei University Research Fund and by a grant for the Research on Measures for Intractable Diseases, from the Japanese Ministry of Health, Labour and Welfare (2004–2006). References [1] S. Tsuji, P.V. Choudary, B.M. Martin, B.K. Stubblefield, J.A. Mayor, J.A. Barranger, E.I. Ginns, A mutation in the human glucocerebrosidase gene in neuronopathic Gaucher’s disease, N. Engl. J. Med. 316 (1987) 570–575. [2] N.J. Weinreb, J. Charrow, H.C. Andersson, P. Kaplan, E.H. Kolodny, P. Mistry, G. Pastores, B.E. Rosenbloom, C.R. Scott, R.S. Wappner, A. Zimran, Effectiveness of enzyme placement therapy in 1028 patients with type 1 Gaucher disease after 2 to 5 years of treatment: a report from the Gaucher Registry, Am. J. Med. 113 (2002) 112–119. [3] H. Andersson, P. Kaplan, K. Kacena, J. Yee, Eight-year clinical outcomes of longterm enzyme replacement therapy for 884 children with Gaucher disease type 1, Pediatrics 122 (2008) 1182–1190. [4] O. Ringden, C.G. Groth, A. Erikson, S. Granqvist, J.E. Mansson, E. Sparrelid, Ten years’ experience of bone marrow transplantation for Gaucher disease, Transplantation 59 (1995) 864–870. [5] D. Elstein, C. Hollak, J.M. Aerts, S. van Weely, M. Maas, T.M. Cox, R.H. Lachmann, M. Hrebicek, F.M. Platt, T.D. Butters, R.A. Dwek, A. Zimran, Sustained therapeutic effects of oral miglustat (Zavesca, Nbutyldeoxynojirimycin, OGT 918) in type 1 Gaucher disease, J. Inherit. Metab. Dis. 27 (2004) 757–766. [6] H. Ida, K. Iwasawa, H. Kawame, O.R. Rennert, K. Maekawa, Y. Eto, Characteristics of gene mutations among 32 unrelated Japanese Gaucher disease patients: absence of the common Jewish 84GG and 1226G mutations, Hum. Genet. 95 (1995) 717–720. [7] H. Ida, O.M. Rennert, K. Iwasawa, M. Kobayashi, Y. Eto, Clinical and genetic studies of Japanese homozygotes for the Gaucher disease L444P mutation, Hum. Genet. 105 (1999) 120–126. [8] H. Ida, O.M. Rennert, T. Ito, K. Maekawa, Y. Eto, Type 1 Gaucher disease: phenotypic expression and natural history in Japanese patients, Blood Cells Mol. Dis. 24 (1998) 73–81. [9] H. Ida, O.M. Rennert, H. Kawame, K. Maekawa, Y. Eto, Mutation prevalence among 47 unrelated Japanese patients with Gaucher disease: identification of four novel mutations, J. Inherit. Metab. Dis. 20 (1997) 67–73. [10] O. Goker-Alpan, K.S. Hruska, E. Orvinsky, P.S. Kishnani, B.K. Stubblefield, R. Schiffmann, E. Sidransky, Divergent phenotypes in Gaucher disease implicate the role of modifiers, J. Med. Genet. 42 (2005) e37. [11] S. Dreborg, A. Erikson, B. Hagberg, Gaucher disease – Norrbottnian type, Eur. J. Pediatr. 133 (1980) 107–118. [12] L. Svennerholm, A. Erikson, C.G. Groth, O. Ringdén, J.E. Månsson, Norrbottnian type of Gaucher disease – clinical, biochemical and molecular biology aspects: successful treatment with bone marrow transplantation, Dev. Neurosci. 13 (1991) 345–351. [13] M. Masuno, S. Tomatsu, K. Sukegawa, T. Orii, Non-existence of a tight association between a 444 leucine to proline mutation and phenotypes of Gaucher disease: high frequency of a NciI polymorphism in the nonneuronopathic form, Hum. Genet. 84 (1990) 203–206.
A. Tajima et al. / Molecular Genetics and Metabolism 97 (2009) 272–277 [14] G. Altarescu, S. Hill, E. Wiggs, N. Jeffries, C. Kreps, C.C. Parker, R.O. Brady, N.W. Barton, R. Schiffmann, The efficacy of enzyme replacement therapy in patients with chronic neuronopathic Gaucher’s disease, J. Pediatr. 138 (2001) 539–547. [15] A. Erikson, H. Forsberg, M. Nilsson, M. Aström, J.E. Månsson, Ten years’ experience of enzyme infusion therapy of Norrbottnian (type 3) Gaucher disease, Acta Paediatr. 95 (2006) 312–317. [16] E.H. Davies, A. Erikson, T. Collin-Histed, E. Mengel, A. Tylki-Szymanska, A. Vellodi, Outcome of type III Gaucher disease on enzyme replacement therapy: review of 55 cases, J. Inherit. Metab. Dis. 30 (2007) 935–942. [17] H. Lin, Y. Sugimoto, Y. Ohsaki, H. Ninomiya, A. Oka, M. Taniguchi, H. Ida, Y. Eto, S. Ogawa, Y. Matsuzaki, M. Sawa, T. Inoue, K. Higaki, E. Nanba, K. Ohno, Y. Suzuki, N-octyl-beta-valienamine up-regulates activity of F213I mutant betaglucosidase in cultured cells: a potential chemical chaperone therapy for Gaucher disease, Biochim. Biophys. Acta 1689 (2004) 219–228. [18] J.L. Capablo, R. Franco, A.S. de Cabezón, P. Alfonso, M. Pocovi, P. Giraldo, Neurologic improvement in a type 3 Gaucher disease patient treated with imiglucerase/miglustat combination, Epilepsia 48 (2007) 1406–1408.
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[19] J. Cox-Brinkman, M.J. van Breemen, B.T. van Maldegem, L. Bour, W.E. Donker, C.E. Hollak, F.A. Wijburg, J.M. Aerts, Potential efficacy of enzyme replacement and substrate reduction therapy in three siblings with Gaucher disease type III, J. Inherit. Metab. Dis. 31 (2008) 745–752. [20] R. Schiffmann, E.J. Fitzgibbon, C. Harris, C. DeVile, E.H. Davies, L. Abel, I.N. van Shaik, W. Benko, M. Timmons, M. Ries, A. Vellodi, Randomized controlled trial of miglustat in Gaucher’s disease type 3, Ann. Neurol. 64 (2008) 514– 522. [21] A. Vellodi, B. Bembi, T.B. de Villemeur, T. Collin-Histed, A. Erikson, E. Mengel, A. Rolfs, A. Tylki-Szymanska, Neuronopathic Gaucher disease task force of the European working group on Gaucher disease, management of neuronopathic Gaucher disease: a European consensus, J. Inherit. Metab. Dis. 24 (2001) 319– 327. [22] R.R. Lonser, S. Walbridge, G.J. Murray, M.R. Aizenberg, A.O. Vortmeyer, J.M. Aerts, R.O. Brady, E.H. Oldfield, Convection perfusion of glucocerebrosidase for neuronopathic Gaucher’s disease, Ann. Neurol. 57 (2005) 542–548.
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Clinical and genetic study of Japanese patients with type 3 Gaucher disease Asako Tajima a,*, Takayuki Yokoi a, Masamichi Ariga a, Takeru Ito a, Eiko Kaneshiro a, Yoshikatsu Eto b, Hiroyuki Ida a a b
Department of Pediatrics, Jikei University School of Medicine, Japan Lysosomal Disease Research Center/Institute for Genetic Disease, Jikei University School of Medicine, Japan
a r t i c l e
i n f o
Article history: Received 7 March 2009 Received in revised form 1 May 2009 Accepted 2 May 2009 Available online 10 May 2009 Keywords: Type 3 Gaucher disease Gene mutation Outcome Enzyme replacement therapy Phenotype
a b s t r a c t Information on the phenotypic variations seen in patients with type 3 (chronic neuronopathic) Gaucher disease (GD) is still limited compared with type 1 GD. We retrospectively investigated the clinical features of 42 Japanese patients with type 3 GD. The 42 patients classified as type 3 fell into two groups: those diagnosed as having type 3 GD at diagnosis (group A; n = 24) and those thought to have type 1 at diagnosis but who later developed neurological symptoms (group B; n = 18). The genotype of group A patients varied widely; however, L444P/L444P and L444P/F213I genotypes accounted for 83% in group B. All the patients who did not receive enzyme replacement with alglucerase or imiglucerase (4 in group A, 2 in group B) died. Nineteen patients received enzyme replacement in group A; however, 7 of these died despite the therapy. On the other hand, 14 patients received enzyme replacement alone in group B and 13 of them survived. Among the ERT-treated patients who survived, only one of 12 in group A and 12 out of 13 in group B can walk unaided. In conclusion, some Japanese GD patients who are thought to have type 1 at diagnosis develop neurological symptoms during their clinical course, and careful observation is essential for patients with characteristic genotypes. Moreover, enzyme replacement alone might not have a sufficient effect on the early onset neurological symptoms in type 3 patients. A different treatment strategy is needed to improve the prognosis of these patients. Ó 2009 Elsevier Inc. All rights reserved.
Introduction Gaucher disease (GD) is the most prevalent sphingolipid storage disease caused by deposition of glucocerebroside in cells of the macrophage–monocyte system. It is an autosomal recessively inherited disorder of metabolism, and more than 180 mutations have been detected since the first report of the causative gene [1]. Clinical phenotypes are classified mainly into three groups according to the absence or presence of neurological involvement and its progression: type 1, non-neuronopathic form; type 2, acute neuronopathic form; type 3, subacute neuronopathic form. Type 1 is the most common form and may be diagnosed at any age. The diagnosis can be made only by hematological, visceral, and bone manifestations and, with treatment, the prognosis is good. Type 2 disease is characterized by severe and progressive neurological deterioration and is either fatal at birth or within 2–3 years of life. Type 3 GD includes patients with any form of neurological involvement who have survived the first few years of their lives.
* Corresponding author. Address: Department of Pediatrics, Jikei University School of Medicine, 3-25-8 Nishi-shinbashi, Minato-ku, Tokyo 105-8461, Japan. Fax: +81 3 3435 8665. E-mail address: [email protected] (A. Tajima). 1096-7192/$ - see front matter Ó 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.ymgme.2009.05.001
Since type 1 is prevalent worldwide, its clinical course and treatment outcome have often been reported, mainly from Western countries, indicating a good prognosis and effectiveness of enzyme replacement therapy (ERT) with imiglucerase or alglucerase [2,3]. Strategies such as bone marrow transplantation (BMT) and substrate reduction therapy (SRT) have also been reported to be effective in certain cases [4,5], although BMT carries a high risk of mortality and is not commonly used in type 1 patients and SRT is currently only approved for use in patients in whom enzyme replacement is not an option. In contrast, information on type 3 GD patients is still limited. The prevalence of mutations and phenotypes in Japanese GD patients differs from that in the non-Asian population [6–8]. Namely, type 1 GD patients were found to have more severe and progressive disease compared to Caucasians; the disease is characterized by earlier onset of symptoms with more severe bone involvement and hepatosplenomegaly. Moreover, because the N370S mutation, which is a neuroprotective factor for GD, is absent in Japanese patients, it is possible that there could be more individuals with the neuronopathic form in Japan but their disease follows a different course compared to patients in other populations. The current study, therefore, aim to investigate the clinical features of Japanese individuals with type 3 GD with regard to the genetic and phenotypic perspectives. Furthermore, the appropriate therapeutic strategy for this disorder is discussed.
A. Tajima et al. / Molecular Genetics and Metabolism 97 (2009) 272–277
Patients and methods Patients A total of 124 individuals who were clinically diagnosed as having GD by the attending physicians have been referred to our institution for diagnostic confirmation from all over Japan since 1990. Their diagnoses were confirmed by the assay of beta-glucosidase (EC 3.2.1.45) enzyme activity and/or genetic analysis. Since this procedure is not commercially available in Japan, institutions where enzyme activity can be measured are limited. Our institution is one of them, and because of this situation, our data covers the majority of Japanese Gaucher patients. According to the clinical features of these 124 cases, 54 (43.5%), 28 (22.6%), and 42 (33.9%) were classified as type 1, 2, and 3 at final evaluation, respectively. In general, making a clear distinction between type 2 and 3 is difficult because of the overlap of age at onset. In this study, we classified patients with onset of any neurological symptom at the age of 1 and older as type 3 (mean age at onset of the type 2 patient group was 7 months). However, during the time course we became aware of patients who had been diagnosed as having type 1 GD at diagnosis but later developed symptoms related to central nervous system (CNS) involvement. The phenotypic diagnosis for this group of patients was corrected to type 3. We have distinguished former type 3 patients as group A (‘‘original” type 3) and the latter as group B (‘‘transitioned” type 3). As for clinical features, we have analyzed age at diagnosis, major clinical findings at diagnosis, other clinical manifestation or neurological manifestation at final evaluation, types of treatment if received, age at treatment initiation, age at present or age of death, and activities of daily living (ADL) if the patient was alive. Methods Diagnosis of GD was confirmed by beta-glucosidase enzyme assay using 4-methylumbelliferyl beta-glucoside, and by genetic analysis according to previously described methods [9]. Genomic DNA was extracted from skin fibroblasts using DNA Midi Kit (QIAGEN, Valencia, CA). DNA was first amplified by polymerase chain reaction (PCR) avoiding the pseudo genes, and 8 common mutations (L444P, F213I, R463C, N370S, 84insG, IVS2+1, RecNciI, and D409H) were detected by enzyme digestion or mismatched PCR fragments. When no common mutation was detected, single strand conformation polymorphism (SSCP) and direct sequencing of the beta-glucosidase gene were performed. The mutations detected through these procedures included N188S, R120W, and G202R. PCR fragments were digested with TspRI, NciI, and MspI, to confirm each mutation. Results Forty-two patients were diagnosed as having type 3 GD among the 124 Japanese GD patients at final evaluation. They were clinically distinguished into two groups. Their characteristics are summarized in Tables 1 and 2. Of 42 type 3 patients, 24 patients (57.1%) presented neurological symptoms such as developmental delay, oculomotor apraxia, and seizures at their diagnosis and were classified as type 3 GD; the other 18 patients (42.9%) whose diagnosis was type 1 GD developed neurological symptoms and their diagnosis was ultimately changed to type 3. Table 1 summarizes the characteristics of group A patients. There were 13 males and 11 females. Their age at diagnosis ranged from 11 months to 51 years. Thirteen patients survived and are now between 6 and 61 years old; the other 11 patients died due to deterioration of CNS involvements and their complications ex-
273
cept 1 case (patient no. D20) who had died of progressive heart failure. The genotypes of group A patients were diverse, including F213I/F213I or heterozygotes with L444P, F213I, and D409H. RecNciI carriers were found only in group A, and there were no L444P homozygotes or L444P/F213I heterozygotes. Mutation prevalence was the highest for F213I (29.2%), followed by D409H (18.8%), RecNciI (6.3%), R120W (4.2%) and L444P (2.1%). Group B consisted of 13 males and 5 females, including 2 pairs of identical twins (patient no. 3 and 4, patient no. 11 and 12) and 1 pair of siblings (patient no. 6 and 7) (Table 2). Age at diagnosis was from 8 months to 20 years old. When the subjects were evaluated, 14 patients (77.8%) had survived, the youngest was 10 years old and the oldest was 47. L444P/L444P accounted for 61% of all genotypes in group B, followed by L444P/F213I and F213I/F213I. There were no D409H carriers in this group of patients. Twenty-six L444P mutations and eight F213I mutations were detected in this group. All patients both in group A and B presented hepatosplenomegaly at diagnosis. Neurological symptom at diagnosis varied in group A. Developmental delay was seen in 14 patients, seizures in 5, oculomotor apraxia in 4, laryngeal spasms in 4, and myoclonus in 3. Strabismus was also found. In group B, oculomotor apraxia and mental retardation were the most frequent neurological symptoms that had developed (found in 9 patients each). Other neurological symptoms included laryngeal spasms (3 patients), seizures (3 patients), ataxia (3 patients), strabismus (2 patients), and nystagmus (1 patient). In this study we have defined ‘‘developmental delay” as a manifestation seen in patients younger than 6 years of age at diagnosis. ‘‘Mental retardation” was used when a patient of 6 years old and older showed regression of psychomotor function at the time of final evaluation. Those who had received enzyme replacement therapy (ERT) took 50–60 U/kg/2 weeks of imiglucerase, which is the limit dose in Japan. In group A, 19 patients received enzyme replacement; age at first infusion ranged from 1 year to 56 years old. One patient received BMT and 4 patients were not treated at all due to financial problems or unavailability of ERT. The 11 deceased patients included all 4 patients without any treatment, but the other 7 patients had been on ERT and died despite the therapy. Overall ADL of the patients who are alive was severely affected. Ten of the 12 patients receiving ERT who survived are bedridden, 1 patient is able to crawl, and 1 patient can walk unaided. The patient who had undergone BMT is alive and is able to roll over. In group B, 14 patients received ERT alone, 1 patient underwent BMT after ERT because the latter was not effective, and 3 patients did not receive any treatment (Table 2). The age at which ERT was started ranged from 1 to 40 years. Two of the 4 deceased patients were not treated. One patient had died of suffocation due to laryngeal spasms (patient no. D15), and the other 2 patients had died due to regression of neurological symptoms (patient no. D16 and D17). The patient who had received BMT after ERT (patient no. D18) had died due to a severe graft versus host disease after BMT. We were able to evaluate the ADL of 13 patients, and only one patient was bedridden. Gross motor function for the other 12 patients was relatively good; they could walk without help. Visceral involvements and hematological disorders were noted in all the patients. Those symptoms were effectively treated in patients who had received ERT (data not shown). Discussion In this study we analyzed 42 patients with type 3, which accounted for a relatively large number in Japanese GD patients. Our data covers the majority of the patients in Japan, therefore, the patients are not biased for selection. We found that quite a large number of Japanese type 3 GD patients (43%) had initially
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Table 1 Characteristics of group A patients. Gender
Age at diagnosis
Genotype
Major clinical findings at diagnosis
Other clinical manifestation at final evaluation
Treatment
Age at treatment initiation
Age at present/age of death
ADL
1
M
2y8m
F213I/F213I
Seizures, myoclonus, mental retardation
ERT
5y3m
18y2m
4
2 3
M F
2y3m 1y7m
F213I/F213I F213I/RecNciI
Seizures Seizures
ERT ERT
2y4m 1y7m
9y11m 11y8m
2 4
4 5 6 7 8 9
F M F F M F
1y1m 1y8m 1y1m 1y7m 51y 1y9m
Seizures, oculomotor abnormality ND ND ND Tremors Hydrocephalus, corneal opacity
ERT ERT ERT ERT ERT ERT
1y1m 1y8m 1y1m 1y8m 52y 1y10m
10y 6y4m 8y3m 7y2m 61y5m 7y8m
4 4 4 4 1 4
10
F
3y8m
Oculomotor apraxia
BMT
4y
20y8m
3
11
M
3y1m
F213I/RecNciI F213I/R120W F213I/? F213I/? F213I/D409H D409H/ R120W D409H/ IVS10-1 D409H/?
Hepatosplenomegaly, oculomotor abnormality Developmental delay, walking disorder Oculomotor apraxia, laryngeal spasms, hepatosplenomegaly, anemia Developmental delay, hepatosplenomegaly Developmental delay, seizures Developmental delay, hepatosplenomegaly Developmental delay, laryngeal spasms, Myoclonus Developmental delay, laryngeal spasms, hepatosplenomegaly Hepatosplenomegaly, laryngeal spasms
3y2m
13y3m
4
M F
12y 1y7m
?/? ?/?
Hydrocephalus, heart valve calcification, corneal opacity ND Seizures
ERT
12 13
ERT ERT
18y6m 1y8m
28y7m 6y4m
4 4
D14 D15 D16
M M M
1y2m 1y1m ND
Oculomotor apraxia, laryngeal spasms Seizures, oculomotor abnormality ND
ERT ERT ERT
1y2m 1y1m 1y8m
7y2m 2y 4y2m
NA NA NA
D17
M
1y5m
L444P/G202R F213I/RecNciI F213I/ del20insTG F213I/?
Oculomotor apraxia, developmental delay, hepatosplenomegaly Myoclonus, seizures Developmental delay, strabismus, hepatosplenomegaly Seizures, splenomegaly Developmental delay, hepatosplenomegaly, ND
ND
None
NA
3y
NA
D18
F
43y
F213I/D409H
Developmental delay, hepatosplenomegaly, seizures Myoclonus, hepatosplenomegaly
Seizures
ERT
56y
NA
D19
F
31y
Oculomotor apraxia, mental retardation
NA
F
1y3m
Hydrocephalus, heart valve calcification, corneal opacity Heart valve calcification
None
D20
D409H/ D409H D409H/?
Age of death not known 31y
ERT
3y4m
7y
NA
D21
M
1y7m
D409H/?
ERT
8y1m
15y
NA
D22
F
14y
None
NA
25y
NA
D23 D24
M M
4y4m 11m
N188S/ 55 bp del ?/? ?/?
Seizures, oculomotor abnormality, hydrocephalus, heart valve calcification Myoclonus, oculomotor abnormality Oculomotor abnormality ND
None ERT
NA 1y
8y 3y3m
NA NA
Oculomotor apraxia, developmental delay, hepatosplenomegaly Developmental delay, hepatosplenomegaly Seizures Developmental delay, splenomegaly Developmental delay, hepatosplenomegaly, tonic posture
D, deceased; ADL, activities of daily living; ERT, enzyme replacement therapy; BMT, bone marrow transplantation; ?, not identified; NA, not applicable; ND, no data. 1, walks; 2, crawls; 3, rolls over; 4, bedridden.
NA
A. Tajima et al. / Molecular Genetics and Metabolism 97 (2009) 272–277
No.
NA NA NA Hepatosplenomegaly Hepatosplenomegaly Hepatosplenomegaly 1y4m 7y 2y3m F M F D16 D17 D18
L444P/F213I L444P/F213I ?/?
Hepatosplenomegaly L444P/L444P 1y4m M D15
, à, identical twins; , siblings; D, deceased; ADL, activities of daily living; ERT, enzyme replacement therapy; BMT, bone marrow transplantation; ?, not identified. NA, not applicable; ND, no data; 1, walks; 2, crawls; 3, rolls over; 4, bedridden.
7y 44y 9y3m NA 40y 3y10m None ERT ERT ? BMT
NA 3y2m NA None
4 12y 1y ERT F213I/F213I M 14
1y
1y 4y 20y 16y 1y11m 1y4m 5y3m 2y1m 2y1m 2y3m M F M M M F F M M M 4 5 *6 *7 8 9 10 à11 à12 13
L444P/L444P L444P/L444P L444P/L444P L444P/L444P L444P/L444P L444P/L444P L444P/L444P L444P/F213I L444P/F213I F213I/F213I
Hepatosplenomegaly Splenomegaly Splenomegaly, arthralgia Splenomegaly, bone fracture Hepatosplenomegaly Hepatosplenomegaly Hepatosplenomegaly Hepatosplenomegaly Hepatosplenomegaly Hepatosplenomegaly, bone crisis Hepatosplenomegaly
Oculomotor apraxia, mental retardation, ataxia Laryngeal spasms, oculomotor abnormality Oculomotor apraxia, seizures, myoclonus Seizures Ataxia, nystagmus
1 1 1 1 1 1 ND 1 1 1 16y4m 40y1m 47y5m 43y8m 11y7m 10y7m 37y11m 15y7m 15y7m 12y8m 3y 28y4m 36y 32y 2y 1y4m NA 3y10m 3y10m 2y ERT ERT ERT ERT ERT ERT None ERT ERT ERT
1 1 1 23y2m 31y1m 16y4m 7y 19y 3y ERT ERT ERT
Strabismus Oculomotor apraxia, ataxia Mental retardation, laryngeal spasms, seizures Mental retardation, laryngeal spasms Oculomotor apraxia, hearing loss Seizures Strabismus Oculomotor apraxia, mental retardation Oculomotor apraxia, mental retardation Mental retardation Oculomotor apraxia, mental retardation Oculomotor apraxia, mental retardation Oculomotor apraxia, mental retardation Hepatosplenomegaly Hepatosplenomegaly Hepatosplenomegaly L444P/L444P L444P/L444P L444P/L444P 2y11m 8m 1y M M M 1 2 3
Age at diagnosis Gender No.
Table 2 Characteristics of group B patients.
Genotype
Major clinical findings at diagnosis
Neurological manifestation at final evaluation
Treatment
Age at treatment initiation
Age at present/age of death
ADL
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been diagnosed as having type 1 GD, but had later developed symptoms indicative of CNS involvement and thus were reclassified as type 3 GD. Ida et al. [7] and Goker-Alpan et al. [10] also observed that some of the patients diagnosed as having type 1 GD developed neurological symptoms despite treatment. Our transitioned type 3 GD patients were unique, L444P/L444P being the most frequent genotype (11 cases, 61.1%), followed by L444P/ F213I (4 cases) and F213I/F213I (2 cases). These results matched the findings of Ida et al., in that delayed onset of neurologic symptoms is often seen in L444P homoallelism. On the other hand, the genotypes of the original type 3 GD group varied. We have distinguished these two groups, and in addition to the difference of the genotypes, we have shown that their clinical courses and prognoses were clearly distinctive. The linkage of L444P/L444P genotype to neuronopathic form of GD has already been reported in Caucasians and in patients from the Norrbotten region of Sweden [11,12]. However, there is a study by Masuno et al. suggesting that L444P homoallelism is associated with non-neurological form in Japan and that that there may be a genetic heterogeneity between different ethnic groups [13]. In Ida et al.’s first report on the Japanese L444P homozygotes, the patients did not have neurological abnormalities at diagnosis [7]. The authors proposed that the patients were still young thus neurological signs may have not yet developed, and that early initiation of enzyme replacement therapy (ERT) may contribute in preventing those symptoms. After following the patients from the same cohort for 8 years, we found that some of them did develop neurological symptoms even though they had been on ERT from the time of the diagnosis. Therefore, neurological symptoms in Japanese GD patients with L444P homoallelism seem to be unique in that they are often very mild and difficult to detect clinically. As for the various manifestations of a same genotype, Goker-Alpan et al. have suggested the influence of modifier loci for L444P, although other mechanisms such as promoter mutations, environment, and other causes may influence the occurrence of symptoms [10]. Although this is still an unknown field, finding modifier genes might lead to a more clear explanation for the complex phenotypes of GD. L444P homozygous patients diagnosed as having type 1 are still alive, and they should be carefully monitored for the possibility of neurological involvement. Another finding in this report is the existence of F213I, which is a unique mutation among the GD patients from Asia. Understanding the phenotype of patients carrying F213I is significant, because it is still unknown worldwide. There were F213I homozygotes in both group A and B. It is not yet clear how the F213I mutation affects the clinical course, however, it is possible that neurologic symptoms might have not been noticed at the time of diagnosis in the patients in group B. Four L444P/F213I patients were found in group B, and 2 are alive and 2 are deceased. Of the deceased, 1 patient was not treated at all (patient no. D16) and one patient had not been treated for 33 years (patient no. D17). On the other hand, the two living patients had started ERT at an early age. The interval between onset of the disease and the initiation of the treatment might have affected their prognosis. In our study, L444P homozygotes, F213I homozygotes and L444P/F213I compound heterozygotes presented neurologic symptoms subsequently. Since oculomotor apraxia and mental retardation were often detected in these groups of patients, we suggest that ophthalmological investigation by a specialist and neuropsychometrical assessment of intelligence quotient are particularly important. GD patients are mainly diagnosed and followed by a pediatrician in Japan. There is a possibility that neurological symptoms in some patients included in this study might have been detected if examined by a neurologist at onset. We should be aware that there are many cases with a very mild
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neurological impairment that could not be detected without a thorough assessment at onset and a regular follow up. Moreover, a comprehensive care comprised of pediatrician, neurologist, and ophthalmologist in the least is essential in the care and management of GD. It is important to refer to the recombinant allele because in our patients RecNciI mutation was associated with a very poor outcome. RecNciI is sometimes mistaken as L444P depending on the methodology of genetic analysis. In our study F213I/RecNciI was detected only in group A patients (Table 1, patients no. 3, 4, and 15). All of them were very young at the onset of symptoms and despite the initiation of ERT as soon as they were diagnosed, their clinical courses were severe. This shows that F213I/RecNciI carriers present the initial symptoms while they are relatively young, and detecting this specific mutation is essential in predicting their prognosis. If we focus on the efficacy of enzyme replacement for the neurological aspects of GD, we might say that the onset of neurological symptoms may not be totally prevented by enzyme replacement alone in transitioned type 3 GD patients. ERT may slow the progression of the disease, but the already acquired symptoms will not disappear. Our results were not exactly the same as previously reported studies on the efficacy of enzyme replacement in type 3 GD patients [14–16]. For example, although ERT was not effective in patients with myoclonus in the study by Altarescu et al. cognitive improvement and amelioration of saccadic eye movement abnormalities were seen. Moreover, Erikson et al. reported that ERT might have contributed in slowing down or stabilizing neurological signs. The reason may be the relatively high doses of enzyme they used, which is not currently available in Japan. Another aspect we would like to point out is that the patients in the study by Altarescu et al. seem to have had a milder form of type 3 GD, since most of them were L444P homozygotes. As we have shown, all L444P homozygotes in our study were classified as transitioned type 3 GD, showed slow progression of neurological symptoms and their gross motor function was much better than that of the original type 3 GD group. This may explain the difference in the outcome between our report and the previous ones. In our study, all patients not treated with enzyme replacement died, while many of the patients treated with ERT survived. Hematological impairment and hepatosplenomegaly were improved in all ERT-treated patients. This fact suggests that ERT is effective for the life-threatening hematologic, visceral, and skeletal symptoms of the disease and improves mortality and modality. However, since Japanese GD patients are more neurologically affected compared to Caucasian patients, ERT itself may not be enough to improve their prognosis. In this regard, novel strategies are being considered to deal with CNS involvement. In 2004, Lin et al. introduced a potential therapy using N-octyl-b-valienamine, which works as a pharmacologic chaperone to move mutant beta-glucosidase into the lysosome [17]. The activity of beta-glucosidase was successfully enhanced in in vitro studies, and the results suggested a promising future for GD patients with specific mutations, including F213I. Since F213I is the second most frequent mutation among the Japanese GD patients and we found F213I carriers among our type 3 GD patients, N-octyl-b-valienamine might eventually become a promising therapy, although it has not yet been successfully tested in vivo. Other reports came from Capablo et al., who described positive results obtained with high-dose imiglucerase combined with miglustat in an adult type 3 GD patient, and from Cox-Brinkman et al., who reported a pediatric patient with stabilized CNS symptom whose treatment was started at the age of 5 months with a similar combination therapy [18,19]. This combination of imiglucerase and miglustat once seemed to be hopeful, however, in a recent report, miglustat did not appear to be effective in improving the neurological symptoms of type 3
patients [20]. This study evaluated the efficacy of the treatment using the vertical saccadic eye movement as the primary endpoint, which is an essential examination in assessing the neurological involvement in Gaucher disease [21]. This study was done in a larger cohort, however, we could not ignore the results from the first two reports regarding several points. Seizures, myoclonus, and other general neurological status such as walking, speech, and sleep improved in the report from Capablo et al., and the patients described by Cox-Brinkman et al. showed stabilized oculomotor apraxia and epileptic symptoms had not occurred despite the abnormality in their electroencephalogram. Therefore, we speculate that the efficacy of imiglucerase and miglustat might be enhanced through interaction and may be beneficial for the major neurological symptoms such as seizures and deterioration of motor function. Although currently available therapies are limited, other new techniques are being developed, such as the convection-enhanced delivery for distribution of beta-glucosidase to the brain, which has been successful in rodents [22]. Combination of ERT with one of these potential therapies will be needed in the future to improve the outcome of Japanese type 3 GD patients. Acknowledgments The authors thank all patients, their families, and the physicians who have participated in our research. This research was supported by the Jikei University Research Fund and by a grant for the Research on Measures for Intractable Diseases, from the Japanese Ministry of Health, Labour and Welfare (2004–2006). References [1] S. Tsuji, P.V. Choudary, B.M. Martin, B.K. Stubblefield, J.A. Mayor, J.A. Barranger, E.I. Ginns, A mutation in the human glucocerebrosidase gene in neuronopathic Gaucher’s disease, N. Engl. J. Med. 316 (1987) 570–575. [2] N.J. Weinreb, J. Charrow, H.C. Andersson, P. Kaplan, E.H. Kolodny, P. Mistry, G. Pastores, B.E. Rosenbloom, C.R. Scott, R.S. Wappner, A. Zimran, Effectiveness of enzyme placement therapy in 1028 patients with type 1 Gaucher disease after 2 to 5 years of treatment: a report from the Gaucher Registry, Am. J. Med. 113 (2002) 112–119. [3] H. Andersson, P. Kaplan, K. Kacena, J. Yee, Eight-year clinical outcomes of longterm enzyme replacement therapy for 884 children with Gaucher disease type 1, Pediatrics 122 (2008) 1182–1190. [4] O. Ringden, C.G. Groth, A. Erikson, S. Granqvist, J.E. Mansson, E. Sparrelid, Ten years’ experience of bone marrow transplantation for Gaucher disease, Transplantation 59 (1995) 864–870. [5] D. Elstein, C. Hollak, J.M. Aerts, S. van Weely, M. Maas, T.M. Cox, R.H. Lachmann, M. Hrebicek, F.M. Platt, T.D. Butters, R.A. Dwek, A. Zimran, Sustained therapeutic effects of oral miglustat (Zavesca, Nbutyldeoxynojirimycin, OGT 918) in type 1 Gaucher disease, J. Inherit. Metab. Dis. 27 (2004) 757–766. [6] H. Ida, K. Iwasawa, H. Kawame, O.R. Rennert, K. Maekawa, Y. Eto, Characteristics of gene mutations among 32 unrelated Japanese Gaucher disease patients: absence of the common Jewish 84GG and 1226G mutations, Hum. Genet. 95 (1995) 717–720. [7] H. Ida, O.M. Rennert, K. Iwasawa, M. Kobayashi, Y. Eto, Clinical and genetic studies of Japanese homozygotes for the Gaucher disease L444P mutation, Hum. Genet. 105 (1999) 120–126. [8] H. Ida, O.M. Rennert, T. Ito, K. Maekawa, Y. Eto, Type 1 Gaucher disease: phenotypic expression and natural history in Japanese patients, Blood Cells Mol. Dis. 24 (1998) 73–81. [9] H. Ida, O.M. Rennert, H. Kawame, K. Maekawa, Y. Eto, Mutation prevalence among 47 unrelated Japanese patients with Gaucher disease: identification of four novel mutations, J. Inherit. Metab. Dis. 20 (1997) 67–73. [10] O. Goker-Alpan, K.S. Hruska, E. Orvinsky, P.S. Kishnani, B.K. Stubblefield, R. Schiffmann, E. Sidransky, Divergent phenotypes in Gaucher disease implicate the role of modifiers, J. Med. Genet. 42 (2005) e37. [11] S. Dreborg, A. Erikson, B. Hagberg, Gaucher disease – Norrbottnian type, Eur. J. Pediatr. 133 (1980) 107–118. [12] L. Svennerholm, A. Erikson, C.G. Groth, O. Ringdén, J.E. Månsson, Norrbottnian type of Gaucher disease – clinical, biochemical and molecular biology aspects: successful treatment with bone marrow transplantation, Dev. Neurosci. 13 (1991) 345–351. [13] M. Masuno, S. Tomatsu, K. Sukegawa, T. Orii, Non-existence of a tight association between a 444 leucine to proline mutation and phenotypes of Gaucher disease: high frequency of a NciI polymorphism in the nonneuronopathic form, Hum. Genet. 84 (1990) 203–206.
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