- Email: [email protected]
Ring chromosome 9: An atypical case
ELSEVIER
Brain & Development
Q
1996; 18: 2 16-2 I9
Case report
Ring chromosome
9: an atypical case
Giovanni Lanzi a3*, Elisa Fazzi a, Pierangelo Veggiotti a, Emanuela Pagliano a, Marisa Gariglio b, Clara Bonaglia ‘, Santo Landolfo b aDepartment of Child Neuropsychiatry,
‘C. Mondino’ Foundation, Neurological Institute IRCCS, University of Pacia,Via Palestro 3, 27100 Pacia, Italy b Microbiology Institute, Uniuersity of Turin, Turin, Italy ’ General Biology and Medical Genetics Institute, Unioersity of Pauia, Pauia, Italy Received 3 1 July 1995; accepted
13 November
1995
A new case of ring chromosome 9 in a 36-month-old child is presented. In addition to the pathognomonic features of this rare disorder (only 21 cases reported), our patient presents some peculiarities, such as corpus callosum hypoplasia and epileptic seizures (infantile periodic spasms). We also observed a reduced level of leukocyte interferon (Y whose synthesis is controlled by a gene on chromosome 9 and which could be responsible for the recurrent respiratory tract infections, typical and sometimes fatal in these patients. Keywords:
Ring chromosome
9; Interferon;
Seizure
1. INTRODUCTION Ring chromosome 9 occurs when deletion of part of the short and the long arm of chromosome 9 leads to the formation of a ring whose diameter is proportional to the length of the deleted segment [l-3]. The main clinical signs and features of this rare phenomenon (only 21 cases reported) include severe microcephaly, dysmorphic features similar to those observed in partial monosomy 9 [4-61 (i.e. exophthalmia, strabismus, upslanting palpebral fissures with epicanthus, anteverted nostrils, hypertelorism, long philtrum, micrognathia, retrognathia, malformed ears, cleft palate and bifid uvula), delayed physical (height and weight) and psychomotor development, congenital heart malformation [7,8] (ranging from septal defects to severe disorders such as tetralogy of Fallot and pulmonary valve atresia), and early or delayed bone maturation or skeletal disorders (e.g. aplasia and/or hypoplasia of the radius and partial fusion of the C2-C3 vertebrae). Genital anomalies [9] are also frequent (especially hypospadias and cryptorchidism), as are infectious, and particularly respiratory complications. Manouvrier-Hanu et al. [lo] described the association between respira-
Abbreviations: CT, computerized tomography; PS, periodic spasms; IFN-cx, interferon-a; PLB, peripheral blood leukocytes; PHA, phytohemagglutinin; TPA 0, tetradecanoylphorbol 13 acetate; VPA, valproic acid; BZP, benzodiazepines. * Corresponding author. Fax: (39) (382) 380286. 0387.7604/96/$15.00 0 1996 Elsevier Science B.V. All rights reserved SSDI 0387-7604(95)00144-l
tory tract infections, gastroesophageal reflux (see also Leung’s case [ 1 I]> and decreased level of leukocyte interferon. Our case is peculiar in its neuroradiological, neurophysiological and immunological aspects.
2. CASE REPORT Our patient is a male and the second child of healthy non-consanguineous parents aged 36 (mother) and 38 (father) at his birth. He has two sisters, aged 6 and 1, who are in apparent good health. The family history is negative. He was born at term by a normal delivery following an uneventful pregnancy. His birth weight was 3250 g, length 47 cm and head circumference 3 1 cm (less than the 10th percentile). Dysmorphic features were observed: receding forehead, micrognathia and retrognathia, short nose, small ears, anteverted nostrils and moderate exophthalmia. Physical examination revealed cleft palate, cryptorchidism and micropenis. His heart, chest and abdomen were normal. During the following months, the child presented with psychomotor delay associated with global hypotonia and subnormal physical growth. A chromosomal analysis was thus performed which detected ring chromosome 9. At 3 months of age, the patient had an episode of ab-ingestis bronchopneumonia. We first observed the child at the age of 5.5 months, and follow-up lasted until 36 months. The child presented with delayed (less than the 10th percentile), but nevertheless proportional physical growth, generalized hypotonia, poor spontaneous
G. Lanzi etal./Brain
& Decelopmenr
An echocardiogram revealed an interatrial septum defect similar to a small ostium secundum and a very small interventricular muscle defect. The results of metabolic screening tests (plasma and urine amino acids, organic acids), visual and auditory evoked potentials and renal and abdominal echography were normal. The child suffered his first epileptic episode (characterized by flexion of the head and adduction of the arms) at 14 months of age. These episodes occurred in short series particularly on waking and after meals. These symptoms remained unchanged for about two months. Shortly afterwards came the onset of complex, long-lasting epileptic episodes with partial seizures and spasms in varying patterns. The spasms were sometimes preceded by rotation of the head towards the right, the patient presenting with protruding lips, perioral cyanosis and decreased alertness. The spasms then occurred in bursts, and were always asymmetrical and followed by crying. Only at this point did the child appear able to respond to his mother’s call. In other instances, the spasms were followed by partial prolonged seizures, and then by a second series of shorter spasms. At the present time, the pattern of the seizures has changed again and there is a prevalence of tonic spasms. The corresponding EEG recordings can be schematically subdivided into two periods: during the partial seizure, the recording is characterized by a clear hemispherical asymmetry with spikes and poly-spike-waves, prevalently in left anterior regions, while, during the spasms, there is a repetitive pseudo-periodic activity made up of slow wide di- or tri-phasic waves in both hemispheres, but with clear prevalence in the left (Fig. 2). The interictal EEG recording was characterized by an unrecognizable background activity together with brief sequences of slow waves mixed with slow spikes and slow spike-waves asynchronously recorded in both hemispheres. Different antiepileptic drugs were tried (VPA, BZP. ACTH) without any response.
Fig. 1. Brain MRI: 5.5 T. SE, T2-weighted (TR = 3000, TE = 100) axial image. The black area indicates a focal lesion in the white matter of the parietal lobe. The bodies of the lateral ventricles are parallel and dysmorphic, as in case of corpus callosum hypoplasia.
motility and delay in head control. At 7 months of age, he scored a developmental quotient of < 50 in Bayley’s mental and motor scales; brain magnetic resonance imaging detected severe hypoplasia of the corpus callosum; the septum pellucidurn was absent; as in cases of dysraphism, the lateral ventricles were dysmorphic with widened frontal horns and particularly pronounced anterior and posterior comers; the intermediate and T2-weighted images presented small hyperintense areas in the white matter of the right parietal region probably caused by gliosis, due to parenchymal damage of unknown etiology; the white matter was reduced but regularly myelinated for the patient’s age. There were no signs of superficial atrophy (Fig. 1). At 11 months of age, X-ray of the wrist showed absence of the distal epiphyseal nucleus of the radius, normally present at 9 months. Meanwhile, the pyramidal nucleus which normally presents at a later age. was detectable.
Zk
“PI
Fig. 2. Ictal EEG recording
,.“I.
I.
of a cluster of asymmetric
217
1996; 18: 216-219
2.1. Cytogenetic
methods
Chromosome analysis was performed on peripheral blood lymphocytes of the patient and his parents using routine and high resolution banding techniques.
1*mon*.
spasms. Left predominance
of abnormalities
is recognized.
G. Lanzi et al./Brain
218
& Development 1996; 18: 216-219
The child’s parents did not allow a skin biopsy to be taken from him.
Table 1 Levels of IFN- LY or IFN- y in supematant of stimulated PBL ,from a ring chromosome Y-bearing patient Treatment
2.2. Immunological
methods
Our patients’s recurrent febrile episodes of bronchitis are similar to those observed in the subject reported by ManouvrierHanu et al. [12], who had a reduced amount of interferon. We thus decided to measure the level of leukocyte interferon, the (Y fraction of which is controlled by a gene on chromosome 9 [18]. Purified peripheral blood leukocytes (PBL) from the patient were stimulated with synthetic dsRNA (poly rI:rC) in the presence of poly-L-lysine in order to produce IFN-o_, or with phytohemagglutinin (PHA) in the presence of TPA 0 (tetradecanoylphorbol 13 acetate) to induce IFN-?/ production. Presence of IFN-o or of IFN-?/ in the leukocyte supematant was evaluated using an enzyme kit (CELBIO) and compared with normal values. PBL from various normal individuals were tested and values from one representative are reported. The significance of differences in the production of IFN units was determined by a one-tailed Student’s I-test. Two log differences are significant with a P < 0.001. Standard deviations (SD) did not exceed 5% of the mean and were therefore not included. PBL were obtained from heparinized blood samples following separation on a Lymphoprep (Nycomed, Pharma AS, Oslo, Norway) gradient. All the reagents were purchased from Sigma (Munich, Germany).
2.3. Cytogenetic
results
A karyotype 46,XY,r(9) (~24 q34) was found in 48 cells, while one cell had 45 chromosomes (45,XY, - 9>, and one showed a duplicated ring (see Fig. 3). The karyotype of both parents was normal.
2.4. Immunological
results
The results of IFN analysis (Table 1) demonstrate that leukocyte supernatant from the patient’s blood stimulated with poly rI:rC and poly-L-lysine contained less than 20 pg/ml of INF-(r as compared with leukocyte supematant from the blood of a normal subject stimulated with poly rI:rC and poly-L-lysine which contained 1060 pg/ml of IFN-alpha.
_ PoIy rI:rC + poly-L-lysine TPA + PHA ’
b
Normal PBL
Ring chr. 9 PBL
IFN-o
IFN-?/
IFN-a
IFN-y
16 a 1060 63
4 60 500
<4 8 <4
4 31 450
a pg/ml. b Poly rI:rC: 50 kg/ml; poly-L-lysine: ’ TPA: 10e9 M; PHA: 3 pg/ml. PBL: peripheral blood lymphocytes.
1 mg/ml.
Table 2 Main features of ring chromosome 9 Feature
Mental retardation Gestation, 37-42 weeks Short stature, proportionate Microcephaly Anteverted nostrils Cardiac abnormalities a Short neck Trigonocephaly Prominent eyes (incl. proptosisl Small mandible/micrognathia Epicanthic folds Palpebral fissures slant up Strabismus/gaze palsy Generalized hirsutism High palate Cryptorchid testes Hypospadias Small ears Small/short nose Hypotonia Seizures/abnormal EEG Microcephaly, prenatal onset Delayed skeletal maturation
Cases (n = 21) n
%
17 13 12 11 10 10 9 7 8 8 7 7 7 6 6 6 6 5 5 5 5 5 3
80.9 61.9 57.1 52.3 47.6 47.6 42.8 33.3 38.0 38.0 33.3 33.3 33.3 28.5 28.5 28.5 28.5 23.0 23.0 23.0 23.0 23.0 14.2
a Ventricular septal defect, atria1 septal defect, tetralogy tation of the aorta or patent ductus arteriosus.
Our case
+ + + + + + i + + + + $ + + f + + + + + + of Fallot, coarc-
In contrast, the amounts of IFN-7 (500 pg/ml vs. 4.50 pg/ml) were similar in the patient and the normal subject.
3. DISCUSSION
Fig. 3. Karyotype
of the patient: 46,XY,r(9).
Our patient’s clinical picture has major features in common with other cases in the literature [13-191 (see Table 2). Mental retardation was mentioned in 17 out of the 21 cases reported. In 4 cases, there was no mention of cognitive development [2,7,11,20]. There are 9 reports of cardiac anomalies including 2 instances of atria1 septal defect, as found in our case. There were no other reports of agenesis or hypoplasia of corpus callosum in r(9) patients, but neuroradiological investigation (CT) was in fact performed in only 2 cases [ 10,12,20]. Corpus callosum was also present in one case studied post mortem [8]. Agenesis of corpus callosum was reported in only 3 out of 46
G. Lanzi et al. /Brain
& Development
cases of pure deletions of chromosome 9 sparring from 9 pter to p21 or ~22. In 4 patients there were reports of seizures or abnormal EEG (no further details given). In our case, the clinical and electroencephalographic characteristics of the seizures enabled us to classify them as so-called periodic spasms (PS) [21]. Rather than being universally recognized as a separate disorder, such PS are usually described as part of the West syndrome [22]. We would emphasize the close link between partial seizures and spasms where the former may facilitate the latter, due to the presence of a focal cerebral lesion [23]. While the mechanism concerning the contribution of genetic factors to epileptogenesis remains unclear, many chromosomal diseases are frequently associated with clinically polymorphic types of epilepsy [24,25]. More accurate studies in other patients may enable us to understand whether hypoplasia of corpus callosum and PS are casually associated with the chromosome anomaly in our patient, or whether this association forms part of the clinical picture of ring chromosome 9. Our study confirms a previous finding [12] that leukocyte interferon deficit could correlate with the recurrent episodes of bronchitis. The gene coding for IFNa maps close to D95126 on 9 p22 [26]. Thus its locus should not be deleted in the ring formation as the breakpoint on the short arm is on 9 ~24. However, ring chromosomes are unstable and may be lost from a number of cells. In fact a cell with karyotype 45,XY, - 9 was found in our patient. It is therefore more likely that the IFN-a deficit is due to the instability of the ring chromosome than to the deletion of the terminal tips of the chromosome. This interpretation is also supported by the finding of Manouvrier-Hanu et al. [12], in whose patient the IFN-a level ranged from slight reduction to almost complete absence. These findings suggest that, despite being unable to improve the general conditions of the patient, treatment with interferon may allow more effective control of infectious disease complications. The wide variation in phenotype among cases must, of course, be ascribed to differences in breakpoints and to the abnormal behavior of the ring chromosome [27,28]. ACKNOWLEDGEMENTS
We wish to thank Professor Cesare Danesino for his useful comments and for reviewing the manuscript. Thanks also to Dr. Carla Uggetti and Dr. M. Grazia Egitto for supplying the neuroradiological images.
REFERENCES I. Fraisse J, Lauras B, Ooghe MJ, Freycon F, Rethore MO. A propos
2. 3.
4. 5.
d’un cas de chromosome 9 en anneau. Identification par denaturation menagee. Ann G&&t 1982; 17: 175-80. Kistenmacher ML, Punett HH. Comparative behavior of ring chromosomes. Am J Hum Genet 1970; 22: 304-18. Kistenmacher ML. Punett HH, Aronson M, Miller RC, Greene AE. Coriell LL. A ring 9 chromosome. Repository identification no. GM, 1-66. CJtogenet Cell Genet 1975; 15: 122-3. Dipierri JE. Matayoshi T. Ring chromosome 9 identification of a new case by G and C banding. Ann G&&t 1982; 25: 243-5. Nakajima S, Yanagisawa M, Kamoshita S, Nakagome Y. Mental retardation and congenital malformations associated with a ring chromosome 9. Hum Genet 1976; 32: 289-93.
1996; 18: 216-219
219
6. Portnoi MF, Van den Akker J, Le Porrier N, Joye N, Joussef S,
7. 8.
9.
IO.
11.
12.
Taillemite JL. Une nouvelle observation de chromosome 9 en anneau. Ann G&h 1982; 25: 164-7. Inouye T, Matsuda H, Shimura K, et al. A ring chromosome 9 in an infant with malformations. Hum Genet 1979: 50: 23 I-5. Smith A, Evans WA, Woolnough H. Post-mortem studies on two patients with l-2 band cytogenetic deletions: lOq26 --) qter and 19 (p24q34). Ann Ge’nit 1989;32 220-4. Metaxotou C, Kalpini-Mavrou A. Ring chromosome 9-46. XY. r(9) in male with ambiguous external genitalia. Hum Genet 1977: 37: 351-4. Manouvrier-Hanu S, Turck D. Farriaux JP. Another case of ring chromosome 9 associated with gastroesophageal reflux. Am J Med Genet 1989; 32: 558. Leung AKC, Rudd NL. A case of ring (9) del(9p) moaaicism associated with gastroesophageal reflux.Am .I Med Cent 1988: 29: 43-8. Manouvrier-Hanu S, Turck D, Gottrand F, et al. Le chromosome 9 en anneau: a propos d’un cas et revue de la litterature. Ann Ge’ne’t 1988; 31: 250-3.
13. Povey S, Falk C, Smith M. Report of the committee on the genetic constitution of chromosome 9. Cytogenet Cell Gertet 1991; 58:40327. 14. Maureen E, Mohandas TK, Kaback MM. Ring chromosome nine: variable phenotypic expression. Bocia,z Pediutr Res 1977; 11: 524. 15. Dickermann LH, Stallard R, Johnson WE. Variations in the phenotype associated with ring 9 mosaicism. Am .I Hum Genet 1983; 35: 129. 16. Fryns JP, Lambrechts A, Jansseune H. van den Berghe H. Moderate mental retardation and non specific dysmorphic syndrome associated with ring chromosome 9. Hum Genet 1979: 50: 29-32. 17. Hess RO, Meisner LF. Apparent Prader-Willi phenotype in a woman with ring chromosome 9. Am / Med Genet 1987; suppl 3: 133-S. 18. Jacobsen P. Mikkelsen M, Rosleff F. A ring chromosome, diagnosed by quinacrine fluorescence as np 9 in a mentally retarded girl. C/in Genet 1973; 4: 434-41. 19. Numabe H. Shimakazi T, Hoshino M, et al. A case of a ring chromosome 9. Teratology 1986; 34: 48 I. 20. Van Maldergen L. Avni F, Mossay B, Merens C, Verloes A, Gillerot Y. Ring chromosome 9 in a newborn male presenting with facial Genrt Coun.v dysmorphia, hypospadia and skeletal abnormalities. 1991; 2: 123-6. Rossi P, Tassinari CA. 21. Gobbi G. Bruno L, Pini A, Giovanardi Periodic spasm: an unclassified type of epileptic seizures in childhood. Del, Med Child Neural 1987; 29: 766-75. 22. Jeavons P, Livet MO. West syndrome: infantile spasms. In: Roger J, Bureau M, Dravet Ch, Dreifuss FE, Perret A, Wolf P, eds. Epileptic syndromes in infancy, childhood und adolescrnce. 2nd ed. London: John Libbey, 1992: 53-65. 23. Carrazana EJ, Lombroso CT. Mikati M, Helmers J, Holmes GL. Facilitation of infantile spasms by partial seizures. Epilepsirr 1993: 24: 97- 109. 24. Dalla Bemardina B, Zullini E, Fontana E. et al. Electroclinical longitudinal study of ten cases of Angelman’s syndrome. Epilepsiu 1993; 34: 71. 25. Viani F, Romeo A, Mastrangelo M, Asi MH, Briscioli V. Epilepsy and Angelman’s syndrome: a clinical and EEG study. Epilepsiu 1993: 34: 70. 26. Kwiatkowski DJ, Armour J, Bale AE, et al. Report on the Second International Workshop on Human Chromosome 9. Cuogenet Cell Genet 1993: 64: 94-8. 27. Zdansky R, Andrle M, Btihler E, Tsuchimoto T, Mayr WR, Rett A. Irregular phenotypic expression of ring chromosomes. Humnngenrtik 1975: 26: 193-8.
28. Zuffardi 0, Danesino C, Poloni L, Pavesi F, Bianchi C. Gargantini L. Ring chromosome 12 and latent centromeres. Cytogenrt Cell Genet 1980: 28: 151-7.
Brain & Development
Q
1996; 18: 2 16-2 I9
Case report
Ring chromosome
9: an atypical case
Giovanni Lanzi a3*, Elisa Fazzi a, Pierangelo Veggiotti a, Emanuela Pagliano a, Marisa Gariglio b, Clara Bonaglia ‘, Santo Landolfo b aDepartment of Child Neuropsychiatry,
‘C. Mondino’ Foundation, Neurological Institute IRCCS, University of Pacia,Via Palestro 3, 27100 Pacia, Italy b Microbiology Institute, Uniuersity of Turin, Turin, Italy ’ General Biology and Medical Genetics Institute, Unioersity of Pauia, Pauia, Italy Received 3 1 July 1995; accepted
13 November
1995
A new case of ring chromosome 9 in a 36-month-old child is presented. In addition to the pathognomonic features of this rare disorder (only 21 cases reported), our patient presents some peculiarities, such as corpus callosum hypoplasia and epileptic seizures (infantile periodic spasms). We also observed a reduced level of leukocyte interferon (Y whose synthesis is controlled by a gene on chromosome 9 and which could be responsible for the recurrent respiratory tract infections, typical and sometimes fatal in these patients. Keywords:
Ring chromosome
9; Interferon;
Seizure
1. INTRODUCTION Ring chromosome 9 occurs when deletion of part of the short and the long arm of chromosome 9 leads to the formation of a ring whose diameter is proportional to the length of the deleted segment [l-3]. The main clinical signs and features of this rare phenomenon (only 21 cases reported) include severe microcephaly, dysmorphic features similar to those observed in partial monosomy 9 [4-61 (i.e. exophthalmia, strabismus, upslanting palpebral fissures with epicanthus, anteverted nostrils, hypertelorism, long philtrum, micrognathia, retrognathia, malformed ears, cleft palate and bifid uvula), delayed physical (height and weight) and psychomotor development, congenital heart malformation [7,8] (ranging from septal defects to severe disorders such as tetralogy of Fallot and pulmonary valve atresia), and early or delayed bone maturation or skeletal disorders (e.g. aplasia and/or hypoplasia of the radius and partial fusion of the C2-C3 vertebrae). Genital anomalies [9] are also frequent (especially hypospadias and cryptorchidism), as are infectious, and particularly respiratory complications. Manouvrier-Hanu et al. [lo] described the association between respira-
Abbreviations: CT, computerized tomography; PS, periodic spasms; IFN-cx, interferon-a; PLB, peripheral blood leukocytes; PHA, phytohemagglutinin; TPA 0, tetradecanoylphorbol 13 acetate; VPA, valproic acid; BZP, benzodiazepines. * Corresponding author. Fax: (39) (382) 380286. 0387.7604/96/$15.00 0 1996 Elsevier Science B.V. All rights reserved SSDI 0387-7604(95)00144-l
tory tract infections, gastroesophageal reflux (see also Leung’s case [ 1 I]> and decreased level of leukocyte interferon. Our case is peculiar in its neuroradiological, neurophysiological and immunological aspects.
2. CASE REPORT Our patient is a male and the second child of healthy non-consanguineous parents aged 36 (mother) and 38 (father) at his birth. He has two sisters, aged 6 and 1, who are in apparent good health. The family history is negative. He was born at term by a normal delivery following an uneventful pregnancy. His birth weight was 3250 g, length 47 cm and head circumference 3 1 cm (less than the 10th percentile). Dysmorphic features were observed: receding forehead, micrognathia and retrognathia, short nose, small ears, anteverted nostrils and moderate exophthalmia. Physical examination revealed cleft palate, cryptorchidism and micropenis. His heart, chest and abdomen were normal. During the following months, the child presented with psychomotor delay associated with global hypotonia and subnormal physical growth. A chromosomal analysis was thus performed which detected ring chromosome 9. At 3 months of age, the patient had an episode of ab-ingestis bronchopneumonia. We first observed the child at the age of 5.5 months, and follow-up lasted until 36 months. The child presented with delayed (less than the 10th percentile), but nevertheless proportional physical growth, generalized hypotonia, poor spontaneous
G. Lanzi etal./Brain
& Decelopmenr
An echocardiogram revealed an interatrial septum defect similar to a small ostium secundum and a very small interventricular muscle defect. The results of metabolic screening tests (plasma and urine amino acids, organic acids), visual and auditory evoked potentials and renal and abdominal echography were normal. The child suffered his first epileptic episode (characterized by flexion of the head and adduction of the arms) at 14 months of age. These episodes occurred in short series particularly on waking and after meals. These symptoms remained unchanged for about two months. Shortly afterwards came the onset of complex, long-lasting epileptic episodes with partial seizures and spasms in varying patterns. The spasms were sometimes preceded by rotation of the head towards the right, the patient presenting with protruding lips, perioral cyanosis and decreased alertness. The spasms then occurred in bursts, and were always asymmetrical and followed by crying. Only at this point did the child appear able to respond to his mother’s call. In other instances, the spasms were followed by partial prolonged seizures, and then by a second series of shorter spasms. At the present time, the pattern of the seizures has changed again and there is a prevalence of tonic spasms. The corresponding EEG recordings can be schematically subdivided into two periods: during the partial seizure, the recording is characterized by a clear hemispherical asymmetry with spikes and poly-spike-waves, prevalently in left anterior regions, while, during the spasms, there is a repetitive pseudo-periodic activity made up of slow wide di- or tri-phasic waves in both hemispheres, but with clear prevalence in the left (Fig. 2). The interictal EEG recording was characterized by an unrecognizable background activity together with brief sequences of slow waves mixed with slow spikes and slow spike-waves asynchronously recorded in both hemispheres. Different antiepileptic drugs were tried (VPA, BZP. ACTH) without any response.
Fig. 1. Brain MRI: 5.5 T. SE, T2-weighted (TR = 3000, TE = 100) axial image. The black area indicates a focal lesion in the white matter of the parietal lobe. The bodies of the lateral ventricles are parallel and dysmorphic, as in case of corpus callosum hypoplasia.
motility and delay in head control. At 7 months of age, he scored a developmental quotient of < 50 in Bayley’s mental and motor scales; brain magnetic resonance imaging detected severe hypoplasia of the corpus callosum; the septum pellucidurn was absent; as in cases of dysraphism, the lateral ventricles were dysmorphic with widened frontal horns and particularly pronounced anterior and posterior comers; the intermediate and T2-weighted images presented small hyperintense areas in the white matter of the right parietal region probably caused by gliosis, due to parenchymal damage of unknown etiology; the white matter was reduced but regularly myelinated for the patient’s age. There were no signs of superficial atrophy (Fig. 1). At 11 months of age, X-ray of the wrist showed absence of the distal epiphyseal nucleus of the radius, normally present at 9 months. Meanwhile, the pyramidal nucleus which normally presents at a later age. was detectable.
Zk
“PI
Fig. 2. Ictal EEG recording
,.“I.
I.
of a cluster of asymmetric
217
1996; 18: 216-219
2.1. Cytogenetic
methods
Chromosome analysis was performed on peripheral blood lymphocytes of the patient and his parents using routine and high resolution banding techniques.
1*mon*.
spasms. Left predominance
of abnormalities
is recognized.
G. Lanzi et al./Brain
218
& Development 1996; 18: 216-219
The child’s parents did not allow a skin biopsy to be taken from him.
Table 1 Levels of IFN- LY or IFN- y in supematant of stimulated PBL ,from a ring chromosome Y-bearing patient Treatment
2.2. Immunological
methods
Our patients’s recurrent febrile episodes of bronchitis are similar to those observed in the subject reported by ManouvrierHanu et al. [12], who had a reduced amount of interferon. We thus decided to measure the level of leukocyte interferon, the (Y fraction of which is controlled by a gene on chromosome 9 [18]. Purified peripheral blood leukocytes (PBL) from the patient were stimulated with synthetic dsRNA (poly rI:rC) in the presence of poly-L-lysine in order to produce IFN-o_, or with phytohemagglutinin (PHA) in the presence of TPA 0 (tetradecanoylphorbol 13 acetate) to induce IFN-?/ production. Presence of IFN-o or of IFN-?/ in the leukocyte supematant was evaluated using an enzyme kit (CELBIO) and compared with normal values. PBL from various normal individuals were tested and values from one representative are reported. The significance of differences in the production of IFN units was determined by a one-tailed Student’s I-test. Two log differences are significant with a P < 0.001. Standard deviations (SD) did not exceed 5% of the mean and were therefore not included. PBL were obtained from heparinized blood samples following separation on a Lymphoprep (Nycomed, Pharma AS, Oslo, Norway) gradient. All the reagents were purchased from Sigma (Munich, Germany).
2.3. Cytogenetic
results
A karyotype 46,XY,r(9) (~24 q34) was found in 48 cells, while one cell had 45 chromosomes (45,XY, - 9>, and one showed a duplicated ring (see Fig. 3). The karyotype of both parents was normal.
2.4. Immunological
results
The results of IFN analysis (Table 1) demonstrate that leukocyte supernatant from the patient’s blood stimulated with poly rI:rC and poly-L-lysine contained less than 20 pg/ml of INF-(r as compared with leukocyte supematant from the blood of a normal subject stimulated with poly rI:rC and poly-L-lysine which contained 1060 pg/ml of IFN-alpha.
_ PoIy rI:rC + poly-L-lysine TPA + PHA ’
b
Normal PBL
Ring chr. 9 PBL
IFN-o
IFN-?/
IFN-a
IFN-y
16 a 1060 63
4 60 500
<4 8 <4
4 31 450
a pg/ml. b Poly rI:rC: 50 kg/ml; poly-L-lysine: ’ TPA: 10e9 M; PHA: 3 pg/ml. PBL: peripheral blood lymphocytes.
1 mg/ml.
Table 2 Main features of ring chromosome 9 Feature
Mental retardation Gestation, 37-42 weeks Short stature, proportionate Microcephaly Anteverted nostrils Cardiac abnormalities a Short neck Trigonocephaly Prominent eyes (incl. proptosisl Small mandible/micrognathia Epicanthic folds Palpebral fissures slant up Strabismus/gaze palsy Generalized hirsutism High palate Cryptorchid testes Hypospadias Small ears Small/short nose Hypotonia Seizures/abnormal EEG Microcephaly, prenatal onset Delayed skeletal maturation
Cases (n = 21) n
%
17 13 12 11 10 10 9 7 8 8 7 7 7 6 6 6 6 5 5 5 5 5 3
80.9 61.9 57.1 52.3 47.6 47.6 42.8 33.3 38.0 38.0 33.3 33.3 33.3 28.5 28.5 28.5 28.5 23.0 23.0 23.0 23.0 23.0 14.2
a Ventricular septal defect, atria1 septal defect, tetralogy tation of the aorta or patent ductus arteriosus.
Our case
+ + + + + + i + + + + $ + + f + + + + + + of Fallot, coarc-
In contrast, the amounts of IFN-7 (500 pg/ml vs. 4.50 pg/ml) were similar in the patient and the normal subject.
3. DISCUSSION
Fig. 3. Karyotype
of the patient: 46,XY,r(9).
Our patient’s clinical picture has major features in common with other cases in the literature [13-191 (see Table 2). Mental retardation was mentioned in 17 out of the 21 cases reported. In 4 cases, there was no mention of cognitive development [2,7,11,20]. There are 9 reports of cardiac anomalies including 2 instances of atria1 septal defect, as found in our case. There were no other reports of agenesis or hypoplasia of corpus callosum in r(9) patients, but neuroradiological investigation (CT) was in fact performed in only 2 cases [ 10,12,20]. Corpus callosum was also present in one case studied post mortem [8]. Agenesis of corpus callosum was reported in only 3 out of 46
G. Lanzi et al. /Brain
& Development
cases of pure deletions of chromosome 9 sparring from 9 pter to p21 or ~22. In 4 patients there were reports of seizures or abnormal EEG (no further details given). In our case, the clinical and electroencephalographic characteristics of the seizures enabled us to classify them as so-called periodic spasms (PS) [21]. Rather than being universally recognized as a separate disorder, such PS are usually described as part of the West syndrome [22]. We would emphasize the close link between partial seizures and spasms where the former may facilitate the latter, due to the presence of a focal cerebral lesion [23]. While the mechanism concerning the contribution of genetic factors to epileptogenesis remains unclear, many chromosomal diseases are frequently associated with clinically polymorphic types of epilepsy [24,25]. More accurate studies in other patients may enable us to understand whether hypoplasia of corpus callosum and PS are casually associated with the chromosome anomaly in our patient, or whether this association forms part of the clinical picture of ring chromosome 9. Our study confirms a previous finding [12] that leukocyte interferon deficit could correlate with the recurrent episodes of bronchitis. The gene coding for IFNa maps close to D95126 on 9 p22 [26]. Thus its locus should not be deleted in the ring formation as the breakpoint on the short arm is on 9 ~24. However, ring chromosomes are unstable and may be lost from a number of cells. In fact a cell with karyotype 45,XY, - 9 was found in our patient. It is therefore more likely that the IFN-a deficit is due to the instability of the ring chromosome than to the deletion of the terminal tips of the chromosome. This interpretation is also supported by the finding of Manouvrier-Hanu et al. [12], in whose patient the IFN-a level ranged from slight reduction to almost complete absence. These findings suggest that, despite being unable to improve the general conditions of the patient, treatment with interferon may allow more effective control of infectious disease complications. The wide variation in phenotype among cases must, of course, be ascribed to differences in breakpoints and to the abnormal behavior of the ring chromosome [27,28]. ACKNOWLEDGEMENTS
We wish to thank Professor Cesare Danesino for his useful comments and for reviewing the manuscript. Thanks also to Dr. Carla Uggetti and Dr. M. Grazia Egitto for supplying the neuroradiological images.
REFERENCES I. Fraisse J, Lauras B, Ooghe MJ, Freycon F, Rethore MO. A propos
2. 3.
4. 5.
d’un cas de chromosome 9 en anneau. Identification par denaturation menagee. Ann G&&t 1982; 17: 175-80. Kistenmacher ML, Punett HH. Comparative behavior of ring chromosomes. Am J Hum Genet 1970; 22: 304-18. Kistenmacher ML. Punett HH, Aronson M, Miller RC, Greene AE. Coriell LL. A ring 9 chromosome. Repository identification no. GM, 1-66. CJtogenet Cell Genet 1975; 15: 122-3. Dipierri JE. Matayoshi T. Ring chromosome 9 identification of a new case by G and C banding. Ann G&&t 1982; 25: 243-5. Nakajima S, Yanagisawa M, Kamoshita S, Nakagome Y. Mental retardation and congenital malformations associated with a ring chromosome 9. Hum Genet 1976; 32: 289-93.
1996; 18: 216-219
219
6. Portnoi MF, Van den Akker J, Le Porrier N, Joye N, Joussef S,
7. 8.
9.
IO.
11.
12.
Taillemite JL. Une nouvelle observation de chromosome 9 en anneau. Ann G&h 1982; 25: 164-7. Inouye T, Matsuda H, Shimura K, et al. A ring chromosome 9 in an infant with malformations. Hum Genet 1979: 50: 23 I-5. Smith A, Evans WA, Woolnough H. Post-mortem studies on two patients with l-2 band cytogenetic deletions: lOq26 --) qter and 19 (p24q34). Ann Ge’nit 1989;32 220-4. Metaxotou C, Kalpini-Mavrou A. Ring chromosome 9-46. XY. r(9) in male with ambiguous external genitalia. Hum Genet 1977: 37: 351-4. Manouvrier-Hanu S, Turck D. Farriaux JP. Another case of ring chromosome 9 associated with gastroesophageal reflux. Am J Med Genet 1989; 32: 558. Leung AKC, Rudd NL. A case of ring (9) del(9p) moaaicism associated with gastroesophageal reflux.Am .I Med Cent 1988: 29: 43-8. Manouvrier-Hanu S, Turck D, Gottrand F, et al. Le chromosome 9 en anneau: a propos d’un cas et revue de la litterature. Ann Ge’ne’t 1988; 31: 250-3.
13. Povey S, Falk C, Smith M. Report of the committee on the genetic constitution of chromosome 9. Cytogenet Cell Gertet 1991; 58:40327. 14. Maureen E, Mohandas TK, Kaback MM. Ring chromosome nine: variable phenotypic expression. Bocia,z Pediutr Res 1977; 11: 524. 15. Dickermann LH, Stallard R, Johnson WE. Variations in the phenotype associated with ring 9 mosaicism. Am .I Hum Genet 1983; 35: 129. 16. Fryns JP, Lambrechts A, Jansseune H. van den Berghe H. Moderate mental retardation and non specific dysmorphic syndrome associated with ring chromosome 9. Hum Genet 1979: 50: 29-32. 17. Hess RO, Meisner LF. Apparent Prader-Willi phenotype in a woman with ring chromosome 9. Am / Med Genet 1987; suppl 3: 133-S. 18. Jacobsen P. Mikkelsen M, Rosleff F. A ring chromosome, diagnosed by quinacrine fluorescence as np 9 in a mentally retarded girl. C/in Genet 1973; 4: 434-41. 19. Numabe H. Shimakazi T, Hoshino M, et al. A case of a ring chromosome 9. Teratology 1986; 34: 48 I. 20. Van Maldergen L. Avni F, Mossay B, Merens C, Verloes A, Gillerot Y. Ring chromosome 9 in a newborn male presenting with facial Genrt Coun.v dysmorphia, hypospadia and skeletal abnormalities. 1991; 2: 123-6. Rossi P, Tassinari CA. 21. Gobbi G. Bruno L, Pini A, Giovanardi Periodic spasm: an unclassified type of epileptic seizures in childhood. Del, Med Child Neural 1987; 29: 766-75. 22. Jeavons P, Livet MO. West syndrome: infantile spasms. In: Roger J, Bureau M, Dravet Ch, Dreifuss FE, Perret A, Wolf P, eds. Epileptic syndromes in infancy, childhood und adolescrnce. 2nd ed. London: John Libbey, 1992: 53-65. 23. Carrazana EJ, Lombroso CT. Mikati M, Helmers J, Holmes GL. Facilitation of infantile spasms by partial seizures. Epilepsirr 1993: 24: 97- 109. 24. Dalla Bemardina B, Zullini E, Fontana E. et al. Electroclinical longitudinal study of ten cases of Angelman’s syndrome. Epilepsiu 1993; 34: 71. 25. Viani F, Romeo A, Mastrangelo M, Asi MH, Briscioli V. Epilepsy and Angelman’s syndrome: a clinical and EEG study. Epilepsiu 1993: 34: 70. 26. Kwiatkowski DJ, Armour J, Bale AE, et al. Report on the Second International Workshop on Human Chromosome 9. Cuogenet Cell Genet 1993: 64: 94-8. 27. Zdansky R, Andrle M, Btihler E, Tsuchimoto T, Mayr WR, Rett A. Irregular phenotypic expression of ring chromosomes. Humnngenrtik 1975: 26: 193-8.
28. Zuffardi 0, Danesino C, Poloni L, Pavesi F, Bianchi C. Gargantini L. Ring chromosome 12 and latent centromeres. Cytogenrt Cell Genet 1980: 28: 151-7.