Severe periodic febrile myalgia in infancy due to carnitine palmitoyltransferase deficiency

Neuromusc. Disord.. Vol. 2, No. 4, pp. 285--288, 1992 Printed in Great Britain

0960-8966/92 $5.00 + 0.00 ©1992 Pergamon Press Ltd

SEVERE PERIODIC FEBRILE MYALGIA IN I N F A N C Y D U E TO CARNITINE PALMITOYLTRANSFERASE DEFICIENCY* RAPHAELSCHIFFMANN,~f~,ELI LAHAT§and ABRAHAMSCHECHTERII ?Pediatric Neurology Unit and the II Department of Pediatrics, Hadassah UniversityHospital, Mount Scopus, Jerusalem, Israel; and §Departmentof Pediatrics, Assaf Harofeh Medical Center, Zerifin,Israel (Received 14 October 1991; revised 27 April 1992; accepted I September 1992)

Abstraet--A 7½-yr-old girl suffered, since early infancy, severe recurrent myalgia during periodic attacks of fever, vomiting and pharyngitis. Neither myoglobinuria nor exercise-induced muscle pain was present. She was found to have carnitine palmitoyltransferase deficiency (CPTD) in leukocytes, fibroblasts and muscle. This case exemplifies the importance of looking for an associated metabolic etiology of recurrent febrile myalgia even in the absence of myoglobinuria. Key words: Myalgia, carnitine palmitoyltransferase deficiency, periodic disease.

function affects the liver only and presents in infancy with severe hypoketotic hypoglycemia

INTRODUCTION

Carnitine palmitoyltransferase deficiency (CPTD) is a disorder o f lipid metabolism [1]. Affected individuals suffer from muscle pain, often with rhabdomyolysis and myoglobinuria after prolonged exercise or prolonged fasting. Rarely, infections, emotional stress or sleep deprivation are thought to be precipitating factors. Carnitine palmitoyltransferase (CPT) facilitates the transfer of activated fatty acids [1] from the cytosol to the mitochondria. Two forms of the enzyme exist. CPTI is present in the outer membrane of the mitochondria and CPT2 in the inner side of the inner mitochondrial membrane [2]. The genetic transmission is autosomal recessive but the male to female ratio of symptomatic individuals is 5.5:1 [I]. This may be due to hormonal and exercise intensity differences between the two sexes. The myopathic form of C P T D is thought to be caused by CPT2 deficiency [3]. Severe CPT2 deficiency may cause a lethal dysfunction of striated and cardiac muscle as welt as of the liver [3]. CPTI dys-

*Presented in part at the 43rd annual meeting of the American Academy of Neurology, Boston, Massachusetts. April 1991. :~Authorto whom correspondenceshould be addressed at: National Institutes of Health, NINDS. Building 10. Room 3D03, 9000 RockvillePike. Bethesda, MD 20892. U.S.A.

[3]. METHODS

Leukocytes were isolated by a dextran method described by Deckelbaum et al. [4]. Assays were performed on fresh leukocytes or after freezing for up to 5 days at - 7 0 " C . Homogenates of leukocytes and cultured skin fibroblasts were prepared by sonication of cell suspension in 50mM Tris buffer, pH 7.6, 0.1M KCL, 5mM MgSO4, lmM E D T A and ImM ATP for two periods o f 20 s in a Kontes sonicator (Kontes, Vineland, NJ, U.S.A.) at maximum output. CPT activity was assayed by the isotope exchange method, by which mostly CPT2 is assayed [5]. This method measures the exchange of labelled carnitine with palmitoyicarnitine. The reaction mixture contained: 0.1M Tris buffer, pH 7.6, 2mM KCN, lmM dithiothreitol, 0.1% bovine serum albumin (fatty acid free), DL-palmitoylcarnitine in two concentrations (0.1 and 0.5 mM), 0.2mM CoA-SH, 5mM DL-[methyl-14C] carnitine (specific activity 300 dpm nmol-~) and 0.2-0.4 mg protein or non collagen protein (NCP) in a final volume of 0.5 ml. The reaction was started by addition ofcarnitine and continued for 20 min at 37"C. The [14C]-palmitoylcarnitine produced was extracted with isobutanol [6] and 0.5 ml of the organic phase was counted in a

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liquid scintillation counter. The enzyme activity in muscle was assayed by the same method. CPT was also measured by the forward reaction which assays the formation of palmitoylcarnitine from palmitoyl-CoA and carnitine. The mixture used was identical to the one described for the isotope exchange method except that no CoA-SH was added and 0.08 mM of palmitoylCoA was used instead of palmitoylcarnitine. The effect of a detergent (Triton X-100 0.4%) on the forward assay was also determined. All assays were done in triplicate. CASE REPORT

A 7½-yr-old girl of Ashkenazi-Jewish extraction was referred because of a 7 yr history of severe recurrent myalgia during febrile episodes. She had healthy unrelated parents and two normal sisters. She was born after a normal pregnancy and delivery. Birth weight was 3620 g. Febrile episodes started at 9 months of age and recurred every 1-2 months, each lasting about 5 days. In a typical episode, during the first 2-3 days there was high fever accompanied by severe vomiting and pharyngitis with little or no oral intake. Subsequently, muscle pain without cramps would develop. During such attacks in infancy she would assume a "'frozen" posture and would refuse to move. Myalgia would gradually wane in the following days. Myoglobinuria was looked for but never detected during these episodes. Between febrile episodes she was asymptomatic with no myalgia even during long hiking trips. Her general examination was unremarkable and neurological examination was normal; in particular it showed normal muscle bulk with no

muscle weakness. During a year and a half of follow up, febrile attacks became less frequent and less severe. Serum creatine kinase (CK) during fever and myalgia episodes was elevated (up to 20,000 U). There was no hypoglycemia during attacks and ketones were present in urine. Between febrile episodes CK values were normal. E M G showed brief, low amplitude polyphasic potentials. Muscle biopsy showed normal histological pattern as well as no increased deposition of fat on Oil Red On staining and on electron microscopy examination. Random serum lactate, serum carnitine and forearm ischemic exercise tests were also normal. CPT values were determined in leukocytes in four separate blood samples (Table 1). The inhibition of the reaction by the high substrate concentration is diagnostic of CPTD [5]. There was unusual sensitivity of the enzyme to freezing and thawing. CPT activity was also found to be reduced in cultured fibroblasts and, between episodes, in muscle (Table 1). During febrile episodes, throat culture was negative for streptococcus beta hemolytic Group A when checked and at least once was negative for pathogenic viruses and anaerobes. A throat smear showed only epithelial cells. Sedimentation rate was elevated up to 120 mm for the first hour, but normal between illnesses. DISCUSSION

This young girl had two coinciding clinical phenomena - - CPTD on the one hand and periodic febrile episodes on the other. The CPTD manifested itself almost exclusively during stereotypical fevers with vomiting and pharyngitis, rarely during the usual viral or bacterial

Table I. Carnitine palmitovltransferase activity in leukocytes fibroblasts and muscle by the two methods used* Isotope exchange

Forward reaction

Substrate concentration (mM) 0.1 0.5 Leukocytes 1patient ) Fresh Frozen Leukocytes [control ~,= 61 Fresh Frozen Fibroblasts Patient ( ~, 5 ~ Control (), = I I ) Muscle (frozen) Patient Control (), = 151

with Triton X-100

f) 76 0.360.27 '0.31

0.36 (I. 1 7 / 0 . 0 0 0 4 2

142

0.34

1.04±0.14 0.95 + 0.06

1.10±0.1'4 1.23 + 0. I I

0.72+0.10

0.31 ±0.02

0.52 ± 0.09 0.99 ~ 0 1(I

0.32 ± 0.13 I. 16 ± 0.0 t)

0.26 ± 0.05 0.50±0.13

0.04 + 0.02 0.23:t:0.04

0.0O 0.93 ± 0.10

0.00 1.62 + 0.29

*Results expre,,sed in nmol mg ' protein rain ~. mean ::r S.D. when available.

not done

Periodic Febrile Myalgia illnesses and never during prolonged exercise. Over the years she therefore had a large number of such episodes. During her periodic fevers she would be in a prolonged fasting state because of her severe vomiting, with increased energy demands due to increased body temperature. Under such conditions, muscle utilizes fatty acid oxidation rather than glucose in order to meet its energy requirements. In this patient, however, the increased demands for fatty acid oxidation in muscle could not be met because of CPTD, presumably causing diminished production of adenosine triphosphate that is needed to maintain sarcolemmal integrity [I]. This caused myalgia with CK leakage through damaged muscle fiber membrane. Muscle pain and myoglobinuria during febrile illnesses in patients with CPTD has been previously described [6] and can be fatal in children [7], mostly because of acute renal failure. Prolonged exercise has the same metabolic effect as prolonged fasting and, indeed, CPTD usually presents in young adult males after strenuous exercise [1, 3, 8]. Rarely, this disorder presents solely as chronic muscle weakness [9]. Onset of symptomatic CPTD in the first year of life causing only myalgia with no myoglobinuria has not, to our knowledge, been described. The absence of symptoms during prolonged physical exercise is of note. Among the 39 cases of CPTD reviewed by DiMauro and Papadimitriou [1] only 6 were women. At least one of them had never had pigmenturia but complained of exercise related myalgia. It seems that, in general, women with CPTD are less severely affected. It may be that our patient was fed on sufficient amounts of carbohydrates during prolonged exercise or that the latter was not strenuous enough to provoke energy crises in voluntary muscle. Alternatively, the absence of symptoms during prolonged exercise may be due to the characteristics of the particular mutant enzyme in this patient. The diagnosis of CPTD in this patient is based on lower levels of enzyme activity by the isotope exchange method, and by an even lower CPT activity with the higher concentration of substrate (substrate inhibition) [2]. The results of the forward reaction show increased sensitivity of the mutant enzyme to a detergent (Triton X- 100) with a decrease to 24% of the original value in the patient vs 44% of the original value in the controls. This suggests an abnormal dependence of the mutant enzyme on its membranous environment [2, 5]. The unusual sensitivity of

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CPT activity to freezing and thawing in our patient is of unknown significance. A similar phenomenon was recently described by Trevisan et al. [8] but these authors do not state whether it is a common finding in patients with CPTD. The extremely low level of activity of CPT found in muscle in our patient is not unusual. In the same laboratory, by the forward reaction, CPT activity in muscle of six patients with the classic "muscle" CPTD, ranged between 0.05 and 0.22 nmol mg -~ protein min -~ using 0.1 mM DLpalmitoylcarnitine and between 0.00 and 0.05 nmol mg-~ protein min-~ using substrate at 0.5 mM. Very low levels of CPT activity in muscle have been detected by others [8, 9]. Other enzyme deficiencies causing muscle pain include phosphorylase, phosphorylase kinase, phosphoglycerate kinase, myoadenylate deaminase, phosphofructo-kinase, phosphoglycerate mutase and lactate dehydrogenase. These disorders are usually associated with myoglobinuria [10]. Decreased CPT activity in three tissues, including muscle, and the absence of storage of glycogen in muscle confirms the diagnosis in our patient. Muscle pain during febrile illness in children is usually associated with a systemic viral or bacterial infection. This is usually due to a "toxic" myopathy and rarely to a direct infection [11]. Occasionally, a viral infection is associated with myoglobinuria [12]. The repeated episodes of fever, vomiting and pharyngitis in our patient are very similar to the periodic syndrome recently described [13]. The cause of this syndrome is unknown. No infectious etiology was ever found, but an unusual chronic infection cannot be ruled out. An abnormality of a part of the immune system is likely. Of interest is the fact that one of the ten cases described by Marshall et al. [13] had myalgia during each of these febrile episodes, but no CK levels are mentioned by the authors. Although the association between the periodic syndrome and CPTD is considered to be fortuitous, the recurrent febrile episodes "uncovered" the metabolic defect at an unusually young age. The metabolic crises in patients with CPTD can be prevented by ensuring ample carbohydrate and protein intake and by avoiding prolonged fasting and prolonged physical exercise [1]. Muscle uses only glycogen as an energy source during brief vigorous exercise and therefore this type of exercise is not contraindicated in patients with CPTD. In conclusion, we suggest that when myalgia is recurrent or severe in children during febrile

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illness, s e r u m C K level s h o u l d be c h e c k e d a n d if e l e v a t e d , a n a s s o c i a t e d m e t a b o l i c d i s e a s e s u c h as C P T D s h o u l d be c o n s i d e r e d , e v e n in the a b s e n c e of myoglobinuria. Acknowledgements--We thank Professor Alisa Gutman for

performing the CPT assays and Sara Berger for her secretarial assistance.

REFERENCES

1. DiMauro S, Papadimitriou A, Carnitine palmitoyltransferase deficiency. In: Engel A G, Banker B Q, eds, Myology. New York: McGraw-Hill, 1986:1697-1708. 2. McGarry J D, Sen A, Esser V, et al. New insights into the mitochondrial carnitine patmitoyltransferase enzyme system. Biochimie 1991; 73: 77-84. 3. Demaugre F, Bonnefont J-P, Colonna M, et al. Infantile form of carnitine palmitoyltransferase II deficiency with hepatomuscular symptoms and sudden death. J Clin Invest 1991; 87: 859-864. 4. Deckelbaum R J, Russell A, Shapira E, et al. Type III glycogenosis: atypical enzyme activities in blood cells in two siblings. J Pediatr 1972; 81: 955-961.

5. Zierz S, Engel A G. Regulatory properties of a mutant carmtine palmitoyltransferase in human skeletal muscle. Eur J Biochem 1985; 149: 207-214. 6. Bertorini T, Yeh Y Y, Trevisan C, et al. Carnitine palmitoyltransferase deficiency: myoglobinuria and respiratory failure. Neurology 1980; 30: 263-271. 7. Kelly K J, Garland J S, Tang T T, et al. Fatal rhabdomyolysis following influenza infection in a girl with familial carnitine palmitoyltransferase deficiency. Pediatrics 1989; 84: 312-316. 8. Trevisan C P, Isaya G, Angelini C. Exercise induced recurrent myoglobinuria: defective activity of inner carnitine palmitoyltransferase in muscle mitochondria of two patients. Neurology 1987; 37:1184-1188. 9. Kieval R 1, Sotrel A, Weinblatt M E. Chronic myopathy with a partial deficiency of the carnitine palmitoyltransferase enzyme. Arch Neurol 1989: 46: 575-576. 10. Tonin P, Lewis P, Servidei S, et al. Metabolic causes of myoglobinuria. Ann Neurol 1990; 27: 181-185. 11. Layzer R B. Muscle pain, cramps and fatigue. In: Engel A G, Banker B Q, eds. Myology. New York: McGrawHill, 1986; 1907-1922. 12. Jehn U, Fink M K. Myositis, myoglobinemia and myoglobinuria associated with enterovirus Echo 9 infection. Arch Neurol 1980; 37: 457-458. 13. Marshall G S, Edwards K M, Butler J, et al. Syndrome of periodic fever, pharyngitis, and aphtous stomatitis. J Pediatr 1987; 110: 43-46.