Fukuyama-type congenital muscular dystrophy

Abstract

CONGENITAL MUSCULAR DYSTROPHY in association with developmental central nervous system abnormalities, first described by Fukuyama et al, 1 is now recognized as a distinct clinical entity and is reported to be the second most prevalent form of progressive muscular dystrophy in Japan, 2 The etiology is unknown but both genetic transmission by recessive inheritance and intrauterine infection have been hypothesized? Despite the relatively high prevalence in Japan, the disorder has not been described in Japanese children born in other parts of the world, thus supporting the concept that a local environmental factor could be important in the pathogenesis. We report the clinical, pathologic, and cranial computed tomographic findings in an infant who was conceived and born in Canada with the characteristic features of this unusual disease. CASE REPORT The patient was born of nonconsanguineous Japanese parents who had been residing in Canada for six years. There was no family history of muscle disease or mental retardation. The pregnancy was normal; the mother, a pi'imigravida, ate a normal diet and was not exposed to any toxin or apparent infection. Subsequent to an uncomplicated labor, a female infant weighing 3.2 kg was born. The patient presented to us atage 4 months with hypotonia which was first noted shortly after birth. Examination revealed a hypotonic infant whose head circumference, length, and weight were in the fiftieth percentile. There were no dysmorphic features. She had moderate weakness of facial, neck, and proximal limb muscles. The tendon reflexes were depressed. There was no muscle pseudohypertrophy. Serum ereatine kinase activity was more than 3,000 units/L (normal < 110). Motor nerve conduction velocities and electromyography were both normal. Electroencephalogram showed generalized slow wave activity with occasional sharp waves from the left hemisphere. A quadriceps muscle biopsy revealed variation in fiber size, areas of muscle fiber necrosis with regeneration, and increased endomysial connective tissue compatible with muscular dystrophy (Fig. 1). Histochemistry was unremarkable. The weakness progressed and at age 2 years she deveioped recurrent generalized seizures requiring maintenance anticonvulsant therapy. At 3 years of age she had no speech, was severely mentally retarded, and had an estimated motor developmental age of 4