Hereditary distal myopathy with onset in early infancy. Observation of a family.

The study of a family affected with hereditary distal myopathy with onset in early infancy is presented. Complete neurological examination was necessary in several members of the two last generations to discover the existence of the abnormalities of which they were unaware. The propositus was the most affected member of the family iwth distal paresis of the upper and lower extremities and selective paresis of the deltoid muscles. In addition he had kyphoscoliosis, talipes valgus and limitation of mobility of several joints. The onset of the disease was estimated as before the age of 2 when the child started walking. There was no progression of the disease. Clinical examination suggested a myopathic origin of the condition. A sural nerve biopsy was normal. Light-microscopy histochemical studies disclosed a predominance of type I fibres which were at the same time hypotrophic. Subsarcolemmal deposits of mitochondria were present although they were scanty and of normal ultrastructural appearance. In view of the morphological presentation it is postulated that this disease should be classified within the groups of myopathies accompanied by disproportion of fibres and selective atrophy of type I fibres.