Early onset distal muscular dystrophy with normal dysferlin expression

A 7-year-old boy, who was noted to be a slow runner at the age of 2 years, had progressive muscle weakness and atrophy, preferentially affecting distal muscles. At 3 years of age, he had scoliosis and difficulty in standing on tip-toe. Serum creatine kinase was 1074 IU/l. Muscle CT scan showed low-density areas in the lower legs and upper arms, but predominantly in the gastrocnemius and soleus muscles. Biopsy of the biceps brachii muscle showed moderate dystrophic changes with normal dysferlin expression on immunohistochemical and western blot analyses. Although muscle involvement mimicked that seen in Miyoshi myopathy (MM), the very early onset of the disease and scoliosis were quite unusual for MM. We, therefore, made the diagnosis of early onset dysferlin-positive distal muscular dystrophy, probably a new type of distal muscular dystrophy.