Familial myopathy associated with Marfanoid features and multicores

The cases of a mother and son with a slowly progressive generalised myopathy and Marfanoid features are described. Muscle biopsies showed atrophy, type 1 fibre preponderance, excessive variation in fibre size and shape, and multiple foci of myofibrillar disorganisation with loss of oxidative enzyme activity of the type found in multicore disease.