Letters to the editor

Abstract

T h e interesting report by Scoppetta et aL2 on distal rnuscular dystrophy prompts us to share our similar experience of a patient with distal weakness, a muscle biopsy showing dystrophic changes, and massive elevation of serum creatine kinase.This 28-year-old male noted leg weakness at age 19 years. Prior to that he had been active in sports, particularly basketball and weight lifting. T h e weakness was most noticeable in the calves, as he was unable to stand o n his toes and his gait was flat-footed. T h e course has been very slowly progressive, and in the past 5 years, mild weakness of distal upper extremity muscles has emerged. Two distant male relatives died of Duchenne dystrophy, an interesting coincidence but irrelevant to our patient's disorder.Examination revealed a healthy appearance, but there was moderate wasting of calf and forearm muscles. His gait lacked effective push-off, arid toe-walking was impossible, although heel-walking was normal. Manual testing showed marked weakness in triceps surae muscles and mild involvement of anterior tibialis muscle and wrist flexors and extensors. T h e ankle tendon jerks were absent, but the remainder were normal. N o muscle hypertrophy, sensory deficit, rnyotonia, o r cranial nerve abnormalities were apparent.Several serum creatine kinase assays have ranged between 12,012 and 17,423 IUlliter (normal <I44 IU/ liter). Electromyography showed a unifhrrn pattern of decreased duration and amplitude of motor unit potentials with increased recruitment. Abundant fibrillation potentials were noted in weak muscles. A biceps brachii biopsy showed marked fiber size variation, many internal nuclei, frequent necrotic fibers, definite fiber hypertrophy, and proliferation of endomyseal connective tissue.In our patient, the evidence indicates a myopathy, and the massive serum enzyme elevation in the face of slowly progressive weakness in a young adult points to a dystrophy and conforms closely to the features summarized in the report of Scoppetta et al.' Idowever, our case is mast reminiscent of' the 17 patients reported by Miyoshy et al.,' who described, in addition to the other features, the early weakness of posterior calf muscles as the characteristic initial manifestation, which is unusual in most dystrophies.It is clear that recessive o r sporadic young adult onset distal muscular dystrophy is distinct from the classical dominantly inherited form described by Welander." Whether or not the former disorder represents several nosologic entities remains unresolved.