Abstract
Twenty haemophilic patients were examined neurologically and found to have varying degrees of muscle atrophy. The pathogenesis of the atrophy was investigated by electromyography, serum muscle enzyme levels, and muscle biopsies. In most cases the EMG showed such abnormalities as reduced numbers of functioning motor units and "myopathic" motor unit potentials. Serum enzyme levels were frequently raised, and type 2 fibre atrophy was found in the three patients who underwent muscle biopsy. These findings suggest the presence of neuromyopathic involvement in haemophilic patients.