OSTEO-CHONDRO-MUSCULAR DYSTROPHY

Three cases of a disorder of bone and of skeletal muscle are reported. Clinical manifestations of this disease begin in infancy with slowly progressive bony deformities, including coxa vara or valga, pectus carinatum, vertebral flattening, dwarfism, and basilar invagination. In addition, there is a mild dystrophic process in muscle, with muscular hypertrophy followed by atrophy, and with prominent myotonia. The descriptive label of osteo-chondro-muscular dystrophy is suggested, since this covers both the skeletal and the neuromuscular aspects of the disease. Present evidence favors a recessive mode of inheritance. Muscle biopsy studies, including electronmicroscopy and determination of muscle electrolytes, suggest a disorder of muscle membranes, with inability to maintain normal gradients of sodium and potassium. An abnormally low potassium concentration in muscle was noted already in a 6-month-old infant with this disease, at a time when dystrophic changes were minimal. Procaine amide therapy was effective in improving muscle function in the two children in whom it was tried.