Onset at the age of 3 to 4 years, with
progressive muscular dystrophy involving, at first, the proximal muscles.
Progressive weakness of the axial muscles, pharyngeal control, and
swallowing. Decreased or absent tendon reflexes and muscular fasciculations.
Progressive respiratory failure as a result of muscular weakness. Cardiac
involvement seems to be significant and includes atrial hyperexcitability,
atrioventricular blocks, and right-sided heart failure as a result of
pulmonary hypertension. Congestive biventricular failure has also been