Danon Disease

Danon disease, like Pompe disease, is a muscle disorder caused by a primary defect in lysosomal proteins. Danon disease (OMIM #300257) is an X-linked dominant disorder, with males being more severely affected than female carriers. In males, mean disease onset is in their early teens and in females in their late twenties. Clinical hallmarks are a severe cardiomyopathy, muscle weakness, and mild mental retardation. Retinal, liver, and pulmonary disease may also occur. Milder, sometimes isolated cardiac phenotypes without mental retardation are also described. Regular cardiac evaluation, even in asymptomatic patients, is obligatory.