OBJECTIVETo analyze the clinical characterization of Danon disease caused by the mutation of lysosome-associated membrane protein-2 (LAMP-2) gene.

METHODSThe clinical features, serum biochemical index, electrocardiogram and echocardiography data were retrospectively reviewed in 5 patients with genetically confirmed Danon disease. Mean follow-up period was (56 ± 6) months.

RESULTSFive patients including 2 men and 3 women in 2 unrelated families with 2 novel mutations in the exon 3 (c.189-190TGdel) and 8 (c.1205Cdel) of the LAMP-2 gene were identified. All patients had cardiomyopathy, 1 patient (1/5) had skeletal myopathy, and none of the patients had mental retardation. The two male patients presented cardiac symptoms at the age of 9 and 10 years, respectively, and all female patients were asymptomatic. Biochemical analysis showed that serum creatine kinase and liver transaminase enzyme were increased in 2 patients (2/5). Abnormal electrocardiogram was observed in all patients, and 2 patients (2/5) had ventricular preexcitation. During the follow-up. One male patient died of cardiac failure at the age of 18 years and three months, and the symptoms of the other male patients rapidly developed with the evolution from hypertrophic cardiomyopathy into dilated cardiomyopathy. However, all female patients remained asymptomatic, and repeat echocardiography indicated only mild ventricular hypertrophy during follow up.

CONCLUSIONPatients with Danon disease mainly present hypertrophic cardiomyopathy, and sometimes presents with skeletal myopathy. The disorder occurs at early, age and progresses quickly and ends with poor prognosis in male patients. Other clinical features include elevations of serum creatine kinase and liver transaminase enzyme, ventricular preexcitation on electrocardiogram, and ventricular hypertrophy detected by echocardiography. Female patients remain asymptomatic till now in our cohort.