Glycogen storage disease type III (GSD III) is an autosomal recessive disease, due to deficiency of glycogen debranching enzyme (GDE), a key enzyme involved in glycogen degradation. Clinical presentation includes hepatomegaly, myopathy, hypoglycemia and cardiomyopathy.

The cardiac natural history of patients with GSD III and its relationship with genetic abnormalities is not well known. We performed a longitudinal study in order to describe the natural history of heart involvement in patients with glycogen GSD III.

47 patients were included our study (16 male/31 female). Mean age was 25.7 years±15.4.

All patients were in sinus rhythm expect one patient (atrial fibrillation). 9 patients/ 47 disclosed abnormal repolarization. Electrical left ventricular hypertrophy was found in 22 patients /47.

Heart failure was found in 10 patients/47 and 2 patients/47 disclosed a left ventricular dysfunction. Hypertrophic cardiomyopathy was found in 23 patients /47; and 4 patients/47 disclosed obstructive hypertrophic cardiomyopathy. Patients with hypertrophic cardiomyopathy depicted 2 codon-stops (p 0.03).

In conclusion, hypertrophic cardiomyopathy is frequent in patients with GSD III.