A case of glycogen storage disease type III (glycogen debranching enzyme deficiency) with liver cirrhosis and hypertrophic cardiomyopathy.

We present a 26-year-old woman with glycogen storage disease type III (debranching enzyme deficiency) complicated with liver cirrhosis and hypertrophic cardiomyopathy. Glycogen debranching enzyme has two catalytic sites, oligo-1,4,-1,4- glucantransferase (EC 2.4.1.25) and amylo-1,6-glucosidase (EC 3.2.1.33). Variability in the clinical phenotype could be a function of the involvement of one or other catalytic site, or differences in tissue expression of the defective enzyme, or both. We hypothesize that some subtypes of glycogen storage disease (GSD) type III may cause liver cirrhosis as seen in GSD type IV due to the accumulation of glycogen of abnormal structure.