Contributor: Gordon K. Klintworth
Glycogenosis type IIb (glycogen storage disease type IIb, X-linked vacuolar cardiomyopathy, Antopol disease, Danon disease, glycogen cardiomyopathy, pseudoglycogenosis type II, glycogen storage disease limited to the heart, lysosomal glycogen storage disease without acid maltase deficiency) is a subtype of glycogenosis type II. It has an X-linked mode of inheritance and is characterized clinically by a cardiomyopathy, myopathy and variable mental retardation. The condition is due to a mutation in the LAMP2 gene.