Glycogen storage disease type IV
（重定向自Amylopectinosis）
Glycogen storage disease type IV is a rare hereditary metabolic disorder. It is the result of a mutation in GBE1 gene, which causes a defect in the glycogen branching enzyme. Therefore, glycogen is not made properly and abnormal glycogen molecules accumulate in cells; most severely in cardiac and muscle cells. The severity of this disease varies on the amount of enzyme produced. Glycogen Storage Disease Type IV is autosomal recessive, which means each parent has a mutant copy of the gene but show no symptoms of the disease. It affects 1 in 800,000 individuals worldwide, with 3% of all Glycogen Storage Diseases being type IV.