Contributor: Gordon K. Klintworth
Glycogenosis type VIII (glycogen storage disease type VIII, hepatic phosphorylase kinase deficiency, X-linked type I  liver glycogenosis, X-linked liver glycogenosis, glycogenosis VIIIA, OMIM #306000) is an X-linked recessive disorder of glycogen metabolism. Glycogenosis type VIII  is one of the mildest glycogen storage diseases.This glycogen storage disease  is characterized by growth retardation, hepatomegaly, hypercholesterolemia, hypertriglyceridemia and elevated serum levels of glutamate-pyruvate transaminase and glutamate-oxaloacetate transaminase. A fasting hyperketosis is also present in this glycogenosis, which results from a deficiency in phosphorylase kinase. The disorder is caused by mutations in the PHKA2 gene. The biochemical abnormalities gradually disappear over time and adults are usually asymptomatic. Ophthalmologic manifestations have not been reported.