Glycogen storage disease type IX (GSD-IX), also known as Phosphorylase kinase deficiency, is a disorder of glycogen metabolism. The liver phosphorylase kinase is a heterotetramer that is composed of four copies each of alpha, beta, gamma, and delta (calmodulin) subunits. In liver, the alpha, beta, and gamma subunits are encoded by the PHKA2 gene, the PHKB gene, and PHKG2 gene respectively. Mutation within these genes has been shown to result in GSD type IX. Presenting symptoms include hepatomegaly, ketotic hypoglycemia, and growth delay. GSD IXd, also known as X-linked muscle glycogenosis, is caused by mutation in the PHKA1 gene, which encodes the alpha subunit of muscle phosphorylase kinase. The typical clinical signs of GSD IXd are exercise intolerance, often combined with cramps, myalgia, weakness or myoglobinuria.
Mutation hotspots in the PHKA2 gene in X-linked liver glycogenosis due to phosphorylase kinase deficiency with atypical activity in blood cells (XLG2).
Burwinkel B, Maichele AJ, Aagenaes O, Bakker HD, Lerner A, Shin YS, Strachan JA, Kilimann MW
タイトル
Autosomal glycogenosis of liver and muscle due to phosphorylase kinase deficiency is caused by mutations in the phosphorylase kinase beta subunit (PHKB).
