PHKA2 and disorder of glycogen metabolism: We also identified a novel maternally inherited variant in PHKA2 (NM_000292.3: c.3374A > T (p.Glu1125Val)) that is associated with glycogen storage disease (GSD), type IXa1/2 (MIM 306000), characterized by phosphorylase kinase deficiency in the liver, leading to hepatomegaly and hypoglycemia.