ABSTRACT Glycogen storage disease type III (GSD III) is an inborn error of carbohydrate metabolism with an autosomal recessive inheritance pattern. Phenotypically, patients can manifest a broad clinical spectrum. Most patients affected with GSD IIIA (85%) have a non‐functional GDE enzyme primarily affecting the liver and cardiac/skeletal muscle (Type IIIA). Initial clinical manifestations of GSD IIIA present in the first year of life. Presentation is very similar to GSD type I. Up to 98% of children affected have hepatomegaly, hypoglycaemia (53%) with marked ketosis (34%), short stature (49%), delayed puberty, and frequent infections (17%). In adulthood, they may have cirrhosis, adenomas, or hepatocarcinomas (11%), cardiomyopathy (58%) and myopathy (34%). Pregnancy has been documented in women with GSD III. Nutritional requirements are increased during pregnancy, especially in the third trimester. We report the management of a woman with GSD IIIA found to be compound heterozygous for two pathogenic AGL variants, c.798C>G p.(Tyr266Ter) and c.4258_4259ins? p.(Asp1420fs), who had a planned pregnancy. Cardiac outcomes are also described/discussed.
