RESUMO
Abstract Glycogen storage disease type IXa (GSD IXa) presents in childhood with hepatomegaly, poor growth, and ketotic hypoglycemia. Clinical course is usually mild, often not requiring treatment with attenuation of symptoms with increasing age. The phenotypic spectrum has recently expanded to include more severe involvement with hepatic fibrosis or cirrhosis warranting dietary therapy. We report a 2-year-old boy with a severe phenotype of GSD IXa presenting with a massive hepatomegaly, significant transaminitis, recurrent ketotic hypoglycemia, and short stature. Aggressive dietary management with regular feeds, frequent uncooked cornstarch doses, and protein supplementation resulted in clinical improvements including enhanced growth velocity, energy levels, overall well-being, and reduction in hepatomegaly with restitutions in biochemical parameters. We concur with a recent report which proposed that GSD IXa is not always a mild condition but instead part of an expanding phenotypic spectrum warranting intensive dietary management to optimize metabolic control and quality of life.