A Case Report of Glycogen Storage Disorder Type IIIa in a Pediatric Patient: Clinical Approach and Molecular Diagnosis.

Glycogen storage disorders are a group of inherited metabolic disorders marked by dysfunctional glycogen metabolism and atypical glycogen buildup in different tissues. Timely diagnosis and sustained therapy are crucial to avoid metabolic complications and progressive organ impairment. We present the case of a 7-year-old male diagnosed with hepatic glycogen storage disease (GSD) type III at the age of two, following evaluation for progressive abdominal distension and hepatomegaly. Imaging and liver biopsy revealed characteristic features. Molecular genetic testing revealed a homozygous pathogenic nonsense mutation in the AGL gene (c. 967C > T), hence validating the diagnosis of GSD III. The patient was treated with dietary adjustments and close monitoring. Despite appropriate management, he presented with recurrent abdominal pain and persistent hepatomegaly on follow-up imaging. This case highlights the importance of early diagnosis, definitive molecular confirmation and continued long-term surveillance, as hepatic manifestations may persist despite standard therapy.