Glycogen Storage Disease Type III Presenting as Recurrent Seizure Disorder in a Second Twin: A Case Report

Abstract

Glycogen storage diseases (GSDs) are a group of genetic autosomal recessive metabolic disorders resulting from deficiencies of enzymes  of glycogen metabolism occurring in the liver, muscles or kidneys. Various types and sub-types exist based on genetic classification  presenting with symptoms and signs of hypoglycaemia, hepatomegaly and myopathy depending on severity, and age of onset. A high  index of suspicion is required for the diagnosis of GSDs. An eighteen-month-old girl who was apparently healthy with normal  development was without any abnormality until about 12 months of age when she had the first episode of afebrile seizure which was  treated with sodium valproate but continued to have occasional seizures. She had a status seizure, which was only aborted with a glucose  infusion. Intra-ictal incident glucose level was 1.4mmol/L. Biochemical investigation revealed deranged liver enzymes, normal  serum cortisol, C-peptide and insulin. Liver histology showed features consistent with GSD III and diagnosis of glycogen storage disease  type III was made based on the liver histology and other supportive laboratory features. Following dietary management, the child  responded very well, was seizure-free and off anticonvulsant therapy. This case highlights the occurrence of symptomatic seizures due to  factors other than epilepsy.