Rare cause of drug-resistant epilepsy due to GABA transaminase deficiency: A case report from India

Abstract

Gama aminobutyric acid (GABA) transaminase deficiency is an autosomal recessive disorder caused by mutations in the 4-aminobutyrate aminotransferase (ABAT) gene. The disorder is characterised by epileptic encephalopathy, hypersomnoloscnec, movement disorders, and tone changes. Here, we report a 4-year-6-month-old boy child born to non-consanguineous marriage with a normal birth history presented with global developmental delay, refractory seizures, and increased sleep. On examination showed normal anthropometry with mild dysmorphism. Neurological examination showed autistic features and spasticity with brisk deep tendon reflexes. On investigation, electroencephalography showed multifocal epileptiform discharges with secondary generalisation, and magnetic resonance imaging of the brain showed mild hyperintensity of the superior cerebellum. Exome sequencing identified compound heterozygous variants in the ABAT gene and segregates with the condition in the family. The child was treated with antiseizure medications and responded partially. For any child with excessive sleep on the background of epileptic encephalopathy with a movement disorder, a diagnosis of GABA transaminase deficiency has to be considered.