Introduction: Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the central nervous system. GABA transaminase is the enzyme responsible for GABA degradation, and its deficiency leads to elevated endogenous GABA levels, resulting in early-onset epileptic encephalopathy and severe neurodevelopmental impairment. It is inherited in an autosomal recessive manner. Case presentation: A 10-month-old girl born to fourth-degree consanguineous healthy parents, with an apparently healthy male sibling, presented with excessive crying, clusters of epileptic spasms and global developmental delay noted since 2 months of age. There was no significant antenatal or perinatal history . Electroencephalography showedhypsarrhythmia. She did not respond to steroids or vigabatrin, and crying worsened after initiation of vigabatrin. On examination, she had central hypotonia, hyperreflexia, oculomotor apraxia, and cerebral visual impairment. The developmental age was less than 3 months across all domains. Brain MRI demonstrated symmetrical signal abnormalities in the bilateralperiventricular deep white matter suggestive of metabolic encephalopathy . Metabolic investigations were normal. Whole-exome sequencing identified a homozygous variant of uncertain significance in the ABAT gene, c.826G>C(p. Glu276Gln), leading to GABA transaminase dysfunction. Replacement of vigabatrin with topiramate resulted in marked improvement in crying and epileptic spasms. Conclusion: Although the ABAT variant was of uncertain significance, the clinical and MRI findings were characteristic of GABA transaminase deficiency . Improvement following withdrawal of vigabatrin, a GABAergic agent, supports the pathogenic nature of the mutation. The report highlights the importance of genetic evaluation in drug-resistant epileptic encephalopathy .