Objective:To explore the genetic basis for a child featuring global developmental delay and epilepsy.Methods:A child who had presented at Guangzhou Women and Children′s Medical Center Liuzhou Hospital on February 19, 2023 was selected as the study subject. Clinical data of the child was collected. The child was subjected to whole exome sequencing, and candidate variant was validated by Sanger sequencing and bioinformatic analysis.Results:The child, an 8-month-old girl, had manifested with global developmental delay, epilepsy, and hyperlactacidemia. Cranial MRI revealed diverse hypomyelinating leukodystrophies. Electroencephalogram showed slow background activities. Genetic testing revealed that she has harbored a homozygous variant of the SLC25A12 gene, namely c. 115T>G (p.Phe39Val), for which both of her parents were heterozygous carriers. Based on the guidelines from the American College of Medical Genetics and Genomics, the variant was predicted to be of uncertain significance (PM2_Supporting+ PM3_Supporting+ PP3_Moderate+ PP4_Moderate). I-Mutant v3.0 software predicted that the variant may affect the stability of protein product. Conclusion:The homozygous c. 115T>G (p.Phe39Val) variant of the SLC25A12 gene probably underlay the pathogenesis of the disease in this child.