Protein arginine methyltransferase 7 (PRMT7) is an enzyme that methylates arginine residues within protein substrates, influencing biological processes such as gene expression regulation, stress response, neuromuscular development, and adipogenesis. PRMT7-related syndrome is a neurodevelopmental disorder characterized by growth impairment, skeletal and endocrine abnormalities, hypotonia, digital and craniofacial malformations, seizures, and obesity. In murine models, PRMT7 has been shown to positively regulate mitochondrial dynamics, suggesting a potential role in mitochondrial function, particularly under stress conditions. Herein, we describe a child presenting with encephalopathy, recurrent seizures, myopathy, cerebral ischemia, and dysmorphic features. The child’s seizures worsened with sodium valproate, prompting suspicion of a mitochondrial disorder. Sodium valproate was discontinued, and anti-seizure medications were adjusted alongside the initiation of supportive treatment for mitochondrial disorder. Following these interventions, the child’s condition improved significantly. Genetic analysis identified a novel homozygous c.82C>T variant in the PRMT7 gene. This case underscores the role of PRMT7 in mitochondrial bioenergetics in humans.