Tehran University of Medical Sciences Case Reports in Clinical Practice 2538-2683 11 2 2026 08 29 67 70 Fatemeh Arab Department of Advanced Technologies, School of Medicine, North Khorasan University of Medical Sciences, Bojnurd, Iran. Mahsa Boogari Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Najmeh Ahangari Rare Pediatric Neurological Diseases Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. Shima Shekari Department of Pediatrics, North Khorasan University of Medical Sciences, Bojnurd, Iran. Meisam Babaei Department of Pediatrics, North Khorasan University of Medical Sciences, Bojnurd, Iran. 2025 11 30 2026 06 29 Mitochondrial Enoyl CoA Reductase Protein-Associated Neurodegeneration (MEPAN) syndrome is an ultra-rare autosomal recessive disorder of mitochondrial fatty acid synthesis, characterized by childhood-onset progressive movement disorder, optic atrophy, and basal ganglia abnormalities. It results from a deficiency of mitochondrial trans-2-enoyl-CoA reductase, an enzyme essential for oxidative phosphorylation and for regulating oxidative stress. We report the first Iranian case of MEPAN syndrome in a 2-year-old boy presenting with developmental delay and several atypical features. Whole-exome sequencing (WES) identified a novel likely pathogenic MECR variant. This case underscores the importance of genetic evaluation in children with unexplained developmental delays and expands the clinical spectrum associated with MECR mutations. https://crcp.tums.ac.ir/index.php/crcp/article/view/1148 https://crcp.tums.ac.ir/index.php/crcp/article/download/1148/781