Am J Case Rep. 2024 Jul 31. 25 e944514
BACKGROUND Leigh disease (LD) is a rare progressive mitochondrial neurodegenerative disorder characterized by subacute necrotizing encephalopathy and symmetrical spongiform lesions in the brain. Cytochrome C oxidase deficiencies due to SURF1 Cytochrome C Oxidase Assembly Factor (SURF1) gene mutations are seen only in 15% of LD cases. Consideration of these genetic mutations in young patients is crucial for early diagnosis, intervention, and further genetic counseling. Although only a few cases of the SURF1 mutation have been reported, there are anecdotal case reports describing imaging features. CASE REPORT We report a case of a 2-year-old boy with developmental delay, hypotonia, involuntary movements, shortness of breath, and reduced activity since age 6 months. On blood examination there was mildly elevated lactate levels and increased lactate to pyruvate ratio and cerebrospinal fluid lactate levels. Magnetic resonance imaging findings showed symmetrical lesions in the dentate nucleus, subthalamic nucleus, midbrain (substantia nigra, periaqueductal gray matter), posterolateral pons, and olivary nucleus of the medulla extending into the cervical spinal cord, with mild elevation of the lactate peak on magnetic resonance spectroscopy. CONCLUSIONS These findings prompted further genetic analysis, which indicated a mitochondrial type IV deficiency with the SURF1 gene defect, an intranuclear type 1 mutation (MC4DN1) (OMIM 220110). Treatment is usually supportive with vitamins supplementation and physiotherapy, and genetic counseling of the parents is mandatory.