COQ8A-related Primary Coenzyme Q10 Deficiency Mimicking Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like Syndrome: A Pediatric Case Report and Review of Mitochondrial Mimics

ABSTRACT: Mitochondrial disorders are multisystem diseases associated with wide phenotypic variability and significant morbidity. Clinical manifestations include asymptomatic carrier states, cardiac conduction abnormalities, hearing loss with or without diabetes, maternally inherited diabetes and deafness, mitochondrial encephalomyopathy, lactic acidosis, and stroke-like (MELAS) syndrome are some of the varied symptoms. A 12-year-old male patient presented with a 7-day history of refractory seizures (20-25 episodes daily) each lasting for 5-10 seconds, characterized by right-sided ocular and facial deviation for which he was evaluated, and magnetic resonance imaging revealed gyriform hyperintense signal in the left temporoparietofrontal cortex, right occipital cortex and right posterior temporal cortex, on T2-weighted/FLAIR, appearing hypointense on T1-weighted images,with diffusion-weighted image (DWI) and low apparent diffusion coefficient values.. Ill-defined hyperintense signal noted in bilateral gray matter and juxtacortical white matter on T2W1/FLAIR, appearing T1 hypointense without diffusion restriction on DWI, likely due to gliosis. Whole-exome sequencing (WES) using the Illumina NovaSeq 6000 platform revealed a pathogenic variant in the COQ8A gene associated with primary coenzyme Q10 deficiency. Post-WES report, the child was started on supplements as per the report, and over time, seizure episodes reduced and the patient was discharged. Primary Q10 deficiency due to COQ8A mutation can present with MELAS and refractory seizures. Recognition of mitochondrial stroke mimics and early genetic diagnosis are essential to guide metabolic therapy and outcomes.