When the Expected Scenario Did Not Occur: A Novel NDUFA12 Mutation Resembling Neuromyelitis Optica Spectrum Disorder.

Mitochondrial complex I transfers electrons from NADH (nicotinamide adenine dinucleotide) to ubiquinone, facilitating ATP synthesis via a proton gradient. Complex I defects are common among the mitochondrial diseases, especially in childhood. NDUFA12, located in complex I's transmembrane domain, is not directly involved in catalytic activity, but the NDUFA mutations are associated with Leigh syndrome and complex I defects. Complex I deficiency typically manifests as bilateral brainstem lesions and presents with dystonia, hypotonia, and optic nerve damage. This article discusses a patient with an NDUFA12 mutation resembling neuromyelitis optica spectrum disorder clinically and radiologically, highlighting the importance of considering NDUFA12 mutations in dystonia and optic neuritis diagnoses, particularly in neuromyelitis optica spectrum disorder cases that do not respond to standard treatments. Further research on NDUFA12 variants is needed for a better understanding of their phenotypic spectrum and to enhance diagnostic accuracy.