NDUFA5 encodes a 13-kDa accessory subunit of mitochondrial respiratory complex I (NADH:ubiquinone oxidoreductase) that plays a crucial role in complex I assembly and function 1. The gene spans 14 kb on chromosome 7 and contains 5 exons 1. NDUFA5 is essential for the formation of the extramembrane arm of human mitochondrial complex I, specifically required for assembly and/or stability of the electron transferring Q module in the peripheral arm 2. The protein functions in mitochondrial electron transport from NADH to ubiquinone, contributing to ATP synthesis through proton motive force. NDUFA5 is subject to post-translational regulation, with acetylation of this subunit leading to reduced complex I activity 3. Disease associations include Parkinson's disease, where MPTP-induced acetylation of NDUFA5 contributes to mitochondrial dysfunction and dopaminergic neuronal death 3. The gene shows differential expression in cyanotic congenital heart disease 4 and serves as a potential biomarker for recurrent venous thromboembolism 5. Additionally, NDUFA5 variants have been associated with autism in Japanese populations 6, and the gene is targeted by miR-33a in hepatic steatosis 7.