NDUFS2

Function

Mitochondrial complex I is the first multimeric complex of the respiratory chain that catalyzes the NADH oxidation with concomitant ubiquinone reduction and proton ejection out of the mitochondria. Mammalian mitochondrial complex I is an assembly of at least 43 different subunits. Seven of the subunits are encoded by the mitochondrial genome; the remainder are the products of nuclear genes. The iron-sulfur protein (IP) fraction of complex I is made up of 7 subunits, including NDUFS2.

Clinical significance

Mutations in the NDUFS2 gene are associated with Mitochondrial Complex I Deficiency, which is autosomal recessive. This deficiency is the most common enzymatic defect of the oxidative phosphorylation disorders. Mitochondrial complex I deficiency shows extreme genetic heterogeneity and can be caused by mutation in nuclear-encoded genes or in mitochondrial-encoded genes. There are no obvious genotype-phenotype correlations, and inference of the underlying basis from the clinical or biochemical presentation is difficult, if not impossible. However, the majority of cases are caused by mutations in nuclear-encoded genes. It causes a wide range of clinical disorders, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, nonspecific encephalopathy, hypertrophic cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease.