Involved in the assembly of mitochondrial NADH:ubiquinone oxidoreductase complex (complex I) at early stages. May play a role in the biogenesis of complex I subunit MT-ND1. Peripherally localized on the matrix face of the mitochondrial inner membrane. Additional isoforms seem to exist. Widely expressed. A lower expression is observed in lung and kidney compared to heart, muscle and liver (PubMed:27466185). In the kidney, expression is high in the basal zone of the proximal tubular cells (PubMed:27466185). The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. A homozygous disease-causing variant located in intron 2 leads to aberrant splicing and altered isoform synthesis. Kidney and lung tissues from affected individuals show specific loss of mitochondrial isoform 1. Patient cells show defects in mitochondrial complex I assembly and altered mitochondrial respiration. Belongs to the NDUFAF6 family. Truncated N-terminus.