Mitochondrial complex I deficiency of nuclear origin: II. Non-structural genes

Complex I deficiency is the most frequent cause of respiratory chain diseases. This large multiprotein complex is composed in human of 45 structural subunits, of which 7 are mitochondrial-encoded and 38 are nuclear-encoded. Most of the pathological mutations responsible for complex I deficiencies have been identified to date in complex I structural subunits. Numerous studies from last decade gave some insight into the biogenesis of this huge multi subunit complex of double genetic origin. A sequential incorporation of the structural subunits as well as ten complex I assembly factors has been described. Here, we present a short overview of the human complex I biogenesis and we review the pathological mutations identified to date in eight of the ten known complex I assembly factors.