As one of the indispensable proteins encoded by mtDNA, serum ND6 was increased in active antineutrophil cytoplasmic antibody-associated vasculitis, and ND6 concentration was negatively correlated with the percentage of normal glomeruli in kidney biopsies [66]. The gene discussed is MT-ND6; the disease is anti-neutrophil cytoplasmic antibody-associated vasculitis.