PCR-SSCP and DNA sequencing analyses were performed for 18 mitochondrial genes (flanking regions of mt-ND1, ND2, COXI, COXII, ATPase8, ATPase6, COXIII, and mt-tRNAsIle, tRNAGln, tRNAMet, tRNATrp, tRNAAla, tRNAAsn, tRNACys, tRNATyr, tRNASer, tRNAAsp, and tRNALys genes) in a total of 200 CHD patients and 160 healthy controls. The gene discussed is MT-CO3; the disease is coronary artery disorder.