MCAT and Leigh syndrome: In total, mutations in 14 mitochondrial genes are known to be associated with Leigh syndrome (MT-ATP6, MT-CO3, MT-ND1, MT-ND2, MT-ND3, MT-ND4, MT-ND5, MT-ND6, MT-T1, MT-TK, MT-TL1, MT-TL2, MT-TV, and MT-TW) (4).