MLH 1 and MSH2 mutations account for 90% of LS, MSH6 mutations for 10% and PMS2 mutations for 6%.[6] In previous studies, there are many reports about MLH1 and MSH2 mutations, occasionally MSH6 mutations can be reported in LS, while PMS2 mutations are very rare. The gene discussed is PMS2; the disease is Leigh syndrome.