PMS2 and Leigh syndrome: Germline variants in MMR genes (MLH1, MSH2, MSH6, and PMS2) are associated with Lynch Syndrome (LS) [33], which is characterized by predisposition to a spectrum of cancers such as stomach, ovary, pancreas, upper urologic tract, and brain tumors, in addition to the most prevalent colorectal and endometrial cancers [34].