Until recently, hereditary non-polyposis colorectal cancer syndrome (HNPCC) was used to describe LS, but nowadays, the term LS is accepted; clinically determined HNPCC with positive MSI includes LS (MMR germline mutations associating colorectal cancer (CRC) and extra-colonic tumors) and Lynch-like syndrome (negative MMR mutations involving CRC and rare extra-colonic cancers), while MSI-negative HNPCC is less described (involving non-MMR genes like POLE gene mutation, etc.)[3,4,5]. Here, MRC1 is linked to Leigh syndrome.