Pathogenic germline variants in MMR genes, causative for LS, were first discovered in the 1990s, with MSH2 being first (1993), followed by MLH1 (1994) and PMS2 (1994), MSH6 (1997), and EpCAM (2009) [2,3,4,5,6]. This evidence concerns the gene EPCAM and Leigh syndrome.