Studies have repeatedly shown that the existing Amsterdam and Bethesda criteria fail to identify a substantial number of LS patients.27, 33, 34 Although these criteria generally select for patients under the age of 50, a recent study of 1002 patients with EC by Goodfellow et al35 determined that 24% of patients with MMR germline mutations are older than 60 years old. Here, MRC1 is linked to Leigh syndrome.