Of the 38 patients with a referral record, records of genetics services consultations were available for 28 (74%), 25 (89% of 28) had a diagnostic genetic test, and 11 (44% of 25) had a pathogenic/likely pathogenic variant in MLH1/PMS2/MSH2/MSH6, thus qualifying for a LS diagnosis (see Additional Files 1 and 5). The gene discussed is PMS2; the disease is Leigh syndrome.