PMS2 and Leigh syndrome: The gene-specific RRs for this combined outcome were 3.1 (95% CIs, 1.4–6.9) for MLH1, 3.6 (95% CIs, 1.9–6.7) for MSH2/EpCAM, 0.3 (95% CIs, 0.0-Inf) for MSH6 and 0 for PMS2. An overview of the RRs for the various cancers in individuals with LS compared to the general population is provided in Table 3.