MSH2 and Leigh syndrome: There have been very few studies on whether alcohol affects colorectal cancer risk in LS patients, apart from a cross-sectional multicentre study that showed that alcohol consumption is significantly correlated with increased risk of early-onset colorectal cancer in LS patients that were carriers of pathogenic MLH1 or MSH2 variants, with tumours located in the proximal colon (Miguchi et al., 2018; Fujiyoshi et al., 2022).