Although growing evidence reveals that germline variations in MLH1 and MSH2 genes are likely responsible for around 60%–70% of LS,13 we have found three probands (As/1, Bg/9, Hm/25) without variants in either MLH1 or MSH2 genes and the primary tumors found on these three unique cases were interestingly left‐sided (Table 2). This evidence concerns the gene MSH2 and Leigh syndrome.