A review of 146 cases of CMMRD conducted by Wimmer et al. concluded that PMS2 mutations were responsible for 60% of cases, with the remaining being MLH1, MSH2 and MSH6 mutations; this is in contrast to Lynch syndrome, where heterozygous MLH1 and MSH2 mutations are responsible for the majority of cases [10]. The gene discussed is MSH6; the disease is Lynch syndrome.