PMS2 and colorectal carcinoma: A study based on data from the United States, Canada, and Australia via the Colon Cancer Family Registry (CCFR) collected data from 5744 CRC patients and 37,634 first-degree relatives and showed that the carrier frequency of pathogenic germline variants in the four MMR genes within the general population was 0.051% (1:1946) for MLH1 mutations, 0.035% (1:2841) for MSH2 mutations, 0.132% (1:758) for MSH6 mutations, and 0.140% (1:714) for PMS2 mutations, resulting in an aggregate carrier [21].