A wide yield of 12%–67% of patients with dMMR tumors not explained by MLH1‐hypermethylation are found to have a germline pathogenic variant in a MMR gene, with the yield for CRC 11%–58% (Adar et al., 2018; Pearlman et al., 2019) and for EC 29%–45% (Adar, 2018; Ryan et al., 2019). The gene discussed is MLH1; the disease is colorectal carcinoma.