1,2 People with Lynch syndrome have an increased risk of colorectal cancer (CRC), endometrial cancer (EC), and other cancers,3 including sebaceous skin tumors (SST).4 Identifying Lynch syndrome is important for clinical management and cancer prevention, but despite advances in next-generation sequencing, the detection of all pathogenic MMR gene variants remains challenging. This evidence concerns the gene MRC1 and colorectal carcinoma.