V-3, a 6-year-old child, warrants attention as WES revealed EpCAM, MSH2, PMS2 and APC co-mutations along with large deletions in EpCAM (exons 8–9) and MSH2 (exons 1–16), paralleling his father’s CRC tissue and suggesting possible germline mosaicism. This evidence concerns the gene MSH2 and colorectal carcinoma.