Germline testing identified a heterozygous nonsense PV in MSH6 (NM_000179.2:c.755C>G; p.Ser252Ter), classified as pathogenic according to the ACMG guidelines, ClinGen InSiGHT Hereditary Colorectal Cancer/Polyposis Expert Panel specifications, and ClinVar Expert Panel (Variation ID: 89566). The gene discussed is MSH6; the disease is colorectal cancer.