Two novel truncating mutations and one novel missense mutation in the MSH2 gene (c.1062_1066delCAGAA, p.Ile356Glyfs*31, c.2557G>T, p.Glu853Ter and c.2039G>A, p.Arg680Gln) were identified in patients 13B-ON2505BD1 (male, rectal cancer at the age of 32 years), 13B-ON2469BD1 (male, sigmoid colon cancer at the age of 31 years) and B1287 (female, rectal cancer at the age of 30 years), respectively. Here, MSH2 is linked to rectal cancer.