sentences:  Hereditary nonpolyposis colorectal cancer (HNPCC), sometimes referred to as Lynch syndrome, is inherited in an autosomal dominant fashion, where inheritance of only one copy of a mutated mismatch repair gene is enough to cause disease phenotype.Mutations in the MSH2 gene account for 40% of genetic alterations associated with this disease and is the leading cause, together with MLH1 mutations.Mutations associated with HNPCC are broadly distributed in all domains of MSH2, and hypothetical functions of these mutations based on the crystal structure of the MutSα include protein–protein interactions, stability, allosteric regulation, MSH2-MSH6 interface, and DNA binding.