Segregation of a novel MLH1 mutation in an Iranian Lynch syndrome family.

Lynch syndrome is an autosomal dominant disorder caused by germline mutations in mismatch repair (MMR) genes. The main feature of this disorder is an early onset of hereditary colorectal cancer in addition to other cancers arising from different tissues. Here, we report an Iranian family with several members affected with Lynch syndrome related cancers. Exome sequencing with focus on 14 genes related with hereditary colorectal cancer has shown a novel mutation in exon 19 of MLH1 gene (c.2133delC, p.Trp712Gly fs*71). This mutation is located in a region coding for the functional domain for the interaction with MLH3/PMS1/PMS2. As some clinical aspects of the disorder have been shown to be associated with certain mutations, identification of causative mutation in each family has implications for surveillance protocols.