Two novel mutations in hMLH1 gene in Iranian hereditary non-polyposis colorectal cancer patients

Among hereditary forms of colorectal cancer, hereditary non polyposis colorectal cancer (HNPCC) is the most common. It is an autosomal dominant disorder resulted from germline mutations in DNA mismatch repair (MMR) genes. In this study we screened hMLH1 gene by PCR-SSCP and direct sequencing method in a group of Iranian HNPCC patients. Here we report two novel mutations in this gene in our studied population. Both of these mutations are frameshift mutation, one resulted from a deletion of "T" in codon 102 in exon 1 which cause defective premature protein and the another one is a frameshift mutation resulted from a deletion of "T" in codon 819 in exon 19. Types of the reported novel mutations in hMLH1 gene in different studies are diverse. Identification of these mutations is necessary in different populations and can help the management of CRC in populations by screening, prevention strategies and follow up of the suspected HNPCC families.