MLPA mutation detection in Argentine HNPCC and FAP families.

Colorectal cancer (CC) is the secondary cause of death in the Western countries of which approximately 15% are considered to be hereditary. The hereditary forms are Familial Adenomatous Polyposis (FAP) and Hereditary Non Polyposis Colorectal Cancer (HNPCC) which is the commonest form. The detection of mutations in the MMR and apc related genes, allows the development of health prevention strategies. Different molecular diagnostic strategies are available for the detection of mutations in these genes, i.e. DGGE, SSCP and direct sequencing. However, deletions and duplications of one or more consecutive exons, which account for around 50% of the total alterations in MMR genes, cannot be detected by PCR based methodologies due to the non quantitative nature of these techniques. The aim of our work has been the standardization of a methodology, called Multiplex Ligation-Dependent Probe Amplification, which allows the detection of genomic deletions and duplications as primary analysis in HNPCC and FAP patients in Argentina. In this case, we inform that the application of MLPA allowed the detection of a missence mutation, without the need for direct sequencing of the complete genes involved. A PCR/RFLP strategy was afterwards designed to detect the C<T change on codon 718 of mlh1 gene in members of the family. For a developing country like Argentina, which has limited resources for genetic diagnosis, this MLPA application has avoided an unaffordable cost as the complete sequencing of all the involved genes. The application of MLPA in our country contributes to improvement in the diagnosis of hereditary CC and allows the development of preventive health interventions.