Molecular genetic analysis of the causes of selected hereditary forms of colorectal polyposis

Colorectal cancer (CRC) is one of the most common cancers worldwide. Hereditary colorectal adenomatous polyposis syndromes are a predisposition to colorectal carcinoma development. The most common analyzed syndromes are familial adenomatous polyposis (FAP) that results from germline mutations in the APC gene and MUTYH - associated polyposis (MAP) caused by germline mutations in the MUTYH gene. The aim of this study was to clarify genetics causes of colorectal polyposis in a set of probands without the germline mutation in the APC gene. Within studyʼs scope the presence of large deletion in APC gene was tested, there was looked for germline mutations in MUTYH gene, alternatively germline mutations in MSH6 gene by probands with monoallelic MUTYH mutation, item there was tested an effect of detected APC variants on gene expression. Screening for large deletions was performed by multiplex ligation dependent probe amplification (MLPA). A set of 120 APC-negative probands was examined for the presence of germline MUTYH mutations by denaturing high performance liquid chromatography (dHPLC). Subsequently a set of 145 APC-negative probands was screened only for germline MUTYH mutation in exon 7 and 13 by high resolution melting (HRM) analysis. Analysis of the effect on expression was tested by ten APC..