Pathogenic Variants in Latvian Familial Adenomatous Polyposis Patients.

Familial adenomatous polyposis is one of the -associated polyposis conditions described as genetically predetermined colorectal polyposis syndrome with a variety of symptoms. The purpose of this study was to determine sequence variants of the gene in patients with familial adenomatous polyposis (FAP) phenotype and positive or negative family history. Eight families with defined criteria of adenomatous polyposis underwent molecular genetic testing. Coding regions and flanking intron regions of the gene were analyzed by Sanger sequencing. Eight allelic variants of the gene coding sequence were detected. All allelic variants of the gene were predicted to be pathogenic based on criteria according to the "Joint Consensus Recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology" (2015), four of them c.1586_1587insAT, c.2336delT, c.3066_3067insGA, and c.4303_4304insC, were considered novel. The timely molecular genetic analysis of germline variants and standardized interpretation of the pathogenicity of novel allelic variants has a high impact on choice for treatment, cancer prevention, and family genetic counseling.