RT info:eu-repo/semantics/article T1 Evaluating the Effect of Unclassified Variants Identified in MMR Genes Using Phenotypic Features, Bioinformatics Prediction, and RNA Assays A1 Pérez-Cabornero, Lucia A1 Infante, Mar A1 Velasco, Eladio A1 Lastra, Enrique A1 Miner, Cristina A1 Durán, Mercedes AB Lynch syndrome is caused by mutations in one of the mismatch-repair system (MMR) genes. A major difficulty in diagnosis and management of Lynch syndrome is the existence of unclassified genetic variants (UVs) with unknown clinical significance, especially mutations with new descriptions and missense-type nucleotide substitutions. We evaluated the pathogenicity of 20 such mutations (6 in MLH1, 4 in MSH2, and 7 in MSH6) found in Spanish patients suspected of Lynch syndrome. The UVs were tested for evidence of MMR defect in tumor samples and were evaluated for co-occurrence with a pathogenic mutation, the cosegregation of the variant with the disease; where sufficient data were available, in silico resources at the protein level and mRNA analysis were used to assess the putative effect on the splicing mechanism. To evaluate the frequency of these UVs in the general population, a case–control study was also performed. Five variants were identified with similar frequencies in both cases and controls, suggesting a nonpathogenic effect in patients. In contrast, abnormal splicing mutations were detected in a high proportion of patients [3/20 (15%)]. In this study, we classified 15 of the 20 UVs: six variants with strong evidence of pathogenicity and nine variants that should be considered neutral variants. Clinical significance of the other five remains unknown. PB Elsevier SN 1525-1578 YR 2013 FD 2013-05 LK https://uvadoc.uva.es/handle/10324/64663 UL https://uvadoc.uva.es/handle/10324/64663 LA spa NO The Journal of Molecular Diagnostics Volume 15, Issue 3, May 2013, Pages 380-390 DS UVaDOC RD 17-may-2024