Functional examination of MLH1, MSH2, and MSH6 intronic mutations identified in Danish colorectal cancer patients

BMC Medical Genetics

Research Article

Mette Dandanell¹  Thomas v O Hansen¹  Sanne M Petersen¹  Finn C Nielsen¹  Lene J Rasmussen²  Lotte N Krogh³  Anne-Marie Gerdes⁴  Friedrik Wikman⁵  Henrik Okkels⁶  Inge Bernstein⁷ 

[1] Center for Genomic Medicine, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, DK-2100, Copenhagen, Denmark;Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark;Department of Clinical Genetics, Odense University Hospital, Odense, Denmark;Department of Clinical Genetics, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark;Department of Molecular Medicine, Aarhus University Hospital, Aarhus, Denmark;Section of Molecular Diagnostics, Department of Clinical Biochemistry, Aalborg University Hospital, Aalborg, Denmark;The Danish HNPCC register, Department of Gastroenterology and Clinical Research, University of Copenhagen, Hvidovre, Denmark;

关键词: Colorectal cancer;    HNPCC;    Lynch syndrome;    Mini-gene assay;    MLH1;    Splicing defect;   

DOI  :  10.1186/1471-2350-14-103

 received in 2013-03-11, accepted in 2013-09-25,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundGerm-line mutations in the DNA mismatch repair genes MLH1, MSH2, and MSH6 predispose to the development of colorectal cancer (Lynch syndrome or hereditary nonpolyposis colorectal cancer). These mutations include disease-causing frame-shift, nonsense, and splicing mutations as well as large genomic rearrangements. However, a large number of mutations, including missense, silent, and intronic variants, are classified as variants of unknown clinical significance.MethodsIntronic MLH1, MSH2, or MSH6 variants were investigated using in silico prediction tools and mini-gene assay to asses the effect on splicing.ResultsWe describe in silico and in vitro characterization of nine intronic MLH1, MSH2, or MSH6 mutations identified in Danish colorectal cancer patients, of which four mutations are novel. The analysis revealed aberrant splicing of five mutations (MLH1 c.588 + 5G > A, MLH1 c.677 + 3A > T, MLH1 c.1732-2A > T, MSH2 c.1276 + 1G > T, and MSH2 c.1662-2A > C), while four mutations had no effect on splicing compared to wild type (MLH1 c.117-34A > T, MLH1 c.1039-8 T > A, MSH2 c.2459-18delT, and MSH6 c.3439-16C > T).ConclusionsIn conclusion, we classify five MLH1/MSH2 mutations as pathogenic, whereas four MLH1/MSH2/MSH6 mutations are classified as neutral. This study supports the notion that in silico prediction tools and mini-gene assays are important for the classification of intronic variants, and thereby crucial for the genetic counseling of patients and their family members.

【 授权许可】

Unknown   
© Petersen et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.