Deletions account for 17% of pathogenic germline alterations in MLH1 and MSH2 in hereditary nonpolyposis colorectal cancer (HNPCC) families.
نویسندگان
چکیده
Hereditary nonpolyposis colorectal cancer (HNPCC) is due to defects in DNA mismatch repair (MMR) genes MSH2, MLH1, MSH6, and to a lesser extent PMS2. Of 466 suspected HNPCC families, we defined 54 index patients with either tumors of high microsatellite instability (MSI-H) and/or loss of expression for either MLH1, MSH2, and/or MSH6, but without a detectable pathogenic point mutation in these genes. This study cohort was augmented to 64 patients by 10 mutation-negative index patients from Amsterdam families where no tumors were available. Deletion/duplication screening using the multiplex ligation-dependent probe amplification (MLPA) revealed 12 deletions in MSH2 and two deletions in MLH1. These deletions constitute 17% of pathogenic germline alterations but elucidate the susceptibility to HNPCC in only 22% of the mutation-negative study cohort, pointing towards other mutation mechanisms for an inherited inactivation of MLH1 or MSH2. We describe here four novel deletions. One novel and one known type of deletion were found for three and two unrelated families, respectively. MLPA analysis proved a reliable method for the detection of genomic deletions in MLH1 and MSH2; however, sequence variations in the ligation-probe binding site can mimic single exon deletions.
منابع مشابه
Evaluation of MLH1 and MSH2 Gene Mutations in a Subset of Iranian Families with Hereditary Nonpolyposis Colorectal Cancer (HNPCC)
متن کامل
Lower incidence of colorectal cancer and later age of disease onset in 27 families with pathogenic MSH6 germline mutations compared with families with MLH1 or MSH2 mutations: the German Hereditary Nonpolyposis Colorectal Cancer Consortium.
PURPOSE The aim of the study was the analysis of the involvement and phenotypic manifestations of MSH6 germline mutations in families suspected of hereditary nonpolyposis colorectal cancer (HNPCC). PATIENTS AND METHODS Patients were preselected among 706 families by microsatellite instability, immunohistochemistry, and/or exclusion of MLH1 or MSH2 mutations and were subjected to MSH6 mutation...
متن کاملGenomic rearrangements in MSH2, MLH1 or MSH6 are rare in HNPCC patients carrying point mutations.
Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant disease with high penetrance, caused by germline mutations in the mismatch repair (MMR) genes MLH1, MSH2, MSH6, PMS2 and MLH3. Most reported pathogenic mutations are point mutations, comprising single base substitutions, small insertions and deletions. In addition, genomic rearrangements, such as large deletions and dupl...
متن کاملسه موتاسیون ژرم لاین جدید در ژن MLH1 در بیماران مبتلا به سرطان کولورکتال ارثی
Abstract Background: Hereditary non-polyposis colorectal cancer is the most common cause of early onset of hereditary colorectal cancer. In the majority of Hereditary non-polyposis colorectal cancer families, microsatellite instability and germline mutation in one of the DNA mismatch repair genes in clouding MSH2, MLH1, MSH6 and PMS2 are found. The Objective of this study was to determine th...
متن کاملLynch syndrome (hereditary nonpolyposis colorectal cancer) diagnostics.
BACKGROUND Preventive programs for individuals who have high lifetime risks of colorectal cancer may reduce disease morbidity and mortality. Thus, it is important to identify the factors that are associated with hereditary colorectal cancer and to monitor the effects of tailored surveillance. In particular, patients with Lynch syndrome, hereditary nonpolyposis colorectal cancer (HNPCC), have an...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Genetic testing
دوره 9 2 شماره
صفحات -
تاریخ انتشار 2005