The Research On The Mutation Detection Of FBN1 For Marfan's Syndrome And Its Clinical Application

Abstract:Marfan's syndrome (MFS) is a common heritable disorder of connective tissue with manifestations involving primarily the skeletal, ocular and cardiovascular systems but also and less systematically investigated the lung, skin and integument, and dura. The incidence of classical Marfan's syndrome is about 2-3 per 10000 individuals.Cardinal manifestations include proximal aortic aneurysm, dislocation of the ocular lens, long-bone overgrowth and severe disorders including neonatal Marfan syndrome. Recent studies on the molecular genetics of MFS are showed that MFS is caused by the mutations of fibrillin-1(FBN1) gene. Patients are diagnosed based on diagnostic criteria,however, the review of the medical problems of surviving patients has revealed possible unidentified pleiotropic manifestations of the Marfan syndrome or manifestations that could be related to aging of this population, and could not appear on the early age. So only a combination of genetic tests and clinical assessment can settle the differential diagnosis.FBN1 lies on the long arm of chromosome 15 at15q15-q21.1.This very large gene is highly fragmented into 65 exons, transcribed in a 10kb mRNA that encodes a 2871 amino acid protein. The mutation detection is difficult for FBNl, for which is a large gene, and the mutations are unique and throughout the whole gene. The difficulty in the international research on Marfan syndrome is the low detection rate for FBN1 mutation. The aid of this research is detecting the mutation of FBN1 and looking for a quick strategy for the gene diagnosis for Marfan's syndrome.Material and Methods 1. Patients:Veinous blood of 11 Marfan's syndrome patients were obtained from Department of Cardiac Surgery, the First Affiliated Hospital, China Medical University, four of the patients belong to two different families.50 Veinous blood samples are from normal individuals without genetic disease.2. Methods:Mutations in the coding region of FBN1 gene in MFS patients were detected by denaturing gel gradinent electrophoresis. PCR-restriction enzyme digestion was applied to confirm the mutations of the FBN1 gene and exclude the SNP site.Results1. A new nonsense mutation C3670T was found in a MFS family.2. PCR-restriction enzyme digestion confirmed the mutation of the FBN1 gene3. A reported SNP site rs3825962 was found in 52th intron.ConclusionWe have detected a new mutation and a reported SNP site by the PCR-DGGE and sequencing methods;The detection rate of the mutation for FBN1 is so low that the availability of the gene diagnose for FBN1 needs to be discussed.