Identification And Validation Of Susceptibility Genes For Aortic Dissection Using DNA Pooling Based Genome-Wide Association Study

Backgrounds:Aortic dissection(AoD) is defined as disruption of the media layer of the aorta with bleeding within and along the wall of the aorta resulting in separation of the layers of the aorta. In the majority of patients (90%), an intimal disruption is present that results in tracking of the blood in a dissection plane within the media. This may rupture through the adventitia or back through the intima into the aortic lumen. AoD has the characters of acute onset, rapid progression, complex and changeable symptoms and high death rate. Population-based studies suggest that the incidence of acute AoD ranges from2to3.5cases per100000person-years.The incidence of AoD is rapidly rising with the changes of people’s living habits.The risk factors of aortic dissection includes:hypertension, particularly if uncontrolled, pheochromocytoma, smoking, cocaine or other stimulant use, trauma, coarctation of the aorta, inflammatory vasculitides,pregnancy, chronic corticosteroid or immunosuppression agent administration and other genetic diseases that affects aortic. In recent years, basic researchs are performed to identify the genetic factors that determined the susceptibility of aortic disease and affected the disease process. However, the relationship of the genetic factors associated with aortic dissection disease is not well understood yet.Genome-wide association study (GWAS),a very wide range of applications for multiple genetic disease screening. GWAS was a effective way to discover minor genes for complex genetic diseases, GWAS was a more suitable way for the study to search for complex disease genetics behind the disease-causing genes or genetic loci, so the genome-wide association study have become the main way to screen the genetic sites of complex genetic disease.Particularly after2005, with the rapid development of genotyping technologies and the costs decrease of the commercialization of SNPs in high throughout genetic testing chip, genome-wide association studies has been in a great development. Scope of the results of microarray selected SNPs for individual genotyping, compare allele frequencies between case and control groups,then analysis the differences in the human genome and eventually found the relationship between the allele and complex genetic diseases.The first genome-wide association studies related article published in2005, to July30,2010, there are at least608GWAS studies were published, at least2996susceptibility genes or loci were found. Up to now, GWAS have been used to find disease-related genes in disease like hypertension, diabetes, rheumatoid arthritis, supranuclear palsy, tumors and other complex disease.In order to achieve the early diagnosis of disease and effective individualized treatment,GWAS was used a way that through a single-nucleotide polymorphisms (SNP), and/or copy number variation to scan to identify disease susceptibility region and the associated gene looking for disease markers.The application of GWAS was limited because of the experimental cost was too high,DNA pooling based GWAS was a cost-efficient way to identify the susceptibility genes or loci of the complex disease. The efficiency is greater than80%, usually higher than95%. Its effectiveness has been confirmed by many studies.Along with more sophisticated experimental design and the rapid development of experimental techniques, DNA pooling based GWAS will be more widely applied.We used a two-stage DNA pooling-based strategy of genome-wide association study to identify genetic markers that affects aortic dissection and may have the chance to know how to prevention the occurrence of aortic dissection and intervention in advance.Aims:The objective of this research was to identify novel susceptibility loci of aortic dissection,we conducted a two-stage pooling-based genome-wide association study for aortic dissection population.Methods:DNA Pooling and Illumina genome-wide SNP chip was used in the first stage for screening,12high-ranked single nucleotide polymorphisms(SNPs) were found in this stage. SNaPshot technique was used in the second stage for individual genotyping to identify the relationship between genetic markers and aortic dissection.150aortic dissection patients and250control subjects were included in the screening stage.The control group selected standard was based on gender, age, smoking status,hypertension and diabetes that matches to the case group. The subjects volunteered to participate and signed informed consent. The diagnosis of aortic dissection relies on thoracoabdominal (including pelvic arteries) aortic CT scan. Exclusion criteria:Marfan syndrome, Ehlers-Danlos syndrome, Turner syndrome, familial thoracic aortic aneurysm, thoracic (abdominal) aortic aneurysm, congenital bicuspid aortic valve malformations, trauma,pregnancy, tumor and patients with coronary artery disease.The second stage was to collect73cases of aortic dissection patients and143cases of matched control group patients to identify the relationship between AoD and genetic markers with SNaPshot technology for individual genotyping.Statistical analysis was performed using SPSS13.0software.Results:(1).Results showed that the number of women in the control group was significantly more than that in the case group(P<0.01).(2).There was no statistical difference in the age, smoking, hypertension and diabetes population(P>0.05).(3).Variants SNPs rs9581424(located in the ATP8A2gene), rs2970873(located in the PPARGCIA gene), rs12678080(located ingene SGCZ), rs489526(in UNC13C gene), rs7651039(located in the BTD gene), rs2345106(in COLQ gene), rs4024044(located in the ABCA13gene), rs7653410(in SNTN gene) rs6080720(in BFSP1gene), rs2298491(located TBCELgene), rs6928665(in TRAM2gene) and located ACCN1gene rs17837003may be related to the incidence of aortic dissection.(4).In consider with second stage individual genotyping results, we found that SNP rs9581424(located in the ATP8A2gene)(OR2.137,95%CI1.307-3.494, P<0.01)and SNP rs7653410(in SNTN gene)(OR1.747,95%CI1.088-2.804, P<0.05) were strongly correlated with the occurrence and development of aortic disease.