| Background and purpose There exists particularly rich diversity in the life world.As the mining of molecular information has reached the level of genes,some phenomena can be gradually explained by the development of molecular biology.In 1994,the item single nucleotide polymorphism(SNP)first appeared in the journal of human molecular genetics.SNPs are the most common form of allelic variation in the human genome.It is estimated that one locus of SNP will occur about every 400-1000 nucleotides,so there may be about 3 million SNPs in the entire human genome.Because of the high density in the genome,the low mutation rate,and the most loci having two alleles make SNPs easily to be genotyped,so it has widely applications in the genetic mapping,drug design,forensic individual identification and paternity testing.Intracranial Aneurysm(IA)is a balloon-like cystic bulge formed by the localized expansion of the intracranial artery wall,which ranks as third of cardiovascular and cerebrovascular diseases in the world.Due to its thin wall,the aneurysms are easy to rupture when the head is subjected to external force.Ruptured IA is one of the most important reasons of SAH,many patients will die and surviving patients also seriously affected the quality of life because of the dysfunction of the central nervous system.Environmental factors such as smoking history,female gender,and hypertension have been shown to be risk factors for intracranial aneurysms.Studies have shown a significant increase in the incidence of intracranial aneurysms in some connective tissue diseases such as Autosomal Dominant Polycystic Kidney Disease,Marfan syndrome,and Ehlers-Danlos syndrome type IV.The incidence of first-degree relatives of patients with intracranial aneurysms is about 4 times higher than that of ordinary people.This suggests that genetic factors play an important role in the pathogenesis of intracranial aneurysms to some extent.From the initial candidate gene linkage analysis,gene expression studies,to the first genome-wide association study conducted in Japan in 2008,as well as the search and identification of IA-related sites in the whole genome combined with high-throughput sequencing platforms,some disease-related gene loci or regions such as EDNRA,9p21,SOX17,ELN have been identified in various populations worldwide.However,many of the results have not been replicated or verified.The reasons include different research groups,environmental differences,sample content and Bonferroni effect.Therefore,it is necessary to further study the genes and chromosomal regions associated with IA in different populations.In this study,64 SNP loci were selected from the reported IA-related genes(or chromosomal regions)to investigate their distribution in the Han population of Henan,China,and to evaluate the forensic significance of them in Henan Han population.Further case-control studies were conducted to discover genes associated with IA in the Henan Han population.Methods1.Peripheral blood samples of 342 patients diagnosed with intracranial aneurysms from the Department of Neurology,the First Affiliated Hospital of Zhengzhou University.was obtained from September 2017 to December 2018.All patients were diagnosed by magnetic resonance angiography(MRA),computed tomography angiography(CTA)or digital subtraction angiography(DSA).Peripheral blood samples from 200 healthy blood donors were obtained from the Red Cross Blood Center in Henan Province.2.Extraction of the DNA from the 542 samples were performed using the 2ml blood genomic DNA extraction kit produced by Shanghai Laifeng Biotechnology Co.,Ltd.,and then the concentration and purity of the extracted DNA were measured.3.64 SNPs were selected from the genes related to IA mentioned in the previous literature,and the samples were genotyped by SNPscan technique.4.Genotyping data obtained were then analyzed.Including the differences in the distribution of alleles and genotypes between the case group and the control group,linkage disequilibrium analysis and haplotypes constructing of the above loci to analyze the association with IA.In the case group,differences in allele and genotype distribution were observed in patients with ruptured and unruptured aneurysms,and risk loci associated with rupture of aneurysms were explored.Then forensic parameters of the control group were calculated to evaluate the forensic significance in Henan Han population.Results1.Except for 3 loci,the distribution of the remaining 61 loci in the control group accords with the Hardy-Weinberg equilibrium.The total probability of discrimination power of the 61 SNP loci was 0.99999999999999999999985,and the cumulative excluding probability of paternity was 0.99994538.which basically reached the performance level of the currently used STR kit.2.The allele frequencies of 3 loci rs1800610,rs3737966,and rs9651118 were observed significant difference in the present control group and the southern Han population(p=0.00000),the present control group and the Beijing Han population(p=0.00901),the control group and the southern Han population(p=0.00000)aiso the southern Han nationality,respectively.The remain loci have no statistic difference.3.Case-control studies found that 12 loci rs10958409,rs12545485,rs1800610,rs9211,rs78410329,rs10759932,rs11536889,rs3768660,rs3918249,rs532166,rs7123600,rs9509 were associated with the risk of intracranial aneurysms.In addition to rs10958409,rs12545485,rs11536889,the other 9 sites are newly associated with intracranial aneurysms.The first 4 of these 12 loci which were rs10958409(G vs A,OR 0.718,95% CI 0.540-0.954,p=0.022),rs12545485(C vs T,OR 1.410,95% CI1.509-1.878,p =0.019),rs1800610(G vs A,OR 1.596,95% CI 1.149-2.219,p=0.005),rs9211(G vs A,1.325,95% CI 1.023-1.715,p=0.033),not only their allele frequency but aslo the genotype distribution of the case-control group was statistically different,and the risk for IA in alleles were consistent with the corresponding genotypes.The frequency of rs1800610 G>A allele located on the TNFα gene was significantly different between IA patients and normal controls(p=0.005),and the results showed that allele G increases the risk of developing IA in the population relative to allele A.The rs78410329(T vs C,OR 0.744,95% CI 0.564-0.982,p=0.036)were only different in allele frequencies and the remaining 7 were only different in the frequency distribution of genotypes.At the same time,it was found that the haplotype AC and GT frequencies composed by rs10958409 and rs12545485 were statistically significant in the case-control group(p=0.016 and p=0.024).It is suggested that the haplotype composed is related to the pathogenesis of IA.4.In the study of ruptured-unruptured aneurysms in patients,the 6 loci rs11536889(p=0.015),rs125994789(p=0.039),rs884843(p=0.001),rs9211(p=0.009),rs2138533,rs2287499 are associated with risk of ruptured intracranial aneurysms.The first four loci were significant both in alleles and genotype frequencies.The latter two sites differ only in genotype distribution.The 2 loci rs9211,rs11536889 were both significant associated with IA development and ruptured IA.Conclusions1.After 3 loci were eliminated,the remaining 61 loci suggest potential application value in forensic identification and paternity identification of Henan Han population.The remaining 61 loci have application value in forensic and paternity identification of Henan Han population,and The three loci of rs1800610,rs3737966 and rs9651118 have certain application value in forensic population genetics.2.The 12 loci rs10958409,rs12545485,rs1800610,rs9211,rs10759932,rs11536889,rs3768660,rs3918249,rs532166,rs7123600,rs9509,rs78410329 are associated with the occurrence of IA in Henan Han population.The haplotypes AC and GT composed by rs10958409 and rs12545485 are related to the occurrence of intracranial aneurysms in Henan Han population.3.The 6 SNP rs11536889,rs125994789,rs884843,rs9211,rs2138533,rs2287499 were associated with risk of ruptured aneurysms in patients with intracranial aneurysms in Henan population. |
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