Association Of The Ctla-4 Gene Polymorphism With The Recurrent Spontaneous Abortion

Objective To investigate the correlation between 4 SNPs (SNP-1722(T/C),SNP-1661(A/G),SNP-318(C/T) polymorphisms in promotor region and the SNP+49(A/G) polymorphisms in exon 1 region of the cytotoxic T lymphocyte-associated antigen-4 gene) and recurrent spontaneous abortion (RSA) in Chinese women. By compare genotype distribution and allele frequency between the patient of recurrent spontaneous abortion (RSA) and normal pregnancy women, to approach the relationship about the haplotype of four SNPs of the cytotoxic T lymphocyte-associated antigen-4 gene with RSA.Methods 242 patients of RSA were recruited from NingXia medical university genetic laboratory as study group with an average age of 27.97±4.49. 228 normal pregnancy women from Maternal and Child Health Hospital were as control group with an average age of 27.67±3.67. The Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) were used to analyse the genotype distribution and allele frequency of promoter region -1722, -1661, -318 and exon 1 region +49 positions in CTLA- 4 gene. The statistical analysis included chi-square test and SPSS11.5 software was used to analyze the data and calculated the distribution of genotype and frequency of allele. Hardy-Weinberg balance, linkage disequilibrium and haplotype analyzed by using software SHEsis.Results①The genotype distribution of the 4 SNPs in CTLA-4 gene reached Hardy-Weinberg equilibrium, indicated that the population in present study were selected randomly.②There were no significantly different in genotype distribution and allele frequencies of CTLA-4 gene SNP-1722, SNP-1661, SNP+49 between the patient of RSA and normal pregnancy women (P>0.05).However, in case group, the frequency of CC genotype at the -318 position was statistically higher than controls, and the frequency of CT genotype was lower than controls (P=0.003,OR=1.941;P=0.007,OR=0.546); and the frequency of C allele in case was higher than control, but the frequency of T allele was lower than control (P=0.002,OR=1.853;P=0.002,OR=0.540).③Each pair of four SNPs in CTLA-4 gene were linkage disequilibrium (D'>0.8).④Among the haplotypes established by the 4 SNPs, there were nine kinds of protective haplotypes significantly different between case and control (P<0.05, OR<1), and two kinds of rise haplotypes also have significant difference between case and control (P<0.05, OR>1).Conclusions (1) There were no significant differences in genotype distribution and allele frequencies of CTLA-4 gene SNP-1722, SNP-1661, SNP+49 between two groups. These polymorphisms locus may not associated with the susceptibility of RSA in NingXia female. (2) CTLA-4 gene SNP-318 polymorphism may have some relevance with RSA, and the CC, CT genotype probably associated with the susceptibility of RSA in NingXia female. Individuals who carry T allele the risk of occur RSA will be significantly decreased. (3) Each pair of 4 SNPs were linkage disequilibrium. (4) The four SNPs in CTLA-4 gene may have nine kinds of protective haplotypes and two kinds of rise haplotypes. Objective To study the distribution traits of genotype and allele frequencies of cytotoxic T lymphocyte-associated antigen-4 gene promoter region SNP-1722(T/C), SNP-1661(A/G), SNP-318(C/T) and exon 1 region SNP+49(A/G) polymorphism in Ningxia Hui-Han population.Methods 525 healthy people from NingXia medical university affiliated hospital were slected as study group with an average age of 24.42±3.69. (208 hui population and 318 Han population). All subjects have no history of chronic disease, radio-chemotherapy and autoimmunity disease, ancestry are hui and han nationality. PCR-RFLP method was used to determine the distribution of CTLA-4 gene promoter region SNP-1722(T/C), SNP-1661(A/G), SNP-318(C/T) and exon 1 region SNP+49(A/G) polymorphisms in Hui-Han population. The distribution of genotype and frequency of allele were calculated by SPSS11.5 software to analyze the difference of CTLA-4 gene four SNPs sites between hui and han population. Hardy-Weinberg of the four SNPs sites were evaluated by SHEsis software.Results There were no significantly different in genotype frequencies and allele frequencies of CTLA-4 gene SNP+49, SNP-318, SNP-1661, SNP-1722 between Hui and Han population (P>0.05). With the combination of Hui and Han population of Ningxia, and then divide into two groups as sex, the genotype distribution and allele frequency of CTLA-4 gene SNP-1661, SNP-318, SNP+49 have no significant difference between Hui and Han population (P>0.05), but the genotype frequencies at -1722 position have significant difference between female and male (χ2=9.280,P=0.010) , and the CC genotype in female was higher than male (16.08%vs7.11%,χ2=8.523,P=0.004). Although there was no significant difference between female and male in the frequency of the C allele at -1722 position (χ2=2.162, P=0.141), it shows that female tend to carry more C allele. The distribution traits of genotype and allele frequencies of cytotoxic T lymphocyte-associated antigen-4 gene of SNP-1722, SNP-1661, SNP-318, SNP+49 polymorphism sites were not all consistent in different Chinese area, as well as in other different contries and races.Conclusions The distribution traits of allele and genotype frequencies of CTLA-4 gene SNP+49, SNP-318, SNP-1661, SNP-1722 positions may be similar with Hui and Han population of Ningxia, but there was significant difference between female and male in the frequency of the CC genotype at -1722 position. Meanwhile, the CTLA-4 gene SNP-1722, SNP-1661, SNP-318, SNP+49 polymorphisms sites have significantly different among different area and races in China and different contries.