The Correlation Analysis Between Polymorphisms Of BAG3 And Dilated Cardiomyopathy In Southwest Chinese Patients

Objective:Studies have shown that 20% to 35% of DCM(Dilated Cardiomyopathy) has obvious family genetic history. So far, has been found in more than 30 varieties of genes associated with the onset of DCM, and among them most are coding cytoskeleton proteins and muscle fibers proteins, such as TNNT2, DES, MYH7, ACTN2, ACTC, TTN, etc.Recent findings on the sarcomere Z-disk structure and high expression level on this structure of the anti-apoptotic Bcl-2 related protein 3(Bcl-2 associated athanogene 3, BAG3) gene variation may be associated with DCM patients. In 2001,Villard E first reported the rs2234962 on BAG3 gene polymorphism loci associated with heart failure caused by DCM, and conjectured BAG3 may be the candidate pathogenesis gene of DCM. Then in Japan is also found in familial DCM patients BAG3 gene mutation points Arg218 Trp and Leu462 Pro and associated polymorphism points(rs3858339 rs196295 rs117671123 rs78439745 rs3858340) associated with DCM. But whether in the Han nationality people in Southwest China are BAG3 gene mutation,as well as its variation is associated with the onset of DCM, there is no relevant studies confirmed. By this experimental study of BAG3 gene single nucleotide polymorphisms(SNPs) and the correlation of DCM han people in Southwest China, to explore the genetic pathogenesis of dilated cardiomyopathy.Methods: The research object is the han people in Southwest China, using case-control study as the research method,four exons of BAG3 gene sequences as the purpose of the amplification. From 144 patients with DCM(DCM group) and 156 cases of healthy controls(control group) to extract DNA in peripheral blood as a template amplification.After designing the primers, amplify the specific sequences of BAG3 gene by polymerase chain reaction(PCR) and determined by sanger dideoxy chain-termination method(or Sanger sequencing method) in two groups. To the results of DNA sequences,analysis of the sequence diagram. Then compared with the standard sequences from SNPs data base of the four exons BAG3 gene. It is concluded that the SNPs associated with DCM or gene mutation locis from the results, then statistics of two groups of related SNPs genotype and allele frequencies. The statistical differences of genotype frequencies and the allele frequencies of SNPs in two groups were compared with chi-square test.Results: 1. This study did not find in han nationality people in southwest China was reported in the Japanese population associated with the onset of DCM Arg218Trp(c.652C>T,rs397514506) and Leu462Pro(c.1385T>C,rs397514507) two mutations, these two mutaions in BAG3 gene exon 3 and exon 4.At the same time, it was not found other mutations on the BAG3 gene linked to DCM.2. Found six BAG3 gene polymorphism locis related to DCM in han nationality people in Southwest China,mainly located in exon 3, 4,but did not find relevant SNPs on exon 1, 2.They are rs117671123(c.772C>T,Arg258 Arg,in exon 3)、rs3858339(c.1002T>G,Pro334 Pro,in exon 4)、rs3858340(c.1220C>T,Pro407 Leu,in exon 4)、rs196295(c.1296A>G,Val432 Val,in exon 4)、rs374858685(c.1299A>G,Gln433 Gln,in exon 4)、rs149358702(c.1587C>T,Ala529 Ala,in exon 4),respectively. Among them SNPs rs117671123、rs196295、rs3858339、rs3858340 site in Japan is also reported in the crowd.3. Found in exon 4 BAG3 gene rs196295 polymorphic loci on significant differences compared with the control groups. The SNP rs196295 polymorphic loci of AG+GG genotype frequency and G allele frequency increased significantly in the DCM group, difference was statistically significant(75% and 51.3%, respectively, 45.8% and 29.5%, P < 0.05). In addition,the DCM groups AG+GG genotype and G allele compared with control groups the OR values were 2.85,2.02.That is to say,namely carry AG+GG genotype and G allele,the risk illed the DCM is 2.85 and 2.02 times to the health. Genotype distribution of two groups were accorded with Hardy-Weinberg equilibrium(P > 0.05). 4. Found in exon 4 rs3858339 polymorphism point on the TG genotype frequency and G allele frequency and exon 4 rs3858340 polymorphism point on the CT genotype frequency and T allele frequency is the same,42.4%, 21.2% respectively in the DCM group, in the control group were 39.7%, 19.9%, there was no statistically significant difference(P > 0.05). 5. Found in exon 3 rs117671123 polymorphism point and in exon 4 rs374858685, rs149358702 polymorphism point in the control group no gene mutation, and also found no homozygous change in DCM group. But found heterozygote changes, including rs117671123 polymorphism point CT genotype frequency was 1.4%, the rs 374858685 polymorphic loci AG genotype frequency was 0.7%, rs149358702 CT genotype frequency of polymorphic loci is 0.7%. The T allele frequency on rs117671123, the G allele frequency on rs374858685, the T allele frequency on rs149358702 are 0.7%, 0.3% and 0.7% respectively, there were no statistically significant difference(P > 0.05).Conclusions: 1. The han people in southwest China reports does not exist in the Japanese population of patients with DCM point mutations associated with the onset of DCM Arg218Trp(c. 652 c > T) and Leu462Pro(c. 1385 T > c), the mutation point of pathogenic may with the difference of genetic background and environmental factors. 2. There is no mutations in four exons of BAG3 gene correlation with DCM in Southwest Chinese Han patients.3. Located on the BAG3 gene exon 4 rs1962952 single nucleotide polymorphism may be associated with DCM in han people of southwest China. With the site of AG+GG genotype and G allele may be an increasing risk of DCM, and this may be a genetic susceptibility factors of DCM. 4. Located on the BAG3 gene exon 4 SNPs rs3858339 and rs3858340 have no association with in Southwest Chingese Han DCM patients. 5. SNPs rs117671123、rs374858685、rs149358702 may have no correlation with DCM in Southwest Chinese Han population.