The Linkage Disequilibrium Study Of The Serotonin Transporter Gene And Attempted Suicide

Objective To investigate the molecular Genetics correlation between the 5 - serotonin transporter (5-HTT) gene promoter region polymorphism (5-HTTLPR) locus and the second intron polymorphism (5-HTTVNTR) locus and suicide attempts.Methods Suicide attempts core families were recruited from the Han population in Chongqing. All of the subjects involved were Chinese of Han Nationality.Collecting elbow vein 5ml from 258 family members of 86 core families,and taking the method of conventional phenol - chloroform extraction of whole blood genomic DNA samples, then choosing the polymerase chain reaction—restriction fragment length polymorphism(PCR—RFLP).Analysing HHRR based on genealogy and the linkage disequilibrium between 5-HTTLPR and 5-HTTVNTR gene polymorphism and molecular genetics of suicide attempts. There are 57 suicide attempts core families.The diagnosis was made in accordance to the diagnostic criteria described for mood disorders of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-Ⅳ),by two psychiatrists whose titles are above attended doctors.Result (1)No significant difference of genotypic frequence of 5-HTT gene polymorphism in the promoter region (5-HTTLPR)and the second intron (VNTR)between the patients and the parents(χ2=0.088,p=0.767;χ2=2.670,p=0.263)(χ2=0.939,p=0.33;χ2=4.892,p=0.087).(2) HHRR showed no difference of genotypic frequence of 5-HTT gene polymorphism in the promoter region (5-HTTLPR)and the second intron (VNTR)between the patient group and the control group.(3) TDT analysis suggested that there were 54 heterozygous parents and 89 heterozygous parents of 5-HTTLPR and 5-HTTVNTR in 86 core families.But no linkage disequilibrium was observed between 5-HTTLPR (χ2=2.67 ,p>0.05),5-HTTVNTR(χ2=1.90,p>0.05)and suicide attempts. Analysing 2 polymorphism locis of 4 haploids of 5-HTT gene,showed no difference(p>0.05),suggested that significantly biased transmission did not exist in the Haplotypes.(4) There were 47 heterozygous parents of 5-HTTLPR in 57 psychiatric suicide attempts core families,25 S alleles and 12 L alleles of which transmitted to the suffered children(χ2=4.57,p<0.05).It suggested no linkage disequilibrium between 5-HTTLPR and suicide attempts. There were 71 heterozygous parents of 5-HTTVNTR in 57 Suicide Attemptors with psychiatric diseases core families, 29 alleles and 42 alleles of which transmitted to the suffered children(χ2=2.38,p>0.05). It suggested no linkage disequilibrium between 5-HTTLPR and suicide attempts. Analysing 2 polymorphism locis of 4 haploids of 5-HTT gene in the families of Suicide Attemptors with psychiatric,showed S12 haplotype may transmit excessively in psychiatric suicide attempts(χ2=4.45,p<0.05),but no linkage disequilibrium between the other three haplotypes and psychiatric suicide attempts(p>0.05).Conclusion (1)No linkage disequilibrium between 5-HTT gene polymorphism and Suicide Attemptors with psychiatric diseases.(2) S12 haplotype may transmit excessively in psychiatric Suicide Attemptors with psychiatric diseases.(3) 5-HIT gene might play a role in the gentic disposion of suicide attempts.