Beden Onur, Senol Ender, Atay Sevcan, Ak Handan, Altintoprak Ayse Ender, Kiyan Guclu Selahattin, Petin Buket, Yaman Utku, Aydin Hikmet Hakan
Ege University, School of Medicine, Department of Forensic Medicine, Bornova, Izmir 35100, Turkey.
Ege University, School of Medicine, Department of Medical Biochemistry, Bornova, Izmir 35100, Turkey.
Leg Med (Tokyo). 2016 Jul;21:15-8. doi: 10.1016/j.legalmed.2016.05.005. Epub 2016 May 18.
Serotonergic dysfunction is implicated in depression, psychiatric disorders and suicidal behaviors. The first and rate-limiting step in the synthesis of serotonin is catalyzed by tryptophan hydroxylase (TPH) which is encoded by TPH1 and THP2 genes. Genetic association studies have revealed contradictory results about the effect of the TPH1 A218C (rs1800532) polymorphism on suicidal behavior in different populations.
In this study, we investigated A218C polymorphism in 109 suicide attempters and 98 healthy controls. Socio-demographic characteristics of participants were obtained through questionnaire. DNA was extracted from peripheral blood and genotyping was performed by Real Time PCR. Fisher's exact test was used to evaluate the significance of the difference among the independent variables. Hardy-Weinberg equilibrium was tested using Pearson's goodness-of-fit chi-squared test.
The frequency of A allele was significantly higher in suicide attempters than controls (46.33% vs. 35.71%, p=0.0357). However, there were no differences in genotype frequencies of this locus between participants having attempted suicide and controls (p>0.05). Among males, frequencies of CC genotype and C allele were found to be significantly higher in controls (p=0.0125, p=0.0298). With regard to the female subjects and female controls, no significant association was detected between suicidal behavior and genotype/allele frequencies (p>0.05).
Our results provide evidence that A allele of TPH1 A218C polymorphism may be associated with suicidal behavior in Turkish population.
血清素功能障碍与抑郁症、精神疾病及自杀行为有关。血清素合成的第一步也是限速步骤由色氨酸羟化酶（TPH）催化，该酶由TPH1和THP2基因编码。基因关联研究揭示了TPH1 A218C（rs1800532）多态性对不同人群自杀行为影响的矛盾结果。
在本研究中，我们调查了109名自杀未遂者和98名健康对照者的A218C多态性。通过问卷调查获取参与者的社会人口学特征。从外周血中提取DNA，并通过实时聚合酶链反应进行基因分型。使用Fisher精确检验评估自变量之间差异的显著性。使用Pearson拟合优度卡方检验检验哈迪-温伯格平衡。
自杀未遂者中A等位基因的频率显著高于对照组（46.33%对35.71%，p = 0.0357）。然而，该位点的基因型频率在自杀未遂者和对照组之间没有差异（p>0.05）。在男性中，发现对照组的CC基因型和C等位基因频率显著更高（p = 0.0125，p = 0.0298）。对于女性受试者和女性对照组，未检测到自杀行为与基因型/等位基因频率之间的显著关联（p>0.05）。
我们的结果提供了证据，表明TPH1 A218C多态性的A等位基因可能与土耳其人群的自杀行为有关。
