OBJECTIVE Suicide is a significant public health issue and a major cause of death in all ages worldwide. Previous studies have shown the involvement of genetics in suicidal behaviour. This study aimed to assess the role of the genetic variants of the serotonin transporter genes (5HTTLPR, SLC6A4 intron 2) and receptor gene (5HTR2AT102C) in individuals who died of suicide. The study compares the serum levels of serotonin between the cases and controls. METHODS We conducted a case control study with 120 cases and 126 controls. Socio-economic details of the subjects were collected using a semi-structured proforma and psychological autopsy was used to collect details of medical and other clinical conditions. Blood was drawn after taking informed consent and serum levels of serotonin were estimated by ELISA. Genotyping was performed using appropriate primers followed by polymerase chain reaction (PCR) and a restriction fragment length polymorphism (RFLP). RESULTS Mean age was 32.59 ± 12.58 for cases and 33.64 ± 9.78 for controls. The risk associated LL genotype of 5HTTLPR was higher among cases. The heterozygous 12/10 genotype of SLC6A4 intron 2 polymorphism was increased among controls. Serum levels of serotonin were lower among cases. Variant genotypes of all the 3 polymorphisms showed significant interaction (OR= 39.26) indicating that this model may increase suicidal tendency. CONCLUSION The findings of this study suggest that low serum levels of serotonin and two variants of the serotonin gene may influence suicide behaviour in a south Indian population.

中文翻译：

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血清素途径基因多态性和血清素水平对自杀行为的影响。

目标 自杀是一个重大的公共卫生问题，也是全世界各个年龄段的一个主要原因。先前的研究表明遗传因素与自杀行为有关。本研究旨在评估自杀死亡个体中血清素转运蛋白基因（5HTTLPR、SLC6A4 内含子 2）和受体基因（5HTR2AT102C）的遗传变异的作用。该研究比较了病例和对照组之间的血清素水平。方法 我们进行了病例对照研究，有 120 例病例和 126 例对照。使用半结构化形式收集受试者的社会经济详细信息，并使用心理尸检来收集医疗和其他临床状况的详细信息。在获得知情同意后抽取血液，并通过 ELISA 估计血清血清水平。使用适当的引物进行基因分型，然后进行聚合酶链反应（PCR）和限制性片段长度多态性（RFLP）。结果 病例平均年龄为 32.59 ± 12.58 岁，对照组平均年龄为 33.64 ± 9.78 岁。病例中与 5HTTLPR LL 基因型相关的风险较高。SLC6A4 内含子 2 多态性的杂合 12/10 基因型在对照组中增加。病例中血清素水平较低。所有 3 个多态性的变异基因型均显示出显着的相互作用（OR = 39.26），表明该模型可能会增加自杀倾向。结论 这项研究的结果表明，低血清水平的血清素和血清素基因的两种变体可能会影响南印度人群的自杀行为。