Possible association between serotonin transporter promoter region polymorphism and extremely violent crime in Chinese males

The neurotransmitter, serotonin, has been implicated in aggressive behavior. The serotonin transporter (5-HTT), which reuptakes serotonin into the nerve terminal, plays a critical role in the regulation of serotonergic function. Previous western reports have demonstrated that the low-activity short (S) allele of the 5-HTT gene-linked polymorphic-region (5-HTTLPR) polymorphism is associated with aggressive behavior and associated personality traits. In the present study, we investigated this 5-HTTLPR genetic polymorphism in a group of Chinese males who had been convicted for extremely violent crime (n = 135) and a normal control group (n = 111). The proportion of S-allele carriers was significantly higher in the criminal group than in the controls (p = 0.006). A significant association was not demonstrated for the relationship between the 5-HTTLPR polymorphism and antisocial personality disorder, substance abuse or alcohol abuse in the criminal group. Our findings demonstrate that carriage of the low-activity S allele is associated with extremely violent criminal behavior in Chinese males, and suggests that the 5-HTT may be implicated in the mechanisms underlying violent behaviors.     

5-羟色胺转运体基因启动子区与心境障碍的关联分析

目的 探讨5-羟色胺转运体基因启动子区5-HTTLPR与心境障碍之间的分子遗传学联系。方法 在中国汉族人群中，以心境障碍核心家系作为研究对象，根据哈佛大学提供的遗传学研究用诊断性检查表(DIGS)自编家系调查表，采用DSM-Ⅳ诊断标准并结合一些心理测评工具，以达到表型一致。在72个情感性精神障碍核心家系，222个家系成员(其中双相障碍56例，重性抑郁症34例)中，应用聚合酶链反应(PCR)和限制性片段长度多态性方法，对5-HTT基因启动子区5-HTTLPR与心境障碍之间的分子遗传学联系进行了以家系为基础的连锁不平衡分析结果基因型和等位基因频率在心境障碍患病组和父母对照组之间无显著差异。GHRR和HHRR分析以及多等位基因ETDT统计分析也没有发现存在连锁不平衡。5-HTTLPR位点除了“L”和“S”片段外，还发现2例出现“L^*”(528^*bp)片段，频率约占1％。结论 5-HTYLPR在心境障碍的发病中可能不起重要作用。     

5-羟色胺转运体启动子区基因多态性与强迫症的关联分析

目的:探索汉族人群中的5-羟色胺转运体启动子区(5-HTTLPR)基因多态性与强迫症的发病关系.方法:对强迫症患者(强迫症组)和正常对照者(对照组)分别采用聚合酶链反应扩增片断长度多态技术测定基因型.结果:强迫症组与对照组5-HTTLPR的基因型频率无显著性差异;两组的等位基因频率有显著性差异.L等位基因与强迫症呈正关联(OR=1.929,P＜0.05).结论:5-HTTLPR基因多态性的L等位基因与强迫症相关联,是强迫症的危险因子.     

Lack of association between the serotonin transporter promoter gene polymorphism and impulsivity or aggressive behavior among suicide attempters and healthy volunteers

The association between a polymorphism in the promoter area of the serotonin transporter (17q11.1-q12) with impulsivity and history of aggressive behavior was studied in a Spanish general hospital. Subjects comprised 216 suicide attempters (152 women and 64 men) and 223 control blood donors (124 women and 99 men). They were classified as S individuals (s/s or s/l) with low expression of the serotonin transporter, and L individuals (l/l) with high expression. The genotype was not associated with high levels of impulsivity (measured with the Barratt Impulsiveness Scale) or history of aggressive behavior (measured with the Brown-Goodwin scale). This lack of association did not appear to be explained by lack of statistical power. High scores on the Barratt Impulsiveness Scale (BIS) and the Brown-Goodwin Aggressive Behavior Scale were associated with being an attempter, male gender and borderline personality disorder. While our Spanish suicide attempters and published US suicide attempters have similar BIS scores, our Spanish suicide attempters have significantly lower aggressive behavior scores. If cross-cultural differences in aggressive behavior scores are definitively established, country norms for aggressive behavior scales will need to be developed to compare genetic studies in different countries.     

Possible association between serotonin transporter gene polymorphism and violent suicidal behavior in mood disorders.

BACKGROUND: Genes involved in the serotonin system are major candidates in association studies of suicidal behavior. In this case-control study we investigated whether the serotonin transporter (5-HTT) gene encoding the protein responsible for the reuptake of serotonin from the synapse after its release from serotonergic neurons is a susceptibility factor for suicidal behavior. METHODS: A functional polymorphism of the 5-HTT gene (a 44-base pair insertion/deletion in the 5-HTT-linked polymorphic region [5-HTTLPR]) was studied in a population of 237 consecutive patients with affective disorder (unipolar or bipolar) and 187 control subjects. Ninety-nine patients had attempted suicide at least once, of whom 26 made a violent attempt. RESULTS: No association was found between the "s" allele of the 5-HTTLPR and suicide attempt; however, there was a significant difference in allele distributions between patients who had made violent suicide attempts and control subjects. CONCLUSIONS: A genetic variant of the 5-HTT gene may predispose individuals to violent suicidal behavior. The precise phenotype associated with the 5-HTT gene is unclear, and therefore further studies are required to replicate these findings.     

Gender difference in association between polymorphism of serotonin transporter gene regulatory region and anxiety

OBJECTIVE: The objective of this study was to verify the hypothesis that variation of the serotonin transporter gene promoter region (5-HTTLPR) is associated with sensitivity to stress. METHODS: Genotyping of 5-HTTLPR and evaluation of emotional states were performed on 194 participants. Participants' emotional states were evaluated using the Perceived-Stress Scale (PSS), the State-Trait Anxiety Inventory (STAI), and the Self-rating Depression Scale (SDS). RESULTS: There was significant GenderxGenotype interaction in STAI (state, P<.05; trait, P<.05). Females with the l/s genotype showed higher anxiety than those with the s/s genotype in both state and trait anxiety. Oppositely, males with the s/s genotype showed higher anxiety than those with the l/s genotype. CONCLUSION: On all emotional scales, females with the l/s genotype showed high scores, contrary to males with the same genotype. Therefore, our results suggest that 5-HTTLPR l allele may be one pathway that activates negative emotion in females but acts contrary in males.     

Association between a serotonin transporter promoter region polymorphism and mood response during tryptophan depletion

This study investigated the relationship between depressive symptom response during tryptophan (TRP) depletion and a functional polymorphism of the promoter region of the serotonin (5-HT) transporter gene (SLC6A4).(1) Forty-three subjects in remission from a major depressive episode who underwent TRP depletion were genotyped. DNA was extracted from blood lymphocytes or from cheek cells.(2) The two common alleles are designated long (l) and short (s). Depressive symptoms were measured with the 25-item Hamilton Depression Rating Scale (HDRS).(3) There was a significant association between the l homozygous genotype and the depressive response to TRP depletion, with a significant main effect of time (F = 8.763, df = 3, 38, P = <0.001), and time x l homozygous allele interaction (F = 3.676, df = 3, 38, P = 0.02). Individuals whose genotype predicted increased 5-HT transporter activity may be more susceptible to depressive changes in response to transient 5-HT perturbations. The use of endophenotypic markers for affective disorders such as the mood response to TRP depletion may facilitate studies of complex genetic traits such as depression by decreasing its heterogeneity.     

A pilot genetic study of the continuum between compulsivity and impulsivity in females: the serotonin transporter promoter polymorphism

According to some authors the obsessive-compulsive (OC) spectrum includes on one extreme, the Obsessive-Compulsive Disorder (OCD) and on the other extreme the most impulsive behaviors. This is a controversial idea and other authors define the OC spectrum in different ways. The serotonin transporter (5-HTT) gene is one of the main genes that control serotonergic function. A polymorphism in the promoter area of this gene classifies subjects with low expression as S individuals (s/s or s/l) and subjects with high expression as L individuals (l/l). This polymorphism was studied in female OCD patients (n = 24), non-impulsive controls (n = 112) and impulsive suicidal patients (n = 118) to support the OC spectrum hypothesis from a genetic perspective. A linear association exists among the serotonin transporter promoter functional genotypes (S versus L individuals) (chi2 linear by linear association = 8.9; df = 1; p = 0.003). The frequency of S individuals (s/l or s/s) was lowest in OCD (54%, 13/24); intermediate in non-impulsive controls (71%, 80/112) and highest in impulsive suicide attempters (82%, 96/117). More importantly, future studies need to consider that genetics may be related to behavioral dimensions (compulsivity to impulsivity) instead of to specific psychiatric disorders defined in clinical terms.     

Association of the serotonin transporter promoter regulatory region polymorphism and obsessive-compulsive disorder.

Although modulation of symptoms of obsessive-compulsive disorder (OCD) by serotonergic agents is well established, it is unclear whether an abnormality in the central serotonergic system is involved in its etiology. The serotonin (5-HT) transporter (5-HTT), which is the key modulator of serotonergic neurotransmission, is the target for serotonin reuptake inhibiting drugs (SRIs) that are uniquely effective in the treatment of OCD. In this preliminary study we report an association of a functional polymorphism in the 5-HTT 5' regulatory-region and OCD. Seventy-five OCD Caucasian patients and 397 ethnically-matched individuals from a non-patient control group were genotyped for the 5-HTTLPR. Population-based association analysis revealed that patients with OCD were more likely to carry two copies of the long allele (l) as compared to controls (46.7% vs 32.3%: chi2 = 5.19, P = 0.023). This finding replicates a recent family-based study of this polymorphism in OCD, and thus indicates that the 5-HTTLPR may be associated with susceptibility to OCD.     

Relationships between serotonin transporter promoter polymorphism, platelet serotonin transporter binding and clinical phenotype in suicidal and non-suicidal adolescent inpatients

Summary. Relationships between the serotonin transporter promoter polymorphism (5-HTTLPR), platelet serotonin transporter (SERT) binding and clinical phenotype were examined in 32 suicidal and 28 non-suicidal Ashkenazi Israeli adolescent psychiatric inpatients. The 5-HTTLPR polymorphism was not associated with transporter binding or with suicidality or other clinical phenotypes. However, in the suicidal group, a significant positive correlation between platelet SERT density and anger scores (n=32, r=.40; p=.027) and a negative correlation between platelet count and trait anxiety (n=32, r=–.42; p=.034) were observed.     

Possible association of the short allele of the serotonin transporter promoter gene polymorphism (5-HTTLPR) with violent suicide

There is abundant evidence that the serotonin (5-HT) system is modulating mood and several behavioural traits and that disturbances in the regulation of this system can be associated with severe behavioural malfunctions, as aggressive implusive and suicidal behaviour.1 Recently a functional polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) was identified2 and the presence of one or two short alleles was associated with anxiety-related personality traits3 and several psychiatric disturbances, such as affective disorder4 or severe alcohol dependence.5 With respect to the importance of the 5-HT transporter in serotonergic transmission, we have genotyped the DNA of 58 Caucasian suicide victims (with unknown psychiatric diagnoses) and 110 healthy controls for the biallelic functional polymorphism in the 5-HTTLPR. We found a highly significant increased frequency of suicide victims being carriers of one or two short alleles (Fisher's Exact Test, two sided, P = 0.0003), which suggests that a genetically altered protein function within the serotonergic pathway might be involved in suicidality, independently from the clinical diagnosis.     

No association of a functional polymorphism in the serotonin transporter gene promoter and anxiety-related personality traits

Serotonergic neurotransmission, which is involved in many psychiatric disorders, is mediated by the serotonin transporter protein. Gene coding for the serotonin transporter protein is designated SLC6A4, which has been differentially associated with anxiety-related behavioral traits and neuroticism in healthy subjects. To confirm the association between the serotonin transporter (5-HTT) gene-linked polymorphic region (5-HTTLPR) and anxiety-related personality traits, we examined 228 healthy unrelated participants (age 38.6 +/- 12.8 years; 115 male, 113 female) of German origin, who were carefully examined with respect to psychiatric health. The self-ratable State-Trait Anxiety Inventory (STAI) and the NEO Five Factor Inventory (NEO-FFI) were performed. No significant association was observed between the 5-HTTLPR genotype and STAI 1 (state, chi2 = 0.82, p < 0.66, d.f. = 2), STAI 2 (trait, chi2 = 2.7, p < 0.25, d.f. = 2) and NEO-FFI scores of any of the 5 major axes, including neuroticism (chi2 = 3.35, p < 0.18, d.f. = 2) in all subjects. Given the small effect of this 5-HTT polymorphism on behaviour in previous studies, a lack of significant genotype differences in these tests could be due to considerable individual variability in these measures.     

Meta-analysis reveals association between serotonin transporter gene STin2 VNTR polymorphism and schizophrenia

The serotonin transporter gene (SLC6A4) is a candidate gene for schizophrenia based on serotonin transporter's crucial role in serotonergic neurotransmission. However, association studies have produced conflicting results regarding the association between two common SLC6A4 gene polymorphisms, the promoter insertion/deletion (5-HTTLPR) and the intron 2 VNTR (STin2 VNTR) polymorphisms, and schizophrenia susceptibility. To further elucidate the putative association between the two SLC6A4 gene polymorphisms and schizophrenia susceptibility, we performed a meta-analysis based on all original published association studies between schizophrenia and the 5-HTTLPR and STin2 VNTR polymorphisms published before April 2004. Our analyses showed no statistically significant evidence for the association between the Short allele of the 5-HTTLPR polymorphism and schizophrenia (random-effects pooled odds ratio (OR)=0.99, 95% Confidence Interval (CI)=0.92-1.07, Z=-0.23, P=0.82) from 19 population-based association studies consisting of 2990 case and 3875 control subjects. However, highly significant evidence for association between the STin2.12 allele of the STin2 VNTR polymorphism (random-effects pooled OR=1.24, 95% CI=1.11-1.38, Z=3.82, P=0.00014) and schizophrenia was found from 12 population-based association studies consisting of 2177 cases and 2369 control subjects. Our meta-analysis suggests that the STin2.12 allele of the STin2 VNTR polymorphism is likely a risk factor for schizophrenia susceptibility. Our data imply that following completion of the International HapMap Project, a comprehensive evaluation of a set of markers that fully characterize the linkage disequilibrium relationships at the SLC6A4 gene should be tested in large well-characterized clinical samples in order to understand the role of this gene in schizophrenia susceptibility.     

Association of the serotonin transporter promoter region polymorphism with biased attention for negative word stimuli

Background: Biased attention for emotional stimuli reflects vulnerability or resilience to emotional disorders. The current study examines whether the 5‐HTTLPR polymorphism is associated with attentional biases for negative word stimuli. Methods: Unmedicated, young adults with low current depression and anxiety symptoms (N=106) were genotyped for the 5‐HTTLPR, including the single nucleotide polymorphism (SNP) rs25531 in the long allele of the 5‐HTTLPR. Participants then completed a standard dot‐probe task that measured attentional bias toward anxiety, dysphoric, and self‐esteem words. Results: The L_AL_A allele group demonstrated an attentional bias away from negative word stimuli. This attentional bias was absent among the S/L_G carriers. Conclusions: These findings replicate previous work and suggest that 5‐HTTLPR L_A homozygotes possess a protective attentional bias that may decrease susceptibility to depression and anxiety. Depression and Anxiety, 2010. © 2010 Wiley‐Liss, Inc.     

中国大学生焦虑相关人格特质与5-羟色胺转运体基因多态性的相关性分析

目的调查5-羟色胺转运体基因上游调控区多态性位点(5-HTTLPR)与第二内含子多态性位点(5-HTTStin2)在中国汉族人群中的基因频率，比较这2个多态位点在种族间的差异，并且首次在中国大学生人群中对这2个多态位点与焦虑相关人格特质进行相关性研究。方法利用聚合酶链反应(PCR)等方法对222名随机健康汉族中国人中的这2个多态性位点进行了群体遗传学研究。并在148名大学生中对这2个位点与焦虑相关人格特质进行了相关分析。结果对于5-HTTLPR多态信息含量为0．352；5-HTTStin2多态信息含量为0．153。等位片段频率在中国汉族人与美国黑人及白人、西欧人、土耳其人有着显著差异，而与日本人相似。在148名大学生中进行的这2个位点与焦虑相关分析未能得出阳性结论。结论5-HTTLPR及5-HTTStin2这2个多态位点在不同种族和人群中的分布有差异；相关分析结果不支持在中国汉族人群中这2个多态位点与焦虑相关人格特质有关。     

Association between serotonin transporter gene promoter polymorphism and suicide: results of a meta-analysis.

BACKGROUND: There is strong evidence supporting a role for serotonin system dysfunction in the pathology of suicidal behavior. Many studies have examined the association between a functional polymorphism of the serotonin transporter gene promoter (5-HTTLPR) and suicide but have yielded inconsistent results. Our goal here, by analyzing the cumulative data from primary literature, was to determine conclusively whether there is an association. METHODS: Three meta-analyses were performed. One compared the 5-HTTLPR polymorphism between suicidal subjects and normal control subjects; another compared suicide attempters with nonattempters of the same psychiatric diagnoses; the last one compared either violent or nonviolent suicidal subjects with normal control subjects. RESULTS: We found no association between 5-HTTLPR polymorphism and suicidal behavior (p =.379). When we compared subjects with the same psychiatric diagnoses, the genotypes carrying the s allele were significantly more frequent in suicide attempters than in nonattempters (p =.004). In addition, the s allele was associated with violent suicide (p =.0001) but not with nonviolent suicide (p = 1.00). CONCLUSIONS: Our results provide significant evidence supporting the association of the s allele of 5-HTTLPR polymorphism with suicidal behavior in the psychiatric population, also with violent suicide. These support a role for decreased serotonin transporter function in the vulnerability to suicide in a select population.     

Meta-analysis of serotonin transporter gene promoter polymorphism (5-HTTLPR) association with selective serotonin reuptake inhibitor efficacy in depressed patients

The serotonin transporter gene promoter polymorphism (5-HTTLPR) has been repeatedly associated with antidepressant response in mood disorder patients, but findings are not consistent across studies. A meta-analysis was performed on 15 studies including data of 1435 subjects. We tested three phenotypes: remission rate, response rate and response rate within 4 weeks using the cochrane review manager. We observed a significant association of the s/s variant of 5-HTTLPR with remission rate (P<0.0001) and both s/s and s/l variants with response rate (P=0.0002). Response rate within 4 weeks was associated in both models (P=0.003-P<0.00001). This effect is quite robust to ethnic differences although a significant heterogeneity is present in Asian samples.