Association study of serotonin 1B receptor (A-161T) genetic polymorphism and suicidal behaviors and response to fluoxetine in major depressive disorder

Serotonin 1B receptors (5-HT1B) are autoreceptors involved in the local inhibitory control of serotonin release, and have been suggested to play a role in the pathogenesis of major depressive disorder (MDD) and the antidepressant effects of the selective serotonin reuptake inhibitors in patients. We genotyped the 5-HT1B A-161T polymorphism in 160 patients with MDD and 160 normal controls. We then tested the hypothesis that the allelic variant, A-161T, of the 5-HT1B gene confers susceptibility to MDD or is associated with suicide attempt. We also examined the association of this polymorphism with therapeutic response in 116 of the MDD patients who received fluoxetine treatment for 4 weeks. No significant difference was found in the A-161T genetic polymorphism between MDD patients and controls. The genotype distribution between patients with and without suicide attempt, or between fluoxetine treatment responders and nonresponders were also similar. Our findings suggest that 5-HT1B A-161T genetic polymorphism does not play a major role in the susceptibility to MDD, nor is it related to suicidal attempt or the therapeutic response to fluoxetine in MDD.     

Allelic variants of the tryptophan hydroxylase (A218C) and serotonin 1B receptor (A-161T) and personality traits

Human personality traits have a considerable hereditary component, and central serotonergic activity is implicated in the personality factors of the Tridimensional Personality Questionnaire (TPQ). Our population-based association study tested the hypothesis that the tryptophan hydroxylase (TPH) A218C and serotonin 1B receptor (HTR1B) A-161T polymorphisms were associated with TPQ personality trait scores in a sample population of 209 young healthy Chinese. No significant differences were demonstrated comparing scores of subjects bearing different TPH or HTR1B genotypes; however, a trend for difference in the novelty seeking score comparing TPH genotype groups was determined for the male population. Our negative findings suggest that the TPH A218C and HTR1B polymorphisms do not play major roles in the determination of TPQ personality traits.     

Association study of serotonin transporter gene VNTR polymorphism and mood disorders,onset age and suicide attempts in a Chinese sample

The human serotonin transporter (5-HTT) gene is an important candidate for the pathogenesis of mood disorders. Associations have been reported between a variable-number tandem-repeat polymorphism in intron 2 of the serotonin transporter gene (5-HTTVNTR) and mood disorders in a number of studies of Western and Chinese populations. However, no such relationships have been determined in other analogous research. To replicate these positive findings in a Chinese population and to determine the association between onset age of bipolar disorder and 5-HTTVNTR, we investigated the prevalence of this polymorphism in an independent Chinese population (83 bipolar disorder patients, 77 major depressive disorder patients and 169 controls), demonstrating no significant association between the 5-HTTVNTR polymorphism and mood disorders or age at onset. Further, no association was demonstrated between this polymorphism and suicidal history in mood disorder patients. These negative findings suggest that 5-HTTVNTR does not play a major role in the pathogenesis of mood disorder in Chinese populations.     

Association study of a brain-derived neurotrophic-factor genetic polymorphism and mood disorders, age of onset and suicidal behavior

Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin growth factor family, has been implicated in both mood disorders and suicidal behavior. This study has examined the association between the BDNF gene Val66Met polymorphism and mood disorders, age of onset and suicidal behavior in a Chinese sample population. The genotype and allele frequencies for the BDNF gene Val66Met polymorphism did not differ comparing depression groups (total, bipolar disorder or major depression) and control subjects. Furthermore, it was not demonstrated that this BDNF polymorphism was associated with age of onset or suicidal history in our mood disorder patients. Based on these results, it seems reasonable to suggest that this polymorphism is unlikely to play a major role in the genetic susceptibility to mood disorders. Given the fact that the positive association between BDNF gene Val66Met polymorphism and bipolar disorder has only been demonstrated for a Caucasian population but not for a Japanese analog or our Chinese sample, it appears likely that this association is ethnicity dependent.     

Association study of a functional catechol-O-methyltransferase genetic polymorphism with age of onset, cognitive function, symptomatology and prognosis in chronic schizophrenia

The gene coding for catechol-O-methyltransferase (COMT), which is involved in the metabolism of catecholamines, has long been implicated as a candidate gene for schizophrenia. This study aimed to assess the relationship between a functional polymorphism (Val158Met) of the COMT gene and age of onset (AOO), symptomatology, global cognitive function and prognosis in patients with schizophrenia. The study enrolled 154 patients with schizophrenia from chronic wards. Results failed to show a significant association between the Val158Met polymorphism and the Brief Psychiatric Rating Scale scores, Mini-Mental State Examination scores, and Social and Occupational Functioning Assessment Scale scores, but COMT Val158Met heterozygotes had a later AOO than homozygous patients. However, by further expanding the number of patients to 228 patients, the differences in AOO among the three COMT genotypic groups was not significant. The COMT Val158Met polymorphism did not appear to significantly affect susceptibility, symptomatology, global cognitive function and prognosis in Chinese patients with schizophrenia, but the possible association with AOO merits further investigation.     

Association analysis of serotonin 2A receptor gene T102c polymorphism and schizophrenia.

The serotonin neurotransmitter has been associated with the pathogenesis of mood disorders and schizophrenia. Serotonin receptors genes may therefore be candidate genes for the study of the genetics of these disorders. In this study, patients with schizophrenia (n=235) and controls (n=344) were analysed to determine the correlation between the 5HT(2A) receptor gene T102C polymorphism and schizophrenia. No association was found between the studied polymorphism and schizophrenia (p=0.854 for alleles and p=0.945 for genotypes). Results were also not significant when analysed by gender (for male p=0.861-allele frequency and p=0.467-genotype frequency, for female p=0.857-allele frequency and p=0.833-genotype frequency). Subgroups with regard to schizophrenia subtypes, age of onset and clinical course of schizophrenia were analysed with negative results.     

Association study of a functional serotonin transporter gene polymorphism with schizophrenia, psychopathology and clozapine response

Serotonin is implicated in the pathogenesis of schizophrenia. Following serotonin release, the serotonin transporter (5-HTT) is the major determinant of serotonin inactivation. The present study tested the hypothesis that a biallelic polymorphism in the 5' regulatory region of the 5-HTT gene (5-HTTLPR) confers susceptibility to schizophrenia, association with the clinical manifestations of schizophrenia or clozapine response. 90 treatment-resistant schizophrenic patients were assessed using the Brief Psychiatric Rating Scale before and after clozapine treatment. The results demonstrated that the 5-HTTLPR variants did not play a major role in the susceptibility, clinical manifestations or clozapine response in schizophrenia.     

短串联重复序列基因座与冲动暴力行为的关联研究

目的 探讨冲动暴力行为与相关短串联重复序列基因座的关联情况.方法 运用AmpFISTR IdentifilerTM荧光标记复合扩增体系,对203例冲动暴力行为罪犯(研究组)与207名非暴力行为健康个体(对照组)样本进行聚合酶链反应复合扩增,然后应用ABI3100型基因分析系统对扩增产物进行电泳和基因检测,观察2组15个STR基因座等位基因及基因型频率的差异.结果 15个STR基因座均符合遗传平衡定律(Hardy-Weinberg定律);研究组与对照组THO1和TPOX基因座的等位基因频率分布的差异有统计学意义(P＜0.05);研究组和对照组THO1-10频率分别为0.0172和0.0580,差异有统计学意义(P=0.002,OR=0.29,95％ CI:0.12 ～0.67);研究组和对照组TPOX-11频率分别为0.3621和0.2391,差异有统计学意义(P=0.000,OR=1.81,95％ CI:1.33 ～ 2.45);其他STR基因座等位基因频率及所有基因型频率2组差异均无统计学意义(P＞0.05).结论 THO1和TPOX基因座多态性与冲动暴力行为可能存在关联,等位基因THO1-10、TPOX-11与冲动暴力行为的发生可能有一定关系.     

Association study of serotonin 2A receptor (5-HT2A) and serotonin transporter (5-HTT) gene polymorphisms with schizophrenia

OBJECTIVE: To investigate (i) the association between four serotonergic polymorphisms (A-1438G and T102C of the 5-HT2A receptor gene, and 5-HTT VNTR and 5-HTTLPR of the 5-HT transporter gene) and schizophrenia and (ii) the potential interaction of those polymorphisms in the development of schizophrenia. SUBJECTS AND METHODS: 227 outpatients with schizophrenia (DSM-IV criteria) and 420 unrelated healthy controls from Asturias (Northern Spain) were genotyped using standard methods. RESULTS: Both groups showed Hardy-Weinberg equilibrium for the analyzed genetic variability. A-1438G and T102C polymorphisms are in complete linkage disequilibrium in our population. There was an apparent difference in the distribution of genotypes for the A-1438G (or T102C) polymorphisms (p=0.018, not significant after a Bonferroni correction). The 5-HT2A -1438A (or 102T) allele was significantly more frequent in patients than controls (0.53 and 0.45, respectively; corrected p=0.028, OR=1.39 (95% CI=1.11-1.75)). Genotype and allele distributions for 5-HTT polymorphisms were similar in both groups. However, assessment of the combined influence of 5-HT2A A-1438G and 5-HTTLPR polymorphisms demonstrated a significant effect (chi(2) (3)=11.51, p=0.009), whereby the combination of -1438A and 5-HTTLPR S alleles was associated with schizophrenia. CONCLUSIONS: Our findings support a possible synergistic effect of genetic factors influencing serotonergic neurotransmission on susceptibility to schizophrenia.     

Association of a polymorphism of the serotonin 1B receptor gene and alcohol dependence with inactive aldehyde dehydrogenase-2

Summary. The use of persons who become alcoholic despite having a well-defined negative risk for alcoholism (inactive aldehyde dehydrogenase-2 or ALDH2) is advantageous in genetic research because of this population's reduced heterogeneity and possible genetic factors conferring susceptibility to alcohol dependence. This investigation of central serotonin neurotransmission, specifically the serotonin 1B (5HT1B) receptor gene and its role in both regulating alcohol consumption and developing alcohol dependence revealed overrepresentation of the C allele of the 861G>C polymorphism of 5HT1B in alcoholics with inactive ALDH2, compared with its frequency in nonalcoholic controls. No significant differences in 5HT1B genotype and allele distributions were observed between alcoholics with active ALDH2 and controls, however. Taken together with recent observations, these results suggest that genetic variability of the 5HT1B receptor is involved in the development of some type of alcohol dependence. Received October 10, 2001; accepted November 9, 2001     

Serotonin 6 receptor polymorphism in schizophrenia: frequency, age at onset and cognitive function

The relative abundance of serotonin 6 receptor (5HT6) in some limbic regions and the high affinity of some antipsychotics for 5HT6 suggest that the 5HT6 gene might play a role in the pathogenesis of schizophrenic disorders. A recent study reported an association between a C267T polymorphism of the 5HT6 gene and schizophrenia. In order to test whether the 5HT6 gene plays a role in the pathogenesis of schizophrenic disorders, patients (n = 148) and control subjects (n = 160) were genotyped for 5HT6. We also investigated the relationship between genotypes and patients' age at onset and cognitive function in schizophrenic patients. Cognitive function in the patients was evaluated by the Mini-Mental State Examination (MMSE). The results demonstrated no significant differences in genotype or allele frequencies between controls and patients. In the patient group, age at onset and MMSE score did not differ significantly among the three 5HT6 genotpyes. The results of this study suggest that the 5HT6 C267T polymorphism plays no major role in susceptibility to the development of schizophrenia and is not related to cognitive impairment or age at onset in schizophrenic patients. Further studies of the relation between 5HT6 polymorphism and the symptoms and the therapeutic response in schizophrenic patients may help to elucidate the role of 5HT6 in the pathogenesis of schizophrenia.     

The serotonin 1A receptor C(-1019)G polymorphism in relation to suicide attempt

Background  

Serotonergic neurotransmission has been implicated in suicidal behavior. Association between suicidal completers and a regulatory C(-1019)G polymorphism (rs6295) in the serotonin 1A receptor (HTR1A) gene was previously reported, whereas a following study showed no association in a sample of suicide attempters.     

Association between a genetic variant in the serotonin transporter gene (SLC6A4) and suicidal behavior in patients with schizophrenia

ABSTRACT: BACKGROUND: The serotonin (5-hydroxytryptamin; 5-HT) system has a central role in the circuitry of cognition and emotions. Multiple lines of evidence suggest that genetic variation in the serotonin transporter gene (SLC6A4; 5-HTT) is associated with schizophrenia and suicidal behavior. In this study, we wanted to elucidate whether SLC6A4 variations is involved in attempted suicide among patients with schizophrenia in a Scandinavian case-control sample. METHODS: Patients diagnosed with schizophrenia from three Scandinavian samples were assessed for presence or absence of suicide attempts, based on record reviews and interview data. Seven SLC6A4 single nucleotide polymorphisms (SNPs) were genotyped in 837 schizophrenia patients and 1,473 control individuals. Association analyses and statistical evaluations were performed with the program UNPHASED (version 3.0.9). RESULTS: We observed an allele association between the SNP rs16965628, located in intron one of SLC6A4, and attempted suicide (adjusted P-value = 0.04), among patients with schizophrenia. No association was found to a diagnosis of schizophrenia, when patients were compared to healthy control individuals. CONCLUSION: The gene SLC6A4 appears to be involved in suicidal ideation among patients with schizophrenia. Independent replication is needed before more firm conclusions can be drawn.     

江苏地区15个STR基因座遗传多态性与自杀行为的关联研究

目的 通过对15个STR基因座遗传多态性的分析,了解自杀行为与STR基因座相关等位基因的关联情况.方法 运用AmpFISTR IdentifilerTM荧光标记复合扩增体系对76名自杀者与147名随机个体进行PCR复合扩增,然后应用AB13100型基因分析系统对扩增产物进行电泳和基因检测.观察两个群体中15个STR基因座等位基因频率的差异.结果 15个STR基因座均符合Hardy-Weinberg平衡;CSF1PO-13(自杀组:10.53%,对照组:5.10%)、D13S317-8(自杀组:38.82%,对照组:27.89%)、FGA-18(自杀组:2.63%,对照组:0.34%)、FGA-19(自杀组:7.89%,对照组:3.06%)、FGA-23(自杀组:17.11%,对照组:27.89%)、vWA-16(自杀组:9.31%,对照组:18.37%)、D2S1338-22(自杀组:0.66%,对照组:5.10%)、D16S539-9(自杀组:25.66%,对照组:35.71%)在两组人群中的等位基因频率存在显著差异(P<0.05);D2S1338-25(自杀组:16.45%,对照组:5.44%)在两组人群中的等位基因频率存在极显著差异(P<0.01).其余STR基因座在两个群体中的等位基因频率均无显著差异(P>0.05).结论 等位基因CSF1PO-13、D13S317-8、FGA-18、FGA-19、FGA-23、D2S1338-22、D2S1338-25、vWA-16、D16S539-9可能与自杀行为的发生有一定关系,在2号、4号、5号、12号、13号和16号染色体上可能存在与自杀行为相关的基因.     

5-HT1B基因A161T多态性与抑郁症的关联研究

目的探讨抑郁症患者与5-HT1B受体基因A161T多态性之间的关系。方法应用聚合酶链式反应（PCR）扩增技术及限制性片段长度多态性（arLP）分别检测365例抑郁症患者（病例组）、365名健康人（对照组）的5-HT1B受体基因A161T多态性。结果5-HT1B受体基因A161T多态性在病例组和对照组的基因型和等位基因分布频率无显著性差异；按照发病年龄（30岁为界）、有无家族史及有无自杀观念分层后，各亚组与对照组间基因型和等位基因分布也无显著性差异。经多因素分析控制年龄、性别因素后各组基因型分布仍无显著性差异。结论5-HT1B受体基因A161T多态性可能不是抑郁症及其各临床亚型发病的一个危险因素。     

A common polymorphism in serotonin receptor 1B mRNA moderates regulation by miR-96 and associates with aggressive human behaviors

Non-coding regulatory elements can transduce the human genome's response to environmental stimuli. Thus, there is a possibility that variation in non-coding regulatory elements may underlie some of the diversity in human behavior. However, this idea has remained largely untested due to the difficulty in accurately identifying regulatory elements in the 98% of the human genome that does not encode protein. The recent recognition that small trans-acting RNAs anneal to mRNA and regulate gene expression provides a means to identify and test such variants. Here, we show that microRNA-directed silencing of mRNA can be attenuated by a common human polymorphism. We have identified an element (A-element) within serotonin receptor 1B (HTR1B) mRNA that confers repression by miR-96. The repressive activity of this element is attenuated by a common human variant (G-element) that disrupts a nucleotide critical for its interaction with miR-96. Because deletion of the HTR1B gene leads to an aggressive phenotype in mice, we hypothesized an association between the A/G polymorphism and aggressive phenotypes in a sample of 359 college students. As predicted, individuals homozygous for the ancestral A-element reported more conduct-disorder behaviors than individuals with the G-element. Our studies suggest that such functional variants may be common and may help to refine the search for genes involved in complex behavioral disorders.     

Attempted suicide and polymorphism of the serotonin transporter gene in Chinese patients with schizophrenia

Abnormalities of serotonin synthesis and metabolism may be associated with suicidality. The serotonin transporter gene (5-HTT) is one of the important genes involved in the regulation of serotonin neurotransmission. We examined the association of suicidal behavior in Chinese schizophrenic patients with a functional polymorphism of the promoter region of the 5-HTT gene (5-HTTLPR). The 5-HTTLPR genotype was determined by polymerase chain reaction for 76 suicidal and 262 non-suicidal patients with a diagnosis of schizophrenia (DSM-IV criteria). All subjects were unrelated to each other, and all were Chinese. There was no significant genotypic or allelic association of the 5-HTTLPR polymorphism with history of attempted suicide. From our results, this 5-HTTLPR polymorphism is unlikely to have a major effect on suicidal behavior in Chinese patients with schizophrenia.     

Distribution of androgen receptor CAG repeat polymorphism in Chinese schizophrenia and its correlation with age at onset

The action of androgens is mediated by the androgen receptors (ARs), which are located throughout the brain. The AR gene is implicated in the pathogenesis of schizophrenia because male siblings with schizophrenia share alleles at this gene at a rate higher than chance predicts, and differences in sex hormone function may explain the gender difference in schizophrenic manifestations. Since the shorter alleles of the AR CAG repeat polymorphism are associated with increased gene expression, we tested the hypothesis that the AR CAG repeat variant confers susceptibility to schizophrenia using a sample of 225 people with schizophrenia and 247 normal controls. Using the median AR repeat length in the normal group as the arbitrary cut-off point (<24 and >25 CAG repeats), the results show no association between the AR repeat length and schizophrenia in either sex. Furthermore. AR CAG repeat length did not affect the age of symptom onset in the schizophrenic population. Our findings suggest that it is unlikely that the AR CAG repeat polymorphism plays a major role in the pathogenesis of schizophrenia. Nevertheless, given that androgens affect cognitive function, violent behavior and mood, the effect of the AR CAG polymorphism on the clinical manifestations of schizophrenia may warrant further exploration.