Lack of association of serotonin‐2A receptor gene polymorphism (T102C) with suicidal ideation and suicide

Serotonergic dysfunction has been implicated in the pathophysiology of affective disorders and suicidality. Especially the density of the 5‐HT2A receptor was claimed as being increased in suicidality, proposed as an adaptive upregulation due to reduced serotonergic transmission. Recent studies have shown an association of allele C of the 5‐HT2A‐T102C polymorphism with suicidal ideation in patients with major depression. The purpose of this study was to test whether this proposed marker indicates susceptibility not only to suicidal ideation in depressed patients but also to suicidality as a syndrome. We investigated the 5‐HT2A‐T102C polymorphism in 131 suicide victims with unknown underlying psychiatric diagnoses, 84 patients with major depression with or without suicidal ideation, and 125 healthy controls. We were unable to find any association of genotype or allele frequencies to major depression, suicidal ideation, or suicide as a syndrome. Thus, our results suggest that this polymorphism may not commonly be involved in the susceptibility to suicidality. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:831–835, 2000. © 2000 Wiley‐Liss, Inc.     

Positive association between a DNA sequence variant in the serotonin 2A receptor gene and schizophrenia

Sixty-two patients with schizophrenia and 96 normal controls were investigated for genetic association with restriction fragment length polymorphisms (RFLPs) in the serotonin receptor genes. A positive association between the serotonin 2A receptor gene (HTR2A) and schizophrenia was found, but not between schizophrenia and the serotonin 1A receptor gene. The positive association we report here would suggest that the DNA region with susceptibility to schizophrenia lies in the HTR2A on the long arm of chromosome 13. © 1996 Wiley-Liss, Inc.     

5-HTR2A基因启动子区-1438G/A多态性与抗精神病药源性肥胖的核心家系关联研究

目的探讨中国汉族首发精神分裂症(schizophrenia,SCH)患者抗精神病药物(antipsychoticagents,APS)治疗过程中体重增加是否与五羟色胺2A受体(5-hydroxytryptamine2Areceptor,5-HTR2A)基因启动区-1438G/A多态性相关。方法对84例首发精神分裂症患者(包含完整核心家系70个)APS(氯丙嗪或利培酮)单药治疗10周,治疗前后测量体重并计算体重指数。采用聚合酶链反应-限制性片段长度多态技术分析5-HTR2A基因启动区-1438G/A多态性基因型和等位基因分布频率,进行APS所致体重增加与5-HTR2A基因启动区-1438G/A多态性的相关分析、传递不平衡检验及数量性状传递不平衡检验。结果治疗10周后患者体重较基础体重增加(8.00±6.13)%。APS治疗10周后,体重增加≥7%和<7%患者组间,5-HTR2A基因-1438G/A多态性各基因型和等位基因分布频率差异均无统计学意义(P>0.05)。5-HTR2A基因-1438G/A多态性的各基因型之间各项指标的差异均无统计学意义(P>0.05);同时未发现5-HTR2A基因-1438G/A在不同体重增加组间存在传递不平衡。结论5-HTR2A基因-1438G/A多态性可能不是影响APS所致体重增加的主要遗传因素。     

Association analysis of the 5-HT2C receptor and 5-HT transporter genes in bipolar disorder

We selected 42 patients with bipolar disorder type I (BPI) and 40 healthy controls for genetic analysis of DNA polymorphisms in the serotonin receptor 2c (5-HTR2c) and serotonin transporter (5-HTT) genes. No significant associations were found in the total patient sample. However, when the individuals were divided according to gender, trends for association with both polymorphisms (P = 0.051 for 5-HTR2c and P = 0.049 for 5-HTT) in female patients were observed. These results suggest that variations in these genes may be responsible for a minor increase in susceptibility for bipolar disorder in women. Am. J. Med. Genet. 74:504–506, 1997. © 1997 Wiley-Liss, Inc.     

Novel mutations in the promoter and coding region of the human 5-HT1A receptor gene and association analysis in schizophrenia

Dysfunction of serotonin systems has been implicated in schizophrenia. In the present study, the human 5-HT_1A receptor gene containing the 5′ untranslated region was screened in order to detect genetic variations, through which alteration of protein function or level of expression might contribute to schizophrenia. Genomic DNAs were isolated from whole-blood samples of 61 unrelated schizophrenic patients and 100 healthy controls. Genetic variations were screened systematically by single-strand conformational polymorphism (SSCP) analysis, followed by direct sequencing of polymerase chain reaction (PCR) product as well as restriction fragment-length polymorphism (RFLP). The novel mutations (−51T → C, −152C → G, −321G → C, −480delA, and −581C → A) were found in the 5′ untranslated region. Furthermore, we found a novel missense mutation (Gly272Asp) in the coding region in addition to the mutations (Pro16Leu, 294G → A, and 549C → T) reported previously. No significant differences in genotype frequencies as well as allele frequencies were found between patients and controls. Our data provided no evidence of association between schizophrenia and the variants in the 5′ untranslated region as well as the coding region of the human 5-HT_1A receptor gene. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 81:434–439, 1998. © 1998 Wiley-Liss, Inc.     

ASSOCIATION ANALYSIS OF 5-HTTLPRVARIANTS, 5-HT2ARECEPTOR GENE 102T/CPOLYMORPHISM AND MIGRAINE

It is well known that migraine has a strong genetic component, although the type and number of genes involved is not yet clear. There is evidence to suggest that serotonin-related genes participate in the pathogenesis of migraine. Previous studies have shown that gender differences influence the serotonergic neurotransmission and, in addition, the migraine prevalence is higher in females than males. Therefore, we investigated the functional polymorphism in the upstream regulatory region of the serotonin transporter gene (5-HTTLPR) and the 102T/Cpolymorphism of the 5-HT_2Areceptor gene in the Hungarian female population. These genes were analysed in 126 migraine sufferers (with or without aura)and 101 unrelated healthy controls using case control design. A borderline association (χ²=3.84, df=1, p=0.049; OR=1.45, 95% CI=1.00–2.12) between 5-HTTLPRshort (S) allele and migraine was found. No significant difference between migraine sufferers and controls was observed for the 102T/Cpolymorphism of 5-HT_2Areceptor gene. Furthermore, there was no significant interaction between5-HTTLPRand 102T/Cpolymorphisms in our study population. In conclusion, our results support that the genetic susceptibility of migraine may be associated with a locus at or near the 5-HT transporter gene.     

男性精神分裂症患者5-HT2A受体基因T102C多态性与迟发性运动障碍的关联

目的探讨5-羟色胺2A(5-HT2A)受体基因T102C多态性与精神分裂症伴迟发性运动障碍(TD)的相关性.方法用异常不自主运动量表(AIMS)评定男性精神分裂症患者;对42例符合TD(AIMS总分≥3分)者和与TD组严格相匹配的51例非TD者,采用简明精神病评定量表(BPRS)评定精神症状;应用聚合酶链反应-限制性片段长度多态性方法分析5-HT2A受体基因T102C多态性的分布频率.结果(1)经吻合度检验,TD组、非TD组的5-HT2A受体基因T102C多态性位点的基因型分布均符合Hardy-Weinberg平衡法则(χ2分别为0.06、0.02,ν均=2,P均＞0.05)(2)TD组与非TD组的基因型总体分布的差异无显著性(χ2=4.37,ν=2,P＞0.05),等位基因频率分布的差异有显著性(χ2=4.36,ν=1,P＜0.05).(3)TD组的AIMS和BPRS的评分分别为(6.5±1.8)分和(51.2±7.8)分,非TD组分别为0分和(50.3±7.4)分,差异无显著性(P＞0.05).结论5-HT2A受体基因的T102C多态性可能与男性精神分裂症患者的TD相关联.     

Investigation of linkage and association/linkage disequilibrium of HLA A‐, DQA1‐, DQB1‐, and DRB1‐alleles in 69 sib‐pair‐ and 89 trio‐families with schizophrenia

The hypothesis that HLA antigens confer susceptibility to schizophrenic disorders has been tested by studying linkage and association in a family sample with 69 sib‐pair families. Suggestive evidence for linkage was obtained by nonparametric multipoint LOD score analysis with a maximum around DQB CAR (P = 0.0004), a microsatellite marker that is in linkage disequilibrium with the HLA antigen DQB1. Spurious evidence for negative association as calculated by the transmission disequilibrium test was found for HLA‐ DRB1*11 (chi‐square = 11.72, corrected P value = 0.03) and for the haplotype DQB1*301—DQA1*501—DRB1*11 (chi‐square = 11.3, corrected P value = 0.043). No evidence of association with these alleles was obtained in a sample of 89 trios with schizophrenic offspring and parents. Our results are not in favor of a direct involvement of the HLA system in development of schizophrenia, but are compatible with the possible existence of a susceptibility gene in the MHC region at chromosome 6p 21.31. © 2002 Wiley‐Liss, Inc.     

5-HT2受体-磷脂酶C的激活易化大鼠基底外侧杏仁核突触可塑性的研究

为了探讨5-HT2受体激动剂盐酸2,5-二甲氧基-4-碘苯基丙烷(DOI)对杏仁核突触可塑性的调节作用,本研究在杏仁核脑片上记录基底外侧杏仁核(BLA)场电位,应用单串的θ频率波刺激(TBS)诱导突触可塑性,观察DOI对TBS诱导的突触可塑性的影响,及5-HT2受体拮抗剂、磷脂酶C抑制剂能否抑制DOI的作用。结果显示:单串的TBS刺激外囊,在BLA仅诱导约为10min的短时程增强。灌流液中加入100μmol/L DOI 20min,对基础的场电位没有作用。但在DOI存在的情况下,单串的TBS即可诱导长时程增强,强直刺激30min后,增强的场电位斜率仍维持在基础值的(162.5±9.7)%(n=9,P<0.01)。DOI对TBS诱导的突触可塑性的易化作用可被5-HT2A/2C受体拮抗剂ketanserin和PLC抑制剂U73122所抑制。以上结果提示5-HT2A/2C受体的激活可通过磷脂酶C通路易化杏仁核的突触可塑性。     

Association analysis of the 5-HT6 receptor polymorphism (C267T) in mood disorders

The serotonergic system is implicated in the etiology of mood disorders. Among those most recently discovered serotonin receptors, the relative abundance of serotonin type 6 receptor (5-HT₆) in the limbic area and the high affinity of some antidepressants to 5-HT₆ receptors suggest that this receptor might be involved in the pathogenesis of mood disorders. In a population-based association study, we tested the hypothesis that the allelic variant (C267T) of the human 5-HT₆ gene confers susceptibility to mood disorders. We genotyped the 5-HT₆ receptor in 139 patients with mood disorders and 147 controls. The results demonstrated that there were no significant differences in genotype or allele frequencies between controls and all patients, or between controls and patients with bipolar disorders or major depression, separately. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:601–602, 1999. © 1999 Wiley-Liss, Inc.     

Genome‐wide scan for linkage to schizophrenia in a Spanish‐origin cohort from Costa Rica

Genetic isolates have been useful cohorts in which to search for genes underlying disorders of unknown pathology. One such cohort is thought to exist in the Central Valley of Costa Rica surrounding the city of San Jose. Previous investigators identified a rare dominant gene for hereditary deafness in this population, and a suggestive linkage of severe bipolar psychosis has been reported in another study. Ninety‐nine families with at least one pair of siblings affected with schizophrenia or a schizophrenia‐spectrum diagnosis had clinical evaluations and DNA collected for genotyping. The Marshfield Medical Research Foundation (NHLBI) Mammalian Genotyping Service performed all genotyping using 404 short‐tandem repeat polymorphic markers (STRPs) spaced on average 10 cM apart. Data were analyzed using the nonparametric program, GeneHunterPlus. The population structure was investigated using the STRUCT program. No region was found with genome‐wide significance for linkage. Using a phenotype of schizophrenia plus schizoaffective disorder, the highest maximum likelihood score (MLS) observed was 1.78 (P < 0.004) at 176.6 cM from pter on chromosome 5q, an area previously implicated by some other groups. In addition, five regions on chromosomes 1p, 2p, 2q, 14p, and 8p had MLSs above 1.0. All other regions produced scores below 1.0. Population genetic analysis reveals no evidence for population substructure, for admixture with other populations, such as Amerindians, or for inbreeding in the parental generation. The latter casts some doubt on this population being an isolate, although there was evidence of inbreeding among the offspring. © 2002 Wiley‐Liss, Inc.     

Exclusion of linkage between schizophrenia and the gene encoding a neutral amino acid glutamate/aspartate transporter,SLC1A5

An abnormality in glutamatergic function has been hypothesized as being of etiological importance in schizophrenia. Twenty-three multiplex English and Icelandic schizophrenia families were genotyped with a polymorphic dinucleotide repeat sequence in the 3′-untranslated region of the glutamate/aspartate transporter gene called SLC1A5. Using the lod and a model-free method of linkage analysis (MFLINK), no evidence of linkage between SLC1A5 and schizophrenia was found. Our results do not support the hypothesis that SLC1A5 gene mutations or allelic variants provide a major gene contribution to the etiology of schizophrenia. However, because of the likelihood of heterogeneity of linkage in schizophrenia, there is a case for testing other pedigrees for linkage to the SLC1A5 locus. The SLC1A5 locus is one of a complex family of genes encoding neutral amino acid transporter proteins and the genetic relation between these other loci and schizophrenia has not yet been established. Am. J. Med. Genet. 74:50–52, 1997. © 1997 Wiley-Liss, Inc.     

Negative association between T102C polymorphism at the 5-HT2A receptor gene and bipolar affective disorders in Singaporean Chinese

BACKGROUND: Serotonergic system abnormalities have been implicated in the pathogenesis of bipolar affective disorders. The 5-hydroxytryptamine type 2A (5HTR2A) receptor gene located on chromosome 13 (13q14-21) can be considered as a candidate gene for bipolar affective disorder (BPAD). METHODS: Seventy-two patients with BPAD and 74 normal population controls were genotyped with restriction fragment length polymorphism (RFLP) in the 5HTR2A receptor gene. RESULTS: We report a negative association between 5HTR2A receptor gene and BPAD. The association was examined using a case-control design. Allele and genotype frequencies as well as homozygote-heterozygote distribution at the 5HTR2A receptor gene polymorphism were compared between the two groups. There were no significant differences in the allelic or genotype frequencies and the homozygote-heterozygote distributions. Limitations: Patients were recruited from one hospital in Singapore. The case-control study design needs replication. CONCLUSION: Our finding indicates that the 5HTR2A receptor gene polymorphism is not a major factor in the genetic susceptibility to BPAD in Singaporean Chinese.     

No association between a promoter dopamine D4 receptor gene variant and schizophrenia

The dopamine D₄ receptor has been implicated in the pathogenesis of schizophrenia. An association between a putative functional promoter polymorphism (?521C/T) in the dopamine D₄ receptor gene (DRD4) and schizophrenia was recently reported. In the present study, patients with schizophrenia (n = 132) and control subjects (n = 388) were analyzed with respect to the DRD4 ? 521C/T polymorphism. No significant case control differences emerged. The present results do not support a major role for DRD4 in the etiology of schizophrenia among Caucasians from Sweden. © 2001 Wiley‐Liss, Inc.     

No association between a common single nucleotide polymorphism,rs4141463, in the MACROD2 gene and autism spectrum disorder

The Autism Genome Project (AGP) Consortium recently reported genome‐wide significant association between autism and an intronic single nucleotide polymorphism marker, rs4141463, within the MACROD2 gene. In the present study we attempted to replicate this finding using an independent case–control design of 1,170 cases with autism spectrum disorder (ASD) (874 of which fulfilled narrow criteria for Autism (A)) from five centers within Europe (UK, Germany, the Netherlands, Italy, and Iceland), and 35,307 controls. The combined sample size gave us a non‐centrality parameter (NCP) of 11.9, with 93% power to detect allelic association of rs4141463 at an alpha of 0.05 with odds ratio of 0.84 (the best odds ratio estimate of the AGP Consortium data), and for the narrow diagnosis of autism, an NCP of 8.9 and power of 85%. Our case–control data were analyzed for association, stratified by each center, and the summary statistics were combined using the meta‐analysis program, GWAMA. This resulted in an odds ratio (OR) of 1.03 (95% CI 0.944–1.133), with a P‐value of 0.5 for ASD and OR of 0.99 (95% CI 0.88–1.11) with P‐value = 0.85 for the Autism (A) sub‐group. Therefore, this study does not provide support for the reported association between rs4141463 and autism. © 2011 Wiley‐Liss, Inc.     

Brief research communication: No evidence for linkage of the CHRNA7 gene region in Canadian schizophrenia families

Schizophrenia patients demonstrate a deficiency in the filtering of sensory information, and one specific measure involves a response to the second of a pair of auditory stimuli. A neurophysiological measure of this consists of the electroencephalographic response to pairs of auditory signals, emitted fractions of a second apart. Schizophrenic patients and some of their unaffected relatives show a failure of inhibition of a second tone if it occurs 50 msec after the first. A recent genome scan indicated that the gating defect is linked to the alpha 7 neuronal nicotinic acetyl choline receptor gene on chromosome 15. We genotyped 5 schizophrenia families with a total of 96 subjects with a dinucleotide polymorphic marker located less than 120 kb from the first exon of the alpha 7 neuronal nicotinic acetylcholine receptor gene. Linkage analysis was undertaken using parametric and nonparametric statistical methods. The results of the parametric analysis showed negative lod scores under both narrow and broad diagnosis (lod = −3.6 and −4.8, respectively, at θ = 0), and dominant and recessive modes of transmission of the disease. Nonparametric analysis using GENEHUNTER produced nonsignificant NPL scores (NPL = −0.4 and −0.3 for broad and narrow diagnoses, respectively). In summary, we did not find any evidence that the α7 neuronal nicotinic acetylcholine receptor gene (CHRNA7) is linked to schizophrenia. However, we have not been able to assess the P50 measures in these families. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 81:361–363, 1998. © 1998 Wiley-Liss, Inc.