Linkage analysis of plasma dopamine β-hydroxylase activity in families of patients with schizophrenia.

Department of Human Genetics, Emory University School of Medicine, Atlanta 30322, GA, USA.
Human Genetics (Impact Factor: 4.52). 04/2011; 130(5):635-43. DOI: 10.1007/s00439-011-0989-6
Source: PubMed

ABSTRACT Dopamine β-hydroxylase (DβH) catalyzes the conversion of dopamine to norepinephrine. DβH enters the plasma after vesicular release from sympathetic neurons and the adrenal medulla. Plasma DβH activity (pDβH) varies widely among individuals, and genetic inheritance regulates that variation. Linkage studies suggested strong linkage of pDβH to ABO on 9q34, and positive evidence for linkage to the complement fixation locus on 19p13.2-13.3. Subsequent association studies strongly supported DBH, which maps adjacent to ABO, as the locus regulating a large proportion of the heritable variation in pDβH. Prior studies have suggested that variation in pDβH, or genetic variants at DβH, associate with differences in expression of psychotic symptoms in patients with schizophrenia and other idiopathic or drug-induced brain disorders, suggesting that DBH might be a genetic modifier of psychotic symptoms. As a first step toward investigating that hypothesis, we performed linkage analysis on pDβH in patients with schizophrenia and their relatives. The results strongly confirm linkage of markers at DBH to pDβH under several models (maximum multipoint LOD score, 6.33), but find no evidence to support linkage anywhere on chromosome 19. Accounting for the contributions to the linkage signal of three SNPs at DBH, rs1611115, rs1611122, and rs6271 reduced but did not eliminate the linkage peak, whereas accounting for all SNPs near DBH eliminated the signal entirely. Analysis of markers genome-wide uncovered positive evidence for linkage between markers at chromosome 20p12 (multi-point LOD = 3.1 at 27.2 cM). The present results provide the first direct evidence for linkage between DBH and pDβH, suggest that rs1611115, rs1611122, rs6271 and additional unidentified variants at or near DBH contribute to the genetic regulation of pDβH, and suggest that a locus near 20p12 also influences pDβH.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Overactivity of dopaminergic neurotransmission is a putative mechanism of tardive dyskinesia (TD). Previous studies have found dysfunction in plasma dopamine beta-hydoxylase (DBH) in schizophrenia with TD. Moreover, DBH, whose activity and levels are strongly controlled by the DBH gene, is a key enzyme in the conversion of dopamine (DA) to norepinephrine (NE) associated with excited behavior. This study examined whether the DBH5'-insertion/deletion (Ins/Del) polymorphism was associated with excited behavior in schizophrenia with TD. The presence of the DBH5'-Ins/Del polymorphism was determined in 741 schizophrenia with TD (n = 345) and without TD (n = 396). The Abnormal Involuntary Movement Scale and Positive and Negative Syndrome Scale were used to assess the severity of TD and psychopathology of schizophrenia. There was no significant difference in the allelic and genotypic frequencies of the DBH5'-Ins/Del polymorphism between schizophrenia with and without TD (both p > 0.05). However, the excited symptoms score was significantly different to the DBH5'-Ins/Del genotypic groups in schizophrenia with TD (p < 0.05) but not in the two groups of non-TD and total patients (both p > 0.05). The excited symptoms score was higher in TD patients with the Del/Del genotype than those with Ins alleles (p = 0.015). Our findings suggest that the DBH5'-Ins/Del polymorphism may not contribute directly to the development of TD in schizophrenia, but it may be involved in the excited behavior of TD patients.
    Journal of Neural Transmission 10/2014; DOI:10.1007/s00702-014-1327-7 · 2.87 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Dopamine beta-hydroxylase (DBH) is the biosynthetic enzyme catalyzing formation of norepinephrine. Changes in DBH expression or activity have been implicated in the pathogenesis of cardiovascular and neuropsychiatric disorders. Genetic determination of DBH enzymatic activity and its secretion are only incompletely understood. We began with a genome-wide association search for loci contributing to DBH activity in human plasma. Initially, in a population sample of European ancestry, we identified the proximal DBH promoter as a region harboring 3 common trait-determining variants (top hit rs1611115, p=7.2 x 10(-51)). We confirmed their effects on transcription and showed that the 3 variants each acted additively on gene expression. Results were replicated in a population sample of Native American descent (top hit rs1611115, p=4.1 x 10(-15)). Jointly, DBH variants accounted for 57% of DBH trait variation. We further identified a genome-wide significant SNP at the LOC338797 locus on chromosome 12 as trans-quantitative trait locus (QTL) (rs4255618, p=4.62 x 10(-8)). Conditional analyses on DBH identified a third genomic region contributing to DBH variation: a likely cis-QTL adjacent to DBH in SARDH (rs7040170, p=1.31x10(-14)) on chromosome 9q. We conclude that 3 common SNPs in the DBH promoter act additively to control phenotypic variation in DBH levels, and that two additional novel loci (SARDH and LOC338797) may also contribute to the expression of this catecholamine biosynthetic trait. Identification of DBH variants with strong effects makes it possible to take advantage of Mendelian randomization (MR) approaches to test causal effects of this intermediate trait on disease.
    Human Molecular Genetics 06/2014; 23(23). DOI:10.1093/hmg/ddu332 · 6.68 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Dopamine-beta-hydroxylase (DBH) metabolizes the conversion of dopamine to noradrenaline. DBH, located on chromosome 9q34.2 has variants with potential functional consequences which may be related to alterations of neurotransmitter function and several psychiatric phenotypes, including alcohol dependence (AD), depression (MD) and suicidal behavior (SA). The aim of this association study in a large multicenter sample of alcohol-dependent individuals and controls is to investigate the role of DBH SNPs and haplotypes in AD risk and associated phenotypes (AD with MD or SA). 1606 inpatient subjects with DSM-IV AD from four addiction treatment centers and 1866 control subjects were included. Characteristics of AD, MD and SA were obtained using standardized structured interviews. After subjects were genotyped for 4 DBH polymorphisms, single SNP case-control and haplotype analyses were conducted. rs1611115 (near 5') C-allele and related haplotypes were significantly associated with alcohol dependence in females. This association with female alcohol dependence also accounts for the significant relationship between this variant and comorbid conditions and traits. This study presents evidence for a potentially functional DBH variant influencing the risk for alcohol dependence while other comorbid conditions are not independently influenced by this SNP. However, the study also supports the possible role of the dopamine system in the etiology of female alcohol dependence.
    Drug and alcohol dependence 07/2013; 133(2). DOI:10.1016/j.drugalcdep.2013.07.002 · 3.28 Impact Factor

Full-text (2 Sources)

Available from
May 15, 2014