An initial report of association between ADHD and the common 148-bp allele of a microsatellite marker located 18.5 kb from the DRD5 gene has been followed by several studies showing nonsignificant trends toward association with the same allele.
Several studies have reported an association between clinically defined ADHD and the seven-repeat allele of a 48-bp tandem repeat polymorphism in the third exon of the dopamine D4 receptor gene (DRD4).
This study aimed to investigate the effects of regulation of the dopamine D4 receptor (DRD4) on functional brain activity during the resting state in ADHD children using the methods of regional homogeneity (ReHo) and functional connectivity (FC).
We tested for the presence of association between the DRD4 48 base repeat and adult ADHD in two independent samples: one comprised of cases and ethnically matched controls, and the second made up of nuclear families.
A positive association was found with the DRD2 and DRD4 polymorphisms in the subgroups of patients with childhood ADHD, or with a high impulsivity score, which represented, respectively, 53.3 and 73.0% of the patients.
An initial report of association between ADHD and the common 148-bp allele of a microsatellite marker located 18.5 kb from the DRD5 gene has been followed by several studies showing nonsignificant trends toward association with the same allele.
This study aimed to assess the role of the catechol-O-methyltransferase (<i>COMT</i>) and of the dopamine transporter (<i>DAT1</i>) genes on ADHD symptoms in the general population.
In conclusion, our results among adults with a clinical diagnosis of ADHD support an association between ADHD and the DRD5 locus, but not the DRD4 or SLC6A3 loci.
There was no significant association between dopamine D4 receptor gene alleles, Novelty Seeking traits, and the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition diagnosis of attention deficit hyperactivity disorder--Hyperactive impulsive type or Inattentive type.
These newly detected associations between DRD4 polymorphisms and ADHD prognosis in adulthood may help to predict the persistence of childhood ADHD into adulthood.
The dopamine D4 receptor gene (DRD4) has been implicated in psychiatric disorders in which deficits of self-regulation are a prominent feature (e.g., attention-deficit hyperactivity disorder and substance use disorders) and in dopamine D4 receptor insensitivity within prefrontal regions of the brain.
Here we describe the haplotype analysis of the 120 base pair duplication (120-bp dup) and three SNPs (-616C/G, -615A/G, -521C/T) in the 5' region of the DRD4 gene among children with ADHD.
An excess of the DRD4 7-repeat allele was observed when both ADHD probands and their parents were compared with an ethnically matched control sample (chi-square = 11.55, P = 0.03; chi-square = 12.17, P = 0.03, respectively).
(2006); Arch Ger Psychiatry 63:462-469] recently reported a potentially important association between two dopamine-related risk polymorphisms (DRD4 variable number tandem repeat (VNTR) in exon 3 and DAT1 VNTR in the 3' UTR) and lowered IQ in ADHD.
To replicate the association between COMT genotype and antisocial behavior in ADHD and to then test whether (1) impaired executive control or (2) impaired social understanding act as intermediate phenotypes for this association and lie on the risk pathway between COMT genotype and antisocial behavior.
Currently, peripheral COMT inhibitors have an important role in the treatment of Parkinson's disease, and central COMT inhibitors have a potential role in the treatment of various neuropsychiatric disorders, such as attention deficit hyperactivity disorder.
This will include the (1) DRD4 gene associated with attentiondeficit/ hyperactivity disorder, located in a locus that underwent a positive selection; the (2) GABRB2 gene, a gene associated with schizophrenia and recently reported as the target of a positive selection; (3) MARK1, a candidate gene for autism that was reported as displaying a signature of adaptative evolution in the human lineage, and (4) the ADH and ALDH2 genes which are associated with alcoholism, and for which evidence of positive selection was identified in the human lineage since the divergence between humans and chimpanzees.
The concentrations of DRD4-mRNA in the whole blood were significantly lower in ADHD and ASD children (19 of 26 comorbid with ADHD) compared to healthy controls.