In this systematic review, we examine the existing literature that combines exposures to chemical and non-chemical stressors (specifically childhood trauma), MAOA characteristics, and ADHD diagnosis to investigate the interrelationships present.
We examined 4 SNPs located on genes previously associated to dyslexia (KIAA0319, DCDC2, DYX1C1 and FOXP2) and 3 SNPs within genes related to ADHD (COMT, MAOA and DBH) in a cohort of Spanish children (N = 2078) that met the criteria of having one, both or none of these disorders (dyslexia and ADHD).
Due to high heritability rate of ADHD, we tested familial transmission of MAOA and MAOB variants to ADHD probands in 190 nuclear families having ADHD probands from Indo-Caucasoid ethnicity.
The simultaneous presence of the low activity MAOA genotype and low birth weight (p < 0.001) and of the 5-HTTLPR LL-allele and respectively pregnancy and delivery complications (p = 0.04) and maternal smoking (p = 0.04) were associated with more ADHD symptoms particularly during early adolescence, and these influences significantly decreased over time.
Polymorphisms in genes such as DAT1, 5HTTLPR, D4DR4, and MAO-A have been linked to attention deficit hyperactivity disorder (ADHD) and susceptibility for opiate addiction.
Monoamine oxidase A (MAOA) and B (MAOB), two isoenzymes bound to the outer membrane of mitochondria, are involved in the degradation of monoamines and were explored for association with ADHD in different ethnic groups.
In conclusion, our findings suggested that the interaction of MAOA and SYP may be involved in the genetic mechanism of ADHD-I subtype and predict ADHD symptoms.
In A hemizygotes of the expression single nucleotide polymorphism rs12843268, which express lower levels of MAOA, ADHD symptoms are associated with lower ventral striatal BOLD response during the monetary incentive delay task and lower inferior frontal gyrus BOLD response during the stop signal task.
The aim of the present study is to investigate the association between ADHD and polymorphisms of MAOA 30 bp-promoter VNTR and DAT1 40 bp 3' UTRVNTR in Saudi population.
Polymorphisms in the CYP2A6 gene and, among females, the MAOA gene interacted with retrospective reports of ADHD symptoms in predicting unpleasant initial reaction to cigarettes.
We tested the interactive effects of the 30-base pair variable number tandem repeat (VNTR) polymorphism of the monoamine oxidase A gene (MAO-A) with positive and negative parenting behavior on parent- and teacher ratings of inattention and hyperactivity symptoms among 150 6-9 year-old boys with and without ADHD.
We conducted transmission disequilibrium tests (TDTs) in 1,253 trios and found no association between five single nucleotide polymorphisms (SNPs) of MAOA with ADHD in general or in the predominantly inattentive (ADHD-I) or combined types (ADHD-C), but with the predominantly hyperactive/impulsivity type (ADHD-HI).
Since our previous association studies between attention deficit hyperactivity disorder (ADHD) and these two functional polymorphisms consistently showed the low activity alleles were preferentially transmitted to inattentive ADHD boys, the goal of the present study was to test the hypothesis that the interaction between COMT Val158Met and MAOA-uVNTR may affect the intelligence in a clinical sample of Chinese male ADHD subjects (n = 264).
Almost all studies on the role of MAOA in ADHD have focused predominantly on boys, making it unknown whether MAOA also has an effect on ADHD in girls, and few studies have investigated the relationship between MAOA and neuropsychological functioning, yet this may provide insight into the pathways leading from genotype to phenotype.
We have, in a population-based sample, studied associations between dimensions of the ADHD/DBD phenotype and Monoamine Oxidase B (MAO-B) activity in platelets and polymorphisms in two serotonergic genes: the Monoamine Oxidase A Variable Number of Tandem Repeats (MAO-A VNTR) and the 5-Hydroxytryptamine Transporter gene-Linked Polymorphic Region (5-HTT LPR).