Z. Hawi et al., No association between catechol-O-methyltransferase (COMT) gene polymorphism and attention deficit hyperactivity disorder (ADHD) in an Irish sample, AM J MED G, 96(3), 2000, pp. 282-284
Pharmacological and biochemical studies have indicated that imbalances in d
opaminergic transmission may contribute to the aetiology of attention defic
it hyperactivity disorder (ADHD). The enzyme catechol-O-methyltransferase (
COMT) plays a key role in the degradation of catecholamines such as dopamin
e, L-DOPA, adrenaline, and noradrenaline and therefore could be considered
as a candidate locus for ADHD susceptibility, We hypothesised that a propor
tion of the genetic susceptibility to ADHD may be a consequence of dopamine
depletion in the synapses due to high-level activity of the COMT gene (all
ele 1), Using the haplotype-based haplotype relative risk method and 94 aff
ected children and their parents genotyped for COMT alleles, we found no si
gnificant differences in the frequency of the transmitted and nontransmitte
d alleles to ADHD cases from their parents. The absence of association betw
een COMT alleles and ADHD indicated that this locus does not play a signifi
cant role or at least a role independent of other genes, in predisposing to
ADHD in the Irish population. Am. J, Med, Genet, (Neuropsychiatr. Genet,)
96:282-284, 2000. (C) 2000 Wiley-Liss, Inc.