ADHD Research Today is a free monthly online journal that collates and summarizes the latest research about ADHD, including details on attention-deficit hyperactivity disorder, drugs, treatment, symptoms.

Quantitative trait locus analysis of candidate gene alleles associated with attention deficit hyperactivity disorder (ADHD) in five genes: DRD4, DAT1, DRD5, SNAP-25, and 5HT1B.

Mill J, Xu X, Ronald A, Curran S, Price T, Knight J, Craig I, Sham P, Plomin R, Asherson P

Social, Genetic, and Developmental Psychiatry Centre, Institute of Psychiatry, De Crespigny Park, Denmark Hill, London, United Kingdom. j.mill@iop.kcl.ac.uk

It has been widely postulated that the categorical diagnosis of attention deficit hyperactivity disorder (ADHD) should be seen as the extreme end of a set of traits quantitatively distributed in the general population. A consequence of this is that the genes associated with DSM-IV ADHD should also influence these underlying traits in non-affected individuals. The aim of this study was to examine if specific candidate loci previously shown to be associated with DSM-IV ADHD, also act as quantitative trait loci (QTLs) for ADHD-symptoms in the general population. We have genotyped five candidate markers in a population-based sample of male dizygous twin-pairs (n = 329 pairs). We found little evidence to support a role for the previously-nominated alleles of a DRD4 VNTR, a 5HT1B SNP, or a microsatellite marker near to DRD5, in the distribution of ADHD-symptoms scores; however, we found some evidence to suggest that the DAT1 3'UTR VNTR and weak evidence that a microsatellite in SNAP-25 may have a role in continuous measures of ADHD-symptoms hyperactivity above and beyond their role in clinical ADHD.

Published 26 January 2005 in Am J Med Genet B Neuropsychiatr Genet, 133(1): 68-73.
Full-text of this article is available online (may require subscription).

© 2004-2008 ADHD Research Today. All Rights Reserved.