Report from the 4th international meeting of the attention deficit hyperactivity disorder molecular genetics network.

Investigators from around the world have convened annually since 1999 to share their work on the molecular genetic basis of attention deficit hyperactivity disorder (ADHD). The 4th meeting of the ADHD Molecular Genetics Network was held in May 2002. This conference began with a discussion of ongoing and proposed collaborative projects. Ongoing collaborations include the International Multi-Center ADHD Genetics (IMAGE) project, a study of additive and interactive effects of DAT1 and DRD4 on ADHD and a meta-analysis of association studies of ADHD and the DRD5 gene. A new collaborative project regarding DNA pooling was also proposed. Over 20 investigators presented recent findings from their individual research sites. Participants also broke up into working groups to discuss additional projects and topics of mutual interest, including population genetic studies using dimensional phenotypic data and a QTL approach, endophenotypes for ADHD and the genetics of ADHD in adults. Finally, participant feedback was obtained about the utility of the ADHD Molecular Genetics Network conferences and the e-mail network. Although technological and statistical advances in the field of molecular genetics have allowed researchers to begin to identify specific genes that are associated with ADHD, continued collaborative efforts are needed to fully elucidate the genetic underpinnings of this complex phenotype. Data collected at the current conference indicate that the ADHD Molecular Genetics Network has facilitated new collaborative as well as single-site projects among ADHD researchers. Copyright 2003 Wiley-Liss, Inc.