Researchers from the Queensland Brain Institute are set to begin a 600-strong study of children with attention deficit hyperactivity disorder (ADHD) to track down a potential genetic link.

The study, funded by the National Health and Medical Research Council and involving researchers from the Mater Children’s Hospital in Brisbane, the Royal Children’s Hospital Melbourne and Curtin University in Perth, aims to investigate the relationship between genetics, cognitive problems and brain function in children with ADHD.

The study will document cognitive ability in children with ADHD and hopes to determine whether there are genetic differences between children with the disorder and those without.

Brain activity will be examined by functional magnetic resonance imaging (fMRI) to study how genes affect brain function in children with ADHD.

DNA from parents and child will be collected and mapped.

Previous research has found links between polymorphisms in the DAT1 and DRD4 genes, both of which are involved in the dopamine system, and ADHD, although the risk factor is considered quite small.

Two other loci were implicated in a 2006 study: the genes for monoamine oxidase A (MAO-A) and adrenergic alpha2A receptor (ADRA2A).

A large study carried out by the University of California, Los Angeles and the University of Oxford in 2002 found there were probably multiple genetic factors, in addition to environmental factors, influencing the progression of the disorder.

The three-year study will begin later this month. Families in Brisbane and Melbourne who are interested in participating in the study should see www.adhdstudy.com.au.