Recent genetic advances in ADHD and diagnostic and therapeutic prospects

Attention deficit hyperactivity disorder (ADHD) is a common behavioral disorder of a complex nature. Genetic and environmental factors are thought to be involved in precipitating the disorder. Pharmacological, animal model and recent molecular studies support the role of genes (of minor or medium effect) from dopamine, serotonin and norepinephrine neurotransmitter systems in ADHD. Several investigations have pointed to the dopamine transporter, the dopamine receptors D4 and D5 and the serotonin transporter as genes of minor effect for ADHD. In addition, recent molecular analysis have also implicated synaptosomal-associated protein-25 and the serotonin receptor5-Hydroxtryptamine 1B as potential susceptibility loci for ADHD. An understanding of the genetics of ADHD will further facilitate refinement and validation of the ADHD diagnosis, and the development of reliable disease markers in the prediction of disease risk. A knowledge of genes that determine treatment response has the potential to be of predictive value and may also assist in rationalizing drug treatment in the ADHD population. However, increased understanding of inheritance brings its own challenges in the interpretation of new knowledge and in its wise and ethical use, especially in relation to future screening of at-risk individuals. This article attempts to review recent genetic advances and their possible implications for improved diagnosis and treatment.