Attention deficit, hyperactivity disorder (ADHD) is familial and highly heritable. Several candidate genes involved in neurotransmission have been identified, however these confer minimal risk, suggesting that for the most part, ADHD is not caused by single common genetic variants. Advances in genotyping enabling investigation at the level of the genome have led to the discovery of rare structural variants suggesting that ADHD is a genomic disorder, with potentially thousands of variants, and common neuronal pathways disrupted by numerous rare variants resulting in similar ADHD phenotypes. Heritability studies in humans also indicate the importance of epigenetic factors, and animal studies are deciphering some of the processes that confer risk during gestation and throughout the post-natal period. These and future discoveries will lead to improved diagnosis, individualized treatment, cures, and prevention. These advances also highlight ethical and legal issues requiring management and interpretation of genetic data and ensuring privacy and protection from misuse.

Josephine Elia is a physician scientist whose clinical and research work has focused primarily on attention-deficit hyperactivity disorder (ADHD). Her earlier work, focused on exploring neurotransmitter metabolites in children with ADHD using pharmacotherapeutic probes, provided support for noradrenergic involvement in ADHD pathophysiology. More recently, she has focused on ADHD genetics and along with her collaborators, she has discovered several rare variants in ADHD families. In addition, she has identified nocturnal enuresis as a potential clinical phenotypic marker that may share deficits in arousal for a subgroup of inattentive ADHD.