Genetic bases of attention deficit hyperactivity disorder

The purpose of this study is to update the information available on the main group of genes that have been related with a susceptibility to attention deficit hyperactivity disorder (ADHD) or with the pharmacological response to different drugs used in the treatment of ADHD, in a number of different association and meta-analysis studies. Different studies have provided evidence of the importance of the genetic load in the susceptibility to ADHD. The work carried out to date point to genes in the dopaminergic system, such as the gene that codes for the dopamine transporter (DAT1 or SLC6A3) and for the dopamine receptor D4 (DRD4); in the noradrenergic system, like the gene coding for the adrenergic alpha-2A receptor (ADRA2A), the COMT gene, which codes for the enzyme catechol-O-methyltransferase and the gene that codes for latrophilin 3 (LPHN3), as genes that are candidates for playing a part in the susceptibility to ADHD, and being involved in the pharmacological response as well as in the risk of presenting associated behavioural disorders. On the other hand, the genes involved in regulating the metabolism of the drugs used in the treatment of ADHD, such as the gene CYP2D6 and gene CES1, play a role in the efficiency and tolerance of these psycho-pharmaceuticals. Although in recent years there has been an increase in the number of pharmacogenetic studies conducted on ADHD, findings differ significantly from one study to another. Integrating and meta-analytical studies are needed to be able to develop a more personalised treatment for ADHD.