Zebrafish Assays to Measure ADHD Endophenotypes

Attention-deficit hyperactivity disorder (ADHD) is a developmental disorder characterized by hyperactivity, impulsivity and inattention. It currently affects around 5% of children worldwide and frequently has long-term consequences. However, although there is a significant genetic component to ADHD, relatively few risk genes have been identified and characterized [1-3]. The drug treatments available for the disease are poor with variable efficacy and significant side effects. Furthermore the etiology of ADHD is poorly understood and there are relatively few animal models for the disease. Recently, Arcos-Burgos and colleagues [4] reported evidence for a risk haplotype in the gene encoding Latrophilin 3 (LPHN3), revealed by a linkage scan in a genetic isolate population and subsequent fine mapping. LPHN3 is a potential G protein-coupled receptor with the propensity to moderate cell-cell interaction (adhesion-GPCR). However the physiological function of LPHN3 is not well understood and endogenous ligands have yet to be identified.