Recent advance in the genetic study of ADHD
Attention-Deficit/Hyperactivity Disorder (ADHD) has a very high heritability (0.8), suggesting that about 80% of phenotypic variance is due to genetic factors. This study used the integration of statistical and functional approaches to discover a novel gene that contributes to ADHD. For the statistical approach, the researchers started with a linkage study based on large multigenerational families in a population isolate, followed by fine mapping of targeted regions using a family-based design. Family- and population-based association studies in five samples from disparate regions of the world were used for replication. Brain imaging studies were performed to evaluate gene function. The linkage study discovered a genome region harbored in the Latrophilin 3 gene (LPHN3).
In the world-wide samples (total n=6360, with 2627 ADHD cases and 2531 controls) statistical association of LPHN3 and ADHD was confirmed. Functional studies revealed that LPHN3 variants are expressed in key brain regions related to attention and activity, affect metabolism in neural circuits implicated in ADHD, and are associated with response to stimulant medication. Linkage and replicated association of ADHD with a novel non-candidate gene (LPHN3) provide new insights into the genetics, neurobiology, and treatment of ADHD.
Authors: M Arcos-Burgos, M Jain, M T Acosta et. al.
National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.
Published in: Molecular Psychiatry advance online publication 16 February 2010;doi: 10.1038/mp.2010.6