Association Analysis of Candidate Genes for ADHD on Chromosomes 5p13, 6q12, 16p and 17p

ABSTRACT

Attention-deficit/hyperactivity disorder (ADHD) is a common, heterogeneous psychiatric disorder of childhood displaying inattentive, hyperactive, and impulsive symptoms. Although the biological basis of ADHD remains unknown, it has been shown that genetic factors substantially contribute to the aetiology of the disorder. Our group has previously reported significant linkage to four chromosomal regions on 5p13, 6q12, 16p13 and 17p11 in genome-wide scans and subsequent fine-mapping. We selected nine positional candidate genes within the linkage intervals for study based on biological plausibility. We analyzed at least 189 ADHD trios to determine if common variants in these genes have a major affect on ADHD risk. None yielded significant association. This does however not completely exclude these genes as potential susceptibility genes for ADHD since it is plausible for common causal variants with low effect size to go undetected due to insufficient power of the study sample. We conclude that none of the tested alleles confer a major risk for developing ADHD and that investigation of other genes within the linked regions is warranted.