Genome-wide association studies of ADHD have been completed in two European samples: a family study of 958 affected offspring trios (i.e. DNA from an affected offspring and both parents) from the International Multi-center ADHD Genetics (IMAGE) study 3 and a case-control study of 343 adult ADHD cases (304 controls). 4 Neither study identified a genome-wide significant association, 4, 5 but secondary analysis of ADHD symptom scores in the IMAGE study 6 suggested association with an overlapping gene of interest from Lesch et al 4 (CDH13) located on chromosome 16q24.2–q24.3 under the genome-wide significant chromosomal region identified in meta analysis. 2 We have conducted an independent multi-site GWAS of DSM-IV-TR ADHD in 735 affected-offspring trios using the Illumina Human1M and Human1M-Duo BeadChip platforms.
