Table 1

 Prevalence of cytogenetic abnormalities in an unselected population of children with ADHD

CitationStudy groupStudy typeOutcomeKey resultsComments
Bastain et al (2002)6Blood samples from 100 children (64 boys, 36 girls, mean age 10.2±3.1 years) with combined type ADHD and normal intelligence were analysed for the presence of fragile X mutation expansions, the 22q11.2 micro deletion associated with velocardiofacial syndrome, and cytogenetic abnormalities that would be detected with high resolution chromosomal bandingUncontrolled cohort (level 4)No. of patients with cytogenetic abnormalitiesOne girl with ADHD had a sex chromosome aneuploidy (47, XXX). One boy had a premutation-sized allele for fragile X; no subjects showed the full mutation. Testing for 22q11.2 micro deletion was negative for all subjects with ADHD screened. None of these differences exceeded those expected by chanceIn the absence of clinical signs or positive family history, these relatively expensive laboratory assessments are not clinically indicated for children with ADHD and normal intelligence, and are not recommended as a component of other genetic investigations of this disorder