Cytogenetic abnormalities in attention-deficit/hyperactivity disorder.

OBJECTIVE

To systematically assess the prevalence of fragile X syndrome, velocardiofacial syndrome, and other cytogenetic abnormalities in a group of children with attention-defict/hyperactivity disorder (ADHD).

METHOD: Blood samples were obtained from 100 children (64 boys) with combined type ADHD and normal intelligence and analyzed for the presence of fragile X mutation expansions, the 22q11.2 microdeletion associated with velocardiofacial syndrome, and cytogenetic abnormalities that would be detected with high resolution chromosomal banding.

RESULTS

One 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 microdeletion was negative for all subjects with ADHD screened. None of these differences exceeded those expected by chance.

CONCLUSIONS

In 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.