ADHD, READING DISABILITY: GENETIC LINKS INVESTIGATED

Between one-fifth and one-quarter of children and teens diagnosed with attention deficit hyperactivity disorder (ADHD) also suffer from a reading disability. A new gene study, by Sandra Loo and colleagues, indicates a genetic link between the two conditions.

Loo et al. measured the reading ability of 233 sibling pairs in which both children were diagnosed with ADHD. They then conducted a linkage study, searching for molecular markers that were shared by the siblings more often than would be expected based on their genetic relationship.

The researchers detected evidence of shared genetic factors for ADHD and reading disability on chromosomes 16, 17, and possibly 10, as well as evidence for genes on chromosomes 2, 8, and 15 that appear to be unique to reading problems.

Their data, Loo and colleagues say, support the idea that common genes underlie ADHD and reading disability, although unique genes also contribute to each.

"Genome-wide scan of reading ability in affected sibling pairs with attention-deficit/hyperactivity disorder: unique and shared genetic effects," S. K. Loo, S. E. Fisher, C. Francks, M. N. Ogdie, I. L. MacPhie, M. Yang, J. T. McCracken, J. J. McGough, S. F. Nelson, A. P. Monaco, and S. L. Smalley, Molecular Psychiatry, November 18, 2003 (Epub). Address: Sandra K. Loo, Neuropsychiatric Research Institute, 760 Westwood Plaza, Los Angeles, CA 90024.