UCLA geneticists find location of major gene in ADHD; targeted region also linked...( dies have implicated the same region as...),Health

ADHD and autism are very distinct clinical conditions. Although certain features are shared, the underlying biological mechanisms are thought to be distinct. If a common risk gene on chromosome 16 were found to underlie ADHD and autism, Smalley said, the finding would illustrate that genes affecting neurobiological mechanisms can cut across clinical boundaries, as most geneticists suspect.

This study provides compelling evidence that ADHD and autism may have a lot more in common than we ever thought, with implications for both diagnosis and treatment, Smalley said. However, further investigation is required to determine the significance of this finding, as it is also quite feasible that distinct risk genes underlying each condition just happen to be in close proximity on chromosome 16.

UCLA researchers spent five years collecting clinical, cognitive and genetic data from 203 families with multiple ADHD children. Their initial search for shared DNA markers suggested regions on chromosomes 16, 10 and 12. Focusing their attention on chromosome 16, researchers found a series of molecular markers shared among sibling pairs at a rate higher than the 50 percent sharing expected due to their degree of relationship.

Based on the observed degree of DNA sharing among ADHD siblings, the researchers estimate that the risk gene if replicated by other scientists studying ADHD might account for as much as 30 percent of the genetic cause of ADHD. As with any initial finding, however, the investigators caution that replication is necessary and that significant work with more families will be needed to find a specific risk gene in that location.

Previous investigations into a genetic cause for ADHD have focused on specific ca
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Contact: Dan Page
dpage@support.ucla.edu
310-794-2265
University of California - Los Angeles
22-Oct-2002