Scientists Search Genome for Drug-Abuse Link

The search for genes predisposing to drug abuse may have been narrowed. George Uhl, M.D., Ph.D., of the National Institute on Drug Abuse’s Intramural Research Program in Baltimore and colleagues zeroed in on some 1,500 regions of the human genome that are known to vary from person to person. They then examined DNA samples taken from about 700 persons with a history of heavy drug use and from some 300 persons with no significant lifetime use of an addictive substance (controls) to determine what genetic variants they possessed at these particular genetic sites. They then attempted to determine whether the two groups differed significantly in possession of any of the variants.

They did, Uhl and his team reported in the December American Journal of Human Genetics. The two groups differed markedly in the possession of some 40 variants.

Thus, some, or perhaps all, of the variants possessed by the heavy drug users may play a role in drug-abuse susceptibility, the researchers believe. In fact, the locations of eight of the 40 variants on the human genome have been previously linked with alcohol or nicotine dependence, bolstering the case that possession of these eight variants at least makes people susceptible to drug abuse.

An abstract of the study, “Polysubstance Abuse-Vulnerability Genes: Genome Scans for Association, Using 1,004 Subjects and 1,494 Single-Nucleotide Polymorphisms,” is posted on the Web at www.journals.uchicago.edu/AJHG/journal/issues/69n6/013154/brief/013154.abstract.html. ▪