Substance abuse in Australia is a major problem, claiming thousands of lives and destroying countless others as a direct result of related crime and financial trauma. Each year alone, over a thousand children are born suffering from neonatal abstinence syndrome as a result of withdrawal from highly addictive substances. While a hereditary link regarding addiction has been suggested for centuries, it is only recently that this hypothesis may be formally tested using emerging genetic techniques.
Researchers at the National Human Genome Center in Shanghai have investigated sequence variations in the mu-opioid receptor gene (OPRM1) responsible for mediating the effects of opiate analgesics, most notably heroin. Variation in this receptor had previously been detected, and the scientists involved hoped to link it to a higher incidence of addiction. The study investigated the idea that single nucleotide polymorphisms (SNPs), a difference of only one nucleotide pair, might have an influence on the receptor, and ultimately on the genetic predisposition of addiction.
Five allelic variations were studied from a pool of 48 former drug addicts and 48 control subjects, however no genetic distinction was observed between the groups. It was, however, noted that the heroin addicts with a particular genotype had a significantly higher daily heroin intake than those with any other. This suggests that ‘drug-seeking’ behaviour has a basis in genetics. Interestingly, this variation was located in an intron of the gene, leading the scientists to propose a total mapping of both coding and noncoding regions of the receptor to determine if these SNPs play modest roles in the expression of the OPRM1 gene.
Sequence variations in the mu-opioid receptor gene (OPRM1) associated with human addiction to heroin. Shi J....Hu G. (2002)
