Special genes suspected to cause lethal overdose in drug addicts
Forensic scientists investigate genes from dead and living drug addicts on suspicion of link between overdose risk and minor variations in the genes.
Between 7,000 and 8,000 EU citizens die from drug-induced deaths every year. The majority of these deaths are caused by harmful use of opioids such as heroin or methadone.
Now, a research project launched by the Institute of Forensic Medicine at the University of Southern Denmark seeks to investigate if certain alterations in our genes make us predisposed to drug overdoses.
The leader of the project, Dorte Rollmann, forensic scientist and PhD student, imagines the knowledge can be used as a precautionary measure towards lethal drug overdoses.
“It would make it possible to predict if a person is at a greater risk, should he end up in a drug abusive behaviour,” says Rollmann.
If the blood levels in a living addict are identical to those of a dead but they differ on a genetic level, I can deduce that this guy died because his genes were different from those of the living drug addict.
Genes could be cause of lethal overdose
The project aims to analyse blood concentrations of heroin and two treatment drugs, methadone and buprenorphine, in both dead and living addicts and compare it with their genetic code.
“If the blood levels in a living addict are identical to those of a dead but they differ on a genetic level, I can deduce that this guy died because his genes were different from those of the living drug addict,” says Rollmann.
The dead addicts have been examined twice to ensure the cause of death indeed was a drug poisoning. Even though it should happen a common flu had caused sufficiently lowered fatigue to put a drug addict in higher risk of dying from an overdose, the amount of test subjects, dead as well as living, more than makes up for it in statistical significance, says Rollmann.
I’ve looked at genes coding for the metabolism and transport of the drugs and how they change certain receptors.
Gene mutations alter our inner coding
The project is the largest of its kind; 1,200 persons are taking part – of these, 400 deceased drug addicts who died from either an overdose of heroin, methadone or a combination of both. The remainder consists of 400 heroin addicts currently enrolled in treatment and 400 non-users making up the control group.
Blood samples have been collected from all 1,200 participants and their genes have been sequenced.
Rollmann wants to put a special kind of mutations in our genes under the loop. They’re called single-nucleoride polymorphisms, shortened SNP, and pronounced as ’snip’. A snip is a small change in the coding of a specific gene.
“I’ve looked at genes coding for the metabolism and transport of the drugs and how they change certain receptors,” says Rollmann.
Based on previous studies and her own assertions 32 SNP’s (snips) have been selected for the study.
Every gene is coded to respond in a particular way – as an example, the UGT2B7 gene is coded to produce a special enzyme responsible for metabolising morphine. If there is a SNP on that gene, it can affect how well the body handles the morphine and for a drug addict it could mean the difference between life and death – and reveal if some could be predisposed to a higher risk of an overdose.
Deceased drug addicts may have different genes
Next step for Rollmann is to take a churn at the massive amount of data she has collected. She hopes the majority of the dead addicts reveal themselves to host a wide range of SNPs, making it difficult for them to metabolise the harmful drugs, while the living drug addicts turn out to have none or few of the gene mutations.
If the blood levels of the harmful drugs are identical in both living and dead, it will be fair to say that SNPs were more than likely the game changer between life and death.
Rollmann expects to have the first results ready by end of summer 2013.
Should her hypothesis prove correct, Rollmann hopes her findings can contribute to a more targeted treatment of drug addicts and also psychiatric patients.
“It would be interesting to have the mentally ill sequenced before they begin their treatment since we don’t know much about how they metabolise the drugs they are prescribed,” says Rollmann.
Translated by: Kristian Secher