Using an entire country — Iceland — as a genetics laboratory, scientists there say they've identified previously unknown gene mutations that could be involved in a range of ailments, from heart disease to Alzheimer's.
The researchers undertook a massive gene-sequencing program involving 2,636 Icelanders, and because of something known as the founder effect — most of the country's inhabitants can trace their lineage back to a small group of founding fathers who came to Iceland from Europe around 1,100 years ago — they found they could infer the distribution of the genetic variants likely in the remaining 325,000 Icelanders.
That allowed them to identify genetic mutations linked to Alzheimer's, atrial fibrillation, liver disease, thyroid disorders and other conditions, says study leader Kari Stefansson, CEO of deCODE Genetics/Amgen.
In addition to genetic mutations, the researchers focused on people who lack a working copy of any particular gene, a condition geneticists call knockouts and consider valuable in understanding the pathways to disease.
"Basically, what we have is a fairly detailed insight into the DNA sequences of an entire nation ... We now have an insight into our fellow countrymen who have had a gene knocked out," Stefansson says.
There are a lot of them, the researchers say, noting that almost 8 percent of Icelanders lack a working copy of some gene.
The researchers identified 1,171 genes that were found to not be working in Icelanders with knockouts.
The fact that people with missing genes aren't necessarily prone to disease suggests some level of built-in redundancy in the human genome that allows particular genes to lose their function without any immediately obvious impact on a person's overall health, Stefansson says. Finding the redundancy might also help understand why certain people get sicker with a disease while others remain relatively unaffected.
Many previous studies have mined large databases of genetic information to find genetic culprits behind diseases like cancer and Alzheimer's, but the study of a genetically-unique population such as that found in Iceland is a golden opportunity to identify even more genetic changes that could also be important contributors to disease, the researchers say.
It could yield a more complete understanding of the genetic roots of health problems and could lead to new drugs and treatments for them, Stefansson says.
"I'm willing to go so far as to say that there is nothing in human nature that may not have a reflection in the genome, or have something in the genome that associates with it," he says. "We are made from the basis of the information coded in the genome."
