A small segment of the country’s population carries a gene that protects against the disease.
Because of its isolation, the Icelandic population of 300,000 is relatively inbred and genetically similar. Its small and homogeneous gene pool is makes it possible to identify rare mutations in genes. In the case of the AD-preventative gene, the mutation was found in only .5 percent of Iceland’s population.
According to the ACSH report, the mutated gene slows the process by which a protein known as APP breaks down and forms the beta-amyloid protein found in the brains of people with AD. In people who have the gene, the breakdown of the APP protein is inhibited, and the risk of developing AD is decreased.
“Compared with their countrymen who lack the mutation, Icelanders who carry it are more than five times more likely to reach 85 without being diagnosed with Alzheimer’s. They also live longer, with a 50% better chance of celebrating their 85th birthday.”
In a paradoxical twist, more recent research has identified a separate genetic variation among Icelanders that predisposes people to early-onset Alzheimer’s. Both of these discoveries add to the knowledge necessary to develop treatment and prevention strategies.