12 April 2010
ByAppeared in BioNews 553
Three new gene variants have been linked to increased risk of brain aneurysms in the largest ever genome-wide study of its kind. The discovery brings the total number of gene variants linked to the condition up to five and paves the way for more targeted drug treatments and early screening tests to identify high-risk individuals, according to an international team led by researchers at the University of Yale, US. The study was published in Nature Genetics.
Murat Gunel, professor of neurosurgery, genetics and neurobiology at Yale and senior author of the paper, said that early treatment and diagnosis is key to saving lives: 'These findings provide important new insights into the causes of intracranial aneurysms and are a critical step forward in the development of a diagnostic test that can identify people at high risk prior to the emergence of symptoms'.
'Given the often-devastating consequences of the bleeding in the brain, early detection can be the difference between life and death', he added.
69 scientists from more than 32 institutions in 10 countries collaborated to recruit the 20,072 volunteers who took part in the study, 5,891 of which had previously been diagnosed with a brain aneurysm. Their genomes were scanned for 832,000 SNPs (single nucleotide polymorphisms) to identify those which occurred more frequently among the aneurysm patients.
This lead to the identification of three new gene variants linked to brain aneurysms - one situated on chromosome 18 near the gene RBBP8, one on chromosome 13 near the gene STARD13-KL and another near a particularly gene-rich region on chromosome 10. Associations with two previously known genetic markers - SOX17 and CDKN2A-CDKN2B - were also confirmed.
The research showed that individuals who carried all five of the gene variants were five to seven times more likely to have brain aneurysms compared to people who had none. But the findings represent only a small part of the genetic contribution of the disease, the researchers said.
'These findings explain about 10 per cent of genetic risk of suffering an aneurysm. This is 10 per cent more than we understood just a couple of years ago, but there is a long way to go', said Professor Gunel.
Brain aneurysms are balloon-like deformities in the blood vessels of the brain, which are prone to haemorrhaging, causing potentially fatal brain damage. The median age when brain haemorrhages occur is 50 years old, but they happen without warning and at present there is no method for their detection. More than 500,000 people worldwide are affected annually.