Genome-wide association studies (GWAS) identify genomic regions associated with complex disease, but it can be difficult to pinpoint the exact gene or gene variant involved in the condition. Sergey Nejentsev at the University of Cambridge, UK, and his co-workers show how resequencing certain sections of the genome can bring researchers closer to an answer.
The group resequenced portions of 10 genes — which have been linked to diabetes or related syndromes — in 960 people, half of whom had type 1 diabetes. They then tested these genomic regions' association with diabetes in more than 30,000 people with and without the disease, and found four rare variants of the gene IFIH1 that seem to protect against diabetes. This gene is involved in the immune response to RNA viruses. The group concludes that resequencing can help to sort out causative from non-causative genes identified by GWAS.