October 3, 2011

New Genes Associated With Type 1 Diabetes

(Ivanhoe Newswire) -- Type 1 diabetes affects 200 million people worldwide. Now, researchers have discovered new genes that will help them better understand the origin of this complex disorder. In a study published online today in Public Library of Science Genetics (PLoS Genetics), two doctors described their findings.

The genes were uncovered during the largest-ever analysis of available genetic data related to type 1 diabetes, a process called meta-analysis.

Study leader Hakon Hakonarson, M.D., Ph.D., director of the Center for Applied Genomics at The Children's Hospital of Philadelphia, collaborated with Constantine Polychronakos, M.D., director of Pediatric Endocrinology at McGill University. Together they investigated DNA data from six large, publicly available datasets of type 1 diabetes.

"Genome-wide association studies, as we used here, have been extremely powerful in identifying gene locations involved in the pathogenesis of complex, common diseases," Dr. Hakonarson was quoted as saying.

The databases contained single nucleotide polymorphisms (SNPs), which are single-base changes in DNA sequence that serve as signposts for gene mutations. SNPs are not disease-causing mutations, but they reside in gene regions associated with the disease.

The current research validated results from previous studies done by Dr. Hakonarson and his colleagues. It also identified, then replicated, three novel SNPs located in regions of considerable interest. The regions are involved in protein-protein interaction inflammation and cell signaling activity.

"Our study found SNPs that we had not expected to have any connection to type 1 diabetes," Hakonarson was quoted as saying. "The strongest association among the three SNPS was in the region of the LM07 gene on chromosome 13. We previously associated another member of the LMO gene family with the childhood cancer neuroblastoma. This gene family plays an important role in protein-protein interactions, but it would not have occurred to anyone that it may be active in type 1 diabetes. GWAS (genome-wide association studies) continues to turn up surprising biological associations."

According to Hakonarson, follow-up studies will focus on re-sequencing the regions linked to the SNPs in an attempt to narrow down causative mutations. Still further investigations will concentrate on how specific mutations function in the development of type 1 diabetes.

SOURCE: PLoS Genetics