Pediatric researchers analyzing DNA variations in type 1 diabetes and inflammatory bowel disease have found a complex interplay of genes. Some genes have opposing effects, raising the risk of one disease while protecting against the other. In other cases, a gene variant may act in the same direction, raising the risk for both diseases.
Both type 1 diabetes (T1D) and inflammatory bowel disease (IBD) are autoimmune disordersconditions in which the body's immune system overreacts, resulting in disease. Many such autoimmune diseases share genes in common, acting on shared biological pathways.
"This finding shows the genetic architecture of these diseases is more complex than previously thought," said study leader Hakon Hakonarson, M.D., Ph.D., director of the Center for Applied Genomics at The Children's Hospital of Philadelphia. "We knew that multiple genes that interact with each other and with environmental factors are needed to bring on these complex diseases, and we are still detecting these genes and uncovering those interactions. But we now see that some genes influence more than one disease, and sometimes in the opposite direction."
Hakonarson and colleagues, including collaborators from more than a dozen institutions in four countries, published the study online in an advance article on Feb. 22 in Human Molecular Genetics.
Inflammatory bowel disease consists of Crohn's disease (CD), which may affect the entire digestive tract, but especially the small intestine, and ulcerative colitis (UC), mainly affecting the large intestine. Type 1 diabetes, also called insulin-dependent diabetes, occurs when the body produces little or no insulin because the immune system destroys insulin-producing cells.
The study team analyzed samples from 1,689 children and adolescents with CD, 777 with UC, and 989 with type 1 diabetes, as well as 6,197 control samples from healthy children. All the children were of European ancest
|Contact: John Ascenzi|
Children's Hospital of Philadelphia