Several risk genes for Sjögren's syndrome identified
For the first time, genetic factors increasing the risk of the rheumatic disease known as Sjögren's syndrome have been examined using analyses of the entire human genome. The results of the international study, in which researchers from Karolinska Institutet have participated, are published in the scientific periodical Nature Genetics.
Sjögren's syndrome is an autoimmune disease, in which the immune system attacks the body's own tissue. For reasons yet unknown, ninety per cent of patients are women. The present large-scale study, the first to systematically analyse genetic factors in the entire human genome, compared the DNA of patients with that of healthy controls with the aim of identifying genetic contributors to the development of the disease.
The researchers found seven gene variants that increase the risk of Sjögren's disease. They also found an additional 29 DNA regions that they suspect of being risk variants, but that had weaker associations with the disease. Most of the identified genes are implicated in one way or another in the function of the immune system.
"The results show how important genes involved in innate and acquired immunity are for Sjögren's syndrome," says research team member Professor Marie Wahren-Herlenius from Karolinska Institutet's Department of Medicine, Solna. "Many of the genes now identified, or the proteins they code for, are conceivable candidates for the development of a treatment."
Sjögren's syndrome leads to inflammation in and the gradual destruction of glands around the body, the most common symptoms being seen in the eyes and mouth, although the gastrointestinal tract, the lungs and kidneys can also be attacked. Many patients complain of muscle and joint pain and severe fatigue.
The present study is the result of an international collaboration involving research groups from Europe, North America and South America. The study was financed with grants from several bodies, including the Swedish Research Council, the Gustaf V 80-Year Foundation, and the Swedish Rheumatism Association.
Variants at multiple loci implicated in both innate and adaptive immune responses are associated with Sjögren's syndrome.
Nat. Genet. 2013 Nov;45(11):1284-92