Sjögren’s syndrome is a late onset chronic autoimmune disease which affects the exocrine glands, mainly the salivary and lacrimal glands, resulting in insufficient secretion by those glands. It is characterized by a progressive lymphoid and plasma cell infiltration of the salivary and tear glands, accompanied by the production of autoantibodies leading to mucosal (dry mouth) and conjunctival (dry eyes) dryness. Sjögren’s may occur alone (primary Sjögren’s) or secondary to other autoimmune disorders such as systemic lupus erythematosus (SLE) and rheumatoid arthritis. Primary Sjögren’s generally affects females (9/10 patients are female) and has an onset at around age 40. The reasons for the gender bias are unknown though hormones such as prolactin have been implicated.
Multiple genetic loci have been shown to contribute to the risk of developing Sjögren’s. Of these, the HLA class II DR and DQ are the most important. HLA-DQA1*05, DQB1*02, and DRB1*03 alleles are the risk factors for disease. Sjögren’s is diagnosed on the basis of screening questions, eye tests and salivary flow rate tests rather than on genetic testing. Genetic testing in Sjögren’s may be of value in providing insights into the mechanism of the disease, thereby potentially suggesting strategies for prevention and treatment.