British Journal of Rheumatology 1993;32:36-^0 THYROID DISEASE AND OTHER AUTOIMMUNE PHENOMENA IN A FAMILY STUDY OF PRIMARY SJOGREN'S SYNDROME

Autoimmune diseases and autoantibodies have been documented in 42 index cases with definite primary Sjogren's syn-drome (1 ° SS), 207 relatives and 39 spouses. The results were compared with control data from a local population survey. Thyroid disease, 1 ° SS and their associated autoantibodies were the commonest autoimmune abnormalities observed and found predominantly in older female relatives. The HLA-DR3 phenotype associated with 1 ° SS, antinuclear factor, hypothyroidism, and thyroid microsomal antibody. Rheumatoid arthritis and systemic lupus erythematosus were not found in excess in the families. Primary Sjogren's syndrome is frequently associated with thyroid disease and we suggest that there is a common genetic predisposition between these diseases which differs from 2 ° SS associated with rheumatoid arthritis and systemic lupus erythematosus. This includes MHC and non-MHC genes. KEY WORDS: Thyroid disease, Genetics, HLA-DR3, Sjdgren's syndrome. PRIMARY Sjogren's syndrome (1 ° SS) is an autoimmune disease of unknown aetiology, characterized by lym-phocyte mediated damage to exocrine glands and extraglandular structures. It is associated with organ and non-organ specific autoimmune diseases and auto-antibodies [1-6]