A genetic variation within the interleukin-6 (IL-6) gene increases susceptibility to systemic juvenile rheumatoid arthritis, according to researchers funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) and the Arthritis Research Campaign.
David N. Glass, M.D., and Susan D. Thompson, Ph.D., at Cincinnati Children's Hospital Medical Center in Ohio, along with researchers from the University College London, St. Thomas' School of Medicine in London, and the Hospital Necker in Paris, collaborated to collect DNA samples (which contain a person's genetic code) from children with systemic juvenile rheumatoid arthritis (JRA) and one or both parents. The transfer of genetic information from parent to child was analyzed in 100 British families, 95 American families and 27 French families. The scientists found excess transmission of a genetic variation (-174G nucleotide variant) within the IL-6 gene from parent to child. Children who developed systemic JRA at age 5 or older showed significantly higher levels of this variant compared to the children who developed the disease before age 5. These findings suggest that there may be distinct genetic profiles for the disease that result in differences in age of onset and disease severity. Continuing to uncover disease-associated genes may lead to clinically useful subgroupings of systemic JRA.
Juvenile rheumatoid arthritis (JRA), which has three main forms, affects each child differently. Some children experience swollen, painful or stiff joints. Other common symptoms include skin rashes, weak muscles, fevers and swollen glands. Systemic JRA, the most severe type, can also affect internal organs such as the heart, liver, spleen and lymph nodes. Twenty percent of children with JRA have the systemic form. Scientists suspect that JRA is caused by a combination of environmental and genetic factors.
The mission of the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a part of the Department of Health and Human Services' National Institutes of Health, is to support research into the causes, treatment and prevention of arthritis and musculoskeletal and skin diseases, the training of basic and clinical scientists to carry out this research, and the dissemination of information on research progress in these diseases. For more information about NIAMS, call the information clearinghouse at (301) 495-4484 or (877) 22-NIAMS (free call) or visit the NIAMS Web site at http://www.niams.nih.gov.
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Ogilvie EM, et. al. The -174 allele of the Interleukin-6 gene confers susceptibility to systemic arthritis in children. Arthritis & Rheumatism, 2003; 48(11): 3202-3206.