Juvenile idiopathic arthritis (JIA) is the most common forms of arthritis in children under the age of 16. It is also called juvenile rheumatoid idiopathic arthritis (JRA) and juvenile chronic arthritis (JCA). Juvenile idiopathic arthritis causes persistent pain, swelling, stiffness and loss of motion in the joints. Some children may experience symptoms for only a few months, while others have symptoms for the rest of their lives. JIA can produce serious complications in more severe cases such as growth problems and eye inflammation. Research has indicated JIA as an autoimmune disorder and that heredity and environment seem to play a role. Scientists suspect that it is a two-step process. First, something in a child’s genetic makeup gives him or her a tendency to develop JIA; then an environmental factor, such as a virus, triggers the development of the disease. Medicines and physical therapy can help maintain movement and reduce swelling and pain.
A gene is the basic physical and functional unit of heredity passed from parent to offspring. Genes are made up of DNA and contains information to make proteins. The Human Genome Project has estimated that humans have between 20,000 and 25,000 genes. Every person has two copies of each gene, one inherited from each parent and this is how height, hair color, skin color, and eye color are determined. Also, mental abilities and natural talents are from genes as well as susceptibility to acquire certain diseases.
Previous studies have demonstrated that there is familial aggregation of juvenile idiopathic arthritis. A current trial sought to determine the relative risk for siblings and cousins of JIA sufferers. The computerized genealogical database that was used in the study matched 862 JIA cases with approximately seven million individuals in the Utah Population Database. Specialized software then reviewed the data to determine familial aggregation of disease. It was found that the relative risk of JIA in siblings was found to be 11.6%. The relative risk of JIA was also significantly elevated in first-cousins at approximately 5.8%. Overall, it was found that 13% of cases of JIA could be linked to familial factors. These results suggest that siblings and first-cousins of patients with JIA have an increased risk of developing JIA, and that risk appears to be influenced by shared genetic factors.1
1 Prahalad S, Zeft A, Pimentel R, et al. Quantification of the familial contribution to juvenile idiopathic arthritis. Arthritis Rheum. 2010.