Researchers may be one step closer to determining the role of genetics in psoriasis, a chronic skin disease of scaling and inflammation.
A team of researchers led by Anne M. Bowcock, Ph.D., at the Washington University School of Medicine in St. Louis, have identified two genes on chromosome 17, SLC9A3R1 and NAT9, which are associated with psoriasis. The region between these two genes acts as a binding site for the protein RUNX1, which normally serves to regulate genes involved in immune reactions. The researchers found that when this region is altered, susceptibility to psoriasis occurs. This defective regulation may cause an increased activation of T cells, a type of white blood cell that normally helps protect the body against infection and disease. Such activation triggers inflammation and rapid turnover of skin cells in people with psoriasis.
It is also possible that the defective regulation could be affecting other cell types such as skin cells known as keratinocytes. In psoriasis, these divide much faster than in normal individuals and do not develop normally.
This study involved 242 European families with 572 individuals diagnosed with psoriasis. The findings from this research, funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases and the National Psoriasis Foundation, indicate further progress toward understanding the cause of psoriasis in patients with a family history of the disease. This information will be used in future studies to investigate other psoriasis populations, as well as to examine other inflammatory diseases, such as atopic dermatitis.
Psoriasis affects between 5.8 and 7.5 million people in the United States. The disease occurs in all age groups and primarily affects adults. Approximately 1 million people with psoriasis experience joint inflammation that produces symptoms of arthritis. Although the exact cause of psoriasis is not yet known, it is considered an autoimmune disease, one in which the body's immune system mistakenly attacks its own cells, tissues and organs.
The mission of the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a part of the U.S. Department of Health and Human Services' National Institutes of Health (NIH), 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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Helms C, et al. A putative RUNX1 binding site variant between SLC9A3R1 and NAT9 is associated with susceptibility to psoriasis. Nature Genetics2003;35:349-356.