The inflammatory arthritis diseases or spondyloarthropathies include various diseases such as Ankylosing spondylitis, the arthritis of bowel disease, reactive arthritis and the arthritis associated with psoriasis. The typical linking features of these diseases are enthesitis (an inflammation at the bone/ligament junction) and the presence of HLA B27, a gene on white blood cells. The inflammation at the entheses can develop into fibrosis and eventually to fusion of the joints from bone formation. The frequency of the HLA B27 gene in the population determines the number of people with Ankylosing spondylitis, the most common disease in the spondyloarthropathy group. AS occurs in about 0.1 to 1.0% of people, being much more common in northern Europe and much less common in equatorial regions and with white people more frequently affected. 100 people may … Read entire article »