Ankylosing spondylitis is characterized by a chronic inflammation of sacroiliac joints (located in low back where sacrum meets iliac bones) and spine. It can cause stiffness and pain in different body parts such as neck, back, jaw and hips. It may also affect some other organs such as heart, eyes, kidneys and lungs. The causes of ankylosing spondylitis are not known. However, some genetic factors are found to be responsible for development of this disease.

Presence of genetic marker, HLA-B27 is one of the most significant causes of ankylosing spondylitis. A person with the age less than 40 and positive for HLA-B27 gene and having the family history of ankylosing spondylitis is at the higher risk of developing this disease. Two more genes including IL23R and ARTS1 are found to be associated with ankylosing spondylitis. Positive HLA-B27 maker, family history of ankylosing spondylitis and frequent gastrointestinal infections are the main risk factors for ankylosing spondylitis.

Genetic predisposition is one of the prominent causes of ankylosing arthritis. About 90% of patients with this disorder are positive for HLA-B27 gene. If either parent has HLA-B27 gene, there are about 50% chances of passing-on this gene to their child. Besides this, excessive immune response to the gastrointestinal bacterial infections such as ulcerative colitis and Crohn’s disease can cause the underlying pathogenesis of ankylosing spondylitis. The secretion of cytokines such as TNF-alpha is supposed to be related to this disease.

Pain and stiffness in the lower back are the early symptoms of ankylosing spondylitis. Inflammation of spine may give rise to stiffness and pain in low back, neck, upper buttock area and remaining area of spine. The severity of symptoms and complications may vary patient to patient. Patients with severe and chronic inflammation of spine may give rise to total bony fusion of spine which is known as ankylosis. It can lead to complete loss of mobility of spine. There may be difficulty in walking or standing. These fused spines are brittle and susceptible for fractures. The lower neck (cervical spine) is more vulnerable area for fractures.

Chronic ankylosing spondylitis may cause forward curving of the upper torso (thoracic spine) which can limit the breathing capacity. It can also affect the areas where ribs connect to the upper spine and can restrict lung capacity. There may be inflammation and scarring of the lungs due to ankylosing spondylitis which may cause coughing and shortness of breath. Breathing difficulty can be one of the serious complications of ankylosing spondylitis.

If the heart is affected by this disease, there may be valve problems such as aortitis (inflammation of the largest artery, aorta). Inflammation of other body parts can give rise to some other conditions such as inflammatory bowel disease, anemia and iritis (painful and inflamed eyes).

Advanced ankylosing spondylitis can cause deposition of protein material known as amyloid into the kidneys resulting in kidney failure. Progressive kidney disease can give rise to nausea and chronic fatigue. Hence, removal of accumulated blood poisons by dialysis is very essential.