AS is a hereditary condition

Q: My cousin is only 25, but he was just diagnosed with arthritis in his back that they said was due to some hereditary condition. What is this?

A: There is a gene called HLA-B27 that is associated with "seronegative spondyloarthropathies," including ankylosing spondylitis. Lots of big words here, so I will discuss this and try to simplify the jargon. You should verify this is what your cousin has.

Certain traits run in families. These include genes that put someone at risk for developing a specific condition. Not everyone who inherits the gene develops the condition, and sometimes people without the gene get the condition anyway; why this is so is still a bit of a medical mystery.

Ankylosing spondylitis (AS) is a type of back arthritis that falls into this category. Ankylos is Greek for bent or crooked and spondylos refers to the bones of the spine, so AS is a disease of the spine that, when severe, can eventually make the affected person become bent-over or hunched. Since this is a hereditary condition, first-degree relatives of someone affected are at an increased risk of developing it.

AS is an inflammatory disease where the body attacks itself. The inflammation erodes the spinal bones (vertebrae), and the body overreacts to this by producing too much new bone. Subsequently two adjacent vertebrae grow into each other and become fused.

AS affects between 1 in 100 and 1 in 10,000 people. This wide variation is because the HLA-B27 gene is much more common in certain ethnic groups. Overall, about 8 percent of caucasians, 5 percent of Chinese, 4 percent of Africans and 0.3 percent of Japanese have the gene. In Lapland, over one-quarter of the population has it. In the United States, the diversity of our population yields about 200,000 whites and 5,000 blacks with the gene.

AS affects up to 5 percent to 6 percent of people with the HLA-B27 gene but is extremely rare in those without the gene. There are other conditions associated with HLA-B27, including Reiter's syndrome and sacroiliitis, but I will not discuss these today.

Like many other forms of arthritis, the initial symptom of AS is pain, usually in the low back. As AS is a generalized inflammatory condition, it is not surprising that other body-wide symptoms, like malaise and stiffness, can occur. Other joints can be affected, including the hips and shoulders, and even the Achilles' heal can be involved. Rarely, other organs such as the heart, lungs and kidneys are also affected.

AS is often diagnosed when X-rays or an MRI of the lower back, done to evaluate persistent pain, demonstrate fusion of the spine. At this point, special tests may be ordered to verify the HLA-B27 gene is present.

The goals of treatment of AS are to improve the symptoms, minimize joint damage and maintain joint function and flexibility. The initial treatment of AS is similar to other causes of low back pain, including anti-inflammatory pain medications such as ibuprofen or naprosyn. Flexibility exercises, a supportive sleeping surface and laying face down to rest for 20 minutes or more per day may be recommended to help maintain movement and function. For those with severe and progressive disease, medications that "modify" the disease by inhibiting the inflammatory process may also be used, but as these have more side effects they are usually not used until other treatment options have failed.

The prognosis of AS depends on the severity of the disease. Those with mild disease are usually able to live a pretty normal life and work into their 50s. Those with more severe disease can have this become an incapacitating condition and, although not usually life-threatening, they may not be able to work by the time they are in their 30s. Indicators of more severe disease include earlier onset (less than 16 years old), hip involvement, having a high ESR blood test (a non-specific measure of inflammation), having decreased range of motion (already being "bent") and having the fingers and toes appear "sausage-like."

So, if you have persistent back pain or other symptoms that may be attributed to AS, especially if at a young age and if you have a family history of AS, you should see your doctor to be further evaluated, usually with X-rays.

Jeff Hersh, Ph.D., M.D., F.A.A.P., F.A.C.P., F.A.A.E.P., can be reached at DrHersh@juno.com.