Genetic Testing: HLA-B27

The specific genetic tissue type or protein factor found frequently in people with spondyloarthropathies is called HLA-B27. About 90 percent of children with juvenile ankylosing spondylitis carry this genetic factor. Only 50 percent of children with juvenile psoriatic arthritis carry it.

The HLA-B27 genetic factor can be passed down from generation to generation. Someone who carries HLA-B27 and has a family member with spondyloarthropathy has a 10 to 20 percent chance of developing spondyloarthropathy himself or herself. If you have it, you might want to consider genetic counseling.