HLA-B27 is an indicator of obligatory spondylitis, and a positive test result suggests that the person being tested may have ankylosing spondylitis. A positive test result for HLA-B27 only suggests that there is a lesion in the gene, but whether the gene mutation causes the disease is also related to environmental factors, depending on the type of expression of the gene mutation and environmental factors. Therefore not all populations develop ankylosing spondylitis. However, the prevalence of HLA-B27 positive people can be as high as 90%, which is relatively high. Because of the high incidence of ankylosing spondylitis, it is recommended that people who are found to be H LA-B27 positive during a medical checkup should undergo regular checkups to find out if there are any signs of the development of ankylosing spondylitis.