If a parent has ankylosing spondylitis and is HLA-B27 positive, the chance of passing the HLA-B27 gene to a child is 50%. However, not everyone with the HLA-B27 gene will develop ankylosing spondylitis. It is estimated that overall the average likelihood of the disease occurring in children of patients with ankylosing spondylitis is less than 1 in 10, increasing to 1 in 5 if the child is HLA-B27 positive, and less than 1 in 20 if it is passed from grandfather to grandson. And one hospital report showed that a survey of five family lines with a family history of ankylosing spondylitis found that of the 53 relatives surveyed, those with The number of cases of ankylosing spondylitis was 21. Therefore, patients with ankylosing spondylitis should be alert to the possibility of similar disease in their next generation. If their children are found to have early symptoms of ankylosing spondylitis, such as unnoticeable transient, asymmetric joint pain in the lower extremities, pain at the attachment points of tendons such as patellar tendon and Achilles tendon, stiffness and discomfort in the lower back, and recurrent iridocyclitis, they should be seen by a hospital with a rheumatology specialty in a timely manner. If the diagnosis is still doubtful, CT film of sacroiliac joint should be taken as early as possible to clarify the diagnosis and provide timely treatment.