The onset of the disease is insidious. Patients gradually develop pain and/or stiffness in the low back or sacroiliac region, waking up in the middle of the night with pain, difficulty turning over, and stiffness in the low back that is evident when rising in the morning or after sitting for a long time, but relieved after activity. Some patients feel dull pain in the buttocks or severe pain in the sacroiliac region, which occasionally radiates to the periphery. The pain can be aggravated by coughing, sneezing, or sudden twisting of the back. In the early stage of the disease, the pain is mostly intermittent on one side, and after a few months, the pain is mostly persistent bilaterally. As the disease progresses from the lumbar spine to the thoracic and cervical spine, pain, restricted movement or spinal deformity occurs in the corresponding area. It has been reported that about 45% of our patients start with peripheral arthritis. Peripheral arthropathy is present in 24%-75% of AS patients at the beginning or during the course of the disease, mostly in the knee, hip, ankle and shoulder joints, with occasional involvement of the elbow and small joints of the hand and foot. Asymmetric, few-joint or single-joint arthritis and arthritis of the large joints of the lower extremities are the characteristics of peripheral arthritis in this disease. In our patients, arthritis or arthralgia of the knee and other joints, except the hip, is mostly transient and rarely or hardly causes joint destruction and disability. The hip joint is involved in 38% to 66% of the cases, showing localized pain, limitation of movement, flexion-twisting and joint ankylosis, most of which are bilateral, and 94% of the hip symptoms start within the first 5 years after the onset of the disease. The disease is more likely to occur at a younger age and in those with peripheral joint disease. The systemic manifestations of the disease are mild, with a few severe cases having fever, fatigue, wasting, anemia, or other organ involvement. Metatarsal fasciitis, Achilles tendinitis, and other areas of tendon terminal disease are common in this disease. 1/4 of patients develop uveitis during the course of the disease, alternating unilaterally or bilaterally, which usually resolves spontaneously and can lead to visual impairment with repeated attacks. Neurological symptoms arise from compressive spinal neuritis or sciatica, vertebral fractures or incomplete dislocations, and cauda equina syndrome, the latter of which can cause impotence, nocturnal urinary incontinence, bladder and rectal dullness, and loss of ankle reflexes. Very few patients develop fibrosis of the upper lobe of the lung. It is sometimes accompanied by cavity formation and is considered tuberculosis, and may be exacerbated by concurrent mycobacterial infections. Aortic valve atresia and conduction disturbances are seen in 3.5-10% of patients, and AS can be complicated by IgA nephropathy and amyloidosis.