The disease is more common in men and usually strikes before the age of 40. Stiffness, aching joints, joints that have lost range of motion (such as bending over or getting out of a chair) are all familiar symptoms. Mobility helps relieve the symptoms, while prolonged sitting or lying down usually aggravate the symptoms. The upper spine and neck become stiff and over time can result in a posture deformity known as kyphosis which is a humped over position with the neck and head pushed forward or downward. Kyphosis
is due to permanently fused spinal bones. The damage to the cartilage between the breastbone and ribs can result in pain with breathing and decreased chest expansion.
Shoulder joints can be affected as well. Fatigue and loss of appetite are other symptoms of this chronic disease.