NCIt related terms : Ankylosing spondylitis of unspecified sites in spine;
NCIt definition : An autoimmune chronic inflammatory disorder characterized by inflammation in the vertebral
joints of the spine and sacroiliac joints. It predominantly affects young males. Patients
present with stiffness and pain in the spine.;
Alternative definition : NICHD: An immune-mediated disease characterized by inflammation in the axial skeleton
including sacroiliac joints, vertebrae and vertebral joints. Peripheral joints may
be involved as well. Clinical features can include low back pain and stiffness, limited
motion of the lumbar spine, and limited chest expansion.;