A 23-year-old man complains of stiffness and pain in his lower back that causes him to awaken at night. He first noticed morning stiffness in his lower back during his college years. He also describes occasional pain in his right eye and sensitivity to light. An X-ray of the sacroiliac region shows fusion of the small joint spaces in the posterior spine and ossification of the intervertebral discs. Serologic tests for rheumatoid factor and antinuclear antibodies are negative. This patient most likely expresses which of the following human leukocyte antigen (HLA) haplotypes?
High-Yield Explanation
Ankylosing spondylitis is an inflammatory arthropathy of the vertebral column and sacroiliac joints. It may be accompanied by asymmetric, peripheral arthritis (30% of patients) and systemic manifestations. Ankylosing spondylitis is most common in young men, and the peak incidence is at age 20 years. More than 90% of patients are positive for human leukocyte antigen-B27 (HLA-B27), although the disorder affects only 1% of persons with this haplotype. None of the other haplotypes are related to the pathogenesis of ankylosing spondylitis.Diagnosis: Ankylosing spondylitis