Which of the following is not commonly associated with Ankylosing Spondylitis?

• A. Elevated C-reactive protein
• B. HLA B27 gene expression
• C. Osteoarthritis
• D. Crohn's disease

Answer: (C)

Ankylosing Spondylitis is a type of inflammatory arthritis primarily affecting the spine and can lead to the fusion of vertebrae. One of the hallmark features of Ankylosing Spondylitis is the presence of elevated inflammatory markers, such as C-reactive protein (CRP), which indicates an active inflammatory process. Additionally, HLA B27 gene expression is strongly associated with this condition, as a significant percentage of individuals with Ankylosing Spondylitis test positive for this gene.

Crohn's disease, an inflammatory bowel disease, can also have a prevalence among individuals with Ankylosing Spondylitis, as both conditions can be associated with spondyloarthritis and share common inflammatory pathways.

In contrast, osteoarthritis is primarily a degenerative joint disease characterized by wear and tear on the joints rather than inflammation. It is not a typical association with Ankylosing Spondylitis, making it the correct choice for what is not commonly associated with this condition. While someone might have both conditions separately, osteoarthritis does not directly relate to the inflammatory processes and characteristics that define Ankylosing Spondylitis.