Identification of Fecal Microbiota Biomarkers of Spondyloarthritis in Patients Suffering From Crohn's Disease.

This study looks for specific patterns in gut bacteria (the microbiome) that may help identify which patients with Crohn's disease also have spondyloarthritis — a type of inflammatory joint disease affecting the spine. Understanding this link could lead to earlier diagnosis and better treatment. **You may be eligible if...** - You are 18 or older - You fall into one of these groups: (1) Crohn's disease with axial spondyloarthritis, (2) Crohn's disease without spondyloarthritis, or (3) axial spondyloarthritis without Crohn's disease - You are able to give informed consent **You may NOT be eligible if...** - You have had part of your colon removed - You have recently taken antibiotics or completed bowel prep - Other specified exclusion criteria apply Talk to your doctor to see if this trial is right for you.