Gastrointestinal Manifestations of Yao Syndrome (NOD2-Associated Autoinflammatory Disease).

backgroundYao syndrome (YAOS) is a NOD2-associated autoinflammatory disease characterized by periodic fevers, dermatitis, polyarthritis, swelling of the distal extremities, and gastrointestinal symptoms in patients with specific NOD2 variants. While gastrointestinal symptoms are a hallmark of the disease, little is known about specific symptoms and their underlying mechanisms.

methodsIn this study, we identified 24 patients with YAOS from an institutional YAOS databse. We evaluated their presenting gastrointestinal symptoms at initial presentation via the validated Gastrointestinal Symptom Rating Scale questionnaire, which 14 participants filled out. We then systematically analyzed all gastrointestinal-relevant blood work, stool studies, imaging, endoscopies, and motility testing.

resultsGastrointestinal symptoms were reported by 100% of patients, with the most prominent symptom being bloating. Most of the workup including stool testing, gastrointestinal-related bloodwork, and endoscopic examinations with biopsies was normal. Abdominopelvic radiographs and cross-sectional imaging studies were most often normal, although an excessive stool burden was commonly identified. A minority of patients had associated diagnoses of collagenous gastritis, celiac disease, autoimmune-like enteropathy, or microscopic colitis. Gastric and colonic motility testing was normal in most patients; however, anorectal manometry with balloon expulsion testing was abnormal in 100% of tested patients. A minority of patients had hepatic steatosis or benign liver lesions.

conclusionsGastrointestinal symptoms of YAOS are universal and severe, and symptoms may arise from both inflammatory and non-inflammatory mechanisms. Bloating and constipation may be driven by dyssynergic defecation.