Phenotypical Characterization of Gastroenterological and Metabolic Manifestations in Patients With Williams–Beuren Syndrome

Gastrointestinal (GI) symptoms are common in patients with Williams-Beuren syndrome (WBS), but their prevalence and possible causes are not yet fully known. This study assessed GI symptoms' prevalence and their possible origin by performing a predefined set of tests in adult WBS patients. Laboratory tests and a questionnaire were administered to assess GI symptoms and dietary habits. All the patients underwent the urea breath test, H₂-lactose and H₂-glucose breath tests, and intestinal ultrasound (IUS) and vibration-controlled transient elastography for liver stiffness measurement (LSM) and controlled attenuation parameter (CAP, dB/m). Thirty-one patients were enrolled (72% of the whole cohort, 17 males, median age 32 years). Gastroesophageal reflux disease (GERD) symptoms were reported in 29% of the patients, abdominal pain in 26%, and altered bowel habits in 48%. Pathologic signs at (IUS) were present in 60% of the cases. Prevalence was 0.26 (95% CI 0.12-0.44) for Helicobacter pylori infection and 0.61 (95% CI 0.42-0.78) for lactose intolerance. LSM was > 6 kPa (in the range of a fibrosis score > F1) in three patients, and CAP values were > 268 dB/m (corresponding to a steatosis score > S2, e.g., moderate steatosis) in nine. The presence of altered bowel habits was significantly related to chronic abdominal pain (OR 13.1, p = 0.03). Increased BMI (> 28 kg/m²) (OR 10.8, p = 0.04) was associated with the presence of moderate-severe hepatic steatosis. After specific treatment and dietary counseling, most patients reported resolution/improvement of symptoms, whereas a few retained/developed symptoms during follow-up. Chronic abdominal pain, GERD symptoms, and unbalanced metabolic parameters were common in our WBS patients, together with an increased prevalence of lactose intolerance/colonic diverticula. Specific counseling and treatment improved symptoms for most patients.