Loss-of-function of lipopolysaccharide-responsive beige-like anchor protein causes inflammatory bowel disease-a case report and literature review.

Background: Most cases of childhood inflammatory bowel disease (IBD) are polygenic in origin, although a subset of patients exhibits monogenic etiologies. Some studies have identified the lipopolysaccharide-responsive beige-like anchor protein (LRBA) gene as a susceptibility gene, but the majority of research has focused on genetic mutations without extensive clinical data. Furthermore, there is a paucity of long-term data on pediatric patients receiving biologic therapy. Case Description: An 11-year-old female patient presented to the Gastroenterology Department with a 1-month history of chronic abdominal pain, diarrhea, and weight loss. Laboratory investigations revealed marked inflammation, anemia, hypoproteinemia, and elevated counts of naive B-cell. Endoscopic examination identified ulcers and polyp proliferation, which was consistent with an initial diagnosis of Crohn's disease. However, despite several months of standardized treatment, there was no significant clinical improvement. Subsequent genetic testing identified LRBA deficiency with a novel mutation. Following the adjustment of her biologic treatment regimen, the patient eventually achieved clinical remission. We also conducted a literature review on LRBA deficiency and IBD. The effective therapies mentioned were hematopoietic stem cell transplantation (HSCT) and abatacept. Conclusions: We described a Chinese IBD and LRBA-deficient patient carrying a novel mutation. In this context, the patient achieved remission under regular biologic therapy, which may offer valuable insights for the treatment of similar cases. Keywords: Lipopolysaccharide-responsive beige-like anchor protein deficiency (LRBA deficiency); inflammatory bowel disease (IBD); Crohn's disease (CD); biologic therapy; case report.