Diagnostic and Treatment Options for Severe IBD in Female X-CGD Carriers with Non-random X-inactivation

Background and Aims: X-linked chronic granulomatous disease [X-CGD] due to hemizygous mutations in CYBB is characterised by invasive bacterial and fungal infections and granulomatous inflammation. Inflammatory bowel disease [IBD] is an additional or isolated manifestation. Allogeneic haematopoietic stem cell transplantation [alloHSCT] is the standard curative treatment. X-CGD carriers are usually healthy but those with non-random X-chromosome inactivation [XCI] may develop infectious or autoinflammatory manifestations. Methods and Results: We report on two female patients with severe treatment-refractory Crohnlike IBD manifesting at age 23 and 8 years, respectively. NADPH-oxidase activity testing and molecular genetics proved X-CGD carrier status with non-random XCI. As in CGD, histopathology from colonic biopsies disclosed pigment-laden macrophages and reduced CD68+ macrophages. Following submyelo-ablative conditioning, the younger patient was treated with alloHSCT at age 20 years. She came into remission within 3 months after transplantation and shows complete mucosal healing after 16 months off all medications. Conclusions: We suggest that children and young adults with refractory IBD should mandatorily be tested for CGD. AlloHSCT should be considered as curative therapy in severely diseased female carriers of X-CGD with non-random XCI.