FOXP3 and immune dysregulation-polyendocrinopathy-enteropathy-X-linked syndrome: As indirect consequence of FOXP3 deficiency, B-cell tolerance is also impaired in IPEX: autoreactive B cells accumulate in the periphery, due to altered control of peripheral B-cell tolerance checkpoints by dysfunctional Tregs, resulting in the production of tissue-specific autoantibodies, which can in turn contribute to the clinical manifestations (49–51).