FAS and endocrine system disorder: In addition, the normal suppressive function observed in vitro and the lack of clinical symptoms usually observed in Treg-deficient patients (i.e., autoimmune enteropathy and endocrinopathy) support the hypothesis whereby Treg functions, in particular inhibition of Tconvs proliferation, are unaffected in patients with FAS deficiency—despite the abnormal phenotype observed for circulating cells.