We report a patient with immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome with a novel splicing mutation of the FOXP3 gene. The patient is a boy, born at 39 + 2 weeks gestation with a birth weight of 3,280 g. The family history was unremarkable. He was well until 11 months of age, when he was diagnosed with type 1 diabetes mellitus. The level of urine C-peptide was 0.58 μg/day (normal range, 44-116 μg/day). Glutamic acid decarboxylase autoantibody was not detected, but a high level of anti-insulin antibody (50 IU/mL; normal range, <5 IU/mL) was noted. This patient presented with unusual clinical features, including pure red cell aplasia, membranous glomerulopathy, and posterior reversible encephalopathy syndrome after a vaccination against influenza A H1N1 virus. The diagnosis of IPEX was made when the patient was 11 years old, which is quite late compared with typical cases.
Conclusion: Although IPEX syndrome is usually a disease of infancy, it should not be ruled out solely on the basis of age. IPEX presentation is so variable that it should be suspected in a male child with one or more autoimmune disorders and severe infections.