Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is an autoimmune genetic disorder caused by mutation of the forkhead box protein 3 gene(FOXP3), a key regulator of immune tolerance.Objective
We sought to provide clinical and molecular indicators that facilitate the understanding and diagnosis of IPEX syndrome.Methods
In 14 unrelated affected male subjects who were given diagnoses of IPEX syndrome based onFOXP3gene sequencing, we determined whether particularFOXP3mutations affected FOXP3 protein expression and correlated the molecular and clinical data.Results
Molecular analysis ofFOXP3in the 14 subjects revealed 13 missense and splice-site mutations, including 7 novel mutations. Enteropathy, generally associated with endocrinopathy and eczema, was reported in all patients, particularly in those carrying mutations withinFOXP3functional domains or mutations that altered protein expression. However, similar genotypes did not always result in similar phenotypes in terms of disease presentation and severity. In addition, FOXP3 protein expression did not correlate with disease severity.Conclusion
Severe autoimmune enteropathy, which is often associated with increased IgE levels and eosinophilia, is the most prominent early manifestation of IPEX syndrome. Nevertheless, the disease course is variable and somewhat unpredictable. Therefore genetic analysis ofFOXP3should always be performed to ensure an accurate diagnosis, and FOXP3 protein expression analysis should not be the only diagnostic tool for IPEX syndrome.