Patients with Compound Heterozygous Mutations in Forkhead Box N1 Have Severe Immunodeficiency While Maintaining Normal Skin and Hair Development

The study reported on three patients with compound heterozygous mutations in the Forkhead Box N1 (FoxN1) gene, which resulted in severe immunodeficiency characterized by low to absent circulating T cells. Despite this, the patients exhibited normal hair and skin development, and no nail dystrophy, which is atypical compared to previously reported phenotypes associated with FoxN1 mutations. The researchers used CRISPR/Cas techniques to introduce these mutations into mice to study the resulting phenotypes and conducted comparative transcriptome analyses of fetal thymii to understand the impact on thymic epithelial gene expression and function. The findings aimed to enhance the understanding of FoxN1's role in epithelial cell development and function in the thymus and skin.