However, several mutations were identified in this screen, including an abrogated splicing mutation of Exon 6 in the winged-helix transcriptional regulator Foxn1 gene [125] Foxn1 mouse mutants are athymic and severely immuno-compromised, while human FOXN1 mutations cause T-cell immunodeficiency [126]. This evidence concerns the gene FOXN1 and T-cell immunodeficiency.