Forkhead box protein N1 is a protein that in humans is encoded by the FOXN1gene.
Mutations in the winged-helix transcription factor gene at the nude locus in mice and rats produce the pleiotropic phenotype of hairlessness and athymia, resulting in a severely compromised immune system. This gene is orthologous to the mouse and rat genes and encodes a similar DNA-binding transcription factor that is thought to regulate keratin gene expression. A mutation in this gene has been correlated with T-cell immunodeficiency, the skin disorder congenital alopecia, and nail dystrophy. Alternative splicing in the 5' UTR of this gene has been observed. In the chick embryo, the FOXN1 gene is expressed in the developing thymus, claws and feathers. The expression of FOXN1 in feathers and claws indicates that it may regulate the feather outgrowth. In feather and claws, FOXN1 can potentially regulate expression of keratins similar to mammalian orthologs. 
^Darnell DK, Zhang LS, Hannenhalli S, Yaklichkin S. (Dec 2014). "Developmental expression of chicken FOXN1 and putative target genes during feather development.". Int J Dev Biol.58 (1): 57–64. doi:10.1387/ijdb.130023sy. PMID24860996.
Nehls M, Pfeifer D, Schorpp M et al. (1994). "New member of the winged-helix protein family disrupted in mouse and rat nude mutations". Nature372 (6501): 103–7. doi:10.1038/372103a0. PMID7969402.
Frank J, Pignata C, Panteleyev AA et al. (1999). "Exposing the human nude phenotype". Nature398 (6727): 473–4. doi:10.1038/18997. PMID10206641.
Gattenlöhner S, Müller-Hermelink HK, Marx A (1999). "Transcription of the nude gene (WHN) in human normal organs and mediastinal and pulmonary tumors". Pathol. Res. Pract.195 (8): 571–4. doi:10.1016/s0344-0338(99)80007-7. PMID10483588.
Adriani M, Martinez-Mir A, Fusco F et al. (2004). "Ancestral founder mutation of the nude (FOXN1) gene in congenital severe combined immunodeficiency associated with alopecia in southern Italy population". Ann. Hum. Genet.68 (Pt 3): 265–8. doi:10.1046/j.1529-8817.2004.00091.x. PMID15180707.
Janes SM, Ofstad TA, Campbell DH et al. (2005). "Transient activation of FOXN1 in keratinocytes induces a transcriptional programme that promotes terminal differentiation: contrasting roles of FOXN1 and Akt". J. Cell. Sci.117 (Pt 18): 4157–68. doi:10.1242/jcs.01302. PMID15316080.
Nonaka D, Henley JD, Chiriboga L, Yee H (2007). "Diagnostic utility of thymic epithelial markers CD205 (DEC205) and Foxn1 in thymic epithelial neoplasms". Am. J. Surg. Pathol.31 (7): 1038–44. doi:10.1097/PAS.0b013e31802b4917. PMID17592270.