FOXN1 Duplication and Congenital Hypertrichosis.

We report a case of congenital hypertrichosis and FOXN1 duplication. FOXN1 is a member of the forkhead box gene family, located on chromosome 17. Its function includes differentiation of epithelial cells and regulation of keratinocytes, especially hair keratins. Loss of function of these transcription factors leads to a disruption in hair growth. As far as we are aware, this is the first case of FOXN1 duplication associated with congenital hypertrichosis to be reported in the literature.