Hair on a gene string: recent advances in understanding the molecular genetics of hair loss.

The hair follicle is finally, after remaining a mystery for many years, beginning to yield some of its molecular secrets. The past decade has seen unprecedented and ever quickening advances in understanding the molecular genetics of the many single gene disorders, which have alopecia as a major feature. This article reviews recent novel clinical and experimental observations, which have shed new light on the basic molecular mechanisms underlying hair morphogenesis, differentiation, keratinization and cycling. We consider recent progress in understanding structural hair defects and complex traits and consider where future developments are likely to occur.