The long and short of hair growth

Abstract

Development![Figure][1] FGF5 controls eyelash length PHOTO: KAREN ROE/FLICKR The length of your eyelashes probably differs from the length of the hair on your head—and unlike your hair, your eyelashes can never reach your shoulders. What controls how long hair can get? To find out, Higgins et al. studied people with a rare disorder called familial trichomegaly, who have very long eyelashes and longer hair on the arms. They found that these people had a mutation in the gene that encodes fibroblast growth factor 5 (FGF5). When human hair follicles produce FGF5, they stop growing hair. Targeting FGF5 could potentially control the growth and rest phases of hair follicles, preventing unwanted hair from sprouting or growing longer lashes and locks. Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1402862111 (2014). [1]: pending:yes