Male androgenetic alopecia is due to hair follicle stem cell inactivation

Evaluation of: Garza LA, Yang CC, Zhao T et al. Bald scalp in men with androgenetic alopecia retains hair follicle stem cells but lacks CD200-rich and CD34-positive hair follicle progenitor cells. J. Clin. Invest. 121, 613–622 (2011).Androgenetic alopecia (AGA) in men, or male pattern baldness, affects at least half of Caucasian men by the age of 50 years and is recognized as a physically and psychologically harmful medical condition. Although the clinical natural history of AGA has been well understood for decades, the exact cellular mechanism underlying its pathogenesis remains unknown. We review a recent article by Garza et al. that studied the hair follicle stem cell population in AGA patients. Their work demonstrates that the active hair germ, but not quiescent stem cell predecessor population, is depleted in patients with AGA. With this new insight into the pathogenesis of AGA, novel targeted therapeutic approaches may be developed in the future.