ABSTRACT
Androgenetic alopecia (AGA) is a genetic condition, characterized by hair loss on the temporal region and the top of the head, that can progress to complete hair loss in men and women, although predominantly in men. Androgenetic alopecia results from the miniaturization of the hair follicle and a decrease in the length of the anagen (long growth) cycle with subsequent increases in telogen (short resting) cycle.1 The androgens testosterone and 5α-dihydrotestosterone (DHT), as well as the androgen receptors, are involved in its pathogenesis. Higher concentrations of DHT, androgen receptors, and the enzyme 5α-reductase, which converts testosterone to DHT, were found in balding scalps.2,3 Eunuchs who lack androgens, individuals lacking androgen receptors, and pseudohermaphrodites who lack 5α-reductase all do not go bald.4-6 Androgenetic alopecia follows a polygenic inheritance pattern involving multiple genes, but the X chromosome is strongly associated with the disease, and the EDAR2 gene on the X chromosome was found to be highly associated with androgenetic alopecia.7 Finasteride, 5αR inhibitor, and minoxidil are the current standard treatments for androgenetic alopecia.
