Are 2D:4D finger-length ratios an indicator of androgenetic alopecia in males?

Background: although the pathogenesis of androgenetic alopecia is not completely understood,the roles of genetic susceptibility and androgens are well-known. a lower ratio of the second digit (index finger = 2d) to the fourth digit (ring finger = 4d) length has been hypothesized to reflect prenatal androgen exposure and/or higher sensitivity to androgens. obj ectives: to determine the relationship between the second to fourth digit length ratio and androgenetic alopecia. methods: finger length measurements were made by a digital vernier calliper. androgenetic alopecia severity was assessed using the hamilton-norwood scale. subjects with an androgenetic alopecia score of grade iii or more were included in the study. results: a total of 189 males with androgenetic alopecia and 171 healthy controls were enrolled in the study. the age range of participants was 19-65 years. the 2d:4d ratios in patients with androgenetic alopecia were significantly lower than those of healthy controls for the right hand; however,no significant difference was found for the left hand. average 2d:4d ratios in androgenetic alopecia patients were also lower than in controls. no significant relationship was observed between androgenetic alopecia severity and 2d:4d ratios. conclusion: our data support the anatomical evidence of in utero androgen exposure and/or an individual’s sensitivity to androgens in patients with androgenetic alopecia. furthermore,the right hand 2d:4d ratio might be an indicator of androgenetic alopecia development. © 2016 by anais brasileiros de dermatologia.