title: Are 2D:4D finger-length ratios an indicator of androgenetic alopecia in males?
abstract: 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.
  
  
  OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Selcuk University, Konya, Turkey.
authors.forename: Özlem
authors.initials: Ö
authors.lastname: Bilgic
authors.affiliation: Selcuk University, Konya, Turkey.
authors.forename: Hilmi Cevdet
authors.initials: HC
authors.lastname: Altınyazar
authors.affiliation: Selcuk University, Konya, Turkey.
authors.forename: Dilek
authors.initials: D
authors.lastname: Eryılmaz
authors.affiliation: Selcuk University, Konya, Turkey.
authors.forename: Zehra Ayça
authors.initials: ZA
authors.lastname: Tuğrul
mesh_terms: D000328:Adult; D000368:Aged; D000505:Alopecia / Q000175:diagnosis* / Q000209:etiology; D000728:Androgens / Q000032:analysis / Q000502:physiology; D000886:Anthropometry / Q000379:methods; D016022:Case-Control Studies; D005260:Female; D005385:Fingers / Q000033:anatomy & histology*; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011237:Predictive Value of Tests; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000175:diagnosis*; D012015:Reference Standards; D012016:Reference Values; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D000728:Androgens; D005819:Genetic Markers