title: Androgenetic alopecia: a review.
abstract: OBJECTIVE
  Androgenetic alopecia, commonly known as male pattern baldness, is the most common type of progressive hair loss disorder in men. The aim of this paper is to review recent advances in understanding the pathophysiology and molecular mechanism of androgenetic alopecia.
  
  
  METHODS
  Using the PubMed database, we conducted a systematic review of the literature, selecting studies published from 1916 to 2016.
  
  
  RESULTS
  The occurrence and development of androgenetic alopecia depends on the interaction of endocrine factors and genetic predisposition. Androgenetic alopecia is characterized by progressive hair follicular miniaturization, caused by the actions of androgens on the epithelial cells of genetically susceptible hair follicles in androgen-dependent areas. Although the exact pathogenesis of androgenetic alopecia remains to be clarified, research has shown that it is a polygenetic condition. Numerous studies have unequivocally identified two major genetic risk loci for androgenetic alopecia, on the X-chromosome AR⁄EDA2R locus and the chromosome 20p11 locus.
  
  
  CONCLUSIONS
  Candidate gene and genome-wide association studies have reported that single-nucleotide polymorphisms at different genomic loci are associated with androgenetic alopecia development. A number of genes determine the predisposition for androgenetic alopecia in a polygenic fashion. However, further studies are needed before the specific genetic factors of this polygenic condition can be fully explained.
authors.affiliation: Department of Experimental Medicine, University of Rome "La Sapienza", Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Lolli
authors.affiliation: Department of Experimental Medicine, University of Rome "La Sapienza", Rome, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Pallotti
authors.affiliation: Department of Internal Medicine and Medical Specialties, University of Rome "La Sapienza", Rome, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Rossi
authors.affiliation: Department of Internal Medicine and Medical Specialties, University of Rome "La Sapienza", Rome, Italy.
authors.forename: Maria C
authors.initials: MC
authors.lastname: Fortuna
authors.affiliation: Department of Internal Medicine and Medical Specialties, University of Rome "La Sapienza", Rome, Italy.
authors.forename: Gemma
authors.initials: G
authors.lastname: Caro
authors.affiliation: Department of Experimental Medicine, University of Rome "La Sapienza", Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Lenzi
authors.affiliation: Department of Experimental Medicine, University of Rome "La Sapienza", Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Sansone
authors.affiliation: Department of Experimental Medicine, University of Rome "La Sapienza", Rome, Italy. francesco.lombardo@uniroma1.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Lombardo
mesh_terms: D000505:Alopecia / Q000235:genetics*; D056426:Genetic Loci; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D020641:Polymorphism, Single Nucleotide; D011944:Receptors, Androgen / Q000235:genetics*
chemical_list: D011944:Receptors, Androgen
keywords: AGA; AGA genetics; Androgen metabolism; Androgen receptor; Finasteride; Male pattern baldness