Current understanding of androgenetic alopecia. Part I: etiopathogenesis

Eur J Dermatol. 2000 Jun;10(4):319-27.

Abstract

Androgenetic alopecia (AGA) is the most common type of hair loss in men and women. This continuous process results in a type of alopecia that follows a definite pattern in those individuals who are genetically predisposed. At present the predisposing genes are unknown but the relatively strong concordance of the degree of baldness in fathers and sons is not consistent with a simple Mendelian trait and a polygenic basis is therefore most likely. AGA can be defined as a DHT-dependent process with continuous miniaturization of sensitive HF. Today we do not understand the molecular steps involved in androgen-dependent beard growth versus androgen-dependent hair loss in AGA. However, recent experimental and clinical advances enable us to explain some pathogenetic steps leading to androgenetic hair loss. Among other steroidogenic isoenzymes such as 17b- and 3b- hydroxysteroid dehydrogenases, the type 2 5a-reductase within the dermal papilla plays a central role by the intrafollicular conversion of T to DHT.

Publication types

  • Review

MeSH terms

  • 17-Hydroxysteroid Dehydrogenases / genetics
  • 17-Hydroxysteroid Dehydrogenases / metabolism
  • Alopecia / etiology*
  • Alopecia / genetics
  • Alopecia / metabolism
  • Androgens / genetics
  • Androgens / metabolism*
  • Animals
  • Aromatase / genetics
  • Aromatase / metabolism
  • Arylsulfatases / genetics
  • Arylsulfatases / metabolism
  • Cholestenone 5 alpha-Reductase
  • Genetic Linkage
  • Genetic Markers
  • Genetic Predisposition to Disease
  • Hair Follicle / metabolism*
  • Hair Follicle / pathology
  • Humans
  • Multienzyme Complexes / genetics
  • Multienzyme Complexes / metabolism
  • Mutation
  • Oxidoreductases / genetics
  • Oxidoreductases / metabolism
  • Polymorphism, Genetic
  • Progesterone Reductase / genetics
  • Progesterone Reductase / metabolism
  • Receptors, Androgen / genetics*
  • Receptors, Androgen / metabolism
  • Sex Chromosome Aberrations / etiology
  • Sex Chromosome Aberrations / genetics
  • Sex Chromosome Aberrations / metabolism
  • Steroid Isomerases / genetics
  • Steroid Isomerases / metabolism
  • Steryl-Sulfatase
  • X Chromosome

Substances

  • 3 beta-hydroxysteroid oxidoreductase-delta(5) 3-ketosteroid isomerase
  • Androgens
  • Genetic Markers
  • Multienzyme Complexes
  • Receptors, Androgen
  • Oxidoreductases
  • 17-Hydroxysteroid Dehydrogenases
  • Progesterone Reductase
  • Aromatase
  • Cholestenone 5 alpha-Reductase
  • Arylsulfatases
  • Steryl-Sulfatase
  • Steroid Isomerases