A common polymorphism in the CYP3A7 gene is associated with a nearly 50% reduction in serum dehydroepiandrosterone sulfate levels

J Clin Endocrinol Metab. 2005 Sep;90(9):5313-6. doi: 10.1210/jc.2005-0307. Epub 2005 Jun 28.


Context: CYP3A7, expressed in the human fetal liver and normally silenced after birth, plays a major role in the 16alpha-hydroxylation of dehydroepiandrosterone (DHEA), DHEA sulfate (DHEAS), and estrone. Due to a replacement of part of the CYP3A7 promoter with a sequence identical with the same region in the CYP3A4 promoter (referred to as CYP3A7*1C), some individuals still express a variant of the CYP3A7 gene later in life.

Objective: The objective of this study was to examine the effect of the CYP3A7*1C polymorphism on serum steroid hormone levels.

Design, setting, participants: Two population-based cohort studies were performed. Study group 1 consisted of 208 subjects randomly selected from the Rotterdam Study, and study group 2 consisted of 345 elderly independently living men.

Main outcome measures: Serum DHEA(S), androstenedione, estradiol, estrone, and testosterone levels were the main outcome measures.

Results: In study groups 1 and 2, heterozygous CYP3A7*1C carriers had almost 50% lower DHEAS levels compared with homozygous carriers of the reference allele [study group 1, 1.74 +/- 0.25 vs. 3.33 +/- 0.15 micromol/liter (P = 0.02); study group 2, 2.09 +/- 0.08 vs. 1.08 +/- 0.12 micromol/liter (P < 0.001)]. No differences in circulating DHEA, androstenedione, estradiol, or testosterone levels were found. However, in study group 2, serum estrone levels were lower in heterozygous CYP3A7*1C carriers compared with homozygous carriers of the reference allele (0.11 +/- 0.002 vs. 0.08 +/- 0.006 nmol/liter; P < 0.001).

Conclusion: The CYP3A7*1C polymorphism causes the persistence of enzymatic activity of CYP3A7 during adult life, resulting in lower circulating DHEAS and estrone levels.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Androstenedione / blood
  • Aryl Hydrocarbon Hydroxylases / genetics*
  • Cohort Studies
  • Cytochrome P-450 CYP3A
  • Dehydroepiandrosterone Sulfate / blood*
  • Estradiol / blood
  • Estrone / blood
  • Genotype
  • Heterozygote
  • Homozygote
  • Humans
  • Male
  • Middle Aged
  • Polymorphism, Genetic*
  • Testosterone / blood


  • Estrone
  • Testosterone
  • Androstenedione
  • Estradiol
  • Dehydroepiandrosterone Sulfate
  • Aryl Hydrocarbon Hydroxylases
  • CYP3A7 protein, human
  • Cytochrome P-450 CYP3A