A promoter polymorphism in the monoamine oxidase A gene is associated with the pineal MAOA activity in Alzheimer's disease patients

Brain Res. 2007 Sep 5;1167:13-9. doi: 10.1016/j.brainres.2007.06.053. Epub 2007 Aug 9.


Background: Monoamine oxidase A (MAOA) is involved in the pathogenesis of mood disorders and Alzheimer's disease (AD). MAOA activity and gene expression have been found to be up-regulated in different brain areas of AD patients, including the pineal gland. Increased pineal MAOA activity might contribute to the reduced pineal melatonin production in AD. A promoter polymorphism of a variable number tandem repeats (VNTR) in the MAOA gene shows to affect MAOA transcriptional activity in vitro.

Methods: Here we examined in 63 aged controls and 44 AD patients the effects of the MAOA-VNTR on MAOA gene expression and activity in the pineal gland as endophenotypes, and on melatonin production.

Results: AD patients carrying long MAOA-VNTR genotype (consisting of 3.5- or 4-repeat alleles) showed higher MAOA gene expression and activity than the short-genotyped (i.e., 3-repeat allele) AD patients. Moreover, the AD-related up-regulation of MAOA showed up only among long-genotype bearing subjects. There was no significant effect of the MAOA-VNTR on MAOA activity or gene expression in controls, or on melatonin production in both controls and AD patients.

Conclusion: Our data suggest that the MAOA-VNTR affects the activity and gene expression of MAOA in the brain of AD patients, and is involved in the changes of monoamine metabolism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Alzheimer Disease / enzymology*
  • Alzheimer Disease / genetics*
  • Alzheimer Disease / physiopathology
  • Biogenic Monoamines / metabolism
  • DNA Mutational Analysis
  • Female
  • Gene Expression Regulation, Enzymologic / genetics
  • Genetic Predisposition to Disease / genetics
  • Genetic Testing
  • Genotype
  • Humans
  • Male
  • Melatonin / biosynthesis
  • Melatonin / metabolism
  • Monoamine Oxidase / genetics*
  • Pineal Gland / enzymology*
  • Pineal Gland / metabolism
  • Pineal Gland / physiopathology
  • Polymorphism, Genetic / genetics*
  • Promoter Regions, Genetic / genetics*
  • Up-Regulation / genetics


  • Biogenic Monoamines
  • Monoamine Oxidase
  • Melatonin