- Official Symbol: MAOA
- Gene type: protein coding
- Gene name: MAOA
- Gene description: monoamine oxidase A
- Chromosome: X; Location: Xp11.3
This gene encodes monoamine oxidase A, an enzyme that degrades amine neurotransmitters, such as dopamine, norepinephrine, and serotonin. The protein localizes to the mitochondrial outer membrane. The gene is adjacent to a related gene on the opposite strand of chromosome X. Mutation in this gene results in monoamine oxidase deficiency, or Brunner syndrome.
Comparison of male alcoholics to male normal controls for the frequencies of two-loci and three-loci haplotypes was statistically significant. 
Polymorphism is associated with aggression in children. 
Present study strongly supports the notion that carrying the 3-repeat allele of the MAO-A-gene promoter increases the risk of male adolescent criminal behavior, when interacting with psychosocial factors. 
Results confirmed previous reports showing an association of the low activity 3-repeat allele of MAOA-uVNTR polymorphism with substance dependence and impulsive/antisocial behaviors. 
MAOA gene variation may modulate the expression of some clinical aspects of severe mood disorders. 
Study did not support the involvement of 5-HTTLPR, TPH, MAO-A, or DRD4 polymorphisms in mood disorders.