MAOA deficiency and abnormal behaviour:
perspectives on an association

Brunner HG.
Department of Human Genetics,
Nijmegen University Hospital,
The Netherlands.
Ciba Found Symp. 1996;194:155-64; discussion 164-7.


We have recently described an association between abnormal behaviour and monoamine oxidase A (MAOA) deficiency in several males from a single large Dutch kindred. Affected males differed from unaffected males by borderline mental retardation and increased impulsive behaviour (aggressive behaviour, abnormal sexual behaviour and arson). Nevertheless, a specific psychiatric diagnosis was not made in four affected males who had psychiatric examination. Since MAOA deficiency raises 5-hydroxytryptamine (5-HT) levels, it provides an interesting exception to the low 5-HT paradigm of impulsive aggression. Even if the possible relationship between MAOA deficiency and abnormal behaviour is confirmed in other kindreds, the data do not support the hypothesis that MAOA constitutes an "aggression gene'. In fact, because genes are essentially simple and behaviour is by definition complex, a direct causal relationship between a single gene and a specific behaviour is highly unlikely. In the case of MAOA deficiency, some of the complexities are illustrated by the variability in the behavioural phenotype, as well as by the highly complex effects of MAOA deficiency on neurotransmitter function. Thus, the concept of a gene that directly encodes behaviour is unrealistic.
'Designer babies'
Procreative liberty
Personal genomics
Genetic enhancement
Human self-domestication
Transhumanism/Brave New World?
Francis Galton and contemporary eugenics
Gene therapy and performance enhancement
Preimplantation genetics and stem cell therapy
The neurogenetics of aggression: role of the serotonin system

and further reading

BLTC Research
Utopian Surgery?
The Good Drug Guide
The Abolitionist Project
The Hedonistic Imperative
The Reproductive Revolution
MDMA: Utopian Pharmacology
Critique of Huxley's Brave New World