The MAOA gene is located on the X-chromosome. Men inherit only one X chromosome, so they have only one version of MAOA. If a man inherits the “warrior” gene, they are more likely to be affected by it.
Women have two X chromosomes; hence they can inherit two different versions of the gene. This means that even if a woman inherits one copy of the “warrior” gene, she is less likely to be affected, because she also carries one normal version of MAOA.
This test looks at how many repeats are present in the regulatory region of the MAOA gene. There are five variants with different numbers of repeats – 2, 3, 3.5, 4 and 5.
- People with 3.5 or 4 repeats have the MAOA-H allele and make high levels of monoamine oxidase A
- People with 2, 3, or 5 repeats have the MAOH-Lallele, known as the “warrior” gene.
