Physiological importance of the MAO-A gene
MAO-A is an essential regulator of brain function and is highly expressed in the brain and heart cells. It mainly assists in the breakdown of neurotransmitters such as i ) Dopamine (the “happy hormone”) is involved in mood, motivation and reward, arousal, memory, learning, focus, and movement control, ii ) Serotonin, which is involved in impulse control, affects regulation, appetite, and sleep, and iii ) Epinephrine triggers the body’s stress and fight-or-flight responses.
Because MAO-A regulates the level of these “behavioral hormones,” too little or too much of this enzyme plays a role in several psychiatric and neurological disorders like schizophrenia and ADHD.
Types Of The MAO-A Gene Carrier of a “warrior variant” of the MAO-A gene? We all have the MAO-A gene but carry different versions (variants) of it. Based on the number of times the sequence of the gene is repeated, there are two types of MAO-A genes: a high-activity (MAOA-H ) and a low-activity (MAOA-L ) type.One of the most frequently studied variants is MAOA-4R , has four repeats associated with high MAO-A enzyme activity. Other forms of MAO-A include the 2-repeat (2R) and 3-repeat (3R) versions.
Monoamine Oxidase Deficiency Monoamine oxidase A deficiency follows an X-linked inheritance pattern , primarily affecting males. Lower levels of MAO-A typically result in the buildup of neurotransmitters in the brain. This buildup manifests as unusual behavioral patterns involving aggressive outbursts and abnormal sexual behavior. A deficiency of MAO-A has also been associated with abnormal brain development, which can directly lead to intellectual disabilities. Lower levels of the enzyme result in a slower breakdown of the neurotransmitters, while higher levels of the enzyme equal a faster breakdown. Lower and higher enzyme levels are popularly associated with ‘worrier’ and ‘warrior’ personalities, respectively. Such differences happen through mutations at specific points in the gene sequence, known as RSIDs. At a specific point, the sequence’s usual allele may be A, and this state of the sequence may be associated with some amount of risk for a given trait. If a mutation occurs, and the allele at that point is now C, this state of the sequence may be associated with a higher or lower risk for that trait.
The Influence Of MAO-A On Your Personality: Increased Risk For Depressive And Bipolar Disorders
A study on around 18,000 people with psychiatric issues identified an SNP rs1137070 associated with major depressive disorder and schizophrenia.People with the T allele had higher enzyme levels and, as a result, lower levels of the neurotransmitters.
G allele of rs6323 had the highest expression of the MAOA enzyme.Subjects with major depressive disorder had the highest activity form of the enzyme (G or G/G).
Increased Risk For ADHD
A study identified an SNP rs3027407 on the MAO-A gene associated with ADHD. This SNP affects dopamine-mediating action, which is related to the symptoms of ADHD in children. The A allele is more frequent in people with ADHD.
Increased Risk For Aggression
The T allele of rs909525 in the MAO-A gene is associated with less aggressive behavior while yhe C allele is associated with more aggressive behavior.
Increased Expression for Anger
A variation in the MAO-A gene was associated with higher levels of anger being expressed. The A allele of rs2064070 was also associated with increased anger expression. This study also confirmed that mutations in rs909525 and rs6323 have links to increased anger expression, as mentioned previously. see this overviewed table on expected outcomes with MAO-A alleles;
RSID (variation) Expressed Allele Likely Outcome
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