The 3-repeat MAO-uVNTR (low-activity) allele was associated with increased severity of autism, as measured by parent and teacher reports, IQ, adaptive skills, language assessments and multiple other scoring methods (Cohen et al., 2003 & 2011) and was found to be associated with ASD in a Korean population cohort (Yoo et al., 2009). In addition, genetic association has been found between MAOA and ADHD in an Indian population cohort (Das et al., 2006).
Molecular Function
The encoded protein degrades amine neurotransmitters.
External Links
References
Type
Title
Type of Disorder
Associated Disorders
Author, Year
Primary
Association of autism severity with a monoamine oxidase A functional polymorphism.
NE concentrations were increased up to twofold, and cytoarchitectural changes were observed in the somatosensory cortex. Pup behavioral alterations, including trembling, difficulty in righting, and fearfulness were reversed by the serotonin synthesis inhibitor parachlorophenylalanine. Adults manifested a distinct behavioral syndrome, including enhanced aggression in males.
References
Type
Title
Author, Year
Additional
Maladaptive defensive behaviours in monoamine oxidase A-deficient mice.
Model Type:
Genetic
Model Genotype:
Homozygous
Mutation:
Spontaneous nonsense point mutation in the 8th exon of Maoa gene.
Allele Type: Spontaenous (Mutation)
Strain of Origin: Not Specified
Genetic Background: 129S6/SvEvTac
ES Cell Line: Not Specified
Mutant ES Cell Line: Not Specified
Model Source: Not Specified
Model Type:
Genetic
Model Genotype:
Homozygous
Mutation:
IFN-beta transgene integration mediated genomic deletion of MAOA exons 2 and 3.
Allele Type: Targeted (Deletion)
Strain of Origin: Not specified
Genetic Background: 129S6
ES Cell Line: Not specified
Mutant ES Cell Line: Not Specified
Model Source: Not Specified
Model Type:
Genetic
Model Genotype:
Homozygous
Mutation:
IFN-beta transgene integration mediated genomic deletion of MAOA exons 2 and 3.
Allele Type: Targeted (Deletion)
Strain of Origin: Not Specified
Genetic Background: C3H/HeJ
ES Cell Line: Not Specified
Mutant ES Cell Line: Not Specified
Model Source: Not Specified
Description: Decreased exploratory activity and escape behavior demonstrated by increase in latency to escape to closed arm
Exp Paradigm: Elevated t maze test
Description: Decreased fear response towards predators as demonstrated by decrease in latency to exit chamber after introduction of object with predator urine or anaesthetized rat
Exp Paradigm: Introduction of forgein objects: object with predator urine & anaesthetized rat
Description: Abnormal defensive burying behavior demonstrated by no change in baseline values, but lower diggy of predator urine-impregnated objects
Exp Paradigm: Defensive burying test of objects impregnated with predator urine or odorless
Description: Increased fear response/defensive behavior indicated by reduced number of approaches towards novel object, tail-rattling response
Exp Paradigm: Novel object exploration test
Description: Increased number and total length of apical dendritic branches of pyramidal neurons in orbitofrontal cortex
Exp Paradigm: Nissl staining from photomicrographs of thickness of molecular and granular layers of cerebellum
Description: Increased perseverative behaviours indicated by higher number of marbles buried and increased in digging duration and frequency
Exp Paradigm: Male mice: marble-burying assay
Description: Decreased social interaction with reduction in duration and number of investigative approaches towards foreign counterparts
Exp Paradigm: Male mice: social investigation test
Description: Decreased social interaction indicated by decrease in frequency, overall duration of sniffing and duration of anogenital sniffing
Exp Paradigm: Male mice: social interaction test
Description: Abnormal exploratory activity with tendency to repeat the exploration of same arms
Exp Paradigm: Male mice: exploratory response in novel t-maze test
Description: Decreased ultrasonic vocalizations with reduction in number and duration of vocalizations
Exp Paradigm: Male mice: maternal separation induced ultrasonic vocalizations
Description: Abnormal response to moderate sound: frantic running and falling over, jumping, or digging to hide under woodshavings
Exp Paradigm: General observations
Description: Increased aggression demonstrated by bite wounds and low latency to attack intruder
Exp Paradigm: General observation/resident-intruder test
Description: Abnormal serotonin (5ht) expression demonstrated by increased density of fibers stained for 5ht in pups, which decreased in adults
Exp Paradigm: Immunochemical analysis of coronal sections using anti-5ht antibodies
Description: Increased expression of serotonin (5ht) in response to adminstration of l-deprenyl
Exp Paradigm: Radiolabeled 5ht measurement from brain after administration of 15 mg/kg, ip of maob inhibitor, l-deprenyl
