National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Monoamine oxidase A deficiency



Other Names:
Brunner syndrome
Categories:

Monoamine oxidase A deficiency is a rare condition that is characterized by mild intellectual disability and behavioral difficulties (including aggressive and sometimes violent behaviors and autistic features). Affected people may also experience night terrors, tremor, stereotypical hand movements, and/or occasional body twitches. Signs and symptoms generally develop in childhood and the condition is seen almost exclusively in males.[1][2] Monoamine oxidase A deficiency is caused by changes (mutations) in the MAOA gene and is inherited in an X-linked recessive manner.[3] Treatment is based on the signs and symptoms present in each person. Some recent studies suggest that cautious treatment with certain medications (called selective serotonin reuptake inhibitors) and dietary modifications can improve symptoms.[2][4]
Last updated: 3/30/2016

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Behavioral abnormality
Behavioral changes
Behavioral disorders
Behavioral disturbances
Behavioral problems
Behavioral/psychiatric abnormalities
Behavioural/Psychiatric abnormality
Psychiatric disorders
Psychiatric disturbances
[ more ]
0000708
Cognitive impairment
Abnormality of cognition
Cognitive abnormality
Cognitive defects
Cognitive deficits
Intellectual impairment
Mental impairment
[ more ]
0100543
5%-29% of people have these symptoms
Motor delay 0001270
1%-4% of people have these symptoms
Diarrhea
Watery stool
0002014
Flushing 0031284
Percent of people who have these symptoms is not available through HPO
Aggressive behavior
Aggression
Aggressive behaviour
Aggressiveness
[ more ]
0000718
Autism 0000717
Headache
Headaches
0002315
Impulsivity
Impulsive
0100710
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific
Mental-retardation
[ more ]
0001249
Kinetic tremor 0030186
Low frustration tolerance 0000744
Self-injurious behavior
Self-injurious behaviour
0100716
X-linked recessive inheritance 0001419
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Last updated: 7/1/2020

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease


These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • Genetics Home Reference (GHR) contains information on Monoamine oxidase A deficiency. This website is maintained by the National Library of Medicine.

In-Depth Information

  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Monoamine oxidase A deficiency. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.


  1. Monoamine oxidase A deficiency. Orphanet. February 2012; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=3057.
  2. Palmer EE, Leffler M, Rogers C, Shaw M, Carroll R, Earl J, Cheung NW, Champion B, Hu H, Haas SA, Kalscheuer VM, Gecz J, Field M. New insights into Brunner syndrome and potential for targeted therapy. Clin Genet. Jan 2016; 89(1):120-127.
  3. BRUNNER SYNDROME. OMIM. June 2014; http://www.omim.org/entry/300615.
  4. Godar SC, Bortolato M, Castelli MP, Casti A, Casu A, Chen K, Ennas MG, Tambaro S, Shih JC. The aggression and behavioral abnormalities associated with monoamine oxidase A deficiency are rescued by acute inhibition of serotonin reuptake. J Psychiatr Res. September 2014; 56:1-9.