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Disease Profile

Gamma aminobutyric acid transaminase deficiency

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

<1 / 1 000 000

US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

GABA transaminase deficiency; Gamma aminobutyrate transaminase deficiency; GABAT;


Congenital and Genetic Diseases; Metabolic disorders; Nervous System Diseases


GABA (gamma-aminobutyric acid) is an important molecule which slows down the activity of cells in the brain.[1] GABA is broken down in the body by a substance known as 4-aminobutyrate aminotransferase, also known as GABA-transaminase or GABA-T.[1] Mutations in the ABAT gene can cause less GABA-T to be made, a condition known as GABA-T deficiency.[1] The symptoms for an individual with GABA-T deficiency can include: psychomotor retardation (a slowing down of thought and activity), low muscle tone, hyperactive responses, lethargy, seizures, and EEG abnormalities.[1] GABA-T deficiency is very rare, with fewer than 5 cases reported in the literature.[2] It is thought to be inherited in an autosomal recessive manner.[3][4]


Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.


    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

      Learn more

      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.

      In-Depth Information

      • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
      • 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 Gamma aminobutyric acid transaminase deficiency. Click on the link to view a sample search on this topic.


        1. ABAT. Genetics Home Reference. March 2015; https://ghr.nlm.nih.gov/gene/ABAT. Accessed 3/20/2015.
        2. Parviz, M. et al.. Disorders of GABA metabolism: SSADH and GABA-transaminase deficiencies. J Pediatr Epilepsy. 2014 Nov 25; 3(4):217-227. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4256671/. Accessed 3/20/2015.
        3. GABA-TRANSAMINASE DEFICIENCY. OMIM. Dec 2009; https://omim.org/entry/613163. Accessed 3/20/2015.
        4. Pearl, P. et al. Inherited Disorders of GABA Metabolism. Future Neurol. 2006; 1(5):632-636. https://www.pndassoc.org/pdf/Pearl.pdf. Accessed 3/20/2015.