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

Ataxia telangiectasia

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Other Names:
AT; Louis-Bar syndrome; Cerebello-oculocutaneous telangiectasia; AT; Louis-Bar syndrome; Cerebello-oculocutaneous telangiectasia; Immunodeficiency with ataxia telangiectasia See More
Categories:
This disease is grouped under:
Ataxia telangiectasia (A-T) is rare condition that affects the nervous system, the immune system, and many other parts of the body. Signs and symptoms of the condition usually begin in early childhood, often before age 5. The condition is typically characterized by cerebellar ataxia (uncoordinated muscle movements), oculomotor apraxia, telangiectasias, choreoathetosis (uncontrollable movements of the limbs), a weakened immune system with frequent infections, and an increased risk of cancers such as leukemia and lymphoma.[1][2] A-T is caused by changes (mutations) in the ATM gene and is inherited in an autosomal recessive manner.[3] Treatment is supportive and based on the signs and symptoms present in each person.[2]
Last updated: 4/5/2016
Ataxia-telangiectasia affects the nervous system, immune system, and other body systems. This disorder is characterized by progressive difficulty with coordinating movements (ataxia) beginning in early childhood, usually before age 5. Affected children typically develop difficulty walking, problems with balance and hand coordination, involuntary jerking movements (chorea), muscle twitches (myoclonus), and disturbances in nerve function (neuropathy). The movement problems typically cause people to require wheelchair assistance by adolescence. People with this disorder also have slurred speech and trouble moving their eyes to look side-to-side (oculomotor apraxia). Small clusters of enlarged blood vessels called telangiectases, which occur in the eyes and on the surface of the skin, are also characteristic of this condition.[3]

Affected individuals tend to have high amounts of a protein called alpha-fetoprotein (AFP) in their blood. The level of this protein is usually increased in the bloodstream of pregnant women. The effect of abnormally high levels of AFP in people with ataxia-telangiectasia is unknown.[3]

People with ataxia-telangiectasia often have a weakened immune system, and many develop chronic lung infections. They are also at an increased risk of developing cancer, particularly leukemia and lymphoma. Affected individuals are very sensitive to the effects of radiation exposure, including medical x-rays. Although people with ataxia-telangiectasia usually live into adulthood, their life expectancy is reduced.[3]
Last updated: 4/15/2016

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
Abnormality of chromosome stability 0003220
Aplasia/Hypoplasia of the thymus
Absent/small thymus
Absent/underdeveloped thymus
[ more ] 		0010515
Ataxia 0001251
Cellular immunodeficiency 0005374
Decreased circulating antibody level 0004313
Delayed puberty
Delayed pubertal development
Delayed pubertal growth
Pubertal delay
[ more ] 		0000823
Elevated hepatic transaminase
High liver enzymes
0002910
Gait disturbance
Abnormal gait
Abnormal walk
Impaired gait
[ more ] 		0001288
Lymphopenia
Decreased blood lymphocyte number
Low lymphocyte number
[ more ] 		0001888
Mucosal telangiectasiae 0100579
Nystagmus
Involuntary, rapid, rhythmic eye movements
0000639
Polycystic ovaries 0000147
Premature graying of hair
Early graying
Premature graying
Premature greying
Premature hair graying
[ more ] 		0002216
Recurrent respiratory infections
Frequent respiratory infections
Multiple respiratory infections
respiratory infections, recurrent
Susceptibility to respiratory infections
[ more ] 		0002205
Strabismus
Cross-eyed
Squint
Squint eyes
[ more ] 		0000486
Telangiectasia of the skin 0100585
Tremor 0001337
30%-79% of people have these symptoms
Dysarthria
Difficulty articulating speech
0001260
Hypopigmentation of hair
Loss of hair color
0005599
Neoplasm 0002664
Seizure 0001250
Short stature
Decreased body height
Small stature
[ more ] 		0004322
Skeletal muscle atrophy
Muscle degeneration
Muscle wasting
[ more ] 		0003202
Spasticity
Involuntary muscle stiffness, contraction, or spasm
0001257
5%-29% of people have these symptoms
Abnormal testis morphology
Abnormality of the testis
0000035
Aplasia/Hypoplasia of the skin
Absent/small skin
Absent/underdeveloped skin
[ more ] 		0008065
Cognitive impairment
Abnormality of cognition
Cognitive abnormality
Cognitive defects
Cognitive deficits
Intellectual impairment
Mental impairment
[ more ] 		0100543
Failure to thrive
Faltering weight
Weight faltering
[ more ] 		0001508
Multiple cafe-au-lait spots 0007565
Type II diabetes mellitus
Noninsulin-dependent diabetes
Type 2 diabetes
Type II diabetes
[ more ] 		0005978
Percent of people who have these symptoms is not available through HPO
Abnormal hair morphology
Abnormality of the hair
Hair abnormality
[ more ] 		0001595
Abnormal spermatogenesis 0008669
Autosomal recessive inheritance 0000007
Bronchiectasis
Permanent enlargement of the airways of the lungs
0002110
Cafe-au-lait spot 0000957
Choreoathetosis 0001266
Conjunctival telangiectasia
Small dilated blood vessels near membrane covering front of eye and eyelids
0000524
Decreased circulating IgA level 0002720
Decreased circulating IgG2 level 0008348
Decreased proportion of CD4-positive helper T cells 0005407
Defective B cell differentiation 0005357
Diabetes mellitus 0000819
Dystonia 0001332
Elevated alpha-fetoprotein 0006254
Female hypogonadism 0000134
Glucose intolerance 0001952
Hodgkin lymphoma 0012189
Hypoplasia of the thymus
Small thymus
0000778
Leukemia 0001909
Lymphoma
Cancer of lymphatic system
0002665
Myoclonus 0001336
Non-Hodgkin lymphoma 0012539
Recurrent bronchitis 0002837
Reduced tendon reflexes 0001315
Sinusitis
Sinus inflammation
0000246
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Last updated: 7/1/2020

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.

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

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
The differential diagnosis should include Ataxia - oculomotor apraxia, types 1 and2 (see these terms).
Visit the Orphanet disease page for more information.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Ataxia telangiectasia. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

Patient Registry

  • Coordination of Rare Diseases at Sanford (CoRDS) hosts a specific registry for patients with ataxia in partnership with the National Ataxia Foundation. The goal of the CoRDS registry is to connect as many patients and researchers as possible to help advance treatments and cures for rare diseases. The CoRDS registry is free for patients to enroll and for researchers to access.
  • The goal of the Global A-T Family Data Platform is to connect patient health, genomic, and potentially other types of data to scientists and researchers who are interested in advancing the understanding, diagnosis and treatment of ataxia telangiectasia.
  • A registry supports research by collecting of information about patients that share something in common, such as being diagnosed with Ataxia telangiectasia. The type of data collected can vary from registry to registry and is based on the goals and purpose of that registry. Some registries collect contact information while others collect more detailed medical information. Learn more about registries.

    Registries for Ataxia telangiectasia:
    European Society for Immunodeficiencies (ESID) Registry
    United States Immunodeficiency Network (USIDENT) Registry
     

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

Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.

Financial Resources

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 Ataxia telangiectasia. This website is maintained by the National Library of Medicine.
  • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
  • The National Cancer Institute provides the most current information on cancer for patients, health professionals, and the general public.
  • The National Institute of Neurological Disorders and Stroke (NINDS) collects and disseminates research information related to neurological disorders. Click on the link to view information on this topic.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • 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 Ataxia telangiectasia. 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. Submit a new question

  • How might ataxia telangiectasia affect a person's ability to move and speak? See answer


  1. NINDS Ataxia Telangiectasia Information Page. National Institute of Neurological Disorders and Stroke (NINDS). July, 2015; http://www.ninds.nih.gov/disorders/a_t/a-t.htm.
  2. Richard Gatti, MD. Ataxia-Telangiectasia. GeneReviews. March 2010; http://www.ncbi.nlm.nih.gov/books/NBK26468.
  3. Ataxia-telangiectasia. Genetics Home Reference (GHR). 2013; http://ghr.nlm.nih.gov/condition/ataxia-telangiectasia.