Ataxia-telangiectasia (A-T) is a genetic condition caused by disease-causing genetic variants (changes) in the ATM gene that is involved in cellular processes in the body, such as response to DNA damage and in DNA repair.^1,2 Hallmarks of A-T include:^2-5

• progressive cerebellar ataxia – loss of ability to control movement of muscles that affects balance and coordination, eye movements, swallowing, and speech, which worsens over time
• telangiectasia – widened (dilated) blood vessels that appear as visible red or pink lines, usually in the eyes or on the skin, particularly areas that are exposed to the sun
• immunodeficiency – weakened immune system, resulting in higher risk of infections
• increased risk of cancer

Symptoms of A-T may present at different stages of life, with the ataxia beginning between 1-4 years,² whilst the telangiectasia is usually observed after 5 years of age.⁵ The cerebellar ataxia is caused by cerebellar degeneration,⁵ which is the loss of cells in the cerebellum, the part of the brain that controls movement and coordination. It is progressive, with symptoms worsening over time.^2-5 Children are initially observed to be wobbly on their feet but may gradually lose their ability to walk, with many progressing to needing a wheelchair. Other symptoms include impaired eye coordination (oculomotor apraxia) making it hard to read, involuntary movements (choreoathetosis), and progressively slurred speech (dysarthria).²

A multidisciplinary medical team is required for the management of A-T, which will include careful monitoring of immune function and for infections, as well as for cancer.^3,4

Louis-Bar syndrome

Universal rare disease classifications provide a common language for recording, reporting and monitoring diseases. Please visit the Rare Disease Classifications page for more information about these internationally recognised classifications.

ORPHA:100 Ataxia-telangiectasia

ICD-11: 4A01.31 DNA repair defects other than combined T-cell or B-cell immunodeficiencies

Symptoms associated with A-T begin to present between 1-4 years of age, starting with the features of ataxia – being unsteady when walking (wobbly gait), as well as lack of balance and coordination.^2,5 The children often lose their ability to walk over time and may require a wheelchair by the time they turn 10.^3,4 Other symptoms that affect motor skills include impaired eye coordination (oculomotor apraxia) making it hard to read, involuntary movements (choreoathetosis), and progressively slurred speech (dysarthria).^2,4,5

The other distinctive feature of A-T is the dilated blood vessels (telangiectasia) that usually presents between 5-8 years of age. This can be seen in the eyes, or on the skin in areas that are exposed to the sun.^2,5

Individuals with A-T have a weakened immune system and are prone to developing infections, particularly in the chest and lungs.² They also have increased risk of developing cancers, such as lymphomas and leukemias during childhood, and cancers in solid organs (gastric, breast, pancreatic and skin cancers) in adulthood.³

Please speak to your medical team to learn more about the symptoms and health implications of A-T.

Rare diseases are often serious and progressive, exhibiting a high degree of symptom complexity, leading to significant disability. Majority of the estimated two million Australians living with a rare disease meet the Australian Government’s definition for disability (in accordance to the Australian Public Service Commission and Australian Bureau of Statistics), and many experience severe and permanent disability impacts. If you or someone you care for is experiencing disability-related impacts from a rare condition, please speak with a health or disability professional for advice. Information about relevant disability support can be found at the RARE Portal’s Disability Support Information page.

A-T is a genetic condition. It is caused by disease-causing genetic changes (variants) in the ATM gene.

All individuals have two copies (alleles) of the ATM gene – one on each chromosome that is inherited from each parent. A-T is an autosomal recessive condition, which means both copies of the ATM gene must have the disease-causing genetic variants.

Individuals with the genetic variants in only one copy are unaffected and are called carriers. If both parents are carriers (each have a copy of the disease-causing variant), there is a 25% chance the child will inherit both disease-causing variants and have A-T. More information on autosomal recessive inheritance pattern can be found at Centre for Genetics Education: Autosomal recessive inheritance.

If you would like to learn more about the inheritance and impact of this condition, please ask your doctor for a referral to a genetic counsellor. Genetic counsellors are qualified allied health professionals who can provide information and support regarding genetic conditions and testing. More information about genetic counselling can be found at:

• Information on Genetic Services
• The National and State Services pages underneath the ‘Genetic Counselling’ sections listed

Diagnosis of A-T may be made based on clinical examination, family history, and genetic testing for mutations (including deletions or duplications) in the ATM gene.^2,5

An A-T diagnosis is often suspected based on characteristic features of A-T, including but not limited to, ataxia, abnormal control of eye movement, postural instability, telangiectasia, and frequent infections.⁵ An A-T diagnosis can sometimes be missed in young children, as they may not yet exhibit all of the characteristic features.⁴ It has been recommended that a A-T diagnosis should be carefully considered for any child with ataxia that has no other identified causes.⁵

Individuals with A-T can have increased levels of serum alpha-fetoprotein (AFP), and some have reduced levels of immunoglobulins (such as IgG and IgA), which are an important part of the body’s immune defence system.⁴

Please speak to your medical team to learn more about the available diagnostic pathways for A-T.

There is currently no curative treatment for A-T. Treatment is targeted at managing symptoms (symptomatic management) and involves a multidisciplinary care team. This may include physical and occupational therapy and use of feeding tubes for those with difficulties with swallowing.⁴ Intravenous immunoglobulin (IVIG) replacement therapy may be used for those with frequent, severe infections and low levels of immunoglobulin G (IgG, an antibody blood protein involved in protecting the body from infections).^2,4 Monitoring of immune function, recurrent infections, pulmonary function, swallowing, nutrition, and scoliosis (sideways curvature of the spine),⁶ as well as for early signs of cancer are recommended.⁴

As individuals with A-T have increased sensitivity to radiation, it has been recommended that cancer treatment (such as radiotherapy and certain types of chemotherapeutic agents) be administered with caution. Lower doses of treatment may be required, as normal doses may be toxic or lethal.^2,4

Individuals with A-T may have an adverse effect to anaesthesia, which may affect their breathing and swallowing, and may need to be monitored carefully during and after surgery.⁴

Please speak to your medical team to learn more about the possible treatment or management options for your condition. Treatment will depend on an individual’s specific condition and symptoms. It is also important to stay connected to your medical team so that you can be made aware of any upcoming clinical trial opportunities.

Clinical care for rare diseases often involves a multidisciplinary team of medical, care and support professionals. Please note that the information provided here is as a guide and that RVA does not necessarily monitor or endorse specific clinics or health experts.

Healthcare professionals involved in the treatment of A-T may include general practitioners (GP), paediatricians, geneticists, allergists/immunologists, dermatologists, endocrinologists, neurologists, oncologists, ophthalmologists, psychiatrists, and physical and occupational therapists.¹ The need for different healthcare professionals may change over a person’s lifetime and extend beyond those listed here.

Clinic:

National A-T Clinic
Wesley Medical Research Centre and Queensland Children’s Hospital

The A-T clinic provides a team of expert doctors who aim to see every child in Australia diagnosed with A-T. Specialist doctors in attendance are from the areas of neurology, immunology, respiratory, genetics, ophthalmology and dermatology, as well as allied health therapists.

Please visit The National A-T Clinic (brashat.org.au) for more information.

We are not aware of any clinical care guidelines for A-T in Australia. If you know of any relevant care guidelines, please let us know via the  Contribute page. 

Development of cancer surveillance guidelines in ataxia telangiectasia: A Delphi‐based consensus survey of international experts is an international consensus statement developed and published in 2023 by experts from 13 countries, including Australia.

Below are recommended A-T management guidelines by specialists from other countries:

• European Respiratory Society (ERS, published in 2015) – ERS statement on the multidisciplinary respiratory management of ataxia telangiectasia
• Netherlands (published in 2017) – Ataxia‐telangiectasia: recommendations for multidisciplinary treatment
• United States (published in 2021) – Multidisciplinary Management of Ataxia Telangiectasia: Current Perspectives

Individuals living with rare diseases may have complex medical issues and disabilities, which are not always visible. It is often useful to refer to their medical history as well as personal information such as a medical card, doctor’s letter, or if available, a rare disease passport, for relevant information.

It may be important to consider the following when managing individuals living with A-T at emergency departments/services:

• individuals have a weakened immune system and are at high risk of infections^2,3
• individuals have increased sensitivity to radiation – it has been recommended that exposure to radiation (such as X-rays) be avoided or minimised as much as possible^2,3
• some individuals may be adversely affected by anaesthesia and prone to impaired swallowing, increased risk of aspiration, reduced pulmonary function, and infection⁴

BrAshA-T Ataxia-Telangiectasia Limited: Research has information about research on A-T in Australia.

There are specific considerations around participating in rare disease research, including clinical trials. It is important to be mindful of issues such as data privacy, research ethics, consent and differences in research regulations between Australia and other countries.

If you are interested in finding clinical trials for your condition, please visit the following websites; however, there may not be any clinical trials available:

• Australian Clinical Trials
• ClinicalTrials.gov

It is best to discuss your interest in any clinical trials with your medical team to determine suitability and eligibility.

Please note that RVA does not necessarily monitor or endorse each group/organisation’s operational governance and activities.

Australian Organisation:

BrAshA-T Ataxia-Telangiectasia Limited (BrAshA-T)
Website: https://brashat.org.au/

BrAshA-T is a non-for-profit charity supporting research into finding a cure and support network for other families living with A-T.

Global Organisation:

A-T Global Alliance 
Website: https://cureat.org/

The Global A-T Alliance is a collective of patient groups and charities from all around the world, which aims to maximise the effort, resources and/or funding committed to finding a cure or treatments for A-T worldwide.

Please note that RVA does not monitor or endorse each group/organisation’s operational governance and activities. When engaging with a group, please consider the information on the RARE Portal’s Finding Helpful Peer and Community Supports page.

A-T varies between individuals, and each person’s experience is unique.

If you would like to share your personal story with RVA, please visit the Rare Voices Australia: Share Your Story page. RVA will consider your story for publishing on our website and inclusion on the RARE Portal.

For information on available government and social services that provide support for individuals with a rare disease, please visit the National and State Services pages.

People living with a rare disease, including families and carers, often face unique challenges such as diagnostic delays, misdiagnoses, limited treatment options, and limited access to rare disease specialists and support. These challenges may impact people’s emotional wellbeing and quality of life. Many people find it helpful to seek mental health and wellbeing support to cope with ongoing stress and uncertainty. Connecting with people who have shared experiences through a support group may also be helpful. Information about relevant mental health and wellbeing support can be found at:

• Mental Health and Wellbeing Support for Australians Living with a Rare Disease
• The National and State Services pages underneath the ‘Mental Health’ sections listed

Further information on A-T can be found at:

• Genetic and Rare Diseases (GARD) Information Center: Ataxia-telangiectasia
• National Organization for Rare Disorders (NORD): Ataxia Telangiectasia

• GeneReviews®: Ataxia-Telangiectasia
• Online Mendelian Inheritance in Man, OMIM^®: #208900; Ataxia-telangiectasia; AT
• Orphanet: Ataxia telangiectasia

This page has been co-developed by Rare Voices Australia (RVA)’s RARE Portal team in consultation with BrAshA-T Ataxia-Telangiectasia Limited.

If you are aware of any additional information that may benefit stakeholders with an interest in this page, or if you notice any broken links or inaccurate information, please let us know via the Contribute page.