Ataxia-Telangiectasia
(A-T; Louis-Bar Syndrome) Compact Guide 2024
S. Nick Russo, M.D.
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Written according to scientific standards; Last updated on 5th of August 2024 Reading time approx. 9 minutes
Ataxia-Telangiectasia: The Rare Hereditary Disease at a Glance
Ataxia-Telangiectasia, also known as Louis-Bar syndrome or A-T, is a very rare hereditary disease that affects both girls and boys starting in early childhood. It usually first becomes noticeable between the ages of one and four years through ataxias.1 Ataxia refers to difficulties with coordinated movement, making activities such as walking or balancing increasingly challenging for affected children. Unintentional movements, such as jerking, are also typical for A-T.
Over time, the disability progresses and children may become dependent on a wheelchair, usually at 10 to 12 years of age. However, the severity of A-T can vary from child to child. In addition to issues with movement coordination, there are other symptoms associated with A-T, such as eye movement disorders and visible dilation of blood vessels (telangiectasia) in the eyes or auricles. Frequent respiratory infections due to a weakened immune system are also typical signs. People with A-T have a significantly increased risk of developing a malignant tumor disease such as leukemia or lymphoma.
It is estimated that A-T occurs in 1 in 40,000 to 100,000 newborns worldwide2. Mutations in a specific gene are the cause; therefore, A-T cannot be cured. So far, treatment options only aim to alleviate the symptoms or prevent them as best as possible. The emphasis lies on physiotherapy, occupational therapy, speech therapy, vaccinations, good cancer prevention, and rapid treatment of infections.
There are currently no pharmacological therapies available to cure A-T. Nevertheless, researchers are developing new and innovative approaches with drugs that could be approved for A-T in the future.
Are you or your child suspected of having A-T or already diagnosed with A-T? This guide aims to encourage you: It brings together a wealth of knowledge and practical information that may help you to understand Ataxia-Telangiectasia better – and can thus offer you support in dealing with your or your child’s rare hereditary disease.
If you or your child are affected by A-T, you may be eligible to take part in a clinical trial investigating an innovative potential treatment for A-T.
Background Knowledge
The Most Important Facts About Ataxia-Telangiectasia
Symptoms may begin in early childhood with uncoordinated movements, a wobbly gait, and difficulty standing upright. In some cases, these symptoms are caused by a hereditary disease which, although very rare, has serious consequences: Ataxia-Telangiectasia, or A-T for short, also known as Louis-Bar syndrome.
A-T is a neurodegenerative systemic disease. Over time, nerve cells in the brain lose their ability to function, leading to a variety of symptoms, e.g., affected children may no longer be able to walk from around the age of ten, become susceptible to respiratory infections, and have a significantly increased risk of tumor diseases.
Unfortunately, this results in a reduced life expectancy for people with A-T, challenges for those affected, their families, and their social environment. Knowing as much as possible about the disease becomes pivotal in managing A-T. Sound knowledge will help you find the proper support for your child and take measures as early as possible to alleviate symptoms and delay severe consequences.
What is the cause of A-T, and how does the disease develop?
Ataxia-Telangiectasia (A-T) is caused by mutations in a specific gene called ATM. A child can only develop A-T if both parents possess the defective ATM gene in their genome (DNA). This type of heredity is known as autosomal recessive. If both parents are carriers of the defective gene, the following probabilities for a pregnancy arise:
How often does A-T occur?
What are the effects of ATM mutations?
Mutations in the ATM gene have a significant impact on the body. The ATM gene provides the blueprint for the essential ATM protein. The ATM protein helps cells recognize and repair DNA damage, i.e., the genetic material, which is a critical process for maintaining the stability and function of our cells.
If both ATM gene copies are defective, the body produces either no ATM protein or only a defective ATM protein. As a result, cells are unable to repair DNA damage. DNA damage gradually accumulates, leading to cell dysfunction or death over time.
Ataxia-Telangiectasia in a Nutshell
Nerve cells in the brain are particularly susceptible to the damaging effects of ATM mutations. In the long term, DNA damage leads primarily to the death of cells in the cerebellum. This is the reason why A-T causes ataxia, i.e., uncoordinated movements that progress continuously.
The ATM gene defect also affects cell types that divide frequently. These include cells of the immune system, blood-forming cells or cells in the skin, and mucous membranes. The consequences include a weakened immune system, an increased risk of certain tumor diseases such as leukemia and lymphoma, as well as the development of telangiectasias. Telangiectasias are dilated small blood vessels that are often visible in the whites of the eyes and on the skin.
Are You Interested in the A-T Study?
Are you or your child affected by Ataxia-Telangiectasia (A-T)? If so, you may now be eligible to take part in a study with an innovative potential treatment against A-T.
Symptoms and Progression
The Different Facets of A-T
Typical features of A-T
- Dysarthria, i.e., speech disorders
- Oculomotor apraxia, i.e., movement disorders of the eyes
- Dysphagia, i.e., swallowing disorders
- other neurological disorders that can lead to involuntary, abrupt, or twisted movements and persistent muscle contractions and twisted postures, for example.
While the neurological symptoms can also have other causes, telangiectasias, i.e., dilated blood vessels, are one of the characteristic features of A-T – and are helpful for a reliable diagnosis. They also typically appear at the age of three to four years.
Unfortunately, the severe symptoms of A-T often have serious consequences in the further course of the disease: the average life expectancy for classic A-T is 20 to 30 years. The most common causes of death include infections caused by A-T and the significantly increased risk of certain cancers, including leukemia and lymphoma.
Good to know: Despite the typical characteristics of A-T, the severity of the symptoms can vary significantly from child to child.
The milder form of A-T
Are You Interested in the A-T Study?
Are you or your child affected by Ataxia-Telangiectasia (A-T)? If so, you may now be eligible to take part in a study with an innovative potential treatment against A-T.
Diagnosis
The Most Important Examinations for Suspected A-T
How A-T is Diagnosed
Comprehensive examinations and tests are necessary for a reliable Ataxia-Telangiectasia diagnosis. The first step is a thorough physical examination with various tests to observe the characteristic features of A-T. These include uncoordinated movements (ataxia), unusual eye movements, and visible skin changes such as dilated blood vessels (telangiectasia).
One example is the finger-nose test: The child places their finger on their nose and then touches the doctor’s finger. With this test, the doctor can assess coordination and hand tremors.
Genetic tests are crucial for confirming a suspected case of A-T: A blood sample is taken from the child to identify the mutation in the ATM gene.6
Other examinations and tests for the diagnostic process include:
Importance of Early diagnosis
Even though A-T is not yet curable, it is important to know that an early and accurate diagnosis might make a decisive contribution to alleviating the symptoms of this rare disease and improving the quality of life of affected children.7,8,9
The problem is that it often takes a very long time to reach a definitive diagnosis. Sometimes, it takes several visits to numerous specialists and several years before it becomes clear that A-T is the cause of the problems.10 For families, this often means great uncertainty and a heavy emotional burden.
In their publication, the scientists from the University of Nottingham in the UK emphasize the need for further research into A-T to better understand the disease and develop targeted treatment options.
Are You Interested in the A-T Study?
Are you or your child affected by Ataxia-Telangiectasia (A-T)? If so, you may now be eligible to take part in a study with an innovative potential treatment against A-T.
Treatment and Care
How to Alleviate Symptoms
With the diagnosis of Ataxia-Telangiectasia (A-T), there is finally certainty as to what is behind your child’s symptoms. Over the years, it will be essential to find suitable doctors and other specialists who can provide you and your child with the best possible support in dealing with the condition.
Early diagnosis allows doctors to develop targeted treatment plans that are specifically tailored to your child’s needs.
The Most Important Treatment Approaches for A-T
- Immunotherapy: Immunoglobulin replacement therapies (IVIG) can help to support the weakened immune system through the administration of immunoglobulins and thus prevent or effectively treat infections.
- Physiotherapy: Targeted exercises help maintain and strengthen muscle strength and improve movement coordination.
- Airway management: Regular exercises such as chest physiotherapy and the use of cough aids help to clear airway secretions and reduce the risk of infections.
- Cancer monitoring: Due to the increased risk of certain types of cancer, such as leukemia, regular screening examinations need to be carried out so doctors can perform appropriate measures in a timely fashion.
- Nutrition: If swallowing disorders (dysphagia) occur, feeding via a gastric tube may be necessary to prevent choking and the risk of suffocation.
Are You Interested in the A-T Study?
Are you or your child affected by Ataxia-Telangiectasia (A-T)? If so, you may now be eligible to take part in a study with an innovative potential treatment against A-T.
Contact Points
Where to Find Help and Support
Contact Points in the USA
A-TCP is a leading organization dedicated to the research and support of patients with Ataxia-Telangiectasia. It was founded by parents whose children suffer from A-T.
What They Offer:
- Research project funding
- Organization of clinical studies
- Support and resources for affected families
- Public relations and awareness-raising
- Fundraising and community-building events
Website: https://atcp.org
NORD is a patient organization that advocates for people with rare diseases, including Ataxia-Telangiectasia.
What They Offer:
- Provide information on rare diseases
- Support in the search for specialized doctors and treatment options
- Patient support and advice
- Research funding
Website: https://rarediseases.org
GARD is a program of the National Center for Advancing Translational Sciences (NCATS) that provides comprehensive information on rare and genetic diseases, including Ataxia-Telangiectasia.
What They Offer:
- Provide information and resources
- Support in the search for clinical studies
- Information on diagnosis and treatment options
Website: https://rarediseases.info.nih.gov
Contact Points in the UK
The A-T Society is the UK’s leading charity dedicated to supporting people with Ataxia-Telangiectasia and their families.
What They Offer:
- Providing information and resources
- Financial support for affected families
- Support with medical care
- Organization of events and conferences
- Promotion of research
Website: https://atsociety.org.uk
Ataxia UK supports people with all types of ataxias, including Ataxia-Telangiectasia, through information, support, and research.
What They Offer:
- Information and helpline services
- Funding and support for research projects
- Self-help groups and social support
- Education and awareness-raising
Website: https://www.ataxia.org.uk
Contact is a national charity that supports families with disabled children, including those with rare diseases such as Ataxia-Telangiectasia.
Services offered:
- Helplines and support services
- Information on rare diseases and disabilities
- Financial support and grants
- Parent forums and networks
Website: https://contact.org.uk
Genetic Alliance UK is an organization that supports people with genetic, rare, and undiscovered diseases, including Ataxia-Telangiectasia.
What They Offer:
- Information and support services
- Lobbying and political advocacy
- Promotion and research funding
- Networking and community building
Website: https://geneticalliance.org.uk
Rare Disease UK is the national network for people with rare diseases, including Ataxia-Telangiectasia, who are campaigning for improved services and support.
What They Offer:
- Education and awareness-raising
- Support with political advocacy
- Networking of patients and families
- Promotion of research initiatives
Website: https://geneticalliance.org.uk/campaigns-and-research/rare-disease-uk/
Contact Points in Germany
DHAG provides information and support for all types of ataxias, including Ataxia-Telangiectasia.
What They Offer:
- Information material and brochures
- Helpline and support
- Self-help groups and local meetings
- Events and seminars
Website: http://www.ataxie.de/
DGM is the largest self-help organization for people with neuromuscular diseases in Germany and offers extensive support for patients and their families.
What They Offer:
- Information centers and regional contacts
- Self-help groups and exchange opportunities
- Support with social law issues
- Research and support for scientific projects
Website: www.dgm.org
The association is a unique contact point for families affected by Ataxia-Telangiectasia. It offers support and information, organizes meetings, and promotes exchanges between affected families.
What They Offer:
- Meetings for families and patients
- Information material
- Exchange platforms and self-help groups
Local and regional self-help groups provide affected families the opportunity to exchange information directly and support each other. These groups can often be found through larger patient organizations such as Deutsche Ataxie Gesellschaft.
What They Offer:
- Regular meetings and exchange opportunities
- Support and counseling with the help of other affected people
- Joint activities and events
Some specialized clinics and centers in Germany offer specific medical care and advice for children with A-T. Here are some examples:
Heidelberg University Hospital offers specialized neurological and genetic counseling and has an Ambulanz für Bewegungsstörungen und Ataxien (outpatient practice for movement disorders and ataxias).
You can find a more comprehensive list of centers and clinics on this website.
There are also several certified centers for rare (neurological) diseases (ZSNE / ZNE) throughout Germany, some of which offer comprehensive care, information, and specialized treatment options, including, for example:
- Berliner Centrum für Seltene Erkrankungen (BCSE) der Berliner Charité
- ZSNE des Universitätsklinikum Tübingen
- Zentrum für Seltene Neurologische Erkrankungen Bonn (ZSEB) des Universitätsklinikum Bonn
- Essener Zentrum für Seltene Erkrankungen (EZSE) des Universitätsklinikum Essen
- Zentrum für Seltene Erkrankungen Freiburg (FZSE) des Universitätsklinikum Freiburg
- Zentrum für Seltene Erkrankungen Heidelberg (ZSEHD) des Universitätsklinikum Heidelberg
- Zentrum für Seltene Erkrankungen München (ZSEM) der LMU München
Are You Interested in the A-T Study?
Are you or your child affected by Ataxia-Telangiectasia (A-T)? If so, you may now be eligible to take part in a study with an innovative potential treatment against A-T.
New Treatments
Development of Novel Therapies
There are currently no approved drug therapies for A-T. Nevertheless, various approaches are being developed or are presently being tested in clinical trials.
One example is an innovative treatment with so-called glucocorticoids: They have a strong anti-inflammatory effect and can improve typical neurological symptoms of A-T. However, to avoid the usual side effects of long-term treatment, glucocorticoids are first encapsulated in the patient’s red blood cells. Doctors then inject this “loaded” blood back into the patient. In this way, the active ingredient is released slowly and evenly.11
Another approach researchers are looking into is antisense oligonucleotide therapy or ASO for short. Roughly speaking, this class of drugs aims to correct the faulty production of the ATM protein caused by genetic ATM mutations. This targeted intervention could also help alleviate neurological symptoms of A-T and slow the progression of the disease.12 However, clinical trials with patients have not yet been conducted.
Are You Interested in the A-T Study?
Are you or your child affected by Ataxia-Telangiectasia (A-T)? If so, you may now be eligible to take part in a study with an innovative potential treatment against A-T.
Further information
Quality guideline
Authors
Medical review
Date
References
Important note
Are You Interested in the A-T Study?
Use our commitment-free questionnaire to find out whether you or your child are eligible to participate in the study.
- Petley E et al. PLOS One. 2023;17(3):e0264177.
- Rothblum-Oviatt C et al. Orphanet J Rare Dis. 2016;11:159.
- Swift M et al. Am J Hum Gen 39: 573-583.
- Riboldi GM et al. Ataxia-Telangiectasia [Updated 2024 Mar 6]. In: StatPearls, accessed 12 July 2024
- Petely E et al. PLoS ONE 17(3): e0264177.
- National Organization for Rare Disorders. Ataxia Telangiectasia – Symptoms, Causes, Treatment https://rarediseases.org/rare-diseases/ataxia-telangiectasia/, accessed 12 July 2024
- Rothblum-Oviatt C et al. Orphanet J Rare Dis. 2016;11:159.
- Khan M et al. The Cerebellum 23: 722-756.
- Petley E et al. PLOS One. 2023;17(3):e0264177.
- Khan M et al. The Cerebellum 23: 722-756.
- Bertini E et al. Lancet Neurol 19(7):541-550.
- Kim J et al. Nature 619: 828-836.
- Guideline on evidence-based health information, version 1.0. 2017.
