Espa?ol
PDFs by language
Our 24/7 cancer helpline provides information and answers for people dealing with cancer. We can connect you with trained cancer information specialists who will answer questions about a cancer diagnosis and provide guidance and a compassionate ear.
Chat live online
Select the Live Chat button at the bottom of the page
Call us at 1-800-227-2345
Available any time of day or night
Our highly trained specialists are available 24/7 via phone and on weekdays can assist through online chat. We connect patients, caregivers, and family members with essential services and resources at every step of their cancer journey. Ask us how you can get involved and support the fight against cancer. Some of the topics we can assist with include:
For medical questions, we encourage you to review our information with your doctor.
Ataxia-telangiectasia (A-T) is a rare hereditary condition that affects the nervous system, immune system, and other body systems. Other names for A-T include Louis-Bar syndrome, cerebello-oculocutaneous telangiectasia, and immunodeficiency with ataxia telangiectasia.
People with A-T have trouble with movement and an increased risk of some types of cancer (see below).
Children with A-T may begin staggering and appear unsteady (called ataxia) shortly after learning to walk. Most people with A-T eventually will need to use a wheelchair. Over time, people with A-T tend to develop slurred speech and have trouble with writing and other tasks.
Red marks called telangiectasias are caused by dilated capillaries and may appear on the skin and eyes as people get older.
People with A-T also have weakened immune systems, are prone to infections, and appear to be particularly sensitive to ionizing radiation, such as x-rays.
A-T is rare. It affects about 1 out of every 40,000 to 100,000 people. The chance that a person is a carrier of a single ATM gene mutation is about 1%, or 1 in 100.
Changes (mutations) in the ATM gene on chromosome 11 cause A-T.
Both parents must have and pass on the mutated ATM gene for their child to have the condition. People with only one ATM mutation gene are carriers of the disease, but they do not have any symptoms.
Options exist for people who carry an ATM gene mutation and might want to have children. For more information, talk with an assisted reproduction specialist at a fertility clinic.
A-T is initially suspected when a child develops signs of ataxia, meaning unsteady walking. To confirm if the child has A-T, imaging and blood tests are done, such as:
People with A-T have an increased risk of developing some types of cancer. The most common types of cancer seen in people with A-T are leukemia and lymphoma. These cancers can appear in childhood, and account for most of the cancers in people with A-T. As people with A-T live longer, there appears to be an increased risk of other cancer types, including breast cancer, ovarian cancer, stomach cancer, melanoma, and sarcoma.
People with one ATM gene mutation (carriers) also have an increased risk of developing breast cancer. Studies have shown that carriers have about twice the lifetime risk of developing female breast cancer compared to the general population. We do not yet know whether there is an increased risk of male breast cancer among ATM carriers.
Some data suggests that ATM mutation carriers may also have an increased risk for ovarian, pancreas, skin and prostate cancers, but this isn’t entirely clear.
More research is needed to clarify the risk of cancer and other conditions among ATM mutation carriers.
Children and adults with A-T should see their doctor regularly and be monitored for signs of cancer. People with A-T who have frequent infections are encouraged to have their immune status checked regularly.
Females with only 1 ATM gene mutation (carriers) also have an increased risk of developing breast cancer. Because of this, the National Comprehensive Cancer Network (NCCN) recommends that these women have yearly breast cancer screening with a mammogram and possibly a breast MRI, often starting at an earlier age than normal.
Screening options may change over time as new technologies are developed and more is learned about A-T. It is important to talk with your health care team about which screening tests to have and when to have them.
If you are concerned about your (or your child’s) cancer risk, talk with the health care team. It can be helpful to bring someone along to your appointments to take notes.
Consider asking the following questions:
If you are concerned about your family history and think your family may carry an ATM gene mutation, consider asking the following questions:
Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
Amirifar P, Ranjouri MR, Lavin M, Abolhassani H, Yazdani R, Aghamohammadi A. Ataxia-telangiectasia: epidemiology, pathogenesis, clinical phenotype, diagnosis, prognosis and management. Expert Rev Clin Immunol. 2020 Sep;16(9):859-871. doi: 10.1080/1744666X.2020.1810570. Epub 2020 Oct 15. PMID: 32791865.
Nissenkorn A, Ben-Zeev B. Ataxia telangiectasia. Handb Clin Neurol. 2015;132:199-214. doi: 10.1016/B978-0-444-62702-5.00014-7. PMID: 26564081.
Veenhuis S, van Os N, Weemaes C, Kamsteeg EJ, Willemsen M. Ataxia-Telangiectasia. 1999 Mar 19 [updated 2023 Oct 5]. In: Adam MP, Feldman J, Mirzaa GM, Pagon RA, Wallace SE, Bean LJH, Gripp KW, Amemiya A, editors. GeneReviews? [Internet]. Seattle (WA): University of Washington, Seattle; 1993–2024. PMID: 20301790.
Last Revised: March 1, 2024
American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.
Sign up to stay up-to-date with news, valuable information, and ways to get involved with the American Cancer Society.
If this was helpful, donate to help fund patient support services, research, and cancer content updates.