Ataxia Telangiectasia
Ataxia telangiectasia is a rare inherited condition that causes progressive problems with movement and coordination in early childhood, along with distinctive small clusters of widened blood vessels in the eyes and on the skin, a weakened immune system, and an increased risk of cancer.
Table of contents
- What is ataxia telangiectasia?
- Other names for this condition
- Medical identification codes
- How common is ataxia telangiectasia?
- What causes this condition?
- How is ataxia telangiectasia inherited?
- Signs and symptoms
- Body systems affected
- How is ataxia telangiectasia diagnosed?
- Treatment and management
- Outlook and life expectancy
What is ataxia telangiectasia?
Ataxia telangiectasia is a rare genetic condition that affects multiple body systems, particularly the nervous system and immune system. The condition causes cells in the body to progressively stop working properly, a process called neurodegeneration (when nerve cells gradually break down and die)[1].
The name of this condition describes its two most recognizable features. Ataxia refers to difficulty with coordinating movements and maintaining balance, while telangiectasia describes the small clusters of widened blood vessels that appear as red “spider veins,” typically seen in the whites of the eyes and on sun-exposed areas of skin[2][3].
People with ataxia telangiectasia typically begin showing symptoms in early childhood, usually between ages 1 and 5, when they start to sit or walk. While they may begin walking at a normal age, they often wobble, sway, or appear unsteady when walking, standing, or sitting[1][6].
Louis-Bar syndrome, cerebello-oculocutaneous telangiectasia, immunodeficiency with ataxia telangiectasia, A-T
Other names for this condition
Ataxia telangiectasia is also known by several other names, including Louis-Bar syndrome, named after the doctor who described the condition in 1941. Medical professionals may also refer to it as cerebello-oculocutaneous telangiectasia or immunodeficiency with ataxia telangiectasia[2][5].
Medical identification codes
G11.3
How common is ataxia telangiectasia?
Ataxia telangiectasia is a rare condition that occurs in approximately 1 out of every 40,000 to 100,000 people worldwide[1][3]. The condition affects males and females equally and occurs in people of all races and ethnic backgrounds[7].
Although ataxia telangiectasia itself is rare, carriers of the gene mutation are more common. About 1 percent of people in the United States carry one altered copy of the gene responsible for the condition. These carriers do not have symptoms of ataxia telangiectasia but may have a slightly higher risk of developing certain types of cancer, particularly breast cancer in women[1][3].
What causes this condition?
Ataxia telangiectasia is caused by changes, called mutations (permanent alterations in genetic material), in a gene called ATM. This gene is located on chromosome 11 and provides instructions for making a protein that helps control how cells divide and repair damaged DNA[3][4].
The ATM protein plays a critical role in recognizing when DNA strands are damaged or broken and coordinates the repair process by activating other proteins that fix these breaks. This function is essential for maintaining the stability of genetic information in cells[3].
When the ATM gene is mutated, the protein either doesn’t work properly or isn’t made at all. Without functional ATM protein, cells cannot effectively repair DNA damage, which causes them to become unstable and eventually die. Brain cells in an area called the cerebellum (the part of the brain that controls balance and coordinated movement) are particularly vulnerable to the loss of ATM protein[3][4].
The inability to repair DNA damage also allows breaks in DNA strands to accumulate over time, which can lead to the formation of cancerous tumors. This explains why people with ataxia telangiectasia have an increased risk of developing cancer[3].
How is ataxia telangiectasia inherited?
Ataxia telangiectasia follows an autosomal recessive inheritance pattern. This means a person must inherit two copies of the mutated ATM gene—one from each parent—to develop the condition[1][3].
Parents who each carry one mutated copy of the ATM gene typically do not show any symptoms of ataxia telangiectasia. However, when both parents are carriers, they have a 25 percent (one in four) chance with each pregnancy of having a child with the condition[4].
People who carry only one mutated copy of the ATM gene are called carriers. While carriers do not develop ataxia telangiectasia, research suggests they may have a slightly increased risk of certain health problems, particularly cancer. Female carriers appear to have a higher risk of developing breast cancer compared to the general population[3][4].
Signs and symptoms
The symptoms of ataxia telangiectasia typically begin in early childhood and worsen progressively over time. The condition affects multiple body systems, leading to a wide range of symptoms[1][2].
Movement and coordination problems
Difficulty with movement is usually the first noticeable symptom of ataxia telangiectasia. Parents may first observe unsteadiness when their toddler begins to walk, with the child swaying when sitting or standing. These coordination problems are caused by abnormalities in the cerebellum[1][3].
Movement-related symptoms include difficulty walking, problems with balance and hand coordination, involuntary jerking movements called chorea (sudden, irregular movements that appear to flow from one body part to another), muscle twitches known as myoclonus (brief, shock-like muscle jerks), and disturbances in nerve function called neuropathy (damage to nerves that can cause weakness, numbness, or pain)[2][3].
Children with ataxia telangiectasia typically develop slurred speech and have trouble moving their eyes smoothly from side to side, a condition called oculomotor apraxia (difficulty with purposefully moving the eyes). Some may also experience involuntary eye movements called nystagmus (rapid, uncontrolled eye movements)[1][2]. Most children never develop completely normal speech due to problems with articulation and placing emphasis on the wrong parts of words[1].
As the condition progresses, most children will need to use a wheelchair by their teenage years, typically between ages 10 and 15[1][5].
Telangiectasias
The characteristic widened blood vessels called telangiectasias typically appear between ages 4 and 8, though not everyone with the condition will develop them. These red “spider veins” most commonly appear in the whites of the eyes and on sun-exposed areas of skin, such as the ears and cheeks[2][4].
Immune system problems
People with ataxia telangiectasia often have a weakened immune system that affects their ability to fight off infections. The immune deficiency can involve both parts of the immune system: the cells that produce antibodies and the cells that directly attack infections[2][4].
This leads to frequent and chronic infections, particularly of the sinuses, ears, and lungs. Many people develop recurrent respiratory infections such as sinusitis, bronchitis, and pneumonia. These repeated lung infections can cause lasting damage to the lungs over time[1][2].
Increased cancer risk
Individuals with ataxia telangiectasia have a significantly higher risk of developing cancer compared to the general population. Approximately 10 to 30 percent of people with the condition will develop cancer, most commonly during childhood or adolescence[4][5].
The most common types of cancer in people with ataxia telangiectasia are leukemia (cancer of blood-forming cells) and lymphoma (cancer of immune system cells), which together account for about 85 percent of cancers in affected individuals. Other cancers that may occur include those of the ovaries, breast, stomach, liver, and skin[3][4][5].
Other symptoms
People with ataxia telangiectasia often have elevated levels of a protein called alpha-fetoprotein in their blood. This protein is normally increased during pregnancy, but it is found at high levels in about 95 percent of people with ataxia telangiectasia. The reason for this elevation and its effects are not well understood[3][4].
Additional symptoms may include poor growth or slowed development, delayed puberty or incomplete sexual development, early menopause in women, type 2 diabetes, premature graying of hair, premature aging of the skin, and extreme fatigue[1][2][6].
People with ataxia telangiectasia are also unusually sensitive to radiation exposure, including medical X-rays. This sensitivity can cause more severe reactions to radiation therapy if cancer treatment is needed[2][3].
Body systems affected
- Brain (particularly the cerebellum)
- Nervous system
- Immune system
- Blood vessels
- Skin
- Eyes
- Lungs
- Endocrine system
How is ataxia telangiectasia diagnosed?
Diagnosing ataxia telangiectasia can be challenging, especially in young children, because symptoms develop gradually and may initially resemble other neurological conditions such as cerebral palsy. The diagnosis is typically made based on the combination of clinical symptoms, laboratory tests, and genetic testing[1][4].
Doctors may suspect ataxia telangiectasia when a child shows an unsteady walk, unusual eye or body movements, frequent infections, or the characteristic telangiectasias. What often leads to the correct diagnosis is the observation that neurological symptoms progressively worsen over time, unlike cerebral palsy where symptoms remain stable[1].
Laboratory tests
A key laboratory finding in ataxia telangiectasia is an elevated level of alpha-fetoprotein in the blood. This protein is found at abnormally high levels (above 10 nanograms per milliliter) in about 95 percent of people with the condition[4].
Blood tests may also reveal abnormalities in the immune system, including low levels of certain antibodies or immune cells[1].
Genetic testing
The definitive diagnosis of ataxia telangiectasia is made through genetic testing that identifies mutations in both copies of the ATM gene. This testing can confirm the diagnosis when clinical symptoms suggest the condition[4].
If parents know they carry the ATM gene mutation or have a family member with ataxia telangiectasia, genetic testing can be performed before a baby is born through procedures such as amniocentesis or chorionic villus sampling[1].
Imaging tests
Brain imaging studies, particularly MRI scans, may show characteristic changes in the cerebellum, including shrinkage of specific areas. These findings can support the diagnosis but are not present in all cases[4].
Newborn screening
Some individuals with ataxia telangiectasia are now identified before symptoms appear through newborn screening programs that test for severe combined immunodeficiency. An abnormal test result may prompt further evaluation and lead to an early diagnosis[4].
Treatment and management
There is currently no cure for ataxia telangiectasia, and no treatment can slow or stop the progressive neurological decline. Management focuses on addressing symptoms, preventing complications, and improving quality of life[2][3].
Managing movement problems
Physical therapy is essential for helping maintain flexibility, muscle strength, and mobility for as long as possible. Occupational therapy (therapy focused on daily living skills) can help people adapt to changing abilities and maintain independence in daily activities[1][2].
Speech therapy can teach children techniques to control breathing and improve speech clarity. Some medications, particularly beta-blockers (drugs that slow the heart rate and reduce blood pressure), may help improve fine motor coordination in some cases[2][11].
Preventing and treating infections
Because of the weakened immune system, preventing infections is a priority. Regular injections of immunoglobulins (antibodies that help fight infections) can help reduce the frequency and severity of infections. Prompt treatment with antibiotics when infections occur is essential and has been shown to significantly prolong life[11].
High-dose vitamins and antioxidants may be helpful in supporting overall health, though their specific benefits in ataxia telangiectasia are still being studied[2][11].
Cancer surveillance and treatment
Regular monitoring for cancer is important given the increased risk. If cancer develops, treatment must be carefully planned because people with ataxia telangiectasia are extremely sensitive to radiation therapy and certain chemotherapy drugs[11].
Some reports suggest that standard doses of chemotherapy can be used, while others recommend reduced doses, especially for drugs called alkylating agents. Certain medications, including bleomycin, actinomycin D, and cyclophosphamide, should generally be avoided[11].
Respiratory care
Managing lung health is crucial due to the risk of chronic lung infections and progressive lung disease. This may include regular monitoring of lung function, prompt treatment of respiratory infections, and techniques to help clear lung secretions[1].
Nutritional support
Many people with ataxia telangiectasia have difficulty swallowing, which can lead to poor nutrition and weight loss. Dietary modifications, swallowing therapy, and in some cases feeding tubes may be necessary to ensure adequate nutrition[1].
Emerging treatments
Several potential treatments are currently being investigated. These include N-Acetyl-DL-Leucine, which may help improve some neurological symptoms, and a system called EryDex that involves encapsulating a medication called dexamethasone into red blood cells. While most treatments are still in early research stages, these approaches show promise for future therapy[14].
Outlook and life expectancy
Ataxia telangiectasia is a progressive condition, meaning symptoms gradually worsen over time. Most children with the condition have stable neurological symptoms for the first 4 to 5 years of life but begin to show increasing problems during their early school years[6].
Life expectancy varies considerably among people with ataxia telangiectasia and depends largely on the specific type of ATM gene mutation and the severity of symptoms. The three main causes of death are cancer, infections (particularly lung infections), and respiratory failure[5].
With proper medical care, many people with ataxia telangiectasia live into early adulthood. Those who have a later onset of symptoms and slower progression of the disease may survive into their 50s. Improved medical care, particularly antibiotic treatment for infections and better supportive care, has significantly extended the lifespan of people with this condition[2][3][11].
Despite the serious challenges posed by ataxia telangiectasia, many affected individuals maintain normal intelligence and complete higher education. With appropriate support and medical care, people with this condition can lead meaningful and fulfilling lives[4].
