Your risk factors depend upon how many people in your family are carriers of the genetic mutation. This article discusses the genetic causes of A-T and associated risk factors.
Common Causes
Genetic Mutation
ATM gene mutations or changes interfere with healthy cell division and DNA strand maintenance and repair. ATM gene mutations are responsible for A-T syndrome.
Chronic Oxidative Stress
Continuous oxidative stress is a feature of A-T in animal studies, but human clinical studies are still necessary. It can play a role in DNA damage, as well as cellular damage and carcinogenesis (when healthy cells turn cancerous).
Researchers point to chronic oxidative stress as a factor in A-T and conditions similar to A-T, like Bloom syndrome and Nijmegen breakage syndrome. In A-T, the damage to nervous system cells contributes to the deterioration of voluntary movement.
Genetics
A-T is known as an autosomal recessive disorder. This means these mutations have to be present on both copies of the gene (one copy from each biological parent) in order to cause A-T in offspring.
If only one gene copy has the mutation, then the offspring becomes a carrier. Carriers usually do not show symptoms.
The mutation is on the long arm (q) of chromosome 11 (11q22.3). Chromosomes are found in the nucleus of all body cells. If two carriers have a child, there is a 25% chance the child will develop A-T.
The chance for a child to receive normal genes from both parents and be genetically normal for that particular trait is 25%. Parents, siblings, and children of a person with A-T (i.e., first-degree relatives) have a 50% chance of inheriting the single gene mutation and becoming a carrier.
Other names for the ATM gene include:
With the ATM mutation, p53 protein doesn’t work nearly as well. Cells with damaged DNA can continue to divide, and some may be cancerous. This is why A-T is known as a hereditary cancer gene.
AT mutatedAT proteinAT1ATAAtaxia-telangiectasia mutatedAtaxia-telangiectasia mutated (includes complementation groups A, C, and D)Ataxia-telangiectasia mutated proteinATCATDATDCATEATM_HUMANHuman phosphatidylinositol 3-kinase homologSerine-protein kinase ATMTEL1TELO1
Lifestyle Risk Factors
Since A-T is an inherited genetic disease and symptoms often start in early childhood, lifestyle risk factors, or things you can change to lower your risk of developing a particular disease, aren’t applicable.
But having A-T raises the risk of developing cancer. Reducing lifestyle risk factors for cancer is even more important for people with the condition and their family members.
People with A-T have about a 40% risk of developing cancer, most likely leukemia or lymphoma. Those two cancers account for 85% of all cancers in people with A-T. People with A-T also have an increased risk of developing breast cancer, ovarian cancer, stomach cancer, skin cancer, and bone and soft tissue cancer.
The American Cancer Society says being a carrier of the ATM gene (inheriting one abnormal copy of the gene) has been linked to a high rate of breast cancer in some families. A 2021 review study identified a specific mutation or ATM variant associated with increased breast cancer risk called the V2424G mutation.
General risk factors for cancer include:
Older ageA personal or family history of cancerUsing tobaccoObesityAlcoholSome types of viral infections, such as human papillomavirus (HPV)Specific chemicalsExposure to radiation, including ultraviolet radiation (UV) from the sun
Summary
Ataxia-telangiectasia is caused by an autosomal recessive gene mutation. Both genetic parents must pass the mutation to a child in order for the condition to develop. This gene normally works to keep damaged cells from dividing. With the mutation, damaged cells may continue to divide, raising the risk of cancer.
A Word From Verywell
If A-T runs in your family, you may be wondering if you’re a carrier. Genetic testing like carrier testing, predictive diagnosis, and genetic counseling can help determine your personal risk of passing down a genetic mutation or developing certain forms of cancer. Talk to your doctor about the pros and cons of genetic testing to see if it’s right for you.
