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# Ataxia-telangiectasia

An inherited childhood disease with unsteady walking, dilated vessels in the eyes, infections and a high cancer risk.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Cerebellum](https://durgical.com/en/anatomy/anterior-quadrangular-lobule/)
- [Vermis](https://durgical.com/en/anatomy/central-lobule/)
- [Cerebellar peduncles](https://durgical.com/en/anatomy/superior-cerebellar-peduncle/)
- [Neck lymph nodes](https://durgical.com/en/anatomy/lymph-nodes-of-neck/)
- [Thymus](https://durgical.com/en/anatomy/thymus/)

## In biochemistry

- [DNA repair](https://durgical.com/en/biochemistry/topics/dna-repair/)

## In the clinical exam

- [Cerebellar syndrome](https://durgical.com/en/clinical-exam/cerebellar-syndrome/)

## Why it happens

- [Genomic instability: mismatch repair, BRCA and xeroderma pigmentosum](https://durgical.com/en/general-pathology/genomic-instability-mismatch-repair-brca-and-xeroderma-pigmentosum/)
- [Cellular aging: telomeres, DNA damage, senescence and proteostasis](https://durgical.com/en/general-pathology/cellular-aging-telomeres-dna-damage-senescence-and-proteostasis/)
- [Radiation and cancer: ultraviolet and ionizing](https://durgical.com/en/general-pathology/radiation-and-cancer-ultraviolet-and-ionizing/)
- [Hereditary cancer syndromes: the table to know](https://durgical.com/en/general-pathology/hereditary-cancer-syndromes-the-table-to-know/)

## What it is

An autosomal recessive disorder caused by variants in ATM, the kinase that senses DNA double-strand breaks and coordinates their repair.

## Who gets it

It affects 1 in 40,000 to 100,000 people worldwide. Single-copy carriers (about 1% of the population) have a higher breast cancer risk. No specific figures for Colombia.

## Causes

- Biallelic variants in the ATM gene (chromosome 11q22-23)
- Autosomal recessive inheritance

## Risk factors

- Parents carrying an ATM variant
- Consanguinity

## Pathophysiology

ATM kinase switches on at a double-strand break and phosphorylates p53, CHK2, BRCA1 and histone H2AX, which halts the cell cycle and starts repair. Without ATM the breaks persist: chromosomes rearrange (especially at the lymphocyte receptor genes on chromosomes 7 and 14), lymphocytes mature poorly (immunodeficiency) and cerebellar Purkinje cells, very sensitive to oxidative stress, die. The cells are hypersensitive to ionising radiation.

## Symptoms and signs

- Ataxia when starting to walk (1–4 years) that progresses; many use a wheelchair by adolescence
- Telangiectasias on the conjunctiva and [skin](https://durgical.com/en/anatomy/skin/) by about 3–6 years
- Slurred speech, abnormal eye movements (oculomotor apraxia) and involuntary movements
- Recurrent respiratory infections
- Poor growth and delayed puberty

## Red flags

- Repeated pneumonia or bronchiectasis
- Lymph node enlargement, fever or weight loss (lymphoma)
- Choking when eating

## Diagnosis

**Clinical**
A child with progressive cerebellar ataxia and, later, ocular telangiectasias and recurrent infections.

**Tests**
Raised alpha-fetoprotein (very characteristic), low immunoglobulins (IgA, IgG2, IgE) and low lymphocytes; ATM genetic testing or absent ATM protein; karyotype with 7;14 translocations and radiosensitivity in culture.

**Imaging**
Brain MRI shows cerebellar atrophy, especially of the [vermis](https://durgical.com/en/anatomy/central-lobule/).

## Treatment

**Rehabilitation**
Physiotherapy, occupational and speech therapy to keep mobility and communication; a wheelchair when needed.

**Medical**
Immunoglobulin replacement and preventive antibiotics in patients with recurrent infections.

**Follow-up**
Cancer surveillance (lymphomas, leukaemias, breast in adult women) avoiding X-rays and CT where possible.

**Conservative**
Nutritional support and swallowing assessment to prevent aspiration.

**Medical**
If cancer appears, chemotherapy and radiotherapy are adjusted for the radiation hypersensitivity.

## Complications

- Lymphomas and leukaemias (mainly in childhood)
- Breast cancer and other solid tumours in adulthood
- Chronic lung disease and bronchiectasis
- Insulin-resistant diabetes
- Premature ageing of skin and hair

## Prognosis

Most live into their second to fourth decade; the main causes of death are cancer and lung disease.

## Prevention

- Genetic counselling and prenatal diagnosis in affected families
- Avoiding unnecessary ionising radiation

## Test yourself

Think of the answer, then tap the question to see it.

## What does the ATM protein do?

It is a kinase that senses DNA double-strand breaks and activates p53, CHK2 and repair.

## Which simple lab finding points to ataxia-telangiectasia in a child with ataxia?

Raised serum alpha-fetoprotein.

## Why are unnecessary X-rays avoided in these patients?

Their cells repair radiation-induced breaks poorly: more toxicity and cancer risk.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/conditions/ataxia-telangiectasia/)

## Related conditions

- [Hereditary breast and ovarian cancer syndrome (BRCA1/BRCA2)](https://durgical.com/en/conditions/hereditary-breast-and-ovarian-cancer-syndrome/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Ataxia-telangiectasia: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/ataxia-telangiectasia/) (MedlinePlus, US National Library of Medicine, 2026); [ATM gene: MedlinePlus Genetics](https://medlineplus.gov/genetics/gene/atm/) (MedlinePlus, US National Library of Medicine, 2026); Textbook of Biochemistry for Medical Students, 6th ed. (Jaypee Brothers Medical Publishers (Vasudevan DM, Sreekumari S, Vaidyanathan K), 2011).

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Source: https://durgical.com/en/conditions/ataxia-telangiectasia/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/ataxia-telangiectasia/