Ataxia-telangiectasia

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Ataxia-telangiectasia

ORPHA:100Disease

Also called Louis-Bar syndrome

What it is

A rare autosomal recessive cerebellar ataxia due to a DNA repair defect characterized by progressive neurological impairment with cerebellar syndrome, oculocutaneous telangiectasia, defects in B and T cell-mediated immunity, and increased susceptibility to malignancies (mainly lymphoid neoplasms). High sensitivity to ionizing radiation limits patient treatments.

Key facts

Prevalence
1-9 / 1 000 000 (Europe)
Age of onset
Childhood, Infancy
Inheritance
Autosomal recessive
Classified as
Disease

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

Signs and symptoms

These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.

Gene

ATMDisease-causing germline mutation(s)

ICD-10 codes

G11.3filed under a broader ICD-10 category — shared with 5 other rare diseases

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Related health topics

Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.

Cross-references

GARD 5862MEDDRA 10003594MESH D001260MONDO 0008840OMIM 208900OMIM 208910UMLS C0004135

Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.

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