08/04/2026
Most people know Ataxia-Telangiectasia as a rare neurodegenerative disease.
But A-T is much bigger than the neurological symptoms we see.
A-T is caused by mutations in the ATM gene, which is one of the body’s most important DNA repair genes.
Every day, our cells experience DNA damage. ATM acts like an emergency response system, detecting double strand DNA breaks, helping repair it, and stopping damaged cells from becoming dangerous.
When ATM does not work, DNA damage builds up.
This affects the brain, where vulnerable cells in the cerebellum, particularly the purkinje cells, are lost over time. This leads to progressive changes in balance, coordination, speech, and movement.
It also affects the immune system, because creating antibodies and immune cells requires carefully controlled DNA changes. Without ATM, that process is disrupted.
And then there is cancer.
ATM is one of the genes that protects us from cancer by helping prevent damaged cells from growing out of control. Without a working ATM gene, children with A-T have a much higher risk of cancers (up to 40% go on to develop cancer). Leukemia and lymphoma are the most common as children, and solid tumors as they age become common as well.
But ATM matters beyond A-T.
Parents of children with A-T are usually carriers, meaning they have one working copy and one nonworking copy of ATM. While they do not develop A-T, having only one working copy can still increase the risk of certain cancers, and researchers took notice of this during earlier stages of A-T research.
A-T is not just a neurological disease.
It is a disease of DNA repair.
And understanding how ATM, the protein these children lack, helps explain why A-T affects so many different parts of the body.
