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Genetics and inheritance

TDP-43

TAR DNA-binding protein 43

A protein found clumped abnormally inside nerve cells in most ALS/MND, whatever the underlying cause.

What it means

Normally the protein helps manage genetic messages inside a cell. In most people with ALS/MND it is instead found gathered abnormally inside nerve cells — the single most consistent finding across the condition, present even when the TARDBP gene that makes the protein carries no inherited change at all. The same clumping links ALS/MND to some forms of frontotemporal dementia, which is part of why the two are often discussed together.

Why you might hear it

  • It is the finding a pathologist looks for after death to confirm ALS/MND, independent of someone's genetic testing results.
  • It comes up constantly in research about what actually damages nerve cells, as distinct from what inherited change may have started the process.

What it is not

Not the gene. TARDBP is the gene and is what a genetic testing panel reads; TDP-43 is the protein it produces, and the protein's clumping is found in about 97% of ALS/MND regardless of whether the TARDBP gene itself is changed.

People who may help

About this explanation

These are plain explanations of words you may come across, not advice about your own situation. Where a word matters to a decision, the question pages go into it properly, and your own team is the place to take it.