Mutations of a single gene, TREM2, can both substantially raise a person’s risk of developing Alzheimer’s, and at a later stage in the disease, protect the brain from damage. Mice without TREM2 suffer much less brain damage than those with it.

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Mutations of a single gene, TREM2, can both substantially raise a person’s risk of developing Alzheimer’s, and at a later stage in the disease, protect the brain from damage. Mice without TREM2 suffer much less brain damage than those with it.