Inside brain cells, errors in DNA can accumulate as we age. But in patients with Alzheimer’s disease, these errors—known as somatic mutations—may build up at a faster rate. A new study by investigators from Brigham and Women’s Hospital and Boston Children’s Hospital found that patients with Alzheimer’s disease (AD) have a greater number of somatic mutations in their brain cells and that these mutations differed from people without Alzheimer’s disease. The team’s results are published in Nature.