Andre Yarham, believed to be Britain's youngest dementia sufferer, has died at age 24. Diagnosed at 22 with frontotemporal dementia, his brain showed changes typical of a 70-year-old. Symptoms included forgetfulness, behavioral changes, and loss of speech. Frontotemporal dementia, which affects personality, behavior, and language, is less common than Alzheimer's and can strike early, often with a genetic component. Yarham's case is expected to aid researchers in understanding the disease.