Frontotemporal dementia

Frontotemporal dementia is a group of neurodegenerative disorders that damage the frontal and temporal lobes of the brain, producing progressive changes in behavior, personality, language and, in some forms, movement. Presentations range from a behavioral variant marked by apathy, disinhibition and loss of empathy to primary progressive aphasia affecting speech and language. Onset typically falls between ages 45 and 64, making it one of the more common causes of dementia beginning before 60. Roughly six in ten cases arise with no known genetic cause, while inherited cases are frequently traced to mutations in the C9orf72, GRN or MAPT genes. Life expectancy after diagnosis commonly ranges from seven to thirteen years, though the course varies widely between patients and subtypes.