Frontotemporal dementia

Frontotemporal dementia (FTD), also known as frontotemporal degeneration, and historically as Pick's disease, is a family of neurodegenerative disorders, caused by frontotemporal lobar degeneration that affects the frontal and temporal lobes. The FTD family includes behavioral variant FTD, primary progressive aphasia (PPA) and its semantic and nonfluent/agrammatic variants, primary progressive apraxia of speech (PPAOS), progressive supranuclear palsy, and corticobasal syndrome. Through a mutual risk gene, FTD and amyotrophic lateral sclerosis (ALS) share a clinical spectrum, where symptoms of both disorders can co-occur. Symptoms of FTD will typically match a specific disorder at first, though symptoms of other disorders will begin to show as the disease progresses to different areas of the brain. FTD disorders are a common young-onset dementia occurring under the age of 60. Approximately 60% of people diagnosed with FTD have no known cause and no family history of FTD or related conditions; this is known as sporadic FTD. While environmental causes and unidentified gene variants are suspected causes of sporadic FTD, research in this area is still ongoing. When people have a family history of FTD, other dementias, or conditions like depression or anxiety, it is referred to as familial FTD, and roughly 20% have an underlying genetic basis. Variants in three genes are responsible for most genetic FTD. Notably, in about 10% of people with seemingly sporadic FTD, a genetic variant is identified. FTD diagnosis currently relies on clinical examination based on the signs and symptoms experienced and imaging of the brain through magnetic resonance imaging or positron emission tomography. FTD disorders have heterogeneous symptoms and pathological features, which contribute to a lengthy differential diagnostic process and high rates of misdiagnosis. A neuropathological examination after death usually provides a definitive diagnosis by identifying the specific features of FTD subtypes. There is no cure for FTD, nor...