Semantic dementia (SD) is a form of frontotemporal dementia (FTD), characterized by the progressive, amodal and profound loss of semantic knowledge (combination of visual associative agnosia, anomia, surface dyslexia or dysgraphia and disrupted comprehension of word meaning) and behavioral abnormalities, attributable to the degeneration of the anterior temporal lobes. The disease is semantic dementia (MONDO_0010857, a Monarch Disease Ontology identifier). Also known as: dementia, frontotemporal, dementia, frontotemporal, with or without parkinsonism, semantic primary progressive aphasia, semantic variant PPA.