Identification and characterization of Frontotemporal Lobar Degeneration (FTLD) using clinical, imaging, genetic, and pathologic features has increased dramatically over the last ten years.Up to 40% may be genetic with known mutations in the tau gene (MAPT) on chromosome 17 leading to tau protein inclusions and mutations in the progranulin gene also on chromosome 17 leading to TDP-43 protein inclusions.Clinical features are characterized by progressive behavioral and cognitive decline with personality change or expressive language or naming impairments.