⁃ Familial FTLD (f-FTLD) participants (either is acceptable):

• members of families in whom at least one member has a known disease-associated mutation in one of the major genes that cause f-FTLD: MAPT, GRN, C9orf72 (or other rare genes)

• an autosomal dominant family history of a FTLD syndrome (without a known gene) verified by medical record review or well-documented family history including family members with a medical history consistent with FTLD or a related disorder.

⁃ Sporadic FTLD (s-FTLD) participants:

⁃ Sporadic participants should be symptomatic with no known family history nor a genetic mutation indicating f-FTLD. All sporadic participants must have an FTLD syndrome as a referring diagnosis; those determined by ALLFTD clinicians to have non-FTLD diagnoses will be excluded from longitudinal visits, but their baseline visit will be included in comparative datasets. For inclusion in the longitudinal follow-up, participants should meet research criteria for one of the following FTLD syndromes:

• Progressive Supranuclear Palsy (PSP)

• Semantic variant Primary Progressive Aphasia (svPPA)

• Nonfluent variant Primary Progressive Aphasia (nfvPPA)

• Corticobasal Degeneration (CBD)/Corticobasal Syndrome (CBS)

• Behavioral variant Frontotemporal dementia (bvFTD)

• Frontotemporal Dementia with Amyotrophic Lateral Sclerosis (FTD/ALS)