Genetic Frontotemporal Dementia Initiative for Neurodevelopment

Inclusion Criteria: 1. Written informed consent must be obtained and documented (from the participant and their substitute decision maker). This can be obtained in person or remotely. 2. Youths between the ages of 9 and 16 inclusive at time of enrollment, followed until age 17. 3. Youths must have a 1st or 2nd degree biological relative who has participated (past or present) in the Genetic Frontotemporal Dementia Initiative (GENFI) study or with genetic FTD (i.e. a known mutation in biological parent or grandparent). 4. Parent(s)/guardian deem appropriate to participate. 5. Must have a study partner who can participate as required in the protocol (provide corroborative information). Study partner must have regular contact with the participant and must be parent/guardian of this participant. 6. Must have age-appropriate awareness that FTD runs in their family as determined by local PI. Exclusion Criteria: 1. Current structural brain abnormality affecting cognition or behaviour not thought to be possibly related to genetic FTD that would prevent completion of study assessments (such as brain tumor, stroke, hydrocephalus). 2. Other concerns that participation in the study may not be in the best interest of the youth or parent, as raised by the participant's parent/guardian/primary care provider, local site PI or psychologist. 3. Lack of study partner. 4. For MRI: meeting any MRI incompatible criteria. Note: Participants may opt to decline MRI scans and complete the other measures.