The longitudinal evaluation of familial frontotemporal dementia subjects protocol: Framework and methodology

•It is important to establish the natural history of familial frontotemporal lobar degeneration (f-FTLD) and provide clinical and biomarker data for planning these studies, particularly in the asymptomatic phase.•The LEFFTDS protocol was designed to enroll and follow members of kindreds with a mutation in one of the three most common f-FTLD genes—MAPT, GRN, or C9orf72.•The theoretical considerations of f-FTLD, aims/objectives of the LEFFTDS protocol, design and methodology for evaluating and rating subjects, and scheme for collecting biofluid samples and performing MRI scans are described.•These data and samples, which are available to interested investigators worldwide, will facilitate planning for upcoming disease-modifying therapeutic trials in f-FTLD.