ALLFTD: Identifying and Characterizing Frontotemporal Lobar Degeneration Participants in a Multi‐center North American Study
Hilary W. Heuer, Leah K. Forsberg, Carly T. Mester, Noah Johnson, Eliana Marisa Ramos, Kejal Kantarci, Walter K. Kremers, Leonard Petrucelli, Howard J. Rosen, Brad F. Boeve, Adam L. Boxer,- Psychiatry and Mental health
- Cellular and Molecular Neuroscience
- Geriatrics and Gerontology
- Neurology (clinical)
- Developmental Neuroscience
- Health Policy
- Epidemiology
Abstract
Background
The ALLFTD (ARTFL‐LEFFTDS Longitudinal Frontemporal Lobar Degeneration) study is an NIH‐funded effort to prepare for clinical trials in sporadic (s‐FTLD) and familial (f‐FTLD) FTLD syndromes by characterizing cohorts, developing new clinical trial outcome measures, and evaluating disease progression. ALLFTD represents the merger and continuation of two prior studies: Advancing Research and Treatment of Frontotemporal Lobar Degeneration (ARTFL) and Longitudinal Evaluation of Familial Frontotemporal Dementia Subjects (LEFFTDS).
Methods
ALLFTD recruits participants with FTLD spectrum disorders (bvFTD, svPPA, nfvPPA, FTD‐ALS, CBS or PSP), with strong family histories of FTLD, or known FTLD‐associated genetic variants within the family. 26 sites in North America enroll participants for clinical and neuropsychological evaluations, MR Imaging, blood draws, and CSF collection in willing participants; participants are requested to return annually for follow‐up evaluation. All participants are genotyped for dementia‐associated mutations. Participants also enroll in the FTD Disorders Registry for follow‐up surveys. A subset of participants undergo remote assessment via the ALLFTD app. Visits conducted under ARTFL and LEFFTDS are included in the ALLFTD dataset.
Results
ALLFTD has been successful in developing methods to conduct remote or hybrid visits and in actively evaluating participants. Since ALLFTD began in January 2020, 1034 participants (736 new; 298 previously enrolled in ARTFL or LEFFTDS) have been evaluated in the longitudinal arm; an additional 119 participants have been participated in a shortened, biofluid‐focused visit. 349 have returned for follow‐up visits. Including prior participants, the ALLFTD dataset contains 3871 visits from 2343 individuals. 1277 people have sporadic syndromes; 1045 were enrolled as familial. Among s‐FTLD, bvFTD is the most common phenotype (32.8%) followed by PSP (15.9%). 61.4% of f‐FTLD participants were clinically normal at first visit; bvFTD is the most common syndrome in symptomatic f‐FTLD (40%). 477 are confirmed carriers of FTLD‐associated genetic mutations. MRIs were obtained for 2594 visits; 3492 visits have associated blood biospecimens banked; 978 visits have associated CSF samples.
Conclusions
The ALLFTD consortium is actively evaluating participants across North America to better characterize FTLD syndromes and support the planning and development of FTLD clinical trials. Longitudinal datasets including clinical, genetic, and imaging data are available by request.