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Dryad

Plasma neurofilament light for prediction of disease progression in familial frontotemporal lobar degeneration

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Feb 10, 2022 version files 346.97 KB

Abstract

Objective: We tested the hypothesis that plasma neurofilament light chain (NfL) concentrations identify asymptomatic carriers of familial frontotemporal lobar degeneration (FTLD)-causing mutations at risk of disease progression.

Methods: Baseline plasma NfL concentrations were measured with Simoa in original (n = 277) and validation (n = 297) cohorts. C9orf72, GRN and MAPT mutation carriers and non-carriers from the same families were classified by disease severity [asymptomatic, prodromal and full phenotype] using the CDR® Dementia Staging Instrument plus behavior and language domains from the National Alzheimer’s Disease Coordinating Center FTLD module (CDR®+NACC-FTLD). Linear mixed effect models related NfL to clinical variables.

Results: In both cohorts, baseline NfL was higher in asymptomatic mutation carriers who showed phenoconversion or subsequent disease progression compared to non-progressors (original: 11.4 ± 7 pg/mL vs. 6.7 ± 5 pg/mL, p = 0.002; validation: 14.1 ± 12 pg/mL vs. 8.7 ± 6 pg/mL, p = 0.035). Plasma NfL discriminated symptomatic from asymptomatic mutation carriers or prodromal disease (original cutoff: 13.6 pg/mL, 87.5% sensitivity, 82.7% specificity; validation cutoff: 19.8 pg/mL, 87.4% sensitivity, 84.3% specificity). Higher baseline NfL correlated with worse longitudinal CDR®+NACC-FTLD sum of boxes scores, neuropsychological function and atrophy, regardless of genotype or disease severity, including asymptomatic mutation carriers.

Conclusions: Plasma NfL identifies asymptomatic carriers of FTLD-causing mutations at short-term risk of disease progression, and is a potential tool to select participants for prevention clinical trials.

Classification of evidence: This study provides Class I evidence that in familial FTLD, elevation of plasma NfL predicts short-term risk of clinical progression.