Presymptomatic GRN Carrier Intervention Timing — Biomarker-Guided Therapy Initiation

SUMMARY

# Presymptomatic GRN Carrier Intervention Timing — Biomarker-Guided Therapy Initiation ## Background and Rationale Progranulin (GRN) haploinsufficiency causes frontotemporal dementia through reduced progranulin protein levels, presenting a unique opportunity for biomarker-guided therapeutic intervention in presymptomatic mutation carriers. This longitudinal clinical study aims to determine the optimal timing for initiating neuroprotective therapy by tracking biomarker changes that precede clinic

METHODOLOGY NOTES

**Phase 1: Participant Recruitment and Baseline Assessment (Months 1-6)** • Recruit 300 presymptomatic GRN mutation carriers through genetic counseling centers and FTD family registries • Conduct comprehensive clinical assessments including Montreal Cognitive Assessment (MoCA), Clinical Dementia Rating (CDR), and Frontotemporal Dementia Rating Scale (FRS) • Collect baseline biomarker samples: CSF (progranulin, neurofilament light, TDP-43), plasma (progranulin, NfL, GFAP), and serum inflammatory markers • Perform structural MRI with volumetric analysis focusing on frontal and temporal regions • Establish baseline neuropsychological battery scores and functional assessments **Phase 2: Biomarker Risk Stratification (Months 6-9)** • Stratify participants into risk groups based on composite biomarker scores: Low risk (>75th percentile progranulin, normal NfL), Intermediate risk (25-75th percentile progranulin, elevated NfL), High risk (<25th percentile progranulin, significantly elevated N