GFAP

Chr 17AD

glial fibrillary acidic protein

Also known as: ALXDRD

The protein forms intermediate filaments in mature astrocytes and serves as a specific marker for these glial cells during development. Mutations cause Alexander disease, a rare astrocyte disorder of the central nervous system, inherited in an autosomal dominant pattern. The pathogenic mechanism involves a dominant-negative effect where mutant protein disrupts normal astrocyte function.

OMIMResearchSummary from RefSeq, OMIM, UniProt, Mechanism
DNmechanismADLOEUF 1.031 OMIM phenotype
VCEP Guidelines: LeukodystrophyPilot
ClinGen Panel
Clinical SummaryGFAP
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Gene-Disease Validity (ClinGen)
Alexander disease · ADDefinitive

Definitive — sufficient evidence for diagnostic panels

Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.
💊
Clinical Trials
12 active or recruiting trials — potential therapeutic options may be available

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Tolerant — LoF & missense variants common in population
LoF Constraint
1.03LOEUF
pLI 0.000
Z-score 1.48
OE 0.63 (0.411.03)
Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint
0.93Z-score
OE missense 0.84 (0.760.94)
233 obs / 276.5 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.63 (0.411.03)
00.351.4
Missense OE0.84 (0.760.94)
00.61.4
Synonymous OE0.73
01.21.6
LoF obs/exp: 12 / 19.0Missense obs/exp: 233 / 276.5Syn Z: 2.28
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
definitiveGFAP-related Alexander diseaseDNAD
DN
0.96top 5%
GOF
0.87top 5%
LOF
0.1498th %ile

This gene has evidence for multiple mechanisms of pathogenicity (gain-of-function and dominant-negative). The Badonyi & Marsh model scores dominant-negative highest among its predictions, but genomic evidence (constraint, ClinVar variant spectrum, and literature) most strongly supports gain-of-function. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.

GOFprediction above median · 1 literature citation
DNprediction above median

Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.

Literature Evidence

GOFDominant gain of function mutations in GFAP lead to the fatal neurodegenerative disorder, Alexander disease (AxD), which is characterized by cytoplasmic protein aggregates known as Rosenthal fibers along with variable degrees of leukodystrophy and intellectual disability.PMID:24259590

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

GFAP · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

3D Protein StructureAlphaFold

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

Alzheimer's Disease

A Phase 2b/3 Clinical Study Evaluating T3D-959 in Mild-to-Moderate Alzheimer's Disease Subjects

NOT YET RECRUITING
NCT06964230Phase PHASE2, PHASE3T3D Therapeutics, Inc.Started 2026-10-26
T3D-959Placebo Comparator
Schizophrenia

A Study of ANAVEX3-71 in Adults With Schizophrenia

ACTIVE NOT RECRUITING
NCT06245213Phase PHASE2Anavex Life Sciences Corp.Started 2024-03-15
ANAVEX3-71 oral capsulesPlacebo oral capsules
Alzheimer DiseaseMild Cognitive Impairment (MCI)Subjective Cognitive Decline (SCD)

Biomarker-based Trial of NPC-1 for Alzheimer's Pathology

RECRUITING
NCT07236190Phase PHASE2Massachusetts General HospitalStarted 2026-04-01
natural product combination-1 (NPC1)
Amyotrophic Lateral Sclerosis (ALS)

A Patient-tailored Genetic/Biomarker/iPSC Combined Approach in ALS - PERMEALS

RECRUITING
NCT06917924A.O.U. Città della Salute e della ScienzaStarted 2023-05-20
lumbar puncture
Relapsing Remitting Multiple Sclerosis (RRMS)

Indole-3-PROpionic Acid Clinical Trials - Multiple Sclerosis

RECRUITING
NCT07318129Phase NAGlostrup University Hospital, CopenhagenStarted 2026-01-26
PlaceboIndole-3-propionic acid (IPA)
Parkinson's Disease (PD)

Safety, Tolerability and Exploratory Efficacy of EC5026 in Parkinson's Disease (STEP Study)

RECRUITING
NCT07142044Phase PHASE1, PHASE2EicOsis Human Health Inc.Started 2025-10
EC5026 oral tabletPlacebo
Aging

Evaluation of the Efficacy of Calcium a -Ketoglutarate(AKG-Ca) in Improving Human Aging

ACTIVE NOT RECRUITING
NCT07114536Phase NAShenzhen Hygieia Biotech Co., LtdStarted 2025-08-20
Calcium-a-ketoglutaratePlacebo(starch)
Mild Cognitive ImpairmentAlzheimer's DiseaseAlzheimer's Disease, Early Onset

Development of a Database to Investigate Digital and Blood-Based Biomarkers and Their Relationship to Tau and Amyloid PET Imaging in Older Participants Who Are Cognitively Normal (CN), Have Mild Cognitive Impairment (MCI), or Have Mild-to-Moderate AD Dementia

RECRUITING
NCT06584357GAP Innovations, PBCStarted 2024-09-26
Biomarker Data CollectionMK6240
Cerebral Blood FlowAPOE 4

A Nutritional Intervention for Body, Brain, and Longevity Effects (NIBBLE)

NOT YET RECRUITING
NCT06682767Phase NACedars-Sinai Medical CenterStarted 2026-03
FMD1 (LNT22-017-1)Dietary Guidance
Subjective Cognitive Decline (SCD)Subjective Cognitive Complaints (SCCs)Subjective Cognitive Impairment

The Signature of Alzheimer's Disease in Subjective Cognitive Decline

RECRUITING
NCT07402161IRCCS Policlinico S. DonatoStarted 2025-10-01
Huntington Disease

Safety and Efficacy of AMT-130 in European Adults With Early Manifest Huntington's Disease

ACTIVE NOT RECRUITING
NCT05243017Phase PHASE1, PHASE2UniQure Biopharma B.V.Started 2021-10-07
intra-striatal rAAV5-miHTT
Mild Cognitive Impairment (MCI)Mild DementiaAlzheimer's Disease

Study to Evaluate the Efficacy and Safety of KDS2010 in Patients With Alzheimer's Disease With Mild Cognitive Impairment and Mild Dementia Due to Alzheimer's Disease

RECRUITING
NCT07027072Phase PHASE2NeuroBiogen Co., LtdStarted 2025-08-06
KDS2010Placebo
Clinical Literature
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Full-Text Mentions
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