GPC1

Chr 2

glypican 1

Also known as: glypican

The GPC1 protein is a cell surface heparan sulfate proteoglycan that binds collagen, participates in Schwann cell myelination, and regulates skeletal muscle differentiation by sequestering FGF2 signaling. Mutations cause autosomal recessive omodysplasia types 1 and 2, characterized by congenital limb malformations and facial dysmorphism. The gene shows low constraint against loss-of-function variants, consistent with recessive inheritance patterns.

Summary from RefSeq, UniProt
Research Assistant →
6
Active trials
27
Pubs (1 yr)
102
P/LP submissions
0%
P/LP missense
0.62
LOEUF
Multiple*
Mechanism· predicted
Clinical SummaryGPC1
Population Constraint (gnomAD)
Constrained for loss-of-function variants (OE-LoF 0.33) despite low pLI — interpret in context.
📋
ClinVar Variants
100 unique Pathogenic / Likely Pathogenic· 132 VUS of 254 total submissions
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Clinical Trials
6 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
0.62LOEUF
pLI 0.016
Z-score 2.87
OE 0.33 (0.190.62)
Tolerant

Typical tolerance to LoF variation

Missense Constraint
0.33Z-score
OE missense 0.95 (0.871.04)
346 obs / 363.9 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.33 (0.190.62)
00.351.4
Missense OE0.95 (0.871.04)
00.61.4
Synonymous OE1.06
01.21.6
LoF obs/exp: 7 / 21.3Missense obs/exp: 346 / 363.9Syn Z: -0.65
DN
0.6939th %ile
GOF
0.6542th %ile
LOF
0.2777th %ile

This gene has evidence for multiple mechanisms of pathogenicity (dominant-negative and gain-of-function). Both the Badonyi & Marsh prediction and the broader genomic evidence point to dominant-negative as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.

DNprediction above median
GOFprediction 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.

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

ClinVar Variant Classifications

254 submitted variants in ClinVar

Classification Summary

Pathogenic93
Likely Pathogenic7
VUS132
Likely Benign6
Benign2
93
Pathogenic
7
Likely Pathogenic
132
VUS
6
Likely Benign
2
Benign

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

ClassificationLoFMissense + InframeNon-codingSynonymousTotal
Pathogenic
0
0
93
0
93
Likely Pathogenic
0
0
7
0
7
VUS
0
121
11
0
132
Likely Benign
0
4
0
2
6
Benign
0
0
0
2
2
Total01251114240

LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly

View in ClinVar →

Protein Context — Lollipop Plot

GPC1 · protein map & ClinVar variants

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

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

Liver CancerRhabdomyosarcomaMalignant Rhabdoid Tumor

Interleukin-15 Armored Glypican 3-specific Chimeric Antigen Receptor Expressed in T Cells for Pediatric Solid Tumors

ACTIVE NOT RECRUITING
NCT04377932Phase PHASE1Baylor College of MedicineStarted 2021-08-08
AGAR T cells
Liver CancerRhabdomyosarcomaMalignant Rhabdoid Tumor

Interleukin-15 and -21 Armored Glypican-3-specific Chimeric Antigen Receptor Expressed in T Cells for Pediatric Solid Tumors

RECRUITING
NCT04715191Phase PHASE1Baylor College of MedicineStarted 2024-05-24
CARE T cellsCytoxanFludara
Solid Tumor (Excluding CNS)Hepatocellular CarcinomaLiver Cell Carcinoma

Cytokine Armored GPC3 Specific Chimeric Antigen Receptor Expressing T-cells in Adults With Solid Tumors

NOT YET RECRUITING
NCT07224568Phase PHASE1Seattle Children's HospitalStarted 2026-04-01
SC-CAR.GPC3xIL15.21 CAR T cells
Liver Cell CarcinomaSolid TumorWilms Tumor

Interleukin-15 Armored Glypican 3-specific Chimeric Antigen Receptor Expressed in Autologous T Cells for Solid Tumors

ACTIVE NOT RECRUITING
NCT05103631Phase PHASE1Baylor College of MedicineStarted 2021-06-17
CATCH T cells
Solid Tumor (Excluding CNS)Liver Cell CarcinomaMalignant Rhabdoid Tumor

Immunotherapy for Solid Tumor Malignancies in Pediatrics Using Interleukin-15 and -21 Armored Glypican-3-specific Chimeric Antigen Receptor T Cells

RECRUITING
NCT07148050Phase PHASE1Seattle Children's HospitalStarted 2025-12-22
SC-CAR.GPC3xIL15.21 CAR T cells
Liver Cancer

Glypican 3-specific Chimeric Antigen Receptor Expressed in T Cells for Patients With Pediatric Solid Tumors (GAP)

ACTIVE NOT RECRUITING
NCT02932956Phase PHASE1Baylor College of MedicineStarted 2018-12-17
GAP T cellsCytoxanFludara
Clinical Literature
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