C1QBP

Chr 17AR

complement C1q binding protein

Also known as: COXPD33, GC1QBP, HABP1, SF2AP32, SF2p32, gC1Q-R, gC1qR, p32

NCBI Gene: 708ENSG00000108561UniProt: Q07021

The human complement subcomponent C1q associates with C1r and C1s in order to yield the first component of the serum complement system. The protein encoded by this gene is known to bind to the globular heads of C1q molecules and inhibit C1 activation. This protein has also been identified as the p32 subunit of pre-mRNA splicing factor SF2, as well as a hyaluronic acid-binding protein. [provided by RefSeq, Jul 2008]

Primary Disease Associations & Inheritance

Combined oxidative phosphorylation deficiency 33MIM #617713
AR
235
ClinVar variants
37
Pathogenic / LP
0.00
pLI score
0
Active trials
Clinical Summary— C1QBP
🧬
Gene-Disease Validity (ClinGen)
mitochondrial disease · ARDefinitive

Definitive — sufficient evidence for diagnostic panels

⚡
Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.
📋
ClinVar Variants
37 Pathogenic / Likely Pathogenic· 79 VUS of 235 total submissions

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD
Tolerant — LoF & missense variants common in population
LoF Constraint?LOEUF (Loss-of-function Observed/Expected Upper bound Fraction) is the upper bound of the 90% CI for LoF OE — the preferred gnomAD v4 metric. Lower = more intolerant to LoF. LOEUF < 0.35 = highly constrained.
1.47LOEUF
pLI 0.000
Z-score 0.36
OE 0.89 (0.56–1.47)
Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint?Missense Z-score: standard deviations fewer missense variants observed vs. expected. Z > 3.09 (p < 0.001) = gene does not tolerate missense variation. OE missense < 0.6 is also considered constrained.
1.06Z-score
OE missense 0.75 (0.64–0.88)
105 obs / 140.4 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios?Shaded band = 90% confidence interval. Vertical tick = point estimate. Grey threshold line = gnomAD constraint cutoff for that variant class.
LoF OE?Ratio of observed to expected LoF variants. Upper CI bound (LOEUF) ≤ 0.35 = strong LoF constraint signal.0.89 (0.56–1.47)
0≤0.351.4
Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.75 (0.64–0.88)
0≤0.61.4
Synonymous OE?Control metric — synonymous variants are largely neutral and expected near OE = 1.0. Significant deviation may indicate annotation issues.1.07
0≤1.21.6
LoF obs/exp: 11 / 12.4Missense obs/exp: 105 / 140.4Syn Z: -0.45

ClinVar Variant Classifications

235 submitted variants in ClinVar

ClinVar

Classification Summary

Pathogenic33
Likely Pathogenic4
VUS79
Likely Benign101
Benign16
Conflicting2
33
Pathogenic
4
Likely Pathogenic
79
VUS
101
Likely Benign
16
Benign
2
Conflicting

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

ClassificationLoFMissense + InframeNon-codingSynonymousTotal
Pathogenic
3
3
27
0
33
Likely Pathogenic
2
1
1
0
4
VUS
0
64
14
1
79
Likely Benign
0
5
34
62
101
Benign
0
2
12
2
16
Conflicting
—2
Total5758865235

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

View in ClinVar →

Protein Context — Lollipop Plot

C1QBP · protein map & ClinVar variants

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

Gene2Phenotype Curations

C1QBP-related severe neonatal-, childhood-, or later-onset cardiomyopathy associated with combined respiratory-chain deficiencies

strong
ARUndeterminedAltered Gene Product Structure
Dev. Disorders
G2P ↗
missense variantinframe deletioninframe insertion

Gene2Phenotype curations · DECIPHER consortium patient cohort (public variants) · deciphergenomics.org

OMIM — Genotype-Phenotype Relationships

1 OMIM entry

OMIM

Combined oxidative phosphorylation deficiency 33

MIM #617713

Molecular basis of disorder known

Autosomal recessive
Clinical Literature
Landmark / reviewRecent case evidence
Key Publications
Landmark & review papers · by relevance
PubMed
Exosome-delivered CD44v6/C1QBP complex drives pancreatic cancer liver metastasis by promoting fibrotic liver microenvironment.
Xie Z et al.·Gut
2022
Circular RNA MTCL1 promotes advanced laryngeal squamous cell carcinoma progression by inhibiting C1QBP ubiquitin degradation and mediating beta-catenin activation.
Wang Z et al.·Mol Cancer
2022
The C1q Receptors: Focus on gC1qR/p33 (C1qBP, p32, HABP-1)(1).
Ghebrehiwet B et al.·Semin Immunol
2019Review
Loss of CHCHD2 Stability Coordinates with C1QBP/CHCHD2/CHCHD10 Complex Impairment to Mediate PD-Linked Mitochondrial Dysfunction.
Ren YL et al.·Mol Neurobiol
2024
C1QBP Drives M2 Macrophage Polarization Via TRAF2-CCL2 to Promote Oral Squamous Cell Carcinoma Progression.
Qin X et al.·Int Dent J
2025
gC1qR: A New Target for Cancer Immunotherapy.
Lei Y et al.·Front Immunol
2023Review
Bu-fei decoction ameliorates naïve CD4(+) T cell senescence and attenuates age-related COPD by regulating the C1qbp-cGAS-STING signaling pathway.
Xu G et al.·Phytomedicine
2025
Role of the Host Genetic Susceptibility to 2009 Pandemic Influenza A H1N1.
Pérez-Rubio G et al.·Viruses
2021Review
Circulating Metabolites Treat Human TMJ-OA by Eliminating Senescent Chondrocytes via the C1QBP/C1q/p14ARF Axis.
Meng B et al.·J Extracell Vesicles
2026
Recent topics: the diagnosis, molecular genesis, and treatment of mitochondrial diseases.
Murayama K et al.·J Hum Genet
2019Review
Top 10 resultsSearch PubMed ↗
Recent Gene-Specific Literature
Gene in title · MEDLINE · newest first
Europe PMC
Top 5 resultsSearch Europe PMC ↗

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

ClinicalTrials.gov

No active trials found for this gene.

Search ClinicalTrials.gov →

External Resources

Links to major genomics databases and tools