Affinage

C1QB

Complement C1q subcomponent subunit B · UniProt P02746

Round 2 corrected
Length
253 aa
Mass
26.7 kDa
Annotated
2026-04-28
48 papers in source corpus 18 papers cited in narrative 18 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

C1QB encodes the B-chain of complement subcomponent C1q, an essential structural and functional constituent of the classical complement pathway that assembles with the A- and C-chains into a heterotrimeric globular head (gC1q) atop a collagen-like stalk (PMID:1706597, PMID:12960167). Charged residues on the B-chain globular head mediate differential recognition of IgG, C-reactive protein, pentraxin 3, and phosphatidylserine on apoptotic cells, and upon engagement of hexameric IgG–antigen complexes the C1q arms condense to activate C1r₂s₂ proteases and initiate the complement cascade (PMID:16566583, PMID:29449492, PMID:18250442). Loss-of-function mutations in C1QB abolish C1q assembly and secretion, causing complete C1q deficiency, and additionally destabilize C1qA expression, demonstrating that the B-chain is indispensable for heterotrimeric complex integrity (PMID:25454803, PMID:24160257). Beyond innate immunity, C1QB is expressed in microglia under transcriptional control by TGF-β1 (suppressive) and the TCF7L2/COX-2 axis (inductive), and is functionally required for monocyte-to-macrophage differentiation (PMID:1426121, PMID:11074155, PMID:41534674, PMID:36464147).

Mechanistic history

Synthesis pass · year-by-year structured walk · 13 steps
  1. 1976 High

    Establishing the quaternary organization of C1q required identifying inter-chain disulfide linkages; pepsin digestion showed that the B-chain collagen-like region forms a disulfide-linked A–B heterodimer, defining the basic subunit architecture of the collagen-like stalk.

    Evidence Pepsin digestion, chromatography, SDS-PAGE of purified human C1q

    PMID:7240

    Open questions at the time
    • Precise disulfide positions not resolved to single cysteine residues
    • Stoichiometry of the full hexameric assembly not addressed
  2. 1979 High

    Complete sequencing of the B-chain collagen-like region revealed a break in the Gly-X-Y repeat (Ala at position B-9), providing the first evidence that the collagen-like stalk of C1q has built-in flexibility sites that could affect its conformational dynamics.

    Evidence Protein sequencing of pepsin-derived collagen-like fragments

    PMID:486087

    Open questions at the time
    • Functional significance of the Gly→Ala disruption not tested
    • Complete primary structure of the globular domain not yet determined
  3. 1988 High

    Mapping the IgG binding site on C1q required identifying the cognate residues on the antibody; mutagenesis localized the C1q contact to Glu318/Lys320/Lys322 in the IgG CH2 domain, confirming that the gC1q heterotrimer (including ghB) engages a conserved ionic motif on immunoglobulins.

    Evidence Systematic surface mutagenesis of mouse IgG2b, complement lysis inhibition with synthetic peptides

    PMID:3258649

    Open questions at the time
    • The specific C1q residues contacting these IgG residues were not identified
    • Applicability across all human IgG subclasses not tested
  4. 1991 High

    Cloning of the C1QB gene and its genomic context established the A-C-B gene cluster on chromosome 1p and revealed a shared intron placement within the collagen-like coding region, suggesting coordinated evolution of the three chains; separately, direct binding of C1q to HIV-1 gp41 demonstrated antibody-independent activation of the classical pathway by a viral target.

    Evidence cDNA cloning/genomic sequencing for gene structure; radiolabeled C1q binding and reconstituted C1 complex activation for gp41 interaction

    PMID:1706597 PMID:1744579

    Open questions at the time
    • Transcriptional regulatory elements of C1QB not characterized
    • Whether gp41-C1q activation benefits host or virus was unresolved
  5. 1992 Medium

    The cellular source of C1qB in the brain was unknown; in situ hybridization co-localized C1qB mRNA with CR3-positive microglia and showed upregulation after cortical injury, establishing microglia as the primary C1qB-expressing cell type in the CNS.

    Evidence In situ hybridization and immunohistochemistry in rat brain lesion models

    PMID:1426121

    Open questions at the time
    • Functional role of microglial C1qB in synaptic remodeling not yet tested
    • Neuronal expression under pathological conditions not excluded
  6. 2000 Medium

    Upstream regulation of C1qB in the brain was undefined; TGF-β1 was shown to suppress C1qB mRNA both in vivo (intraventricular infusion) and in cultured microglia, identifying the first negative transcriptional regulator of C1qB in the CNS.

    Evidence Intraventricular TGF-β1 infusion in rats and primary microglia culture with Northern blot quantification

    PMID:11074155

    Open questions at the time
    • Direct promoter mechanism of TGF-β1-mediated repression not characterized
    • Whether TGF-β1 acts through SMAD signaling on the C1QB promoter was unknown
  7. 2003 High

    Resolving the atomic structure of the gC1q heterotrimer at 1.9 Å revealed how the A, B, and C globular heads assemble with a Ca²⁺ ion and provided the framework for understanding how a single trimeric module recognizes structurally diverse ligands including pentraxin 3.

    Evidence X-ray crystallography; recombinant globular head binding assays and C4 deposition assay for PTX3

    PMID:12645945 PMID:12960167

    Open questions at the time
    • Full-length C1q structure not resolved
    • Mechanism by which PTX3 switches between complement activation and inhibition was unclear
  8. 2006 High

    Site-directed mutagenesis of individual ghB residues showed that specific charged amino acids on the B-chain globular head are differentially required for binding IgG1, CRP, and PTX3, demonstrating that C1q versatility arises from overlapping but distinct contact surfaces on the same heterotrimer.

    Evidence Recombinant globular head modules, site-directed mutagenesis, ELISA and SPR binding assays

    PMID:16566583

    Open questions at the time
    • Complete binding footprint with full-length ligands not determined
    • Contribution of avidity from six gC1q heads not quantified
  9. 2008 High

    The identity of the C1q receptor for apoptotic cell clearance was debated; direct binding of the gC1q domain to phosphatidylserine was demonstrated with nanomolar affinity and structural validation, establishing PS as a key eat-me signal recognized by C1q.

    Evidence SPR kinetics, cosedimentation, X-ray crystallography, confocal microscopy with annexin V competition

    PMID:18250442

    Open questions at the time
    • Relative contributions of PS versus other apoptotic ligands in vivo not quantified
    • Downstream signaling linking C1q-PS engagement to phagocytosis not defined
  10. 2014 High

    How C1q is activated on target cells was a long-standing question; the discovery that IgG forms ordered hexamers via Fc–Fc contacts on antigen-bearing surfaces, and that these hexamers are the physiological unit recruiting C1, explained the stoichiometric requirement for complement activation; concurrently, patient mutations confirmed that C1QB loss-of-function causes complete C1q deficiency with secondary C1qA destabilization.

    Evidence Cell surface complement assays, EM, native MS, Fc mutagenesis; deep sequencing, hemolytic/ELISA assays and qPCR in patient-derived cells

    PMID:24160257 PMID:24626930 PMID:25454803

    Open questions at the time
    • Whether non-immune C1q ligands also require multivalent display was unknown
    • Genotype–phenotype correlation for distinct C1QB mutations not systematically established
  11. 2018 High

    The structural mechanism coupling ligand recognition to protease activation was resolved when cryo-EM of the C1–IgG1 hexamer complex showed that antibody binding induces arm condensation and stalk tilting, transmitting a conformational change to the C1r₂s₂ proteases.

    Evidence Cryo-EM structural analysis complemented by functional IgG1 mutant validation

    PMID:29449492

    Open questions at the time
    • Dynamic intermediates of the activation transition not captured
    • Structural basis for how non-IgG ligands activate C1 remained unresolved
  12. 2022 Medium

    C1QB was known as a complement component but its role in myeloid cell fate was unexplored; siRNA and lentiviral knockdown demonstrated that C1QB is required for monocyte-to-macrophage differentiation and for macrophage-mediated β-cell damage in a type 1 diabetes model.

    Evidence C1QB siRNA in cultured monocytes; lentiviral knockdown in streptozotocin-induced T1DM rats with histological quantification

    PMID:36464147

    Open questions at the time
    • Mechanism by which C1QB promotes differentiation (autocrine signaling vs. complement activation) not defined
    • Whether other C1q chains are equally required was not tested
  13. 2026 Medium

    A direct transcriptional activator of C1QB was identified: TCF7L2 binds the C1QB promoter and drives its expression in the epileptic brain, linking Wnt/TCF signaling to complement-mediated synaptic pruning and neuronal damage.

    Evidence ChIP, luciferase reporter assay, lentiviral Tcf7l2 knockdown in kainic acid epilepsy mouse model with immunohistochemistry

    PMID:41534674

    Open questions at the time
    • Whether TCF7L2 regulation of C1QB operates in non-CNS tissues is unknown
    • Interaction between TGF-β1 suppression and TCF7L2 activation at the promoter level not studied

Open questions

Synthesis pass · forward-looking unresolved questions
  • Key unresolved questions include the structural basis for how non-antibody ligands (CRP, PTX3, PS) activate or modulate the C1r₂s₂ protease arm, the mechanism by which C1QB promotes monocyte-to-macrophage differentiation independently of canonical complement activation, and how the opposing TGF-β1 and TCF7L2 regulatory inputs are integrated at the C1QB promoter.
  • No cryo-EM or structural data for C1q bound to non-IgG ligands
  • Cell-intrinsic versus complement-dependent role of C1QB in myeloid differentiation unresolved
  • Promoter architecture and combinatorial transcription factor binding not mapped

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0048018 receptor ligand activity 5 GO:0005198 structural molecule activity 4
Localization
GO:0005576 extracellular region 4 GO:0031012 extracellular matrix 1
Pathway
R-HSA-168256 Immune System 6 R-HSA-1643685 Disease 3
Partners
C1QAC1QCC1RC1SCRPPTX3TCF7L2
Complex memberships
C1 complex (C1q:C1r2:C1s2)C1q heterotrimer (A:B:C chains)

Evidence

Reading pass · 18 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1991 The C1QB gene encodes the B-chain polypeptide of human complement subcomponent C1q. The three genes encoding C1q A-, B-, and C-chains are aligned in the order A-C-B on a 24 kb stretch of DNA on chromosome 1p, each containing one intron located within a codon for a glycine residue in the collagen-like region. The B-chain collagen-like region participates in the triple-helical stalk structure of C1q. cDNA cloning, genomic cosmid library isolation, Southern blot, DNA sequencing The Biochemical journal High 1706597
1979 The complete amino acid sequence of the collagen-like region of the C1q B-chain was determined; the B-chain has an alanine residue at position B-9 where glycine would be expected in the Gly-X-Y collagen repeat, representing a break in the collagen-like sequence. Protein sequencing of pepsin-derived collagen-like fragments The Biochemical journal High 486087
1976 Partial pepsin digestion of human C1q revealed that the B-chain collagen-like region (N-terminal ~91 residues) is disulfide-linked to the A-chain collagen-like region via a single disulfide bond between residue B2-B6, forming an A-B heterodimer that constitutes part of the collagen-like stalk of C1q. Pepsin digestion, CM-cellulose chromatography, SDS-PAGE, amino acid composition analysis The Biochemical journal High 7240
2003 Crystal structure of the C1q globular head domain (gC1q) resolved to 1.9 Å revealed a compact heterotrimeric assembly of the C-terminal regions of A, B, and C chains held together mainly by non-polar interactions, with a Ca2+ ion bound at the top. The B-chain globular head (ghB) contributes to ligand recognition. Structural models suggest the gC1q heterotrimer is key to the versatile recognition properties of C1q. X-ray crystallography at 1.9 Å resolution, molecular modeling The Journal of biological chemistry High 12960167
2006 Mutational analysis of recombinant globular head modules showed that charged residues on the ghB module (side of the ghB) are crucial for C1q binding to IgG1, C-reactive protein, and pentraxin 3. The ghB module has specific and differential binding properties, and a set of charged residues from the apex of the gC1q heterotrimer (with participation of all three chains including ghB) mediate ionic and hydrogen bonds with ligands. Recombinant expression of globular head modules, site-directed mutagenesis, binding assays (ELISA, SPR) Biochemistry High 16566583
2003 The globular head region of C1q (including contributions from the B-chain) mediates binding to pentraxin 3 (PTX3), as shown by experiments with recombinant individual globular head modules of A, B, and C chains. C1q binding to PTX3 activates the classical complement pathway via C4 deposition, and enhances C1q binding to apoptotic cells; however, fluid-phase PTX3 pre-incubated with C1q inhibits complement activation. Recombinant globular head domain binding assays, C4 deposition assay, apoptotic cell binding experiments European journal of immunology High 12645945
2008 The globular domain of C1q (including the B-chain globular head) binds phosphatidylserine (PS) on apoptotic cells specifically and avidly (KD = 3.7–7 × 10−8 M) through multiple interactions between its globular domain and the phosphoserine group of PS, demonstrated by cosedimentation, surface plasmon resonance, X-ray crystallography, and confocal microscopy showing colocalization of C1q with PS in membrane patches at early stages of apoptosis. Surface plasmon resonance, cosedimentation, X-ray crystallography, confocal microscopy, annexin V competition assay Journal of immunology High 18250442
1988 The binding site for C1q on IgG was localized to three residues in the CH2 domain (Glu318, Lys320, Lys322 in mouse IgG2b); a peptide mimic of this sequence inhibits complement lysis, establishing that the C1q B-chain globular head (among other gC1q chains) contacts this conserved IgG motif. Systematic surface residue mutagenesis of IgG2b, complement lysis inhibition with peptide mimics Nature High 3258649
2018 Cryo-EM structures of C1 bound to IgG1 hexamers revealed that C1q arms (formed by the A, B, and C chains including the B-chain) condense upon antibody binding, inducing rearrangements of C1r2s2 proteases and tilting C1q's cone-shaped stalk, providing a structural mechanism for how danger pattern recognition activates complement. Distinct C1q binding sites on the two Fc-CH2 domains of each IgG were identified, including previously unknown interactions, validated by functional IgG1 mutant analysis. Cryo-electron microscopy, IgG1 mutant functional analysis Science High 29449492
2014 IgG antibodies form ordered hexamers via specific noncovalent Fc-Fc interactions after antigen binding on cell surfaces, and these hexamers recruit and activate C1 (which requires C1q including the B-chain) to trigger the complement cascade. Manipulating Fc-Fc interactions modulated complement activation and target cell killing across all four human IgG subclasses. Cell surface complement activation assays, electron microscopy, native MS, mutagenesis of Fc segments Science High 24626930
1991 HIV-1 activates the classical complement pathway independent of antibody through direct binding of C1q to specific sites in the transmembrane glycoprotein gp41 (residues 591–605 and 601–620). Soluble gp41 bound C1q and activated the C1 complex (C1q+C1r+C1s) in a dose- and time-dependent manner; gp120 was ineffective. The C1q interaction with gp41 is mediated through the recognition function shared by the A, B, and C chains of C1q. Radiolabeled C1q binding, gel exclusion chromatography, C1 complex reconstitution and activation assay, synthetic peptide inhibition The Journal of experimental medicine High 1744579
1992 C1qB mRNA in rat brain is expressed specifically in microglia-macrophages (identified by CR3 immunoreactivity) and is upregulated in response to cortical deafferentation and excitotoxic lesions, establishing microglia as the primary source of C1qB in brain injury responses. In situ hybridization, immunohistochemistry (CR3 co-localization), Northern blot Experimental neurology Medium 1426121
2000 TGF-β1 decreases C1qB mRNA expression in rat brain cortex and hippocampus in vivo (after intraventricular infusion) and in cultured glia, establishing a regulatory link between TGF-β1 signaling in microglia and complement C1qB gene expression. Intraventricular TGF-β1 infusion in rats, primary microglia culture treatment, Northern blot/in situ hybridization quantification Neuroscience Medium 11074155
2001 Neuronal overexpression of human COX-2 in transgenic mice selectively induces C1qB expression in neurons (without inducing C3 or C4), and this induction is reduced by treatment with the selective COX-2 inhibitor nimesulide, placing COX-2-mediated inflammatory signaling upstream of neuronal C1qB expression. Transgenic mouse model, COX-2 inhibitor treatment (nimesulide), Northern blot/in situ hybridization for C1qB mRNA Acta neuropathologica Medium 11810182
2022 Silencing C1QB in monocytes inhibited their differentiation into macrophages and reduced macrophage numbers both in vitro and in a rat model of type 1 diabetes mellitus, demonstrating that C1QB is functionally required for monocyte-to-macrophage differentiation and for macrophage accumulation in pancreatic islets causing β-cell damage. C1QB siRNA knockdown in cultured monocytes, lentiviral knockdown in streptozotocin-induced T1DM rat model, cell counting, histology Pharmacological research Medium 36464147
2013 A novel homozygous splicing mutation in C1QB (c.187+1G>T) causes complete C1q deficiency in a Japanese patient, demonstrating that the C1QB B-chain is essential for assembly and secretion of functional C1q protein. Clinical genetics, PCR-based mutation identification, complement functional assays (persistent hypocomplementemia with normal C3/C4) Pediatric rheumatology online journal Medium 24160257
2014 A homozygous non-coding mutation two nucleotides before the splice site of the second exon of C1QB causes complete absence of C1qB mRNA and intracellular C1qB protein, with secondary reduction of C1qA mRNA (but not C1qC), resulting in complete C1q deficiency. This demonstrates that C1qB is required for stable C1qA expression and for C1q complex assembly. Deep sequencing, ELISA, hemolytic assay, Western blot, qPCR of C1qA/B/C mRNAs, in silico splice-site analysis Immunobiology High 25454803
2026 TCF7L2 directly binds the C1QB promoter and positively regulates C1QB transcription; lentiviral knockdown of Tcf7l2 in a kainic acid-induced epilepsy mouse model reduced C1qb overexpression, attenuated microglial activation, and ameliorated neuronal injury, establishing a TCF7L2→C1QB regulatory axis that promotes synaptic pruning-dependent neuronal damage in epilepsy. ChIP assay, luciferase reporter assay, lentiviral Tcf7l2 knockdown in kainic acid epilepsy mouse model, immunohistochemistry, neuronal injury quantification Brain research bulletin Medium 41534674

Source papers

Stage 0 corpus · 48 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2002 Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences. Proceedings of the National Academy of Sciences of the United States of America 1479 12477932
2015 The BioPlex Network: A Systematic Exploration of the Human Interactome. Cell 1118 26186194
2017 Architecture of the human interactome defines protein communities and disease networks. Nature 1085 28514442
2020 A reference map of the human binary protein interactome. Nature 849 32296183
2021 Dual proteome-scale networks reveal cell-specific remodeling of the human interactome. Cell 705 33961781
2014 Complement is activated by IgG hexamers assembled at the cell surface. Science (New York, N.Y.) 631 24626930
1988 The binding site for C1q on IgG. Nature 501 3258649
2004 The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC). Genome research 438 15489334
2003 The crystal structure of the globular head of complement protein C1q provides a basis for its versatile recognition properties. The Journal of biological chemistry 287 12960167
2003 Biochemical and functional characterization of the interaction between pentraxin 3 and C1q. European journal of immunology 285 12645945
2008 C1q binds phosphatidylserine and likely acts as a multiligand-bridging molecule in apoptotic cell recognition. Journal of immunology (Baltimore, Md. : 1950) 226 18250442
2011 Toward an understanding of the protein interaction network of the human liver. Molecular systems biology 207 21988832
2014 Extracellular matrix signatures of human primary metastatic colon cancers and their metastases to liver. BMC cancer 203 25037231
1991 Characterization and organization of the genes encoding the A-, B- and C-chains of human complement subcomponent C1q. The complete derived amino acid sequence of human C1q. The Biochemical journal 194 1706597
1991 Human immunodeficiency virus type 1 activates the classical pathway of complement by direct C1 binding through specific sites in the transmembrane glycoprotein gp41. The Journal of experimental medicine 189 1744579
2017 Characterization of the Extracellular Matrix of Normal and Diseased Tissues Using Proteomics. Journal of proteome research 185 28675934
1976 Isolation, by partial pepsin digestion, of the three collagen-like regions present in subcomponent Clq of the first component of human complement. The Biochemical journal 176 7240
2020 UFMylation maintains tumour suppressor p53 stability by antagonizing its ubiquitination. Nature cell biology 168 32807901
2015 Emerging and Novel Functions of Complement Protein C1q. Frontiers in immunology 152 26175731
1980 The Clq receptor site on immunoglobulin G. Nature 148 6776418
2018 Structures of C1-IgG1 provide insights into how danger pattern recognition activates complement. Science (New York, N.Y.) 146 29449492
2006 The DNA sequence and biological annotation of human chromosome 1. Nature 144 16710414
2021 SARS-CoV-2 RNAemia and proteomic trajectories inform prognostication in COVID-19 patients admitted to intensive care. Nature communications 137 34099652
2014 The central role of EED in the orchestration of polycomb group complexes. Nature communications 131 24457600
2013 Proteomic analysis of podocyte exosome-enriched fraction from normal human urine. Journal of proteomics 126 23376485
2001 Substrate specificities of recombinant mannan-binding lectin-associated serine proteases-1 and -2. The Journal of biological chemistry 125 11527969
1976 Physicochemical and functional characterization of the C1r subunit of the first complement component. Journal of immunology (Baltimore, Md. : 1950) 123 814163
2006 Interaction of C1q with IgG1, C-reactive protein and pentraxin 3: mutational studies using recombinant globular head modules of human C1q A, B, and C chains. Biochemistry 122 16566583
1992 Complement C1qB and C4 mRNAs responses to lesioning in rat brain. Experimental neurology 119 1426121
1979 Complete amino acid sequences of the three collagen-like regions present in subcomponent C1q of the first component of human complement. The Biochemical journal 119 486087
1976 Activation of C1r by proteolytic cleavage. Journal of immunology (Baltimore, Md. : 1950) 108 1249422
1994 Selective expression of clusterin (SGP-2) and complement C1qB and C4 during responses to neurotoxins in vivo and in vitro. Neuroscience 83 7870303
2011 Transcriptome profiling of whole blood cells identifies PLEK2 and C1QB in human melanoma. PloS one 40 21698244
2024 Cholesterol efflux from C1QB-expressing macrophages is associated with resistance to chimeric antigen receptor T cell therapy in primary refractory diffuse large B cell lymphoma. Nature communications 32 38890370
2022 Single-cell RNA sequencing highlights the roles of C1QB and NKG7 in the pancreatic islet immune microenvironment in type 1 diabetes mellitus. Pharmacological research 26 36464147
2011 Association of C1QB gene polymorphism with schizophrenia in Armenian population. BMC medical genetics 26 21951915
1994 Expression of complement C1qB and C4 mRNAs during rat brain development. Brain research. Developmental brain research 25 7955342
2001 Induction of the complement component C1qB in brain of transgenic mice with neuronal overexpression of human cyclooxygenase-2. Acta neuropathologica 24 11810182
2000 Transforming growth factor-beta1 induces transforming growth factor-beta1 and transforming growth factor-beta receptor messenger RNAs and reduces complement C1qB messenger RNA in rat brain microglia. Neuroscience 24 11074155
2018 Jun, Gal, Cd74, and C1qb as potential indicator for neuropathic pain. Journal of cellular biochemistry 20 29331040
2013 The identification of a novel splicing mutation in C1qB in a Japanese family with C1q deficiency: a case report. Pediatric rheumatology online journal 15 24160257
2014 Identification of a novel non-coding mutation in C1qB in a Dutch child with C1q deficiency associated with recurrent infections. Immunobiology 14 25454803
2021 IRF4-activated TEX41 promotes the malignant behaviors of melanoma cells by targeting miR-103a-3p/C1QB axis. BMC cancer 11 34915882
2024 Identification of the C1qDC gene family in grass carp (Ctenopharyngodon idellus) and the response of C1qA, C1qB, and C1qC to GCRV infection in vivo and in vitro. Fish & shellfish immunology 3 38447782
2024 Causal relationship between complement C1QB and colorectal cancer: a drug target Mendelian randomization study. Frontiers in genetics 1 39109334
2026 TCF7L2 transcriptionally regulates C1QB to exacerbate synaptic pruning-dependent neuronal injury in the epileptic hippocampus. Brain research bulletin 0 41534674
2026 Differential expression of CD74 and C1QB in jaw versus long bone osteosarcoma: Insights from animal models, public datasets and clinical cohorts. Journal of bone oncology 0 41705027
2025 Identification of a Novel Homozygous C1QB Mutation in an Iranian Girl: Expanding the Clinical Spectrum of C1q Deficiency. International journal of immunogenetics 0 40506420