C1Q deficiency 3

Summary

C1Q deficiency 3 (MONDO:0958188) is a disease with 1 cohort gene.

At a glance

• Cohort genes: 1
• ClinVar variants: 3

Clinical features

No curated clinical features (Orphanet) for this disease.

Identifiers

Disease identifiers

Field	Value
Canonical name	C1Q deficiency 3
Mondo ID	MONDO:0958188
OMIM	620322
UMLS	C5830423
MedGen	1841059
GARD	0026964
Is cancer (heuristic)	no

Data availability: 3 ClinVar variants.

Disease family

Classification path: disease › human disease › disease by body system or component › immune system disorder › inborn error of immunity › complement deficiency › immunodeficiency due to a classical component pathway complement deficiency › C1Q deficiency › C1Q deficiency 3

Related subtypes (2): C1Q deficiency 1, C1Q deficiency 2

Genetics & variants

GWAS landscape

No GWAS associations recorded — common-variant (GWAS) studies don’t cover this disease (typical for Mendelian / rare diseases). See the curated gene cohort and Mendelian overlap below.

Variant details and genetic-evidence tiers

ClinVar germline variants

3 retrieved; paginated sample, class counts are floors:

2 uncertain significance, 1 conflicting classifications of pathogenicity

ClinVar	Variant (HGVS)	Gene	Classification	Review
3718107	NM_172369.5(C1QC):c.212_213del (p.Pro71fs)	C1QC	Conflicting classifications of pathogenicity	criteria provided, conflicting classifications
17069	NM_172369.5(C1QC):c.213del (p.Gln74fs)	C1QC	Uncertain significance	criteria provided, single submitter
440743	NM_172369.5(C1QC):c.490G>A (p.Gly164Ser)	C1QC	Uncertain significance	criteria provided, single submitter

Genes & proteins

Mendelian disease overlap and somatic drivers

GenCC: 0 · Orphanet: 1 · OMIM-shared: 0 · Dual-evidence (GWAS+Mendelian): 0

Orphanet rare-disease linkage (cohort genes)

Gene	Orphanet ID	Rare disease
C1QC	Orphanet:169147	Immunodeficiency due to a classical component pathway complement deficiency

Cohort genes → proteins

1 cohort genes, 1 distinct canonical proteins.

Evidence partition

Subset	Genes
multi_evidence	1

Cohort genes (full)

Symbol	HGNC	Ensembl	UniProt	Name	Evidence
C1QC	HGNC:1245	ENSG00000159189	P02747	Complement C1q subcomponent subunit C	clinvar

Cohort function summary

Lead sentence per gene, UniProt-curated.

Symbol	Protein name	Function (lead sentence)
C1QC	Complement C1q subcomponent subunit C	Core component of the complement C1 complex, a multiprotein complex that initiates the classical pathway of the complement system, a cascade of proteins that leads to phagocytosis and breakdown of pathogens and signaling that strengthens t…

Protein-family classification

Druggable: 0 · Difficult: 0 · Unknown: 1 · Druggable fraction: 0.0

Family distribution

Cohort families vs a genome-wide background (hypergeometric, BH-FDR; fold = observed/expected). Counts kept; sorted by enrichment, so the catch-all Other/Unknown bucket no longer leads.

Family	Genes	Fold	FDR
Other/Unknown	1	1.8×	0.558

Per-gene assignment

Symbol	Family	Druggable?	EC	InterPro (top 3)
C1QC	Other/Unknown	no		C1q_dom, Collagen, Tumour_necrosis_fac-like_dom

Expression context

Cohort genes with no expression data: 0.

1 cohort gene are a single-cell marker in ≥1 SCXA experiment.

Breadth distribution (Bgee present_calls)

Bucket	Genes
narrow (1-5 tissues)	0
moderate (6-20)	0
broad (>20)	1
unknown	0

Top tissues across cohort

Tissue	Cohort genes
decidua	1
ileal mucosa	1
spleen	1

Per-gene tissue summary (top 30)

Symbol	Bgee breadth	FANTOM5 breadth	SCXA	Top tissues
C1QC	237	broad	marker	decidua, spleen, ileal mucosa

Protein interactions among cohort

Intra-cohort edges: 0.

Hub genes (top 10 by interactor count)

Symbol	Interactor count
C1QC	1,899

Structural data

PDB: 1 · AlphaFold-only: 0 · No structure: 0

Cohort genes with PDB structures (top 30)

Symbol	UniProt	PDB entries
C1QC	P02747	11

Function

Pathway analysis

Distinct Reactome pathways touched by cohort: 7. Enrichment computed across 1 evidence-associated genes (1 with Reactome annotation).

Pathways by enrichment

Over-representation of cohort genes vs the genome-wide background (hypergeometric test, Benjamini-Hochberg FDR; fold = observed/expected over 1 annotated cohort genes). Counts and members are kept as ground-truth; sorted by enrichment.

Pathway	Cohort genes	Fold	FDR	Sample cohort genes
Creation of C4 and C2 activators	1	1903.3×	0.002	C1QC
Classical antibody-mediated complement activation	1	1903.3×	0.002	C1QC
Complement cascade	1	634.4×	0.003	C1QC
Initial triggering of complement	1	601.0×	0.003	C1QC
Regulation of Complement cascade	1	233.1×	0.006	C1QC
Innate Immune System	1	25.5×	0.046	C1QC
Immune System	1	13.0×	0.077	C1QC

GO biological processes by enrichment

Over-representation of cohort genes vs the genome-wide background (hypergeometric test, Benjamini-Hochberg FDR; fold = observed/expected over 1 annotated cohort genes). Counts and members are kept as ground-truth; sorted by enrichment.

GO term	Cohort genes	Fold	FDR	Sample cohort genes
synapse pruning	1	2407.4×	9e-04	C1QC
negative regulation of granulocyte differentiation	1	2106.5×	9e-04	C1QC
negative regulation of macrophage differentiation	1	2106.5×	9e-04	C1QC
complement activation, classical pathway	1	543.6×	0.003	C1QC
immune response	1	47.1×	0.025	C1QC
innate immune response	1	33.6×	0.030	C1QC

Therapeutics

Drug target analysis

Approved (phase 4): 0 · Phase ≥3: 0 · Phased (≥1): 0 · Undrugged: 1

Druggability breadth: 0 of 1 evidence-associated genes (0%) have a ChEMBL target (buckets above are over the deeply-mined display cohort).

Top cohort targets by molecule count

Symbol	Molecules	Max phase
C1QC	0	0

Bioactivity and enzyme data

Enzyme cohort genes (≥1 EC): 0.

Pharmacogenomics

Cohort genes with a PharmGKB record: 1; with CPIC/DPWG dosing guidelines: 0.

No cohort gene has a CPIC/DPWG genotype-guided dosing guideline (PharmGKB).

Chemical tractability of cohort targets

0 approved/phased compounds have measured bioactivity against a cohort gene (and aren’t yet in disease-level trials). This is a research / tractability signal, NOT a therapeutic recommendation — a bioactivity row often reflects off-target or screening binding (e.g. promiscuous kinase inhibitors against a cohort kinase), implying no disease mechanism.

Druggability pyramid

Cohort genes binned by druggability tier (high → low):

Tier	Definition	Genes	Symbols
A	Approved (phase 4 drug)	0
B	Phased (≥1) drug, not yet approved	0
C	Druggable family + PDB, no drug	0
D	Druggable family + AlphaFold only, no drug	0
E	Difficult family or no structure, no drug	1	C1QC

Undrugged target profiles

1 cohort genes are undrugged. Ranked by ‘starting-point quality’ (assay depth + drugged-partner adjacency).

Symbol	ChEMBL assays	Drugged partners (top 3)
C1QC	0	—

Clinical trials & evidence

Clinical trials

Clinical trials: 0.