C1QBP

Chr 17AR

complement C1q binding protein

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

NCBI Gene: 708 ENSG00000108561 UniProt: Q07021 OMIM: 601269

C1QBP encodes a multifunctional protein involved in mitochondrial protein synthesis, pre-mRNA splicing, complement system regulation, and ribosome biogenesis. Mutations cause combined oxidative phosphorylation deficiency 33 with autosomal recessive inheritance. The gene shows high tolerance to loss-of-function variants (very low pLI score), suggesting the disease mechanism may be complex and potentially involve specific functional domains rather than simple protein loss.

OMIM ResearchSummary from RefSeq, OMIM, UniProt

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]

OMIM ResearchGenerating clinical summary…

ARLOEUF 1.471 OMIM phenotype

Clinical Summary— C1QBP

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Gene-Disease Validity (ClinGen)

mitochondrial disease · ARDefinitive

Definitive — sufficient evidence for diagnostic panels

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Population Constraint (gnomAD)

Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.

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ClinVar Variants

15 unique Pathogenic / Likely Pathogenic· 71 VUS of 214 total submissions

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Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Tolerant — LoF & missense variants common in population

LoF Constraint?

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?

1.06Z-score

OE missense 0.75 (0.64–0.88)

105 obs / 140.4 exp

Tolerant

Mild missense constraint

Observed / Expected Ratios?

LoF OE?0.89 (0.56–1.47)

0≤0.351.4

Missense OE?0.75 (0.64–0.88)

0≤0.61.4

Synonymous OE?1.07

0≤1.21.6

LoF obs/exp: 11 / 12.4Missense obs/exp: 105 / 140.4Syn Z: -0.45

ClinVar Variant Classifications

214 submitted variants in ClinVar

ClinVar

Classification Summary

Pathogenic12

Likely Pathogenic3

VUS71

Likely Benign101

Benign16

Conflicting2

Pathogenic

Likely Pathogenic

VUS

101

Likely Benign

Benign

Conflicting

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

Classification	LoF	Missense + Inframe	Non-coding	Synonymous	Total
Pathogenic	5	3	4	0	12
Likely Pathogenic	2	1	0	0	3
VUS	0	66	4	1	71
Likely Benign	0	5	34	62	101
Benign	0	2	12	2	16
Conflicting	—				2
Total	7	77	54	65	205

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

View in ClinVar →

23 pathogenic / likely-pathogenic (of 31) ClinVar copy-number / structural variants overlap C1QBP — these span large chromosomal regions, not the gene specifically, and are excluded from the counts above. Explore in CNV tools →