F12

Chr 5ADAR

coagulation factor XII

Also known as: HAE3, HAEX, HAF

Factor XII is a serum glycoprotein that initiates blood coagulation, fibrinolysis, and generates bradykinin and angiotensin by activating coagulation factors VII and XI. Mutations cause factor XII deficiency, which typically has no clinical symptoms despite prolonged clotting times, and hereditary angioedema type 3, which can follow either autosomal dominant or recessive inheritance patterns. The gene shows moderate constraint against loss-of-function variants (LOEUF 0.775).

OMIMResearchSummary from RefSeq, OMIM, UniProt
GOFmechanismAD/ARLOEUF 0.782 OMIM phenotypes
Clinical SummaryF12
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Gene-Disease Validity (ClinGen)
congenital factor XII deficiency · ARDefinitive

Definitive — sufficient evidence for diagnostic panels

2 total gene-disease associations curated

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

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Tolerant — LoF & missense variants common in population
LoF Constraint
0.78LOEUF
pLI 0.000
Z-score 2.57
OE 0.52 (0.350.78)
Tolerant

Typical tolerance to LoF variation

Missense Constraint
0.92Z-score
OE missense 0.86 (0.790.95)
307 obs / 356.1 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.52 (0.350.78)
00.351.4
Missense OE0.86 (0.790.95)
00.61.4
Synonymous OE0.95
01.21.6
LoF obs/exp: 17 / 32.9Missense obs/exp: 307 / 356.1Syn Z: 0.48
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
definitiveF12-related angioneurotic oedema, hereditary, with normal C1 inhibitor concentration and functionGOFAD
DN
0.6452th %ile
GOF
0.6737th %ile
LOF
0.2874th %ile

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

GOFprediction above median · 1 literature citation
DNprediction 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.

Literature Evidence

GOFThe data strongly suggested that T328K is a gain-of-function mutation that markedly increases F12 amadolytic activity but that does not alter F12 plasma levels.PMID:17186468

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

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

F12 · protein map & ClinVar variants

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

3D Protein StructureAlphaFold

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

No active trials found for this gene.

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Clinical Literature
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Recent Gene-Specific Literature
Gene in title · MEDLINE · newest first
Europe PMC