PF4
Chr 4platelet factor 4
Also known as: CXCL4, PF-4, SCYB4
The protein functions as a CXC chemokine released from activated platelets that regulates platelet aggregation, hematopoiesis, immune cell migration, and has anticoagulant effects through heparin binding. Mutations cause autosomal dominant thrombocytopenia-5, a bleeding disorder characterized by reduced platelet counts and abnormal platelet function. The gene shows low constraint to loss-of-function variation, suggesting that complete loss of protein function may be tolerated.
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly tolerant — LoF variants common in population
Mild missense constraint
The highest-scoring mechanism for this gene is dominant-negative.
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.
Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.
ClinVar Variant Classifications
0 submitted variants in ClinVar
Protein Context — Lollipop Plot
PF4 · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
3D Protein StructureAlphaFold
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
Safety and Efficacy of Injectable Klotho Plasmid Gene Therapy in Humans
RECRUITINGSafety and Efficacy of Klotho and Follistatin Gene Therapy
RECRUITINGExternal Resources
Links to major genomics databases and tools