Factor VIII deficiency: genes and variants
Factor VIII deficiency is linked to 1 analyzed protein (F8). 5 DNA variants are known to cause it; 1 more are uncertain, and 0 of those already look disease-causing on computable evidence.
Last updated 2026-09-30. Research information, not medical advice.
Genes linked to Factor VIII deficiency
F8: Coagulation factor VIII
After activation, it acts as a cofactor for factor IXa and greatly accelerates factor X activation during coagulation. Loss-of-function variants cause X-linked hemophilia A, with bleeding severity determined largely by residual factor VIII activity.
5 disease-causing and 1 uncertain variants in F8 are linked to Factor VIII deficiency.
Known disease-causing variants in Factor VIII deficiency
| Variant | Position | Protein part | Clinical label |
|---|---|---|---|
| F8 R546W | 546 | Plastocyanin-like 3 | Disease-causing (★★) |
| F8 H1973L | 1973 | Plastocyanin-like 6 | Disease-causing (★★) |
| F8 E1701K | 1701 | Disease-causing (★★) | |
| F8 Y175C | 175 | Plastocyanin-like 1 | Disease-causing (★) |
| F8 S1907R | 1907 | Plastocyanin-like 6 | Disease-causing (★) |
Same protein, different disease
- Hereditary factor VIII deficiency disease is also caused by F8 variants; they fall mostly in different places as the Factor VIII deficiency variants (273 disease-causing).
- Hereditary factor IX deficiency disease is also caused by F8 variants; they fall mostly in different places as the Factor VIII deficiency variants (35 disease-causing).
- Thrombophilia, X-linked, due to factor 8 defect is also caused by F8 variants; they fall mostly in different places as the Factor VIII deficiency variants (15 disease-causing).
Diseases related to Factor VIII deficiency
- Hereditary factor VIII deficiency disease, also linked to F8
- Hereditary factor IX deficiency disease, also linked to F8
- Thrombophilia, X-linked, due to factor 8 defect, also linked to F8
Frequently asked questions
Which genes are linked to Factor VIII deficiency?
In CATVariant, Factor VIII deficiency is linked to 1 analyzed protein: F8 (Coagulation factor VIII).
How many genetic variants are linked to Factor VIII deficiency?
6 variants: 5 are classified as disease-causing (pathogenic or likely pathogenic) in ClinVar and 1 are of uncertain significance or have conflicting reports.
Which uncertain variants in Factor VIII deficiency look disease-causing?
None of the uncertain variants currently reaches the likely-pathogenic range on computable evidence alone.
About this data
Variant–disease links come from ClinVar, Open Targets and UniProt, pooled from the latest public CATVariant analysis of each human protein. Evidence scores use the ACMG/AMP Bayesian points scale with computable criteria only (position among known disease variants, rarity in gnomAD, calibrated predictors, deep mutational scanning); there is no family or patient data, so they prioritise variants for expert review and never classify them.
Download every variant as CSV · Browse all diseases · Methods · About the Center