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Trait

Reduced factor IX activity

Decreased activity of coagulation factor IX. Factor IX, which itself is activated by factor Xa or factor VIIa to form factor IXa, activates factor X into factor Xa.

HPO HP:0011858

Summary

Also called
Low factor IX activity
Body system
Abnormality of blood and blood-forming tissues

6 genes linked to Reduced factor IX activity

Changes in these genes cause rare conditions in which Reduced factor IX activity is seen. Most people with this trait have none of those conditions, and a gene on this list says nothing about anyone's own genome.

GeneHow often it is seenConditions
F9coagulation factor IXAlwaysIn 1 condition
GGCXgamma-glutamyl carboxylaseAlwaysIn 3 conditions
SLC37A4solute carrier family 37 member 4Often (30–79%)In 1 condition
VKORC1vitamin K epoxide reductase complex subunit 1Often (30–79%)In 2 conditions
PMM2phosphomannomutase 2Sometimes (5–29%)In 1 condition
MGAT2alpha-1,6-mannosyl-glycoprotein 2-beta-N-acetylglucosaminyltransferaseNot recordedIn 1 condition

How often is among people with one of the gene's conditions, the most often across them, as the Human Phenotype Ontology records it. These pages describe traits and the research behind them; they are not a diagnosis, and a doctor or genetic counsellor is the person to ask about symptoms.

Broader traits

Abnormal factor IX activity

Where this comes from

  • The Human Phenotype Ontology, release 2026-09-01: the trait, its names, its definition and the genes linked to it. Find out more at hpo.jax.org.
  • Data release 2026.10.16-c6eea6bf.

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