24th July 2024

Protein C deficiency

Protein C is a vitamin K-dependent anticoagulant whose main role is to inactivate factor V. Low levels can, therefore, lead to a prothrombotic state. Deficiency can either be inherited or acquired – secondary to conditions such as liver disease, use of vitamin K antagonists, infection and uraemia.

The vast majority of patients remain asymptomatic. Skin necrosis as a side effect of warfarin is more prevalent in those with protein C deficiency.

Diagnosis is by demonstrating low protein C levels. Acquired cases tend to have higher levels than inherited forms.

If VTE is confirmed, warfarin is to be avoided if possible, and another anticoagulant used. No other specific management is required.