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Report teaching·Source file updated: Sep 16, 2026

PAI-1 4G/5G & homocysteine

Dr. Purser’s teaching
Teaching by Dan Purser, MD2 min read

WHAT YOU’LL LEARN

In this articleUnderstand the connectionFollow the pathwayBring these questions to your visit

Understand the connection

PAI-1, encoded by SERPINE1, helps regulate the breakdown of clots by inhibiting tissue and urokinase plasminogen activators. The 4G/5G promoter variation is commonly identified as rs1799889.

Follow the pathway

Dr. Purser discusses fibrinolysis, the process of dissolving clots, alongside homocysteine and blood-vessel inflammation. These are interacting risk considerations; a common PAI-1 variant is not the same as having a clot or needing a blood-thinning treatment.

Bring these questions to your visit

Ask how personal or family clot history, medicines, homocysteine, and other cardiovascular findings affect your risk. Aspirin, anticoagulants, and products such as nattokinase can increase bleeding risk and need an individualized discussion.

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