Utkarsh Rajendra Bhattad, Rahul Prahlad Ladda, Dhivay Mukesh Bathija, Anannya Anand Mukherji
Congenital protein S deficiency is an autosomal dominant disease, and the heterozygous state occurs in approximately 2% of unselected patients with venous thromboembolism (VTE). Protein S deficiency is rare in the healthy population without abnormalities. Frequency is approximately one out of 700 based on extrapolations from a study of over 9000 blood donors who were tested for protein C deficiency. When looking at a selected group of patients with recurrent thrombosis or family history of thrombosis, the frequency of protein S deficiency increases to 3-6%. Very rarely, protein S deficiency occurs as a homozygous state, and these individuals have a characteristic thrombotic disorder, purpura fulminans. Purpura fulminans is characterized by small-vessel thrombosis with cutaneous and subcutaneous necrosis, and it appears early in life, usually during the neonatal period or within the first year of life.
