What is the morbidity associated with protein S deficiency?

Updated: Jan 03, 2021
  • Author: Mohammad Muhsin Chisti, MD, FACP; Chief Editor: Perumal Thiagarajan, MD  more...
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Congenital protein S deficiency is an autosomal dominant disease, with variable penetrance and heterogeneous genetic basis. VTE develops in almost 50% of patients who are heterozygous for protein S deficiency. The remaining patients are asymptomatic and some heterozygous individuals never develop VTE. Annual incidence of venous thrombosis was found to be 1.90%, with median age of presentation being 29 yrs in a retrospective cohort study of 2479 relatives. [13]

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. [18]

Though it is controversial, no clear association exists between protein S deficiency and arterial thrombosis. Many case reports and small case series describe protein S deficiency as one factor in patients with arterial thrombosis, most commonly stroke. However, prospective and cohort studies have not shown convincing increased risk for arterial thrombosis.

Protein S deficiency is also associated with fetal loss in women, in the absence of VTE. Some authors suggest that as many as 40% of women with obstetric complications other than VTE may carry some form of thrombophilia. Protein S deficiency is one of these factors along with several other more common genetic thrombophilic states.

Cases of warfarin-induced skin necrosis have been reported in patients with protein S deficiency. [19]

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