Thromb Haemost 1989; 62(02): 763-766
DOI: 10.1055/s-0038-1646898
Original Article
Schattauer GmbH Stuttgart

Familial Dysfunction of Protein S

P M Mannucci
The A. Bianchi Bonomi Hemophilia and Thrombosis Center and the Institute of Internal Medicine, University of Milano, Italy
,
C Valsecchi
The A. Bianchi Bonomi Hemophilia and Thrombosis Center and the Institute of Internal Medicine, University of Milano, Italy
,
A Krachmalnicoff
The A. Bianchi Bonomi Hemophilia and Thrombosis Center and the Institute of Internal Medicine, University of Milano, Italy
,
E M Faioni
The A. Bianchi Bonomi Hemophilia and Thrombosis Center and the Institute of Internal Medicine, University of Milano, Italy
,
A Tripodi
The A. Bianchi Bonomi Hemophilia and Thrombosis Center and the Institute of Internal Medicine, University of Milano, Italy
› Author Affiliations
Further Information

Publication History

Received 05 January 1989

Accepted after revision 03 March 1989

Publication Date:
30 June 2018 (online)

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Summary

We describe a previously unreported defect of protein S characterized by low levels of cofactor activity for activated protein C contrasting with low normal levels of total and free protein S antigen. The distribution of protein S between the free form and the form complexed with the complement component C4b-binding protein was normal on two-dimensional immunoelectrophoresis. The proband developed juvenile deep-vein thrombosis while taking oral contraceptives. Her defect was transmitted in an autosomal dominant fashion from her asymptomatic mother. Other relatives carrying the same laboratory abnormality (mother, maternal uncle, two sisters and one brother) were also asymptomatic. We postulate that the defect is due to a dysfunctional protein S present in plasma in normal amounts and with normal proportions of the free and complexed forms of the protein.