Low thrombosis rate seen in blood donors and their relatives with inherited deficiencies of antithrombin and protein C: correlation with type of defect, family history, and absence of the factor V Leiden mutation.
We have previously identified a group of blood donors with inherited deficiencies of either antithrombin (AT) or protein C who appear to have a relatively low thrombosis rate. In the 5 years that have elapsed since initial identification of these individuals, resistance to activated protein C (APC resistance), which is associated with the factor V Leiden gene mutation, has emerged as an important and highly prevalent inherited thrombophilic risk factor. We have followed 28 donors/relatives with deficiency of AT (median age 48 years, range 16-77) and 23 with deficiency of protein C (median age 44 years, range 15-79) over a period of 5 years. During the study period only one individual, who was previously symptomatic, has suffered a thrombotic event which occurred spontaneously whilst on warfarin. We have now excluded coinheritance of APC resistance due to the factor V Leiden mutation in our cohort. Our findings demonstrate that individuals with single inherited thrombophilic defects are not uncommon and are frequently asymptomatic. The absence of the factor V Leiden mutation may in part explain the low thrombosis rate observed, and lends support to the hypothesis that multiple thrombophilic defects may be necessary for the development of thrombosis.
McColl
M
M
Department of Haematology, Southern General Hospital, Glasgow, UK.
Tait
R C
RC
Walker
I D
ID
Perry
D J
DJ
McCall
F
F
Conkie
J A
JA
D000293:Adolescent; D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D000990:Antithrombin III / Q000235:genetics; D020152:Antithrombin III Deficiency; D001782:Blood Donors; D004351:Drug Resistance / Q000235:genetics; D005165:Factor V / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D011486:Protein C / Q000235:genetics; D020151:Protein C Deficiency; D012307:Risk Factors; D013927:Thrombosis / Q000097:blood* / Q000235:genetics* / Q000517:prevention & control
D000925:Anticoagulants; D011486:Protein C; C095381:factor V Leiden; D000990:Antithrombin III; D005165:Factor V