Factor V Leiden (FV R506Q) in families with inherited antithrombin deficiency.
Thromb Haemost
; 75(3): 417-21, 1996 Mar.
Article
em En
| MEDLINE
| ID: mdl-8701400
ABSTRACT
We investigated the presence of the gene mutation of factor V, FV R506Q or factor V Leiden, responsible for activated protein C resistance, in DNA samples of 127 probands and 188 relatives from 128 families with antithrombin deficiency. The factor V mutation was identified in 18 families. Nine families were available to assess the mode of inheritance and the clinical relevance of combined defects. The factor V and antithrombin genes both map to chromosome 1. Segregation of the defects on opposite chromosomes was observed in three families. Co-segregation with both defects on the same chromosome was demonstrated in four families. In one family a de novo mutation of the antithrombin gene and in another a crossing-over event were the most likely explanations for the observed inheritance patterns. In six families with type I or II antithrombin deficiency (reactive site or pleiotropic effect), 11 of the 12 individuals with both antithrombin deficiency and the factor V mutation developed thrombosis. The median age of their first thrombotic episode was 16 years (range 0-19); this is low compared with a median age of onset of 26 years (range 20-49) in 15 of 30 carriers with only a defect in the antithrombin gene. One of five subjects with only factor V mutation experienced thrombosis at 40 years of age. In three families with type II heparin binding site deficiencies, two of six subjects with combined defects experienced thrombosis; one was homozygous for the heparin binding defect. Our results show that, when thrombosis occurs at a young age in antithrombin deficiency, the factor V mutation is a likely additional risk factor. Co-segregation of mutations in the antithrombin and factor V genes provides a molecular explanation for severe thrombosis in several generations. The findings support that combinations of genetic risk factors underly differences in thrombotic risk in families with thrombophilia.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Trombose
/
Fator V
/
Antitrombina III
Tipo de estudo:
Etiology_studies
/
Prognostic_studies
/
Risk_factors_studies
Limite:
Adolescent
/
Adult
/
Female
/
Humans
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Male
/
Middle aged
Idioma:
En
Ano de publicação:
1996
Tipo de documento:
Article