title: Reevaluation of the incidence of thromboembolic complications in congenital factor XII deficiency--a study on 73 subjects from 14 Swiss families.
abstract: To further elucidate the debated role of hereditary FXII deficiency as a thrombophilic risk factor this follow-up study on 65 subjects out of 12 Swiss families was undertaken (follow-up: 6 yrs). Fifteen severely FXII deficient subjects (FXII:C < 1%), 35 partially FXII deficient subjects (FXII:C > or = 1-59%), 10 with normal FXII values (FXII:C > or = 70%), and 5 non-classifiable subjects (FXII:C > or = 60-69%) were reevaluated. Eight subjects (4 severely and 3 partially FXII deficient, 1 non-classifiable) were newly enrolled. Four instances of deep vein thrombosis, one superficial vein thrombosis and one myocardial infarction were noted in 2 out of 19 severely FXII deficient subjects during a total life-time period of 866.6 patient-years. In 38 partially FXII deficient subjects (1862.8 patient-years) one ischemic cerebrovascular stroke and one superficial vein thrombosis were recorded in 2 individuals. The 10 subjects with normal FXII values (498.2 patient-years) remained thrombosis-free. One superficial vein thrombosis occurred in an unclassifiable woman. None of the 3 different FXII gene defects revealed in our patients was specifically associated with thromboembolic complications. Kaplan-Meier analysis of thrombosis-free survival suggests that hereditary partial (and probably severe) FXII deficiency does not constitute a thrombophilic condition.
authors.affiliation: Central Hematology Laboratory, University Hospital of Bern, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Zeerleder
authors.forename: M
authors.initials: M
authors.lastname: Schloesser
authors.forename: M
authors.initials: M
authors.lastname: Redondo
authors.forename: W A
authors.initials: WA
authors.lastname: Wuillemin
authors.forename: W
authors.initials: W
authors.lastname: Engel
authors.forename: M
authors.initials: M
authors.lastname: Furlan
authors.forename: B
authors.initials: B
authors.lastname: Lämmle
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005174:Factor XII / Q000235:genetics; D005175:Factor XII Deficiency / Q000150:complications* / Q000151:congenital / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D013923:Thromboembolism / Q000453:epidemiology* / Q000209:etiology*
chemical_list: D005174:Factor XII