Factor IX Level in Various Conditions

In newborns the factor IX level is only 20-60% of that observed in adults. This implies that factor IX levels have to increase with age, as was demonstrated already by Simpson and Biggs (1962). A rapid rise might occur in the first year of life, as is the case for albumen. During life, then, a slow rise continues, as was also demonstrated for factors V and VII (Brozovic 1976, 1974). It is of special interest that for factors VII and IX, both vitamin K dependant clotting factors, not onlyage but also hormones influence the activity level. Both the oestrogen containing contraceptive pill and pregnancy cause a substantial rise in factor IX level, both activity and CRM. 7 Years ago we started to measure factor IX levels every 3 months in 10 children, now at the age of 19, to see whether an abrupt rise would occur during puberty; this was not so. This information was considered relevant for the explanation of the appearance of factor IX activity and CRM in patients with hemophilia B Leyden during puberty. After a rise from <1% to 20% factor IX in the age period from 15 to 20 factor IX continues to rise at a slower rate and may reach 50% in old age. Clinical symptoms disappear. There is no good explanation for this phenomenon that occurs in patients from two probably related kindreds with hemophilia B in The Netherlands.

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch

References and Relationships

• Bibliographic citation: Factor IX Level in Various Conditions ; volume:38 ; number:05 ; year:1977 ; Konferenz: XIIth Congress of The World Federation of Hemophilia; 1977-06-22; Philadelphia ; Thrombosis and haemostasis ; 38, Heft 05 (1977)

Classification and Topics

• Classification: Nachrichtenmedien, Journalismus, Verlagswesen

Contributors, Places and Time

• Contributor: Veltkamp, J.J.

Further information

• DOI: 10.1055/s-0039-1682479
• URN: urn:nbn:de:101:1-2412190830225.671643646253
• Rights: Open Access unbekannt; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 15.08.2025, 7:32 AM CEST