English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

QUESTION UNDER STUDY: In most countries hypersensitivity to vitamin K antagonists (VKA) is considered to be a rare congenital bleeding diathesis. It occurs in patients with FIX propeptide mutations at locus -10. We present a Swiss family with two patients who suffered major bleedings under oral anticoagulant treatment in the presence of therapeutic or subtherapeutic INR levels and abnormally prolonged aPTT. In both patients a mutation in the propeptide of FIX at locus -10 with substitution of alanine by threonine (Ala-10Thr) was found. In one patient FIX clotting activity was found to be severely reduced (2%). The observed bleeding tendency is related to this--compared to the other vitamin K dependent factors (FII, FVII, FX)--excessively and disproportionately low level of FIX. Three generations of this family were tested for propeptide mutations, which are transmitted in an X-chromosomal recessive mode of inheritance. Apart from the two symptomatic male patients we found another male with the mutation who has not been exposed to VKA, six female carriers and four potential male carriers in the fourth generation who have not been tested. A founder effect for this mutation has been previously described for cases in Switzerland and Germany. CONCLUSION: FIX propeptide mutation-associated hypersensitivity to VKA is a rare occurrence in Switzerland. The severity of associated bleeding complications and the reversible nature of the bleeding diathesis may nonetheless warrant increased awareness on the part of primary care physicians in Switzerland

swiss medical weekly

Congenital hypersensitivity to vitamin K antagonists due to FIX propeptide mutation at locus -10: a (not so) rare cause of bleeding under oral anticoagulant therapy in Switzerland