GGCX mutations show different responses to vitamin K thereby determining the severity of the hemorrhagic phenotype in VKCFD1 patients

Ghosh, Suvoshree; Kraus, Katrin; Biswas, Arijit; Müller, Jens; Buhl, Anna-Lena; Forin, Francesco; Singer, Heike; Höning, Klara; Hornung, Veit; Watzka, Matthias; Czogalla-Nitsche, Katrin J. und Oldenburg, Johannes (2021): GGCX mutations show different responses to vitamin K thereby determining the severity of the hemorrhagic phenotype in VKCFD1 patients. In: Journal of Thrombosis and Haemostasis, Bd. 19, Nr. 6: S. 1412-1424

Abstract

Background Vitamin K dependent coagulation factor deficiency type 1 (VKCFD1) is a rare hereditary bleeding disorder caused by mutations in gamma-glutamyl carboxylase (GGCX). VKCFD1 patients are treated life-long with high doses of vitamin K in order to correct the bleeding phenotype. However, normalization of clotting factor activities cannot be achieved for all VKCFD1 patients. Objective The current study aims to investigate the responsiveness to vitamin K for all reported GGCX mutations with respect to clotting factors in order to optimize treatment. Methods This study developed an assay using genetically engineered GGCX(-/-) cells, in which GGCX mutations were analyzed with respect to their ability to gamma-carboxylate vitamin K dependent pro-coagulatory and anti-coagulatory clotting factors by ELISA. Additionally, factor VII activity was measured in order to proof protein functionality. For specific GGCX mutations immunofluorescent staining was performed to assess the intracellular localization of clotting factors with respect to GGCX wild-type and mutations. Results All GGCX mutations were categorized into responder and low responder mutations, thereby determining the efficiency of vitamin K supplementation. Most VKCFD1 patients have at least one vitamin K responsive GGCX allele that is able to gamma-carboxylate clotting factors. In few patients, the hemorrhagic phenotype cannot be reversed by vitamin K administration because GGCX mutations on both alleles affect either structural or catalytically important sites thereby resulting in residual ability to gamma-carboxylate clotting factors. Conclusion With these new functional data we can predict the hemorrhagic outcome of each VKCFD1 genotype, thus recommending treatments with either vitamin K or prothrombin complex concentrate.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Chemie und Pharmazie > Department Biochemie
• Themengebiete: 500 Naturwissenschaften und Mathematik > 540 Chemie
• ISSN: 1538-7933
• Sprache: Englisch