Thromb Haemost
DOI: 10.1055/s-0040-1715443
Coagulation and Fibrinolysis

Genetics and Hemostatic Potential in Persons with Mild to Moderate Hemophilia A with a Discrepancy between One-Stage and Chromogenic FVIII Assays

Annelie Strålfors
1  Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
2  Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
,
Danijela Mikovic
3  Hemostasis Department and Hemophilia Center, Blood Transfusion Institute of Serbia, Belgrade, Serbia
,
David Schmidt
4  Coagulation Unit, Department of Hematology, Karolinska University Hospital, Stockholm, Sweden
5  Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
,
Liselotte Onelöv
2  Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
,
Nida Mahmoud Hourani Soutari
1  Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
2  Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
,
Maria Berndtson
1  Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
2  Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
,
Roza Chaireti
1  Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
4  Coagulation Unit, Department of Hematology, Karolinska University Hospital, Stockholm, Sweden
,
Margareta Holmström
4  Coagulation Unit, Department of Hematology, Karolinska University Hospital, Stockholm, Sweden
5  Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
,
Jovan P. Antovic
1  Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
2  Clinical Chemistry, Karolinska University Laboratory, Karolinska University Hospital, Stockholm, Sweden
,
Maria Bruzelius
1  Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
4  Coagulation Unit, Department of Hematology, Karolinska University Hospital, Stockholm, Sweden
5  Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
› Author Affiliations
Funding M.B. was supported by funds from Stockholm County Council.

Abstract

Background Factor VIII (FVIII) activity (FVIII:C) can be measured by different methods including one-stage clotting assays (OSAs) and chromogenic assays (CSAs). Discrepancy between FVIII:C assays is known and associated with genetic variations causing mild and moderate hemophilia A (HA). We aimed to study the discrepancy phenomenon and to identify associated genetic alterations. Further, we investigated if hemostatic global assays could discriminate the group with discrepant FVIII:C from them.

Methods The study contained plasma samples from 45 patients with HA (PwHA) from Hemophilia Centers in Stockholm, Sweden, and Belgrade, Serbia. We measured FVIII:C with OSA and CSA, sequenced the F8 gene, and performed two global hemostatic assays; endogenous thrombin potential and overall hemostatic potential.

Results Nineteen of 45 PwHA had a more than twofold higher FVIII:C using OSA compared to CSA and were considered discrepant. Thirty-four causal mutations were detected, where of five had not previously been associated with assay discrepancy. These novel mutations were p.Tyr25Cys, p.Phe698Leu, p.Met699Leu, p.Ile1698Thr, and Ala2070Val. We found no difference between discrepant and nondiscrepant cases with either of the global assays.

Conclusion There was a discrepancy between FVIII:C assays in almost half of the PwHA, which for some could lead to missed HA diagnoses or misclassification of severity. Genotyping confirmed that mutations associated with FVIII:C discrepancy cluster in the A domains of F8, and five mutations not previously associated with FVIII:C discrepancy was identified. Global hemostatic assays did not contribute to distinguish assay discrepancy in PwHA.

Authors' Contributions

A.S. analyzed and interpreted the data and wrote the manuscript. M.B. was involved in the recruitment of patients, interpretation of the data, and contributed to the writing of the manuscript. D.M. was involved in the recruitment of patients. L.O. and M.B. took part in designing the study. N.M.H.S. performed laboratory measurements and critically revised the manuscript. R.C. and M.H. were involved in the recruitment of patients and critically revised the manuscript. D.E.S. interpreted data and critically revised the manuscript. J.A. took part in designing the study, interpreted data, and critically revised the manuscript.


Supplementary Material



Publication History

Received: 12 February 2020

Accepted: 02 July 2020

Publication Date:
13 August 2020 (online)

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