Genetic Landscape of Factor VII Deficiency: Insights from a Comprehensive Analysis of Pathogenic Variants and Their Impact on Coagulation Activity

Authors: Preisler, Barbara; Pezeshkpoor, Behnaz; Merzenich, Anja; Ohlenforst, Sandra; Rühl, Heiko; Ivaškevičius, Vytautas; Scholz, Ute; Bönigk, Hagen; Eberl, Wolfgang; Zieger, Barbara; Pavlova, Anna; Oldenburg, Johannes

Affiliations: Institute of Experimental Hematology and Transfusion Medicine, University of Bonn, Faculty of Medicine, University Clinic Bonn, 53127 Bonn, Germany. Center of Hemostasis, MVZ Labor Leipzig, 04289 Leipzig, Germany. MVZ Limbach Magdeburg, Lab Dr. Franke, Bönigk and Colleagues, Center of Coagulation Disorders and Vascular Diseases, 39104 Magdeburg, Germany. Pediatric Hematology and Oncology, Klinikum Braunschweig, 38118 Braunschweig, Germany. Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Center-University of Freiburg, Faculty of Medicine, 79110 Freiburg, Germany.

Publication: Int J Mol Sci. 2024. 25

ABSTRACT: Congenital factor VII (FVII) deficiency is a rare genetic bleeding disorder characterized by deficient or reduced activity of coagulation FVII. It is caused by genetic variants in the F7 gene. We aimed to evaluate the rate of detection of pathogenic variants in the F7 gene in a large group of patients with FVII deficiency and investigate the correlations between the F7 genotype and FVII activity (FVII:C). Moreover, the influence of the common genetic variant rs6046: c.1238G>A; p.(Arg413Gln), designated as the M2 allele, on FVII:C was investigated. Genetic analysis of the F7 gene was performed on 704 index patients (IPs) using either direct Sanger- or next-generation sequencing. Genetic variants were detected in 390 IPs, yielding a variant detection rate (VDR) of 55%. Notably, the VDR exhibited a linear decline with increasing FVII:C levels. We identified 124 genetic variants, of which 48 were not previously reported. Overall, the frequency of the M2 allele was considerably higher in patients with mild deficiency (FVII:C > 20 IU/dl). Furthermore, IPs lacking an identified pathogenic variant exhibited a significantly higher prevalence of the M2 allele (69%) compared to IPs with a disease-causing variant (47%). These results strongly support the association of the M2 allele with decreased FVII:C levels. This study shows the utility of FVII:C as a predictive marker for identifying pathogenic variants in patients with FVII deficiency. The M2 allele contributes to the reduction of FVII:C levels, particularly in cases of mild deficiency.