First description of the molecular and clinical characterization of hereditary factor V deficiency in Saudi Arabia: report of four novel mutations.

Coagulation factor V plays a significant role in the blood coagulation cascade as part of the prothrombinase complex. Factor V deficiency (FVD) is a rare autosomal recessive bleeding disorder with a variable phenotypic expression which varies from being asymptomatic-to-severe bleeding episodes. The aim of this study was to perform molecular and clinical characterization of FVD in patients originating from Saudi Arabia. Eleven patients (two males and nine females) with confirmed FVD were recruited in the study with ages ranging between 5 and 53 years. A next-generation sequencing-based hematology panel encompassing 393 known genes was used. A total of six sequence variations in F5 gene were identified, including four missense mutations (p.Pro189Leu, p.Trp2004Arg, p.Met2148Thr, p. Arg2202Cys), a deletion (p.Arg872Lysfs*12) and a splicing variant (c.1118+5G>T). Four variants were identified for the first time in this study. Three patients were homozygous for their respective mutations and seven patients were heterozygous. We were not able to identify a pathogenic variant in one patient of the cohort. In-silico and three-dimensional structural analyses were performed to predict the possible impact and functional consequences of the identified variants. To our knowledge, this is the first study addressing factor V mutations in patients with Arab ancestry. Results have helped in providing a definitive diagnosis to the patients and carrier detection in extended family members. Overall, the hematology panel assay was an efficient platform, demonstrating a formidable approach for the molecular diagnosis of other suspected bleeding disorders.