Molecular Characterization of Iranian Patients with Inherited Coagulation Factor VII Deficiency

Factor VII Padua in Iran: clinical and laboratory findings of three unrelated patients

The congenital factor VII (FVII) deficiency with an estimated incidence of one per 300 000 is the most common rare congenital bleeding disorder. The heterogeneous clinical pictures, including asymptomatic to life-threatening manifestations, are seen in patients with FVII deficiency. A variety of gene variants throughout the FVII ( F7 ) gene have been reported so far. In this setting, very rare FVII Padua polymorphism provokes an interesting condition in which results of prothrombin time and FVII activity are different based on the thromboplastin sources used in these tests. The current study aimed to report the phenotype and genotyping of patients with Padua variant. During the workup of the laboratory for FVII deficiency for diagnosis of FVII Padua, all patients with FVII deficiency who had prolonged prothrombin time, normal activated partial thromboplastin time, and variable FVII activity results using different sources of thromboplastin were included. Demographic data and clinical findings were recorded. For the molecular study, the F7 gene sequencing was performed using the Sanger sequencing technique. Five patients with FVII Padua and a history of mild-to-moderate bleeding, including easy bruising, epistaxis, gingivorrhagia, and bleeding after surgical challenges (including dental extraction and tonsillectomy), were detected during the study. DNA sequencing revealed a heterozygote CGG to CAG (Arg364Gln) variant in exon 9 at nucleotide position 1091, consistent with the genetic variant of FVII Padua. Timely diagnosis of FVII Padua is vital to avoid unnecessary exposure of patients to replacement therapy.

Factor VII Gene Defects: Review of Functional Studies and Their Clinical Implications

Coagulation factors belong to a family of plasma glycosylated proteins that should be activated for appropriate blood coagulation. Congenital deficiencies of these factors cause inheritable hemorrhagic diseases. Factor VII (FVII) deficiency is a rare bleeding disorder with variable clinical symptoms. Various mutations have been identified throughout the F7 gene and can affect all the protein domains. The results of previous experiments have partly revealed the correlation between genotype and phenotype in patients with FVII deficiency. Nevertheless, each particular variant may affect the coagulative function of FVII, mainly via altering its expression level, extra-cellular secretion, tissue factor binding affinity, or proteolytic activity. The pathogenicity of the variants and molecular mechanisms responsible for clinical symptoms in patients with FVII deficiency should be characterized via in silico and in vitro, as well as in vivo functional studies. This review has highlighted the most important functional studies reported on F7 gene variants, including relevant reports regarding Iranian FVII deficiency patients.