Clinical phenotype and F7 gene genotype in 40 Tunisian patients with congenital factor VII deficiency.

Abstract

Congenital factor VII (FVII) deficiency is an autosomal recessive bleeding disorder characterized by a weak phenotypic and genotypic correlation. This study aimed to determine the genetic alterations of 40 Tunisian patients and to evaluate their relationships with the collected clinical and biological data. Forty FVII-deficient Tunisian patients have been included in this study. First, diagnosis of the FVII deficiency was made on the basis of FVII coagulant activity (FVII:c) levels performed using the prothrombin time assay. Then, clinical and anamnesis data were set up and filed out from the regional registry of bleeding disorders and the medical file of each patient. Finally, genetic alterations were determined by direct sequencing of the coding regions, intron/exons boundaries of the F7 gene. Clinical heterogeneity was noticed, and the direct sequencing allowed the identification of 13 F7 gene mutations of which one was a novel mutation. The clinical manifestations are variably associated with FVII activity FVII:c levels. Lack of relations between severity of clinical manifestations and genotypes was observed; however, a relationship between the nonpathogeneous mutations and clinical phenotypes was noticed. A wide phenotypic inter-individual variability was detected, which suggests the presence of other extra-genetic components influencing the expressivity of the deficiency.