Genotypes and phenotypes characterization of 17 Iranian patients with inherited factor X deficiency: identification of a novel mutation: Leu487Phe

Abstract

Factor X deficiency is a rare bleeding disorder that affects almost 1 : 1000 000 people worldwide. It derives from multiple mutational changes in the factor X gene (F10). The main objective of the present study was to determine a consistent correlation between the clinical presentations and causative genotype. The phenotype and genotype of 17 Iranian patients with reduced factor X activity (FX:C) from 14 unrelated families were analyzed to screen factor X gene expression for any possible mutations and function alteration. Analysis of the sequencing results led to the identification of eight different mutations besides a single nucleotide variation. One of the mutations was novel (Leu487Phe) as studied by means of online analysis programs and molecular modeling. Eight patients were homozygote; three were heterozygote, while six out of 17 patients were symptomatic cases without any mutations. The Arg40Thr missense mutation was detected in three patients including two siblings and was associated with severe bleeding symptoms. Also, two patients were identified with Gly262Asp missense mutation which commonly presented with bleeding disorder. Each of the other patients was associated with a unique missense mutation including one novel mutation in which the tentative relation of the mutation to bleeding symptoms is reported. Mutations leading to a FX:C of less than 1% are associated with severe bleeding symptoms confirming the strong correlation between clinical severity and FX:C. The novel Leu487Phe mutation with FX:C of 13% may have possible negative effects on factor X protein function resulting in minor clinical manifestation.