Congenital factor V deficiency in a pediatric patient causing mild hemorrhage.

Background and aims: This study aimed to elucidate the phenotype and genotype of a patient (9-year-old) with coagulation factor V (FV) deficiency to enhance our understanding of this specific disorder.

Methods: FV activity and antigen level were evaluated using a clotting assay and ELISA, respectively. Variations in the F5 gene were identified through DNA sequencing. The effects of the identified mutations on protein functionality were investigated using four bioinformatics tools: Expasy-ProtScale, ClustalX-2.1-win, Swiss-PdbViewer, and PyMol. These tools were applied to analyze hydrophobic properties, sequence conservation, and structural alterations.

Results: The proband presented with a prolonged activated partial thromboplastin time (APTT) and a bleeding tendency. His FV activity was reduced to 22% (reference range: 50-150%). Molecular analysis of the F5 gene identified two heterozygous variants in exons: c.1177A > G (p.Lys393Glu) and c.6665A > G (p.Asp2222Gly). In silico analysis predicted the potential deleterious effects of these mutations on FV protein function and structure.

Conclusion: This research identified two distinct variants in the F5 gene, including a novel variant (c.1177A > G/p.Lys393Glu). These findings elucidate the molecular mechanisms underlying the patient's FV deficiency and expand the mutational spectrum associated with this disorder.