Identification of six novel factor VIII gene variants using next generation sequencing and molecular dynamics simulation

Abstract

Hemophilia A is an X-linked recessive hemorrhagic disorder caused by variants in the F8 gene. To identify known and novel causative variants in hemophilia A, we have carried out genetic analysis among Saudi patients. Twenty-one patients, who were negative for inv-1/inv- 22, were selected for analysis by next generation sequencing, thereafter confirmed by Sanger sequencing. In addition, the functionality and structural changes in the variant proteins were assessed using Molecular dynamics (MD) simulation and compared with wild-type and native proteins. In the samples we analyzed, we found 10 variants in 12 individuals; among them, five were novel and five were previously reported. The novel variants were located at positions: c.6130_6131insC, c.5815G>C, c.5493C>G, c.3734_3740delinsATTTCT and c.3744A>T. With the exception of one variant which was silent, the MD simulation revealed that the observed variants were causing severe structural changes when compared to the native protein and resulted in a loss of the protein's function. The MD analysis is in line with clinical data of patients who had <1% Factor VIII levels (severe hemophilia) with episodic bleeding, and were on more than one treatment. Moreover, some patients presented with chronic joint disability. These results will enrich the spectrum of variants and enlarge the factor VIII protein's database in the Saudi Arabian population.