Submitted August 21, 2007
Accepted December 18, 2007
Identification of 31 novel mutations in the F8 gene in Spanish hemophilia A patients - Structural analysis of 20 missense mutations suggests new intermolecular binding sites
Adoracion Vencesla, Maria Angeles Corral-Rodriguez, Manel Baena, Monica Cornet, Montserrat Domenech, Montserrat Baiget, Pablo Fuentes-Prior, and Eduardo F Tizzano*
Department of Genetics and CIBERER ISCIII, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
Cardiovascular Research Center, CSIC-ICCC, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
* Corresponding author; email: etizzano{at}santpau.es.
Hemophilia A (HA) is an X-linked bleeding disorder caused by a wide variety of mutations in the Factor 8 (F8) gene, leading to absent or deficient factor VIII (FVIII). We analyzed the F8 gene of 267 unrelated Spanish patients with HA. After excluding patients with the common intron-1 and intron-22 inversions and large deletions, we detected 137 individuals with small mutations, 31 of which had not been reported previously. Eleven of these were nonsense, frameshift and splicing mutations whereas 20 were missense changes. We assessed the impact of the 20 substitutions based on currently available information about FV and FVIII structure and function relationship, including previously reported results of replacements at these and topologically equivalent positions. Although most changes are likely to cause gross structural perturbations and concomitant cofactor instability, p.Ala375Ser is predicted to affect cofactor activation. Finally, three further mutations (p.Pro64Arg, p.Gly494Val and p.Asp2267Gly) appear to affect cofactor interactions with its carrier protein, von Willebrand Factor, the scavenger receptor LRP, and/or with the substrate of the FVIIIa·FIXa (Xase) complex, factor X. Characterization of these novel mutations is important for adequate genetic counseling in HA families, but also contributes to a better understanding of FVIII structure–function relationship.
