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.
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, 3 further mutations (p.Pro64Arg, p.Gly494Val, and p.Asp2267Gly) appear to affect cofactor interactions with its carrier protein, von Willebrand factor, with the scavenger receptor low-density lipoprotein receptor-related protein (LRP), and/or with the substrate of the FVIIIapi*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.
Venceslá
Adoración
A
Department of Genetics and Centro de Investigación Biomédica en Red de Enfermadades Raras Instituto de Salud Carlos III, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
Corral-Rodríguez
María Angeles
MA
Baena
Manel
M
Cornet
Mónica
M
Domènech
Montserrat
M
Baiget
Montserrat
M
Fuentes-Prior
Pablo
P
Tizzano
Eduardo F
EF
D001665:Binding Sites / Q000235:genetics; D018389:Codon, Nonsense; D015949:Factor IXa / Q000235:genetics / Q000378:metabolism; D005169:Factor VIII / Q000235:genetics* / Q000378:metabolism; D016368:Frameshift Mutation; D006467:Hemophilia A / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007438:Introns / Q000235:genetics; D026502:LDL-Receptor Related Proteins / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D020125:Mutation, Missense; D011485:Protein Binding / Q000235:genetics; D012326:RNA Splicing / Q000235:genetics; D013030:Spain; D013329:Structure-Activity Relationship; D014841:von Willebrand Factor / Q000235:genetics / Q000378:metabolism
D018389:Codon, Nonsense; D026502:LDL-Receptor Related Proteins; D046912:Multiprotein Complexes; D014841:von Willebrand Factor; C078147:F8 protein, human; D005169:Factor VIII; D015949:Factor IXa