F. Peyvandi et al., Molecular characterisation and three-dimensional structural analysis of mutations in 21 unrelated families with inherited factor VII deficiency, THROMB HAEM, 84(2), 2000, pp. 250-257
Factor VII (FVII) is a four-domain glycoprotein that plays a critical role
in the initiation of blood coagulation. Hereditary deficiencies of this pla
sma protein results in a bleeding diathesis that vanes in severity amongst
affected patients. We have analysed the FVII gene in 27 patients with FVII
deficiency from 21 unrelated families predominantly of Middle-Eastern extra
ction. A total of 19 different mutations were identified, of which 12 were
novel and 7 had been previously reported. Nine of the 12 novel mutations we
re missense mutations located in the Gla domain (Ser23Pro), the second epid
ermal growth factor domain (Cys135Arg) and the catalytic serine protease do
main (Arg247Cys, Arg277Cys, Ser282Arg, Pro303Thr, Ser363Ile, Trp364Cys, Trp
364Phe), of which five are homozygous. Three novel splice mutations were id
entified in intron la (IVS1a+5), intron 2 (IVS2+1) and intron 6 (IVS6+1). O
f the seven previously reported mutations, five were missense mutations of
which three are homozygous (Gln100Arg, Arg152Gln, Arg304Gln, Cys310Phe and
Thr359Met), one was a 17 bp deletion (10585del17bp) and one was a splice si
te mutation within intron 7 (IVS7+7). This study has significantly extended
the current database of FVII mutations, including the number of known homo
zygous mutations. Conformational analyses of crystal structures for FVIIa a
nd the FVIIa-tissue factor complex provided likely explanations for the eff
ect of the missense mutations on FVIIa secretion or function. In particular
, since 23 missense mutations were located to the serine protease domain, m
ostly to the region between the catalytic triad and the contact surface wit
h tissue factor, this showed that the orientation of the serine protease do
main relative to bound tissue factor in the complex is crucial for function
al activity.