Summary
Inherited factor XIII (FXIII) deficiency is an autosomal recessive disorder which
results in a serious bleeding diathesis, problems with wound healing and a very high
risk of recurrent miscarriage in deficient females. We have analysed the molecular
basis of factor XIII deficiency in two patients and their parents, who originate from
the North of Pakistan. Four sequence changes were identified: an AGC→AGG (Ser→Arg)
FXIII deficiency-causing mutation in codon 295; G→A at position -246 upstream of exon
1; T→C and C→T at positions -23 and -24, respectively, in intron 9. Using molecular
modelling we predict that the Ser295Arg mutation would prevent the FXIIIA molecule
from folding correctly and thus result in an unstable FXIIIA mutant polypeptide. The
sequence changes −246G→A, −23T→C and −24C→T are normal polymorphisms. RT-PCR analysis demonstrates that the intronic sequence
changes do not appear to affect the accuracy of FXIIIA RNA processing.
Key words
Factor XIII - transglutaminase - deficiency - missense mutation