Efficient mutation screening methods have greatly facilitated the analysis
of the factor VIII gene. The fast growing number of identified mutations ha
s led to an increasing understanding of the genetics in haemophilia A. In c
ombination with the recently generated molecular models of the factor VIII
protein systematic studies of structural-functional relationships of the fa
ctor VIII protein have started. The knowledge of the causative gene defect
has also become an important instrument in haemophilia care with respect to
prediction of the patients' clinical course and safe genetic counselling o
f relatives.