Summary
Desmopressin causes two- to six-fold increase of factor VIII (FVIII) in mild or moderate
haemophilia A patients. However, responses are variable and little is known whether
this is associated with F8 gene mutation. The study objective was to assess the relationship between F8 gene mutation and desmopressin response in haemophilia A patients. Desmopressin response
(absolute and relative) was determined in 97 hemophilia A patients. Four amino acid changes (Arg2169His,
Pro149Arg, Asn637Ser, and Arg612Cys) and a number of other mutations leading to an
aberrant FVIII protein or FVIII deficiency were analysed. Patients with Arg2169His
showed significantly lower FVIII levels before and after desmopressin compared to
all other mutations (p<0.001). Pro149Arg amino acid change showed significantly lower
FVIII levels 1 hour after desmopressin compared to all other mutations (p<0.005).
An absolute response with FVIII ≥0.50 IU/ml after 1 hour was observed in 41% (9 of
22) of patients with Arg2169His; however, this was not sustainable after 6 hours in
any of these subjects. No patients with Pro149Arg mutation (n=6) showed an absolute response with FVIII _0.50 IU/ml. Patients with other mutations showed significantly
more complete and partial responses. Relative responses did not differ between mutations. Our study shows that haemophilia A patients
with amino acid change Arg2169His or Pro149Arg have a decreased desmopressin response
with regard to FVIII levels as compared to other mutations. Our results indicate that
response to desmopressin is dependent on the F8 gene mutation type, despite the fact that multiple factors influence the desmopressin
response, even within families.
Keywords
Desmopressin - haemophilia A - blood coagulation factor VIII - mutation - sustainment
of response