Carrier detection in hemophilia A: a cooperative international study. I.
The carrier phenotype
JB Graham, CR Rizza, J Chediak, PM Mannucci, E Briet, R Ljung, CK Kasper, EM Essien and PP Green
Eight laboratories in six countries cooperated to clarify several issues
concerning the phenotypes of heterozygous carriers of hemophilia "A."
Plasma levels of factor VIII (F.VIII:C, formerly VIII:C) and von Willebrand
factor (VWF:Ag, formerly VIIIR:Ag) of carriers and normal women were
determined by various "in-house" methods; a single lyophilized plasma
standard was used for all assays. Analysis of the collated data from 336
carriers (296 obligatory carriers and 40 sporadic carriers) and 137 normal
women showed that there was no difference in the F.VIII:C levels of
"paternal" carriers (women who had obtained the abnormal gene from their
fathers) and "maternal" carriers. Neither was there a difference in the
VWF:Ag levels of normal women and either type of carrier. Age was found to
have a significant effect on both F.VIII:C and VWF:Ag, values being higher
at very young and very old ages, the minima occurring in the 25- to 30-year
range. ABO blood type had a striking effect. Women of types A, B, and AB
(designated non- O in the study), both normals and carriers, had
significantly higher levels of both factors than did women of type O.
Analysis by laboratories showed that differences in mean levels of both
factors between laboratories were highly significant. It was concluded that
age, ABO blood type, and laboratory variation should be taken into account
in carrier detection.
Volume 67,
Issue 6,
pp. 1554-1559,
06/01/1986
Copyright © 1986 by The American Society of Hematology
