INHERITED COMBINED DEFICIENCY OF FACTOR-XI AND FACTOR-XII WITH VON-WILLEBRANDS-DISEASE

Combined hereditary deficiency of factors XI (FXI) and XII (FXII) asso ciated with the deficeincy of von Willebrand factor (vWF) in a single patient has not been reported so far in the literature. We report on t wo brothers of non-Jewish stock with defciency of FXI, FXII and vWF. T he family studies disclosed FXI and FXII deficiency in the mother of p ropositi. A maternal niece had FXII deficiency. The father of proposit i had vWF deficiency. This study suggests possible existence of a regu latory factor common to genes specifying FXI and FXII. Associated vWF defiency is coincidental.