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Hemophilia in women

Hugues Roest Crollius crollius at rag2.RZ-Berlin.MPG.DE
Thu Apr 25 14:40:01 EST 1996

In article <4lnj1n$sl at caladan.restena.lu>, John Watson <john.watson at ci.educ.lu> writes:
|> Does X-linked hemophilia in women really exist or is a 
|> double dose of the gene leathal?  Is there anyone out there 
|> that can give me a clear answer to this question

Hello John,

In principle X inactivation is random, therefore a female carrying a mutated gene
for haemophilia is not affected. However in some cases X inactivation deviates
from randomness in a "tissue specific" manner. This is described as "lyonization" 
and in these cases, a tissue may contain a much higher proportion of cells 
carrying a mutated gene on the active X chromosome. 

If lyonization of the factor VIII (F8) or IX (F9) genes in liver occurs, it will
result in a case of female with haemophilia. 

There is a description of this phenomenon in a book called "Human Gene Mutation"

D.N. Cooper and M. Krawczak (1993) in "Human Gene Mutations" (Bios Scientific 
Publishers ltd, London) pp308-309

Articles reporting cases of female haemophilia are :

Ingerslev et a., (1989). Female haemophilia A in a familiy with seeming extreme
bidirectional lyonization tendency: abnormal premature X-chromosome inactivation
? Clin. Genet. 35: 41-48

Nisen et al., (1986) The molecular basis of severe hemophilia B in a girl
N. Engl. J. Med. 315: 1139-1142

Others are also referenced in the above book chapter. 

Hope this helps.


Hugues Roest Crollius

Abt. Lehrach
Max-Planck-Institut fuer Molekulare Genetic
Ihnestrasse 73
14195 Berlin
e-mail: roest at mpimg-berlin-dahlem.mpg.de

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