Why do women and girls have genetic testing for haemophilia?
A normal factor VIII or factor IX level test will not tell women or girls whether they carry the gene alteration causing haemophilia. Some women or girls may have normal factor levels, but still carry the gene alteration.
In genetics, all females who have the gene alteration causing haemophilia are called 'carriers'.
A common time for testing whether a girl or woman is a carrier is when she reaches childbearing age and can understand the process and implications fully and make the decision for herself. Finding out whether she has the gene alteration is a process which will take time, sometimes many months. This may involve:
- Discussion with a haemophilia specialist and/or genetic counsellor
- Information and education about haemophilia, treatment and inheritance
- Weighing up the pros and cons of genetic testing with advice and support from specialists, counsellors and other experts - for example, the role of genetic testing in understanding her bleeding disorder; its effect on her perception of herself and on her relationships; her personal understanding of what it’s like to have haemophilia; the impact on children and other family members; her personal religious and cultural beliefs; future disclosure obligations and implications for life or income protection insurance; any costs involved; and other issues relevant to her personal situation
- Looking at the family tree to identify other family members who may have the gene alteration
- Blood tests for other affected family members (eg, a man with haemophilia) to identify the particular genetic mutation causing haemophilia in her family
- A simple blood test for the woman or girl to see if she has the same family genetic mutation
- Genetic analysis in a laboratory. This can take longer if the family mutation is not known - sometimes months.
Many people find that undertaking these tests gives them a lot to think about. The Haemophilia Treatment Centre can help with information and advice about genetic testing and can provide a referral to a genetic counsellor, if needed. Women, their partner, parents or family can talk to the Haemophilia Treatment Centre or genetic counsellor individually or together prior to testing and many find it helpful.
Where can I have a genetic test?
You will need a referral to the specialist clinical genetics service in your state or territory.
It is preferable to have this referral through your Haemophilia Treatment Centre (HTC).
If you are speaking to your general practitioner (GP) about genetic testing, ask them to refer you to an HTC for diagnosis. If your GP is reluctant to refer you for genetic testing, you can request a referral to a clinical genetics service to discuss your options.
What if I change my mind?
If a person starts exploring genetic testing but decides against it, there is no obligation to complete the process.
For more information about genetic testing, see the Policies and Position Statements on the Human Genetics Society of Australasia web site
For more information about testing for haemophilia before birth, read the section in Pregnancy.
For more information about genetic testing for haemophilia, read our booklet:
Haemophilia testing in women and girls: your questions answered
Read more about the experiences of women in our Finding out you carry the gene booklet