Should my fiance be tested even though it only seems to affect women in his family?
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Q. My fiance’s mother had HD and passed away about 9 years ago.
She inherited the gene from her mother. He has an older sister who has not been tested and neither has he.
Should he be tested even though the gene seems to only effect the women in his family? If he were to test positive can he pass it on to our children? If negative will he still carry or pass it on?
Meagan, Young Adult, USA
A. Dear Meagan, Many thanks for your questions.
As you may know, HD is a genetic condition caused by an ‘expansion’ in the HD gene. If someone who carries an expansion has a child, there is a 50% chance (1 chance in 2) that the child will inherit the expansion. Although in your fiancé’s family it sounds like it has only affected women, HD can affect both men and women, and the chance of a child inheriting the expansion is the same for either sex.
Therefore, unfortunately when your fiancé was born, we would assume that he would have had a 50% chance of inheriting the gene expansion. Although predictive genetic testing is available and could clarify whether or not he has an expansion, there are pros and cons of this, and many individuals at risk of HD prefer not to have predictive testing.
If your fiancé did inherit the expansion, any children he has would then also each have a 50% chance of having it. If he did not inherit it, his children would not be at any increased risk.
You/your fiancé may find it helpful to see a genetic counsellor or doctor, who could go over your fiancé’s family tree and explain the inheritance of HD in more detail, as well as providing information about the options around testing, and some of the pros and cons (there are also a range of different options for couples who are considering having children). This website may help you find your local genetics service. If you would like to read more about the HD gene expansion and how it can be passed on in families, you may also find (this HDYO page useful)[/pro/articles/50].
I hope this has helped answer your questions, and please do not hesitate to get back in touch if you have any further queries, or if you have any difficulty locating your local genetics centre.