HD is an autosomal dominant genetic disorder. That is, each child or sibling (brother or sister) of someone with HD has a one in two or 50:50 risk of inheriting the gene. What this means is that if someone with HD has 10 children then on average 5 will inherit the gene and 5 won’t. However, there will be some families where less than half of the children will inherit the gene and some others where  more than half  of the children will inherit the gene.

Men and women are at equal risk of inheriting the gene.

The only certain way to know of if someone has the gene is to have a gene test.

If most of those in a particular family who get HD are women then this is just bad luck for them and good luck for the men of the family. If your boyfriend’s mum had HD then he is at a one in two or 50:50 risk of inheriting the gene even though he’s a man.

Dr Andrew