How is HD inherited?
Huntington disease (HD) is caused by a single altered gene, which is passed on from one generation to the next in affected families. The symptoms of HD usually start to appear in affected people between 30 and 50 years old, but this varies. With one affected parent, each child has a one-in-two chance of inheriting HD. Children who do not carry the altered gene are free from the condition and cannot not pass it on to their own children.