Risk Factors
Family history is the only known risk factor for HD. Because HD is inherited in an autosomal dominant fashion, only one parent needs to have the gene mutation for HD to be passed on to a child. Each child of a parent with the gene mutation has a 50% risk of developing HD. Paternal inheritance is associated with earlier onset. In 8% of cases, there is no family history and a genetic mutation is thought to occur spontaneously during sperm development.