Q: What is Huntington’s disease?
A: Huntington’s disease is a genetic neurodegenerative disease which affects the brain. People with HD may experience involuntary movements (chorea), reduced intellectual abilities, and may experience behavioural and personality changes. HD affects the brain in two particular areas; the basal ganglia which controls and coordinates body movements and the cerebral cortex which is responsible for processes such as thoughts, emotions, perceptions and planning.

Q: What causes HD?
A: HD is caused by a defective gene located on chromosome 4. Everyone has the Huntingtin gene; however people who develop HD have an expansion of a particular region of the gene, called the CAG repeat region. When this region has more than 40 repeats of the CAG sequence, it leads to the production of damaged Huntingtin protein which leads to the damage of nerve cells in the brain. The expansion of the CAG repeat region in the gene is passed on by one parent who has the defective gene. If your parent does not have the defective gene then you can’t inherit it.

Q: Can HD skip a generation?
A: Every child of a parent who carries the defective gene has a 50% chance of inheriting the gene. If your parent does not have the defective gene then you are not at risk of developing HD or of passing it on.