What is Huntington’s Disease (HD)?

About Huntington’s Disease (HD):

• It is a genetic condition that affects the cells in your brain.
• It is an inherited condition that causes brain cells to slowly lose function and die. 
  • If one of your parents has HD, you have a 50% chance of also developing it.
• It affects the cells in parts of your brain that regulate voluntary movement and memory. 
• What causes Huntington’s disease?
  • A genetic mutation of the HTT gene causes Huntington’s disease.
  • The HTT gene makes a protein called huntingtin. This protein helps your nerve cells (neurons) function.
  • If you have HD, your DNA doesn’t have all the information needed to make the huntingtin protein.
  • As a result, these proteins grow in an abnormal shape and destroy (instead of help) your neurons.
  • Your neurons die because of this genetic mutation.
  • The destruction of nerve cells happens in the basal ganglia, or the region of your brain that regulates your body’s movements.
  • It also affects the brain cortex (surface of your brain) that regulates your thinking, decision-making, and memory.
• How common is HD?
  • Huntington’s disease affects an estimated 3 to 7 out of every 100,000 people, most often people of European ancestry (biological family comes from European descent).
• Symptoms:
  • Common symptoms include uncontrollable dance-like movements (chorea) and abnormal body postures, as well as problems with behavior, emotion, thinking, and personality.
  • Other symptoms may include tremor (unintentional back-and-forth movement in the person's muscles) and unusual eye movements. The eye movements can happen early in the disease.
  • These symptoms get worse over time.
• As HD progresses, you will need constant assistance and supervision because of the debilitating nature of the disease.
• People usually die from the disease within 15 to 20 years of developing symptoms.
• Treatment:
  • There is no treatment that can stop or reverse HD, but health care providers can offer medications to help with certain symptoms.
  • Drugs like haloperidol, tetrabenazine, and amantadine are especially helpful for controlling the unusual movements caused by Huntington disease. 

Q1: What is the average age of Huntington’s Disease diagnosis?

The average age of symptom onset is 45 years. However, about 25% of those affected don't experience the onset of Huntington's disease until after the age of 50. It's possible to receive a diagnosis of HD before symptoms begin. Connections in the brain and brain volume can change years before someone has symptoms of HD.

Source: OI