About Huntington's Disease

Huntington´s Disease (HD) is a rare, hereditary, neurodegenerative illness that affects people of all races worldwide. The disease was named after Dr. George Huntington, a physician from Long Island, United States of America, who first published a description of “hereditary chorea” in 1872.  It was due to his essay, entitled On Chorea, that the disorder became known as Huntington´s Chorea. The term chorea is the Greek word for “dance” and refers to the involuntary movements which are seen in many individuals with HD. Since Chorea is not the only symptom, the disorder has in later years been called Huntington´s Disease.

For a long time, little was known or published about HD. In the last 30 years, however, we have learnt a lot about the cause of HD and its effects, as well as the therapies and techniques for managing its symptoms. The gene that causes HD was discovered in 1993 and since then important scientific advances have been made.  To date, there are no drugs to slow or stop the progression of Huntington’s Disease, but scientists are getting closer each day to finding a disease modifying treatment.

HD causes gradual degeneration of brain cells which in turn can result in physical, cognitive and emotional symptoms, which typically become apparent between the ages of 35 and 55, but can also appear much earlier (Juvenile-Onset HD) or later (late onset HD).   

In most cases, individuals affected by HD can maintain their independence for several years after the first symptoms appear. A knowledgeable physician can prescribe treatment to minimize the impact. Allied health professionals, such as social workers, occupational and physical therapists, speech therapists and nutritionists, can all play a useful role in maximizing abilities and prolonging independence.

Genetics

Huntington´s Disease is a hereditary disorder.  Each child of a parent who has HD has a 50% chance of inheriting it.  HD occurs in all races.  Males and females are equally at risk.  Carriers of the HD gene will eventually develop the disease should they live long enough.

Globally, there is estimated to be between 3.6 and 5.7 people with HD for every 100,000 of population. 

Symptoms

HD symptoms can vary significantly from person to person, even among siblings. Symptoms don’t appear in any specific order. Over the course of the disease, some symptoms may be more dominant than others. For some, involuntary movements may be more dominant, even in the early stages, while for others emotional and behavioural disturbances are more worrying, and often go undiagnosed.

Slight intellectual changes are often the first signs of cognitive disturbance.  These can lead to the reduced ability to cope with new situations or perform routine tasks. Below are the most common cognitive HD symptoms:

  • Difficulty organizing, prioritizing or focusing on tasks
  • Lack of flexibility or the tendency to get stuck on a thought, behaviour or action
  • Lack of impulse control that can result in outbursts, acting without thinking and sexual promiscuity
  • Lack of awareness of one’s own behaviours and abilities
  • Slowness in processing thoughts or finding words
  • Difficulty in learning new information

Physical symptoms can include involuntary movements and the impairment of voluntary movements. Involuntary movements typically progress through the middle stages of HD but decline as rigidity increases in the later stages.  Listed below are some of the symptoms:

  • Involuntary jerking or writhing movements (chorea)
  • Muscle problems, such as rigidity or muscle contracture
  • Slow or abnormal eye movements
  • Impaired gait, posture and balance
  • Difficulty with the physical production of speech or swallowing

According to the Mayo Clinic, impairment in voluntary movements — rather than the involuntary movements — may have a greater impact on a person’s ability to work, perform daily activities, communicate and remain independent. In addition to the above symptoms, weight loss is common in people with Huntington’s Disease, especially as the disease progresses.

The most common emotional/psychological disturbance associated with HD is depression. Some people can experience depression for months or even years before it is recognised as an early symptom of HD.  Listed below are some of the other emotional symptoms:

  • Feelings of irritability, sadness or apathy
  • Social withdrawal
  • Insomnia
  • Fatigue and loss of energy
  • Frequent thoughts of death, dying or suicide