A Primer on Huntington's Disease

This is the first in a series of blog posts about Huntington's Disease, and the effect a diagnosis - or fear of a diagnosis - has on families.  This first post gives a brief overview of the disease, and insight into how devastating HD is on the individual and family.

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What did you inherit from your parents?  Do you have a prominent chin, or maybe a nose that seems to cover half of your face?   Have you ever been told you look just like one of your parents, or that you have the same laugh as your grandfather?

Inherited traits are a link to your family’s past and present.   Trying to connect the present and the past is a million dollar industry with websites that help users find ancestors and DNA testing that can be used to develop a family tree going beyond links in documents or the faded memory of an older generation.

For some, however, these DNA links can confirm stories of mysterious and unexplainable symptoms and behavior that go back many generations.   A DNA test has answered a different kind of question about a family trait - a diagnosis of Huntington's Disease.  

Huntington’s Disease is a genetic neurological disorder causing the breakdown of nerve cells in the brain.  Every person has the Huntington gene, but those who develop HD have a mutation of the gene that causes this nerve cell breakdown.  Each child of an affected parent has a 50/50 chance of inheriting the defective gene.  A true “family illness,” it is estimated that about 30,000 people in the United States have been diagnosed with HD, and nearly 200,000 live at risk of inheriting HD.  There is presently no cure, and limited medication for one or two specific symptoms.

Sometimes referred to as the cruelest inherited disease known to man, a person with Huntington’s Disease experiences the symptoms of Alzheimer’s, ALS, and Parkinson’s Disease all at the same time.  There are three aspects to Huntington’s Disease; the motor disorder, the cognitive disorder, and the psychiatric disorder.  Understanding these three facets of the disease gives insight into the difficulties faced by families who deal with HD on a day-to-day basis. 

The motor disorder includes chorea, which is the most recognized symptom.  The majority of people with HD have these involuntary movements.   Search “Huntington’s Disease” on the internet, and a number of resources will pop up describing chorea, including videos documenting this symptom.  The motor disorder affects all movement.  This means that as HD progresses, a person will lose the ability to walk and speak, to feed him or herself, and to swallow.  Eventually, a person with HD also deals with bowel and bladder incontinence. 

The cognitive disorder can actually begin before symptoms of the movement disorder are evident.  While a person with HD does not lose the ability to recognize loved ones, there is loss of the ability to learn and remember, which often affects employment.  People with HD also have difficulty recognizing emotional cues, and often misinterpret the facial expressions of others.  Because the brain is the “CEO” of the emotions and thinking, the loss of this “executive function” is distressing.   The person with HD is often unable to pay attention, plan or organize, and can become irritable and impulsive.  This loss of the ability to think can also be a major factor in the development of many behavior and personality changes.

Finally, the psychiatric disorder associated with the progression of Huntington’s Disease is the most common part of HD, yet one that is less understood.  Persons with HD can suffer from major depression, impaired judgment and fixation on ideas or activities (called perseveration).  Occasionally, a person with HD can also suffer from delusions and hallucinations.  Psychiatric symptoms can be treated with medication, but these symptoms are often the most untreated aspect of Huntington’s Disease. 

Mention Huntington’s Disease, or HD, to someone and there is likely to be a vague recognition “I think I’ve heard of that.”  Family practice physicians have knowledge of the disease through introductions in a medical text, but rarely see a person with HD in their practice.  Because so few individuals have Huntington’s Disease, knowledge is spotty and often based on outdated information. 

Considering the overwhelming nature of this disease, confirming the presence of HD in a family is devastating news.  Often this diagnosis comes as a surprise to children of affected parents, partly because of limited information, and partly because of the shame that previous generations felt about HD.  The demoralizing physical and mental symptoms of HD typically develop during a person’s mid-life, a time when adults are the most productive and active. 

Since HD has symptoms that affect the brain, and all other body systems, those who inherited the disease in past generations were often diagnosed initially with a psychiatric disorder.  The singer Woody Guthrie, the person most associated with HD,  was treated for alcoholism and psychosis before he was finally properly diagnosed with Huntington’s Disease.   

In future posts, I'll share the stories of families who live with HD, or with the possibility of a diagnosis.  Hopefully, those posts will shed light on the complicated decision to test or not to test, and the difficulties facing families who search for support when there is a positive diagnosis.