Huntington’s Disease: What You Need to Know!
What is Huntington's Disease?
Huntington’s disease is a disease of the brain in which cranial nerve cells progressively degrade. The degradation of nerve cells leads to a decline in nervous function, causing symptoms such as involuntary movement, irritability, mood swings, speech impairment, decreased motor function, and lowered cognitive reasoning ability. There are approximately 30,000 people in the United States with Huntington’s disease currently, and nearly 200,000 more who are at risk of inheriting the disease from a parent or relative.
Understanding the Stages of HD
Huntington’s disease occurs in stages of increasing symptomatic severity. Early stage Huntington’s disease is characterized by slight changes in cognitive function and or motor ability, including changes in hand writing, muscle twitches, delayed reasoning ability, and memory loss. During the middle stages of Huntington’s disease, these changes in cognitive and motor function worsen, and can cause significant disruption in day to day activities. Late stage Huntington’s disease is characterized by extremely severe motor and cognitive impairment, so much so that a patient may be unable to swallow, eat, speak, or walk without assistance.
How Do I Know it's HD?
Huntington’s disease typically develops from the ages of 30-50, though symptoms may appear as early as adolescence, and few people do develop the disease after the age of 55. The first symptoms of Huntington’s disease are often slight muscle twitches, changes in memory or reasoning, and decreased dexterity. Since HD is a genetic condition, children with parents with the condition often look for these symptoms as a sign that they have inherited the disease. However, experiencing these symptoms does not necessarily mean that a patient has HD. A genetic test before or after symptoms arise can determine with certainty whether or not an individual has HD.
The HD Gene
Huntington’s disease has long been known as an inheritable disease, but it wasn’t until 1993 that researchers were able to identify the specific genetic mutation that causes the disease. The human genome is contained within 23 pairs of chromosomes, rod-like structures that are tightly packed with genetic material coded in sequences of four proteins – adenine, thymine, cytosine, and guanine. Huntington Disease occurs when the sequence cytosine, adenine, guanine (CAG) occurs in succession too many times in a specific region on the fourth chromosome. The number of CAG sequences on the fourth chromosome of HD patients often increases as the severity of the disease progresses.
Looking Forward After an HD Diagnosis
Huntington’s disease is progressive, meaning that its symptoms worsen with time. The average HD patient lives only 15-20 years after the first symptoms are observed, though this estimate should not be taken as absolute since each individual experiences HD differently. Though there is unfortunately no known cure for Huntington’s Disease, there are different treatments available to help manage symptoms as they arise.
Managing Early HD
Treatment plans for early HD should take into consideration the severity of symptoms, the pace of progression, and the individual patient’s needs. Doctors may choose to prescribe medications such as dopamine blockers, amantadine, and tetrabenazine, to reduce the severity of muscle twitches and excessive movements, as well as anti-depressants to combat HD’s accompanying depression and/or anxiety. Physical therapy and/or exercise regimens may be prescribed to help maintain muscle tone, boost energy levels, and encourage the retention of motor skills.
Hope for a Cure: Brain Tissue Grants
Since Huntington’s disease is caused by a degeneration of brain tissue, much of the research into potential treatments has been directed at finding ways to stimulate neural cell regeneration. One of these methods currently being researched is fetal brain tissue grafts, in which fetal brain tissue is grafted onto diseased adult brain tissue to support the growth of healthy tissue. This method has found success in animal trials but its efficacy has not yet been tested in humans.
Will My Child Have HD?
There is a 50/50 chance that a parent with HD will pass the disease on to his or her child. A child who does not inherit the HD gene cannot pass the disease onto his or her own children. For expecting parents with a family history of Huntington’s disease, the possibility of inheritance can be a source of anxiety. Fortunately, recent developments in reproductive and genetic technologies have allowed doctors and patients to assess the risk of Huntington’s disease more precisely. See the next slide for more information on family planning with HD.
Invitro Fertilization
If a couple wishes to have a child that is guaranteed to be free of the HD gene, they may conceive via specialized in vitro fertilization in which the embryos are genetically screened for the presence of the HD gene before implantation. Once a child is born, it cannot undergo genetic screening to determine whether or not they have the disease until the age of 18, due to concerns about children’s ability to fully and knowingly consent to the test. Children who exhibit HD symptoms at an early age (juvenile Huntington’s disease) may be tested before the age of 18 to help doctors better understand the cause of their symptoms.
Vizualizing HD
Positron emission tomography (PET) scans have become an important part in visualizing the brain cell degradation caused by Huntington’s disease. In a PET scan, patients are given a radioactive substance known as a tracer and are placed beneath a special camera that allows doctors to measure the functioning of a body tissue (the brain, in the case of HD) through observing its cellular and chemical reactions. PET scans have helped both patients and medical specialists better understand how HD nerve cell degradation corresponds to physical symptoms.
Hope for a Cure: HD Clinical Trials
Though there is currently no cure for Huntington’s Disease, ongoing research into potential treatments provides almost constant opportunity to engage in clinical trials for HD drugs. To find clinical trials for which you or a loved one could be an ideal candidate, talk to your doctor or local specialist, or visit Huntington Study Group.
HD and Independent Living
As HD symptoms progress, maintaining an independent lifestyle can be a struggle. If loved ones are unable to be full-time caretakers, visiting nurse services and in-home care services (such as meal programs, physical therapy, and/or occupational therapy) can help a Huntington’s disease patient remain independent. As symptoms worsen, and the need for care increases, live-in aids can help an HD patient with day to day activities, such as eating, bathing, and doing chores around the house. Contact your local or state health service agency for more information on available programs and funding.
The Choice of Assisted Living
Though many loved ones of HD patients would like to provide full-time in-home care, they sometimes find it is not possible due to financial or other circumstance. The choice to move a loved one from home into an assisted living facility is not an easy decision, and it is one that should be after considering both the needs and limitations of both the patient and the caretaker. For assistance in the decision making process, ask your doctor about professional counseling options for care-seekers.
Support for HD Patients
A solid support system is the foundation of an HD patient’s journey through the disease. In addition to the support given by family and loved ones, support for HD patients is available from therapists, social workers, and HD support groups. To find HD support resources in your area, visit Huntington's Disease Society of America.
Support for HD Caregivers
Caring for a loved one with HD can cause an immense amount of stress and is often overwhelming for those who have never been in such a position before. Fortunately, there are many resources available to help educate caretakers on Huntington’s disease, as well as to support caretakers throughout their caretaking experience. The Huntington’s Disease Society of America offers a series of webinars directed towards the caregiving experience. To watch these webinars, visit their website. For other HD caretaker support, visit The Family Caregiver Alliance.
Getting Involved with HD
Each year, hundreds of thousands of dollars are raised to support HD research through programs such as car donations, hope walks, and marathon teams. If you would like to get involved with organizations dedicated to Huntington’s disease research and fundraising, visit hdsa.org
