Huntington's 101: Getting to Know This Rare Condition

Huntington's disease (HD) is perhaps most well-known for three attributes: its rarity, its high risk of familial inheritance, and its seriousness. The Huntington's Disease Society of America estimates that 30,000 people live with HD in the United States, and another 200,000 are at risk of inheriting the disease.

What else should you know about this rare condition? We spoke with Holly Shill, medical director at the Muhammad Ali Parkinson Center, to learn more.

What Is HD?

HD is a disorder of the brain that causes certain nerve cells to break down, leading to problems with physical movement, behavior, and reasoning. Symptoms usually appear between ages 30 and 50, and the disease is not curable.

What's really notable is how commonly HD is inherited, and the fact that everyone who has the gene will develop the disease at some point. It is autosomal dominant, meaning that a person needs to inherit the abnormal gene from only one parent. As Shill explains, "The risk to each child (of a parent with HD) is 50 percent."

"We think the vast majority of HD is genetic," she continues. "However, there are some people who have a lesser concentration of the gene and still are affected (this is called variable penetrance), which suggests there might be other factors, such as environment, that might play a role."

Genetic Testing for HD

If you are at risk of getting Huntington's disease because a parent had the condition, you can choose to undergo genetic testing to determine if you have the gene. If you do, the truth is that you will face a difficult choice regarding whether to have children yourself. This is a highly personal decision, with no right or wrong answer. Also, if you opt not to undergo genetic testing now, it's OK to change your mind and do so later.

According to the Huntington's Disease Society of America, an individual with the HD gene can eliminate the risk of passing the gene to a child by undergoing a specialized in vitro fertilization procedure that ensures the embryo does not have the gene defect. A pregnant woman can also have her unborn child tested for the faulty gene.

Stages of HD

Although HD progresses at a different rate for each person, the disease follows a specific course that includes:

• Early-stage Huntington's. This stage includes mild problems with coordination and thinking. A person in the early stage of HD may have trouble making simple decisions and may seem depressed.
• Middle stage. As HD progresses, you or your loved one may experience more issues with involuntary muscle movements. This condition is called chorea. Swallowing and speech may become more difficult.
• Late stage. In the final phase of the disease, a person with HD becomes unable to walk and possibly unable to speak or swallow. People with late-stage HD must rely on other people for their care.

If You Know Someone Who Has Been Diagnosed with HD

You can contribute to the quality of life of a friend of family member with HD in many positive ways:

• Be on their team. Because HD affects a person's ability to reason, they may need their loved ones to advocate for their wishes on health and legal issues. Provide honest -- but kind -- feedback to your friend or relative about how they are coping with their condition. They may seek your opinion, as well: "Identifying a trusted friend or family member who can give you objective input about how you are really doing can help with the decision on if it's time to stop working or bring in additional help," explained Shill.
• Be sensitive to the challenging lifestyle choices he or she will need to make. Because HD can be passed from parent to child, a person with HD will have a lot to consider when deciding whether to have children. Exhibit empathy by listening to their feelings and trying to put yourself in their position. Try to avoid influencing them toward the choice you feel is best, and instead support whatever decision they make for themselves.
• Stay positive. You don't need to avoid talking about difficult topics, but try to look on the brighter side whenever possible. Emphasize everything the person can still do instead of lamenting their functional losses. Be a one-person support group whenever you interact. Finally, encourage them to put plans in place now to help maximize their quality of life in the face of this progressive disease.