Huntington\'s Disease Although it Was Once Considered

Huntington's Disease

Although it was once considered a rare disease, Huntington's disease (HD) is now known to be one of several frequently encountered hereditary diseases. It is estimated that 30,000 people in the U.S. have the disease. People affected by HD require extensive care from their families and loved ones, and because of this need, this devastating condition affects a wide circle of people close to those who are ill ("Huntington's Disease"). This widespread affect on so many lives is one reason that promoting HD awareness is so important.

HD is an inherited brain disorder that leads to loss of physical control and mental capacity. Caused by an inherited defect in a single gene, HD is an autosomal dominant disorder, which means that a person needs only one copy of the defective gene to develop the disorder. With the exception of genes on the sex chromosomes, a person inherits two copies of every gene, one from each parent. A parent with a defective Huntington gene could pass along either the defective copy of the gene or the healthy copy. Therefore, each child in a family has a 50% chance of inheriting the gene that causes the disorder (Mayo Clinic Staff).

Also, given that the majority of people develop the disease between the ages of 35 and 55, people who are aware of their genetic risk face an additional dilemma. Should they have a test to see if they have the gene? Should they start a family?

Huntington's disease affects approximately 1 person in 10,000, but its genetic nature means that it affects a significant number of family members as well. Approximately 200,000 Americans are at risk of inheriting the disease from an affected parent. Every person who inherits the HD gene will eventually develop the disease if they do not die of other causes first. Even though HD does not affect large numbers of people, a patient with HD is affected for a very long period of time, from 10 to 30 years typically. For all of these reasons, HD represents a significant challenge (Quarrell).

The HD genetic problem causes nerve cell loss in the brain. Symptoms may develop gradually, and will affect an individual's ability to move, think, and process thoughts and feelings. After the onset of HD, a person's functional abilities gradually deteriorate over time, with the rate and progression of the disease varying with each individual. From onset of the disease to death is a period of about 10 to 30 years (Mayo Clinic Staff).

Eventually a person with HD requires help with all activities of daily living and care. In the late stages of the disease, he or she will probably be confined to bed and unable to speak. Common causes of death include pneumonia or other infections, injuries related to falls, and complications related to the inability to swallow (Mayo Clinic Staff).

For researchers, identifying the genetic mistake that causes HD was not necessarily an end in itself as much as helping to remove some of the uncertainties about the diagnosis and allowing the development of reliable predictive tests. Going forward, the objective remains to understand the disease so that effective treatments may be developed that will alter the disease's natural history or delay its onset (Quarrell).