How Huntington's Disease Affects Patients and Their Families

Introduction to Huntington's Disease

Huntington's disease (HD) is a genetic disease that affects the central nervous system, primarily in individuals who are thirty years of age and older, though it does occasionally occur in younger people. When the disease manifests, it does so as an inherited autosomal dominant condition, and it affects all or most of the family members within the same family. The onset of symptoms and the rate of disease progression may differ between family members, and this is an important fact to remember. The symptoms of Huntington's disease include involuntary movements and a loss of motor control. Changes may also occur in the patient's personality, and other symptoms can include memory loss and decreased mental capacity. The various symptoms observed in one individual are generally used to help diagnose other family members and to determine the likely diagnosis for the wider family group.

Several fundamental questions surround the disease: What is Huntington's disease, and how does it affect the patient and his or her family? How does one care for the patient? Is there any cure, and what does current treatment involve? When and by whom was the disease discovered? What forms of support are available from external sources, and how can families access that support? This paper addresses each of these questions in turn, drawing on genetic science, medical history, clinical research, and personal testimony.

Genetics of Huntington's Disease

The human body contains approximately 100 trillion cells, and within each cell is a nucleus. Each nucleus contains 46 chromosomes arranged in 23 pairs; one chromosome of every pair comes from one parent, and the other from the other parent. These chromosomes carry DNA that is tightly coiled within the nucleus, and within this DNA are the genes — literally segments of DNA — that contain the various instructions the human body needs in order to make proteins and the other building blocks of life. Every human being has 23 chromosomes from the mother and another 23 from the father. Chromosomes are of two types: 22 pairs of autosomal chromosomes, and 1 pair of sex chromosomes (two X chromosomes in females, and an X and a Y in males). Because Huntington's disease is autosomal dominant, the gene involved belongs to an autosomal chromosome and not to the 23rd pair — that is, not to the sex chromosome.

Recent research has further revealed that the fourth pair of autosomal chromosomes is responsible for the disease. In an affected person, one gene of the pair on the fourth autosomal chromosome does not function properly. This malfunctioning gene automatically begins to dominate over the properly functioning gene. Because it has nothing to do with the sex chromosome, it can affect both men and women equally, and an affected man has the same probability of passing the disease to his children as an affected woman. Therefore, a parent of either sex can pass on either the unaffected or the affected gene to his or her children, resulting in a fifty percent chance of any child inheriting the affected gene. However, the age of onset, the variation of symptoms, and the rate of progression differ from individual to individual.

Huntington's disease is the inevitable result of a genetically programmed degeneration of brain cells, also known as neurons, in certain areas of the human brain. This degeneration causes uncontrollable movements, deterioration of memory and mental faculties, and severe psychiatric disturbance. Because the disease spreads through a gene, a child has a fifty percent chance of inheriting it from a parent of either sex. If the child has not inherited the disease, he or she will not pass it on to subsequent generations. If the child does inherit it, however, he or she will eventually develop the symptoms of the disease. The fact that one child has inherited the disease does not mean that other children of the same parents have also inherited it; inheritance depends on which gene was passed on to each individual child.

Symptoms, Diagnosis, and Treatment

Some of the early symptoms of Huntington's disease include difficulty remembering things and learning new tasks, severe mood swings, and depression. The disease will make inevitable progress until the patient is unable to feed himself or swallow without assistance. The pace of progression depends on the individual, and the earlier a physician is able to diagnose the disease, the sooner help can be sought. A doctor will generally advise a genetic test, take a complete medical history, and subject the patient to a battery of neurological and laboratory tests. After diagnosis, the patient can begin medication. Those who already have Huntington's disease may seek pre-diagnosis testing for their children. In most cases, however, the disease is not evident in 1 to 3% of individuals who do have a family history of HD.

Experts estimate that one in every 10,000 persons is a sufferer of Huntington's disease, amounting to about 30,000 people in the United States alone. Juvenile Huntington's occurs in approximately 16% of all cases. There is no specific population group, race, ethnicity, or sex that is preferentially affected; the disease affects anyone who has inherited the faulty gene from either parent. Managing Huntington's disease requires informed planning and the knowledge to execute those plans effectively. Researchers today are making significant progress in understanding the molecular basis of the disease, and a large number of clinical trials are now underway, investigating both drugs and other supplements.

Today, a combination of drugs and other modes of treatment is available that can reportedly delay the onset and slow the progression of the disease while researchers continue to search for an actual cure. At present, there is no cure for Huntington's disease. It is a fatal disease with a slow progression rate; the patient eventually dies without full possession of his or her mental faculties and without the ability to care for himself or herself. Despite ongoing research into prevention and cure, there is no medically approved curative treatment, and clinical trials are progressing slowly, partly due to limited numbers of research subjects. The result is that there is not much immediate hope for the many families afflicted with this disease. A so-called "proactive" approach has been advocated for affected individuals, though critics note that it does not offer substantially more than existing options.

The proactive approach involves researching what scientists have discovered about the disease — its symptoms, diagnosis, progression, and treatment — and then deciding individually which interventions to pursue and which to set aside. The individual examines the large body of research material available, weighs the pros and cons, reviews the side effects of prescribed drugs, and then decides on a specific mode of treatment in consultation with a physician. According to the National Institute of Neurological Disorders and Stroke, ongoing research continues to refine understanding of the disease's mechanisms and potential therapeutic targets.

Conclusion

It is best to learn more about the disease and its symptoms before embarking on a treatment regimen, so that the family is better prepared to support the patient through the progression of dementia, depression, obsessive behavior, and the other manifestations of HD. John's advice is instructive: despite believing he knew everything there was to know about the disease and having taken his wife to a neurologist, it was only when he actually met another person living with HD that his entire outlook changed. He recommends joining a support group of people in similar circumstances, because sharing one's burdens helps reduce the weight of them, and seeing another person with the exact same symptoms as a loved one helps put the situation in perspective.