The condition Huntington's Disease got its name because it was

first described by George Huntington, a physician in New York, in 1872.

It use to be commonly known as Huntington's Chorea - chorea being the

Greek word for dancing and describing the strange movements of the

sufferer. Most people now refer to it as Huntington's Disease or HD for

short. The illness probably occurs all over the world, though it has not

been thoroughly researched in many places, particularly in

underdeveloped countries.

The illness begins gradually, usually in one or the other following

ways: by a change in usual behavior, for example, depression,

moodiness, unreasonable outbursts of anger out of character for the

individual, or by unusual jerky, fidgety movements and perhaps

unsteadiness of the hands or feet causing falls and a tendency to be

clumsy. These are early signs. They are mild and increase so slowly that

they may go unnoticed and it is only much later, when looking back,

that relatives realize all has not been well for some years.

These changes are thought to come about because of a disturbance

of one of the chemical substances concerned in normal functioning of

the brain though it is not known exactly which chemical is involved.

Over the years the illness goes on getting more severe, though the rate

at which it progresses varies from individual to individual. However,

once it has started, it goes steadily on. The ungainly jerky movements,

over which the sufferer has no control, increase, causing falls and

making walking difficult. Speech usually becomes slurred and

swallowing difficult. Some, though not all, will at times become

confused and forgetful, at other times angry and unreasonable and

possibly violent.

Alternatively, some people become quite passive. But the illness

has its ups and downs and some days the ungainly movements and

irritability are less. This changing state is confusing and frustrating for

both sufferers and their families. At present there is no known cure,

though medicine may lessen the jerky movements, and sympatheticand

understanding care can help to keep the sufferer less agitated and so less

liable to unreasonable behavior. Ultimately, it may become too difficult

to care for the sufferer at home.

The illness usually lasts 15-20 years, although it may be

considerably longer. Death is often from pneumonia because sufferers

cannot cough well enough to clear the chest if they have infections. The

most common age of onset of the illness is between the age of 30 and

50 years, although it can manifest itself at almost any age. Both men

and women are affected and it is estimated that perhaps 6,000 people

now have the illness in the United Kingdom. HD is hereditary and runs

in families in a way that is well understood. It is called a dominant

disorder.

It is known for certain that HD is a dominant disorder and that the

abnormal gene needs to be present on only one member of a gene pair for

the individual to develop the disorder. This means that each time an

individual who has the gene for HD (though he may not yet have signs

of it) has a child, there is a 1 in 2 chance that the child will inherit the

HD gene. There is also a 1 in 2 chance that the child will inherit the

normal gene. Everyone who inherits the HD gene will eventually develop

the disorder unless he or she dies from some other cause before the

signs appear

Because they are like their affected parent in, say, stature or skin

or eye color, some people fear they may also have inherited the HD gene

too. Physical or temperamental likeness to an affected parent does not

imply that the child has also inherited the HD gene; nor does it change

the 1 in 2 risk. It can only be said that, on average, half the children of a

sufferer will inherit the gene. This does not mean, for example, that

precisely 2 out of 4 or 3 out of 6 children in a family will inherit it, but

that every child has a 50/50 chance of getting it. Some families are

lucky and perhaps 4 out of 4 children will escape; other families, less

fortunate, demonstrate that 4 out of 4 can be affected; but the chance

for any other child remains 1 in 2. When large numbers of families

containing many children are studied, the proportion of 1 in 2 (or

50/50) affected is regularly seen.

For some time researchers have known that the gene for HD was

near the end of chromosome 4. Since the discovery of the HD gene in

March 1993, a new predicting test has been developed. This can

identify the carriers of the faulty gene before they develop the illness.

After a number of counseling sessions at a genetic clinic, blood samples

are taken from the person who wishes to be tested. The DNA which is

extracted from the blood is then analyzed in a special laboratory.

Occasionally the result falls in a 'gray area' where it is still uncertain

whether the person will develop HD or not. Even when the test does

show that someone has the faulty gene, it still does not show the age at

which the disease will start to develop

There is a different type of test which can be carried out on a

fetus. This test analyses DNA from several family members using

markers linked to the gene. It shows whether the baby is at low risk of

inheriting the faulty gene or at the same risk as the parent who is at risk

but so far unaffected.

All over the world research is going on into Huntington's Disease.

One day, sooner or later, the cause will be better understood and a

treatment found. This may come in the lifetime of young people who

still have to face an uncertain future. We all long for the day when the

scourge of this illness, like many others, will be removed from us. In the

meantime, families are joining together worldwide to promote better

treatment and understanding of those who suffer and to make their

needs known.

The International Huntington's Association crosses all boundaries

of race and language and links people in a common cause, to face with

courage what cannot be changed and to change what it is in our power

to change, working together towards greater knowledge and better

services, and above all creating the sense of fellowship that overcomes

fear and isolation. Scientists have come a long way in the past few years

and there is hope for the future.

Works Cited/Consulted

Bram, Leon L. and Norma Dickey. Funk & Wagnalls New

Encyclopedia. New York. Rand McNally 1988

Microsoft Corporation. Microsoft Bookshelf 98.

Seattle. Microsoft 1998

http://www.grolieronline.com/hd/info

Fadiman, Clifton and Daniel Boorstin. The Treasury

of the Encyclopedia Britannica. New York.

Penguin Group 1992

Genetic Disorders:

Huntington's

Disease

Danny Dore

Period 6

12/14/98