Some more genetics

Click on this picture above if you are confused about the genetics of Huntington's disease
"Frank Jakowski's family tree." Daily Herald. 1 Mar. 2009 .http://www.dailyherald.com/graphics/jackowfam.jpg.

How can the disease be treated?

There are medications that can work against the emotional and movement problems that come with Huntington's Disease but there is no way to stop or reverse the progression of the disease. Antipsychotic drugs, such as haloperidol or clonazepam, can prevent choreic movements and can also help control hallucinations, delusions, and violent outbursts. These medications may have severe side effects. such as sedation, and should be taken in the lowest dosage possible. Some physicians may prescribe fluoxetine, sertraline, or nortryptiline to fight depression. Most drugs used to treat Huntington's Disease have side effects such as fatigue, restlessness, and hyperexcitability. Some symptoms are hard to distinguish whether they are caused by the disease or if they are a side effect of a medication.

What is the life expectancy of someone with the disease.

A person with Huntington's can expect to live anywhere from 10-30 more years depending on the severity of the symptoms.

The graph below shows some possibilities for life expectancy for someone with Huntington's Disease(HD) based on the repeats of the codon CAG which are the cause of this disease.

What are the physical symptoms of the disease?

The early signs of Huntington's Disease vary greatly from person to person. However, the earlier the symptoms become visible, the faster the disease progresses. The earliest signs of this disease are usually changes in personality like sudden mood swings. The disease will also affect the individual's cognitive functions. Young people who have this disease will sometimes develop symptoms similar to Parkinson's Disease such as muscle rigidity, tremors and slow movements. Huntington's disease develops slowly and the amount of nerve loss determines the severity of the symptoms. As the disease progresses the individual will develop symptoms such as:

* Sudden jerky, involuntary movements (chorea) throughout your body
* Severe problems with balance and coordination
* Difficulty shifting your gaze without moving your head
* Hesitant, halting or slurred speech
* Swallowing problems
* Dementia

The disease lasts for 10 to 30 years and death usually occurs due to infection (most often pneumonia), injuries related to a fall, or other complications.

How is the disease diagnosed?

An experienced neurologist will obtain the individuals medical history and intensively question the individual to rule out all other possibilities. Many neurologists also use a pedigree to determine whether the individual has Huntington's Disease or not. It is essential for the individuals to be truthful and reveal the family history. The doctors will question the individual about recent intellectual and emotional problems and will test the person's hearing, eye movements, strength, coordination, involuntary movements (chorea), sensation, reflexes, balance, movement, and mental status, and will most likely order many lab entries as well. In some cases, the physician may ask the patient to have a brain imaging test.

What are the chances of a person with this disease passing the disease to their offspring?

Unfortunately the chances are very likely. Huntington's disease is a dominant gene so even if a one parent is heterozygous and the other one is homozygous recessive, there is still a 50% chance for the offspring to inherit this disease. If the parent is homozygous dominant instead of heterozygous there is 100% chance for the offspring to inherit the disease.

In this example one parent is homozygous dominant(HH) and the other parent is not affected at all(hh). All the offspring would all be heterozygous(Hh) for this disease. Since Huntington's disease is dominant, all the offspring would have this disease.

In this example, one parent is heterozygous for Huntington's(Hh) and the other parent is not affected at all by Huntington's(hh). There is a 50% chance of the offspring inheriting Huntington's disease in which case they would be heterozygous.

How prevalent is the disease in the population (include statistics)?

Huntington's disease is considered to be a "rare" disease in the United States and only 30,000 people in the U.S are affected by it. An estimated 150,000 more are at risk of inheriting it from a parent. About 3-7 out of 100,000 people of European ancestry are affected by Huntington's Disease.