Gene Therapy in Huntington’s

DiseaseProject was done by Rejan Chin & Sharisa Ford

What is Huntington’s disease?

Huntington's disease is a progressive, degenerative disease that causes certain nerve cells in your brain to waste away. As a result,

uncontrolled movements, emotional disturbances and mental deterioration can be experienced. Signs and symptoms usually develop in middle age. Younger people with Huntington's disease

often have a more severe case, and their symptoms may progress more quickly. Rarely,

children may develop Huntington's disease. Huntington's disease usually develops slowly, and the severity of signs and symptoms is related to

the degree of nerve cell loss.

Symptoms of Huntington’s• Personality changes, such as irritability, anger,

depression or a loss of interest• Decreased cognitive abilities, such as difficulty making

decisions, learning new information, answering questions and remembering important information

• Sudden jerky, involuntary movements (chorea) throughout your body

• Severe problems with balance and coordination• Jerky, rapid eye movements• Hesitant, halting or slurred speech• Dementia• Young people who develop Huntington's disease may

have signs and symptoms that mimic Parkinson's disease:

• Muscle rigidity• Tremors• Slow movements

How Huntington’s Affects the Gene

• Huntington's disease is an inherited condition caused by a single abnormal gene. the illness is referred to as an autosomal dominant disorder because only one copy of the defective gene, inherited from either parent, is necessary to produce the disease. If one parent has the single faulty gene, the chance that an offspring will have the defect is 50 percent.

• The Huntington gene, which makes the normal Huntington protein, is an essential component to healthy nerve cells, the mutant Huntington gene makes a toxic mutant Huntington protein. Mutant Huntington contains increased levels of the amino acid glutamine, which is generated by a repetition of the DNA triplet CAG.

What is Gene Therapy?

• Gene therapy is a therapy which switch off genes instead of adding new ones could slow down or prevent the fatal brain disorder Huntington's disease. The method, exploits a mechanism called RNA interference .

• Researchers in the United States say tests on mice have shown the treatment could be effective in humans, according to a report in New Scientist magazine. Instead of giving patients drugs to treat or control the symptoms of the disorder, doctors attempt to correct the underlying problem by introducing healthy copies of damaged or missing genes into some of the patient's cells.

• The treatment has shown little evidence until recently that it works. It has been shown to work in animals but there has been only limited success in humans.

• The scientists are confident that even where both genes are faulty they will be able to silence both and insert a new healthy gene.

• In addition, they have carried out tests on a similar disease using human cells and have found that the technique can help to reduce expression of the defective protein.

• In the case of Huntington's this could help to slow down the progress of the disease and reduce symptoms.

• "If you reduce levels of the toxic protein even modestly, we believe you'll have a significant impact," said Dr Davidson.

In conclusion, gene therapy has shown positive signs to be successful in the future for Huntington’s Disease but extensive studies will be needed before the technique could be tried in live patients.