Causes Of Huntington Disease

Huntington’s disease begins affecting the organs, it destroys the function of the multiple roles of the nervous system and the brain cells. The disease causes advanced deterioration and loss of brain cells, and contributes to a devastating loss of motor functions followed by advanced cognitive and intellectual impairment.

At present, there is no cure for the disease, but dynamic progress has been made as researchers explore this illness. HD is inherited as an autosomal dominant condition. In March 1993, scientists realized that HD is caused by a mutation in a gene located on chromosome 4. This gene has a unique genetic sequence for CAG (cytosine-adenine-guanine) and codes for the amino acid glutamine, a building block for the huntingtin pr otein. Normal individuals have this sequence duplicated from 11 to 40 times in their genetic coding without having symptoms of HD. However, individuals with the disease have from 40 up to 100 repeated CAG segments. Juvenile Huntington's Disease occurs wit h 60 or more repeats, linking the longer chains of CAG sequences to earlier and more aggressive onset of the disease.

According to aggregation kinetics, the rate of aggregation formation is dependent upon the amount of polyglutamine polypeptides. Aggregates in Huntington’s disease are formed from the mutant huntingtin fragments when the protein is cleaved at the N-terminal. This occurs after a conformation change into a β-sheet conformation. Huntingtin is cleaved by caspase, known for apoptosis, and calpain. Cleavage at caspase-3 sites and inhibited cleavage caspase-6 sites did not produce Huntington’s disease characteristics. Mutant huntingtin proteins contain more active calpains because of the increase in neurotransmitter – glutamate – release, enhancing NMDA-receptor activity. An increased glutamate level on spiny neurons was found to increase apoptosis in nerve cells. There are currently no treatment or cures for Huntington’s disease. However, new therapy ideas are centered on the inhibition of proteolytic cleavage.

4. “Huntington Disease - Genetics Home Reference.” U.S. National Library of Medicine, National Institutes of Health, ghr.nlm.nih.gov/condition/huntington-disease.

An increase in the size of the CAG segment leads to the production of an abnormally long version of the huntington protein. The elongated protein is cut into smaller, toxic fragments that bind together and accumulate in neurons, disrupting the normal functions of these cells. The dysfunction and eventual death of neurons in certain areas of the brain underlie the signs and symptoms of Huntington

DNA plays a role in in heritance by our genetic make-up. Genetics make us who we are. This means our eye color, hair color, and even our intelligence. 80% of genetics comes from our mother and father. That means that if your mother or father were different, you would be a completely different person (National Library of Medicine (U.S.), 2017, p.5-13).

Huntington’s disease is a neurological (nervous system) condition caused by the inheritance of an altered gene. A neurological disorder is a disease that can affect the central and peripheral nervous systems. Huntington’s disease is an incurable genetic brain disorder. The disease is an autosomal dominant disease, meaning a child only needs to inherit the gene from one parent to develop Huntington’s. Nerve cells become damaged when someone holds the HTT gene that produces a protein called huntingtin, as too much of this protein damages cells, and causes various parts of the brain to gradually deteriorate. Huntington’s disease causes changes in the central area of the brain, the basal ganglia, which can affect movement, emotions, and mental

It is a disease that progressively breaks down the nerves in the brain. The genetic mutation that underlies the disease is in chromosome 4. The gene codes for the huntingtin protein, which makes up about 6% of the DNA in cells (Genetic Home Reference). This mutation deals with the trinucleotide repeat of the cytosine-adenine-guanine (CAG) sequence. This sequence repeat can repeat up to 40 times to be considered normal, but after this sequence repeats more than 41 times then it is considered Huntington's disease. Huntington’s protein can form inclusions seen in both the cytoplasm and the nucleus (Suchowersky). These inclusions are correlated with neuronal cell death, which occurs within the nerves. Interestingly, Huntington protein seems to be very important for early development (Suchowersky), but in high concentrations appears to become toxic especially to nerve cells. Overall, Huntington’s disease has a very intense effect on the body and behavior

Huntington’s Disease is caused by a defective gene inherited from the parents, carried on chromosome 4. It is responsible for making ‘huntingtin’. Basically, it means that certain proteins needed to make brain chemicals are unable to make them in your brain as normal. This leads to damage and the death of some brain cells, called neurons, in the basal ganglia and the cortex, located in the brain. This leads to Huntington disease, and a buildup of dopamine, a chemical that is produced to make you feel good, contributes to the problem.

Human beings have two copies of genes that provide genetic information to produce Huntington, which is a protein. The two copies are usually labeled HTT (Hayes & Reichsman, 2009). A portion of this gene is as a result of a repetitive section referred to as a trinucleotide repeat that changes in terms of length from one person to the other, as well as between different generations. In case the repeat section of the gene is present in a gene that is considered healthy, then an active mutation might lead to an increment in the repeat sections, which might in turn lead to a gene that is defective (Marks & Neill, 2007). Subsequently, the length of the repeat portion might reach a given level where it leads to the production of altered and defective proteins

HD is a rare, progressive neurodegenerative disease which usually manifests itself between 30 and 45 years of age . It's characterised by a loss of motor control, jerky movements, psychiatric symptoms, dementia, altered personality and a decline in cognitive function. As the disease is adult onset, many people have already had children before they are diagnosed and have passed the mutant gene onto the next generation. In 1983, a genetic marker linked to HD was found on Chromosome 4, making it the first genetic disease to be mapped using DNA polymorphisms. However, the gene was not finally isolated until 1993

Huntington’s disease is caused by a mutation in the gene for a protein called huntingtin. The defect causes the cytosine, adenine, and guanine (CAG) building blocks of DNA to repeat many more times than is normal leading to a overproduction of this protein resulting

The Huntington disease is a condition inherited in an autosomal, dominant pattern, meaning one copy of the altered gene in each cell, sufficient to cause this disorder. The affected person inherits the altered gene from the affected parent. HTT gene is passed from generation to generation and when the CAG trinucleotide repeats over time, it increases in size. People with adult-onset with the form of the Huntington disease have around 40-50 CAG repeats in a HTT gene. People with a juvenile form of disorder have more than 60 CAG repeats, whilst an individual person have around 27-35 CAG repeats in a HTT gene which cannot develop the Huntington disease but have the risk of having children who will develop this disorder.

Huntington’s disease is a brain disorder, which is passed down from one generation to the next through irregular genes. Children who have parents suffering from Huntington’s disease have a 50% chance of having the gene that can later develop into the disease. The irregular genes are caused by a copying error in which a part of the gene is copied too many times. The disease slowly kills brain cells and causes a gradual progression in symptoms. Symptoms include things such as psychosis, hallucinations, involuntary movements, difficulty understanding things and confusion. In the early stages of Huntington’s disease symptoms are manageable, however as it progresses symptoms worsen and individuals can suffer memory loss and personality changes.

In 1972, George Huntington described an illness “Huntington’s Chorea” from the Greek work “Chorea” meaning dancing which is commonly refers to as Huntington Disease (HD) today. The movement made by the Huntington disease patients seems like a jerky dancing therefore it was refers as Huntington’s chorea (HC) 1 in every 10,000 people in United State of America (U.S.A.) suffers from hunting affecting male and female of all ethnicity and race equally but risk are higher for person’s in thirties or forties.. That approximately 30,000 people in the U.S.A., while more than 150,000 are at 50% risk of developing HD. HD is an inherited neurological, degenerative brain disorder which results in physical, mental, and emotional changes that affect