Huntington Disease

Question: Huntington Disease? For my genetics class we have to give a presentation on different genetic disorders. My topic is Huntington Disease. Is the type of mutation that causes HD considered an expansion mutation????? Also, does anyone know a website that explains SIMPLY the mechanism of action of the normal protein and how its disrupted by the defect in the disease??? HELP!

Answer: Is the type of mutation that causes HD considered an expansion mutation? Yes. The gene involved in Huntington's disease is located on the short arm of chromosome 4. In the first part (5'end) of the HD gene, there is a sequence of three DNA bases, cytosine-adenine-guanine (CAG), that is repeated multiple times (i.e. ...CAGCAGCAGCAG...); this is called a trinucleotide repeat. CAG is the genetic code for the amino acid glutamine, thus a series of CAG forms a chain of glutamine known as polyglutamine or (polyQ). A polyQ length of less than 36 glutamines, produces a cytoplasmic protein called huntingtin protein (Htt), whereas a sequence of 40 or more produces an erroneous form of Htt, mHtt (standing for mutant Htt). Also, does anyone know a website that explains SIMPLY the mechanism of action of the normal protein and how its disrupted by the defect in the disease? Sorry, but it isn't a well-understoon protein. Like all proteins, Htt and mHtt are translated, perform or affect biological functioning, and are finally cleared up in a process called degradation. The exact mechanism in which mHtt causes or affects the biological processes of DNA replication and programmed cell death (apoptosis) remains unclear, so research is divided into identifying the functioning of Htt, how mHtt differs or interferes with it, and the effects of remnants of the protein (known as aggregates) left after degradation. This is the best description I've found, but it is quite long: http://www.stanford.edu/group/hopes/caus…

Question: huntington disease? how is huntington disease tranmitted genetically what are the gene called basically?

Answer: American doctor George Huntington first described the disorder in 1872. Huntington's disease is a disorder passed down through families in which nerve cells in the brain waste away, or degenerate. Huntington's disease is caused by a genetic defect on chromosome #4. The defect causes a part of DNA, called a CAG repeat, to occur many more times than it is supposed to. Normally, this section of DNA is repeated 10 to 35 times. But in persons with Huntington's disease, it is repeated 36 to 120 times. As the gene is passed on from one generation to the next, the number of repeats - called a CAG repeat expansion - tend to get larger. The larger the number of repeats, the greater your chance of developing symptoms at an earlier age.

Question: Is it possible for a person to have two dominate alleles for huntington disease? If this is possible than would they have a 100% chance of passing huntington disease on to their children?

Answer: I don't think so, I am not sure one person can have a100% chance.

Question: Huntington disease is governed by autosomal dominant inheritance. What is the likelihood that a person who has Huntington disease is governed by autosomal dominant inheritance. What is the likelihood that a person who has one heterozygous affected parent and one normal parent will develop the disease? a) 50% b) 75% c) 0% (impossible) d) 100% (certain)

Answer: a) 50 % Because a child receives one gene from each parent. The heterozygous affected parent has one normal gene and one affected gene. This parent must give one of the two to his/her child, therefore, the probability is 50%.

Question: Can restriction enzymes be used to treat huntington disease? If you have a, lets say, a 60bp (GTCx20) restriction enzyme, which will cut out 20 triplet codons CAG (huntington disease), will the person be cured if given to all cells? In huntington the tripket repeats are over 45 maybe more, so the idea was cutting out 20 or more and leave enough for proper functioning of protein. I am not sure if there are other genes that has this many repeats of CAG.

Answer: Sure it WOULD work if there were means to deliver it to each cell, ensure 100% restriction efficiency & specificity, and ligate the DNA nick afterwards. So far it is sci-fi; prenatal diagnostics is the way to go for now.

Question: 1. If a man had a father who died of Huntington’s disease (an autosomal dominant trait) and a mother who is st 1. If a man had a father who died of Huntington’s disease (an autosomal dominant trait) and a mother who is still alive at an advanced age, what is the probability that the man will also die of Huntington’s?

Answer: 50/50 heredity factor...................and then again, it can skip a generation............

Question: What are the pros and cons of knowing that their is a possibility to carry the gene for Huntington Disease? Should insurance companies be informed of genetic disease that runs in a family? Why or Why not

Answer: I don't think they would unless you told your doctor how could they. I would say get insured then get the genetic test done. I have a friend in this boat as well.

Question: How does trinucleotide repeat mutation cause the symptoms in Huntington disease? Any help or info about it would be greatly appreciated. Please do not copy or paste a lot of Wikipedia stuff. thank you.

Answer: Trinucleotide repeat disorders that is a genetic malfunction essentially. It is when the trinucleotide repeats in certain genes exceeding the normal, stable, threshold, which differs per gene. The mutation repeats itself. If the repeat is present in a healthy gene, a dynamic mutation may increase the repeat count and result in a defective gene. Huntington’s disease (HD) and the spinocerebellar ataxias (and this is a a group of genetic disorders characterized by slowly progressive loss of coordination when you walk and often associated with poor coordination of hands, speech, and eye movements which you see in Huntingtons) that are caused by a repeat expansion in protein-coding portions of specific genes.

Question: Are strokes and cancer symptoms of Huntington's disease? Are strokes and cancer symptoms of Huntington's disease?

Answer: A stroke is a symptom of cancer in extreme cases. But honestly, I don't think cancer and Huntington's is related.

Question: what category of mutation that causes Huntington disease? what is the mutation disorder for this disease? what is a karyotype of Huntington disease? pictures plz..

Answer: Read here. Hope it helps.