Huntingtin

The HTT gene was known as the IT15 (interesting transcript 15) which codes for a protein called the huntingtin protein (Htt) (Interesting Transcript 15). This gene has a repeated section called a trinucleotide repeat which is combined to make a codon (Huntington Disease). A codon has three bases on an mRNA molecule that code for a particular amino acid. While a normal person has less than 26 repeated codons, a person with this disease has more (Interesting Transcript 15). When the length of this repeated section reaches more than 36 consecutive series, it produces an altered form of the protein, mutant Huntingtin protein (mHtt). This type of mutation changes the decay rate for certain neurons (Interesting Transcript 15). The gene only affects some neurons and hence not all of the parts of the brain. Depending on how many repeated codons the person has it will determine the severity of the disease. A person with 40 or more repeated codons for this gene will have a severe Huntington disease (Huntington Disease). While the primary purpose for the Huntingtin protein (Htt) is unclear, it certainly interacts with proteins found in cell signaling, intracellular transporting and transcription (Interesting Transcript 15). There are multiple cellular changes through which the wrong function of mHtt may manifest and produce the…

Pathophysiology Huntingtin is a protein whose exact function is unknown. What is understood about it though is how important of a part it serves for the nerve cells in the brain (HTT, 2016). When the gene HTT that codes for this protein becomes mutated (mHTT), it causes what is known as Huntington disease (HD). This is an autosomal dominant disorder meaning only a single gene needs to be altered in order to cause this disease (Huntington disease, 2016). If there is one parent affected, each…

Huntington’s disease is a continuous brain disorder that is the source of involuntary motion, emotional and mental instability as well as cognition damage. It is an inherited disorder relatively common in adults aged thirty to forty. People of European decent typically have a higher chance of being born with the gene that causes HD, while those of Asian and African background have a lower probability. For HD to be developed only one copy of the mutated huntingtin (HTT) gene must be inherited.…

In 2001, Auerbach et al. studied the effect of mutation in HD when the protein huntingtin was limiting. Generally, the study showed that there were lethal neurological effects observed in the heterozygous Hdh knock-in mice with low levels of mutant huntingtin containing 111 glutamines (Q111) and 20 glutamines (Q20). They also found out that there were brain deficits and abnormal development with the mice having low level of Q20 huntingtin in the absence of Q111. Together, the study showed a…

egg. The cause of these spontaneous mutations is still unknown (Payne, 2016). Huntington’s disease is traced back to the fourth chromosome where the Huntington’s disease gene is located. This gene codes for the protein huntingtin (National Human Genome Research Institute, 2011). Symptoms displayed in Huntington’s disease patients are caused by a repeat expansion of the DNA building blocks cytosine, adenine, and guanine (CAG) (United States National Library of Medicine, 2016). In an effective…

Some researchers have specialized in the CAG repeats. Others have focused on the protein, huntingtin, and how it ties into our functioning body. Others take a look at the deconstruction of certain parts of the brain and try to work backwards. For many Huntington’s disease patients it is just a trial and error to try and find a set of drugs that can help manage some of the symptoms without making any of the other ones worse. Usually medicine will consistently be adjusting over the course of the…

mutation caused by a (CAG) trinucleotide repeat within the Huntingtin gene (HTT) on Chromosome 4 [6]. Due to the dominant inheritance pattern of this disease, offspring have a 50% risk of inheriting the disease [7]. HD affects both sexes equally (as seen in figure 1) [8], and manifests itself in all races and ethnic groups around the world. Due to the unstable mutations within the disease gene, ‘anticipation’ typically occurs with the disease manifesting itself earlier and more severely with…

(7, 8) Excessive number of repeats in CAG chain results in mutation that leads to the development of HD.(7) The CAG repeat is located within the coding sequence. It is then translated and transcribed with the rest of the gene, giving rise to a polyglutamine array which is a protein known as huntingtin (HTT).(2, 8) The abnormal HTT produced from the mutated gene forms inclusions within neurons leading to their death.(2, 7) HTT consist of repeated units of about 50 amino acids, termed HEAT repeats…

locate and enter the neurons in order to silence huntingtin expression (Dessy and Gorman 2011). Another drawback observed is the fact that high dosages of silencing molecules could have a toxic effect on the cells. This shows how imperative it is to find an ideal dosage that is both safe and effective. As mentioned above, researchers still face challenges with specificity and off target effects for neurodegenerative diseases such as Huntington’s disease (HD). When applying gene silencing as…

Huntington’s is an inherited disease that targets the brain’s function. The disorder takes over and kills parts of the brain causing the individual with the disease to lose motor function, memories and the ability to rationalize. The defect occurs in a single gene and because Huntington’s is an autosomal dominates disorder the offspring only needs one copy of the abnormal gene to possibly develop the disease. The Huntington’s mutation occurs in the HTT gene, this gene controls the production…