Research led by Rensselaer Polytechnic Institute researcher Chunyu Wang, has recently revealed molecular processes behind the genetically heritable Familial Alzheimer' Disease, which leads to memory loss and general deterioration of the brain, which is deadly to the patient with the condition. The researchers studied two mutations that are known to cause Familial Alzheimer' Disease: V44M and V44A sequences. These cause composition changes in the brains.
Two polypeptide chains: Amyloid Beta-42 (42 amino acids long) and Amyloid Beta-40 (40 amino acids long), are found in about a 1 to 9 ratio in a normal brain. However, Amyloid Beta-42 which is 2 amino acids longer than Amyloid Beta-40, is much more lethal for the brain, and is responsible for memory failure. Patients with Familial Alzheimer' Disease have a much higher ratio of Amyloid Beta-42 to Amyloid Beta-40 in the brain.
The way an orginal polypeptide chain, amyloid precursor protein(APP) is processed, determines the ratio of resulting Amyloid Beta-42 to Amloid Beta-40. Normally, an enzyme called γ-secretase cuts the protein in such a way that Amyloid Beta-40 is more inclined to be produced. However, the V44M and V44A mutations change the amyloid precursor protein, so that when it is cut by γ-secretase, the cut happens in a slightly different place, resulting to production of the lethal Amyloid Beta-42 polypeptide.
Basically, APP is cut differently due to mutations, and the result is the memory-failure-inducing Amyloid Beta-42 in higher ratios.
The study describes a way in which a phenotype is changed based on a mutation, thus it relates to the topic of molecular genetics. The study additionally describes how the trait of having Familial Alzheimer' Disease is inheritable, or able to be passed from one generation to the next. Also, how such a trait could possibly play a role in evolution as a genetic disease does relate to the study of evolution, and the resulting lack of evolutionary fitness of people with the disease.
How might this help in treating Alzheimer's?
ReplyDeleteWhile identifying the processes from mutation to FAD, this study can help patients avoid passing on the mutation by labeling them positive, or negative for the mutation (DNA analysis). And if patients do genetically contain these mutations, there can be therapies applied to help manage the effect on the brain. Even though this type is genetic, and laws prohibit the genetically modifying of humans, treatments as shown in the following article covers up treatment of general Alzheimer' Disease. http://www.nytimes.com/health/guides/disease/alzheimers-disease/overview.html (scroll down to the section labeled 'treatments')
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