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The causative gene (which is one of the first identified to cause an inherited disease) is located on chromosome 4. The product of this gene is a 350KDa cytoplasmic protein called huntingtin . The continuous aggregation of huntingtin molecules in neuronal cells gives rise to cell death, especially in the frontal lobes and the basal ganglia (mainly in the caudate nucleus) by some unknown mechanism. Huntingtin has a characteristic sequence of 40 or fewer glutamine (CAG amino acid) residues in the normal form; the mutated huntingtin causing the disease has more than 40 residues.
While theories as to how the mutation brings about disease remain diverse and speculative, researchers have identified many specific subcellular abnormalities associated with the mutant protein, as well as unusual properties of the protein in vitro. Just as one example, in 2001, Max Perutz discovered that the glutamine residues form a nanotube 1 in vitro, and the mutated forms are long enough in principle to pierce cell membraneA component of every biological cell, the cell membrane (or plasma membrane is a thin and structured bilayer of phospholipid and protein molecules that encapsulate the cell. It separates a cell's interior from its surroundings and controls what moves in as.
Symptoms of Huntington's disease onset increasingly early the more glutamines a person carries within the repeating portion of their mutant huntingtin proteins. This number increases as the disease gene is passed on, so that the age of onset decreases with successive generations (although not infinitely early, since patients with childhood symptoms tend not to have children themselves). Currently most Huntington's patients start to show symptoms in the 4th decade of life. These symptoms include the loss of cognitive abilities, changes in personalityIn psychology, personality is a collection of emotion, thought, and behavior patterns unique to a person. There are several theoretical perspectives on personality in psychology, which involve different ideas about the relationship between personality and, quick jerking movements of face and body (i.e. chorea) and unsteadiness of gaitA gait can refer to: a particular way or manner of moving on foot: walking and running are the two basic human gaits; see also gait analysis and Gait (human). horse gaits: any of the ways, such as a canter, trot, or walk, by which a horse can move by lift. The diagnosis is established by neurological examination findings and demonstration of cell loss, especially in the caudate nucleus, supported by a cranial CTComputed axial tomography (CAT computer-assisted tomography computed tomography CT or body section roentgenography is the process of using digital processing to generate a three-dimensional image of the internals of an object from a large series of two-di or MRI scan findings.
Although dopamineDopamine is a neurotransmitter in the brain. As a member of the catecholamine family, dopamine is a precursor to epinephrine ( adrenaline) and norepinephrine ( noradrenaline) in the biosynthetic pathways for these neurotransmitters. Dopamine is synthesize receptor blockers may have restricted benefits, there is no definite treatment for disease. In 2004 it was found that a simple sugarThis article deals with sugar as food and as an important, widely traded commodity; the word also has other uses; see Sugar (disambiguation A sugar is a form of carbohydrate; the most commonly used sugar is a white crystalline solid, sucrose; used to alte called trehalose can alleviate symptoms in genetically modified mice giving hope for a treatment.