Gene for early, aggressive Alzheimer's.An international team of scientists has discovered a gene for a rare, but very aggressive form of inherited Alzheimer's disease Alzheimer's disease (ăls`hī'mərz, ôls–), degenerative disease of nerve cells in the cerebral cortex that leads to atrophy of the brain and senile dementia. . The gene may be responsible for the majority of familial cases of Alzheimer's that strike before the age of 60.Alzheimer's usually sets in after age 65, but this early-onset form ravages rav·age v. rav·aged, rav·ag·ing, rav·ages v.tr. 1. To bring heavy destruction on; devastate: A tornado ravaged the town. 2. its victims in midlife mid·life n. See middle age. adj. Of, relating to, or characteristic of middle age. , affecting some people as early as their thirties. Even though this gene accounts for only a small percentage of all cases, its discoverers hope their work will aid understanding of the disease in all its forms. "The gene may not be mutated in other forms of Alzheimer's disease," says team member Peter St. George-Hyslop of the University of Toronto Research at the University of Toronto has been responsible for the world's first electronic heart pacemaker, artificial larynx, single-lung transplant, nerve transplant, artificial pancreas, chemical laser, G-suit, the first practical electron microscope, the first cloning of T-cells, . "But it probably does play some role." Previously, scientists had noted that mutations in the gene for apolipoprotein E apolipoprotein E A 34-kD cholesterol-binding glycoprotein, which comprises 15% of VLDL; apoE maps to chromosome 19, is secreted by macrophages that mediate the uptake of lipoproteins–VLDL, HDL, LDL and cholesterol esters into cells via distinct binding , found on chromosome 19 (SN: 8/14/93, p.108), played a role in some familial cases that begin after age 65. And mutations in the gene for beta-amyloid precursor protein, found on chromosome 21 (SN: 2/23/91, p.117), account for some early-onset cases of Alzheimer's. To find this third Alzheimer's gene, the team gathered genetic information from 21 families afflicted af·flict tr.v. af·flict·ed, af·flict·ing, af·flicts To inflict grievous physical or mental suffering on. [Middle English afflighten, from afflight, by the early-onset form of the disease. In six of those families, the researchers report in the June 29 Nature, mutations in the S182 gene on chromosome 14 account for up to 70 percent of all early-onset cases of Alzheimer's. What's more, the mutated gene amounts to a ticking ticking a coat color pigmentation pattern in which hairs of one color are distributed in small groups throughout the background color, e.g. Australian cattle dog. Called also speckling. time bomb; virtually all who inherit it will be stricken during midlife. How the mutation leads to Alzheimer's remains a mystery. The researchers speculate that the protein produced on instructions from the mutated gene may not process beta-amyloid precursor protein correctly. The finding will enable researchers to explore the function of the gene in animal models, St. George-Hyslop says. And because mutations in S182 occur in only 6 of the 21 early-onset families, he believes that research will uncover a few more genes associated with Alzheimer's. |
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