Location And Cause
The early-form of Alzheimer's are caused by mutations on the genes APP, PSEN1, or PSEN2 on Chromosomes 1, 14, 19, 21. When any of these genes are altered, large amounts of a toxic protein fragment called amyloid beta peptide are produced in the brain. This peptide can build up in the brain to form clumps called amyloid plaques, which are characteristic of Alzheimer disease. A buildup of toxic amyloid beta peptide and amyloid plaques may lead to the death of nerve cells and the progressive signs and symptoms of this disorder.
Those who have Down syndrome appear to be at increased risk: Due to having an extra chromosome 21, those chromosomes also contain an extra APP gene, in their cells, they have an increased risk of obtaining a defective APP gene.
The late-form of Alzheimer's doesn't appear to have a specific run in families, but rather is related to variations of genes in combination with lifestyle and environmental factors. A gene called APOE seems to have some connection to it as a risk factor, with a variant of this gene called the e4 allele that seems to increase an individual's risk for developing late-onset Alzheimer disease
Those who have Down syndrome appear to be at increased risk: Due to having an extra chromosome 21, those chromosomes also contain an extra APP gene, in their cells, they have an increased risk of obtaining a defective APP gene.
The late-form of Alzheimer's doesn't appear to have a specific run in families, but rather is related to variations of genes in combination with lifestyle and environmental factors. A gene called APOE seems to have some connection to it as a risk factor, with a variant of this gene called the e4 allele that seems to increase an individual's risk for developing late-onset Alzheimer disease