Genetically Linked, Or Early Onset Of Alzheimer Disease ( Fad )

1013 Words Oct 22nd, 2016 5 Pages
Genetically linked AD, or early-onset familial Alzheimer disease (FAD), is linked to three gene defects: amyloid precursor protein (APP) on chromosome 21, presenilin 1 (PSEN1) on chromosomes 14, and presenilin 2 (PSEN2) on chromosome 1 (McCance & Heuther, 2014). Mutations in APP, PSEN1, and PSEN2 lead to FAD by increasing the rate that the brain produces a peptide called beta amyloid (Kumar, Abbas, & Aster, 2013). The overproduction of beta amyloid leads to: neuritic plaques, neurofibrillary tangles, and neuronal and synaptic loss within the brain (McCance & Heuther, 2014).
The most common form of AD, sporadic AD, is associated with progressive loss of brain cells (McCance & Heuther, 2014). The cellular pathologic mechanisms for early-onset AD and late-onset AD are the same. As human’s age the cells in the brain die and a build-up of beta-amyloid proteins, referred to as neuritic plaques, form between the dead or dying cells (McCance & Heuther, 2014). As neuritic plaques build-up, the tau protein within the neuron detaches, and forms neurofibrillary tangle, which leads to neuron death (McCance & Heuther, 2014). Consequently, as plaques and tangles accumulate within the cerebral cortex and hippocampus, the sulci widen and the gyri thin, the ventricles enlarge to fill the empty space, and the brain atrophies losing weight and volume (McCance & Heuther, 2014).
Body Systems Level Alzheimer disease affects many different body systems, including the central nervous system…

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