Alzheimer's disease (AD) is an neurodegenerative disease characterised clinically by progressive deterioration of memory and cognition and neuropathologically by the presence of extracellullar deposition of amyloid (senile plaques) and the accumulation of predominantly intracellular neurofibrillary tangles. The principal underlying cellular features of AD are the neurodegeneration and eventual loss of neuronal cells. The aetiology of the disease remains unclear and it is an accumulation of amyloid (Aβ) that is most commonly recognised as the clue feature in the pathogenesis of the disease. There are at least four genetic loci that are involved in the mechanism of AD. Researchers are hopeful that two recently discovered genes which cause familial forms of AD hold the key to understanding of the molecular basis of the disease. These genes, presenilin 1 and presenilin 2, are homologous in structure and one of them, localised on chromosome 14, is believed to cause the majority of familial AD cases. Mutations of these genes appear to be involved in the formation of neurotoxic β-amyloid (Aβ) peptides. Some other putative genetic loci are also taken into account, although their existence is now only speculative. The growing knowledge of AD genetics can potentially lead to the development of new treatment and prevention strategies.

Keywords: Alzheimer Disease, genetic diseases, Molecular pathology, neurodegeneration