Genetic Basis of Alzheimer’s Disease

Alzheimer’s disease, a progressive neurodegenerative and fatal disorder is the most common cause of dementia. It has been reported that 10% of the persons having the age more than 70 years have significant memory loss and more than half of them probably have this disease. This disease generally starts with mild symptoms and ends with a devastating brain damage. The two major neuropathology of this disease include neurotic plaques and neurofibrillary tangles of which the former appears earlier. Depending on the age of onset Alzheimer’s disease is categorized into early onset and late onset types. The victims of the early onset form of this disease comprise only 1-6% of the total cases. The major causes of the early onset type of this disease are the mutations mainly in two genes namely-APP and PSEN1. However, mutations in the gene PSEN 2 contribute to some extent also. Although the late onset Alzheimer’s disease has a genetic background, it is influenced by other factors, greatest of which is the age. However, recently genome wide association studies has identified some susceptible genes that can contribute also to late onset form of this disease.