Question: How many people are affected by Alzheimer disease ?
Answer: Alzheimer disease currently affects an estimated 2.4 million to 4.5 million Americans. Because the risk of developing Alzheimer disease increases with age and more people are living longer, the number of people with this disease is expected to increase significantly in coming decades.
Source: GHR

Question: What are the genetic changes related to Alzheimer disease ?
Answer: Most cases of early-onset Alzheimer disease are caused by gene mutations that can be passed from parent to child. Researchers have found that this form of the disorder can result from mutations in one of three genes: APP, PSEN1, or PSEN2. When any of these genes is 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. Some evidence indicates that people with Down syndrome have an increased risk of developing Alzheimer disease. Down syndrome, a condition characterized by intellectual disability and other health problems, occurs when a person is born with an extra copy of chromosome 21 in each cell. As a result, people with Down syndrome have three copies of many genes in each cell, including the APP gene, instead of the usual two copies. Although the connection between Down syndrome and Alzheimer disease is unclear, the production of excess amyloid beta peptide in cells may account for the increased risk. People with Down syndrome account for less than 1 percent of all cases of Alzheimer disease. The causes of late-onset Alzheimer disease are less clear. The late-onset form does not clearly run in families, although clusters of cases have been reported in some families. This disorder is probably related to variations in one or more genes in combination with lifestyle and environmental factors. A gene called APOE has been studied extensively as a risk factor for the disease. In particular, a variant of this gene called the e4 allele seems to increase an individual's risk for developing late-onset Alzheimer disease. Researchers are investigating many additional genes that may play a role in Alzheimer disease risk.
Source: GHR

Question: Is Alzheimer disease inherited ?
Answer: The early-onset form of Alzheimer disease is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person inherits the altered gene from one affected parent. The inheritance pattern of late-onset Alzheimer disease is uncertain. People who inherit one copy of the APOE e4 allele have an increased chance of developing the disease; those who inherit two copies of the allele are at even greater risk. It is important to note that people with the APOE e4 allele inherit an increased risk of developing Alzheimer disease, not the disease itself. Not all people with Alzheimer disease have the e4 allele, and not all people who have the e4 allele will develop the disease.
Source: GHR

Question: What are the treatments for Alzheimer disease ?
Answer: These resources address the diagnosis or management of Alzheimer disease: - Alzheimer's Disease Research Center, Washington University School of Medicine - Gene Review: Gene Review: Alzheimer Disease Overview - Gene Review: Gene Review: Early-Onset Familial Alzheimer Disease - Genetic Testing Registry: Alzheimer disease 2 - Genetic Testing Registry: Alzheimer disease, type 3 - Genetic Testing Registry: Alzheimer disease, type 4 - Genetic Testing Registry: Alzheimer's disease - MedlinePlus Encyclopedia: Alzheimer's Disease - Michigan Alzheimer's Disease Research Center - University of California Davis Alzheimer's Disease Center These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
Source: GHR