What Is Alzheimer’s?
In Alzheimer’s disease, changes to the brain cause increasing cognitive dysfunction called dementia. Alzheimer’s is characterized by an abnormal buildup of two peptides, or protein molecules, in the brain: beta-amyloid and tau.
Beta-amyloid accumulates between brain cells (neurons) to form plaques. Collections of tau proteins within brain cells form neurofibrillary tangles.
Alzheimer’s shares some overlap with other forms of dementia and cognitive deficits. Amyloid plaques and neurofibrillary tangles are sometimes observed in people with other neurodegenerative diseases, such as Parkinson’s disease. People with Alzheimer’s are also sometimes diagnosed with other forms of dementia, including vascular dementia. People with Down syndrome are also at increased risk for developing Alzheimer’s disease.
Beta-amyloid plaques and neurofibrillary tangles often begin in areas of the brain that are responsible for memory and then spread through the brain. This is why memory problems are often among the earliest noticeable symptoms of Alzheimer’s.
As plaques and tangles spread, they destroy nerve cells, shrink brain tissue, and cause worsening symptoms. Eventually, they lead to an inability to function independently and death.
What Causes Alzheimer’s?
The cause of Alzheimer’s disease is not well understood. Most cases of Alzheimer’s are believed to be caused by a combination of family history, lifestyle, and environmental risk factors.
In some rare cases, risk of Alzheimer’s is determined by inherited genes that make it extremely likely for a person to develop the disease. This genetic risk accounts for less than 1 percent of cases and often leads to early onset Alzheimer’s disease that occurs in middle age.
credit to myALZteam
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