What Are the Causes of Alzheimer’s Disease?

The statistics says that by 2016 more than 40 million people had Alzheimer’s disease or related dementia. In America Alzheimer’s disease is considered to be the sixth leading cause of death. In spite of the fact that this disease is so wide-spread, the scientists unfortunately still can name only possible causes of dementia.

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Alzheimer’s disease is a chronic, fatal disease which leads to the death of cells of the temporal and parietal areas of the cerebral cortex. It causes the loss of memory and severe disorders of intelligence, orientation in time and space, as well as to serious changes in the personality of the patient. The risk of getting the disease is higher for people over 65 years old, but the medicine knows the cases when people struggled with Alzheimer’s disease in even earlier age. Nowadays the scientists cannot clearly state what the factors that cause dementia are.

Is the key in our brain?

The most evident manifestation of Alzheimer’s disease is decline of the ability to remember new information. It happens because the number of neurons and their connections in regions of the brain that are responsible for keeping new information reduces. The scientists say that the problem lays in accumulation of two types of protein. They are beta-amyloid that is accumulated outside the neurons and tau protein which is stored inside of neurons of the brain. These accretions in brain tissues cause disorders of neural connections and death of cells, which leads to degeneration of the brain substance.

Amyloid plaques form in the tissues of the hippocampus and then gradually spread in the entire brain that prevents it from proper functioning. Amyloid increases the concentration of calcium in brain cells that cause their death. But despite the reliability of data about the influence of beta-amyloid, the cause of its accumulation in the brain tissues is unknown. And, thus, no medicines that can prevent the accumulation of amyloid or promote its resorption have been invented yet.

Also Alzheimer himself studying the brain of one of his patients after their death noticed neurofibrillary tangles that consisted of an insoluble tau protein, which also disrupts the normal functioning of the brain. Unfortunately the causes of formation of such tangles are not clear and because of that their appearance cannot be prevented.

Can genetics be a reason?

The studies show that Alzheimer’s disease can be inherited from close relatives. Many people who struggle this disease say that they had or have a person in their family with the same disorder.

Genes have the information about our body structure. Some genes may have variations and even change, thus, leading to the development of certain diseases. Serious damage of genes can lead to appearance of so-called mutations. Genetics say that mutations in the 1st, 14th, 19th and 21st chromosomes can cause Alzheimer’s disease. Each of these mutations influences the breakdown of amyloid precursor protein.

It is stated that if a person inherits any of the mutation in the above stated chromosomes the risk to get early-onset Alzheimer’s disease is higher. It means that the symptoms of the pathology can manifest themselves when the person is over 30 years old.

There is still no clear information about the reasons of Alzheimer’s disease and that’s why no medicine which can cure people of this pathology can be invented. People still have to live and die because of progression of the disease. But we hope that due to fast development of technologies this pathology will be claimed curable and will leave the chart of the most common causes of death.

References:

What Causes Alzheimer’s Disease? – National Institute on Ageing
APOEε2 is associated with milder clinical and pathological Alzheimer’s disease – US National Library of Medicine
2014 Alzheimer’s Disease. Facts and Figures – Alzheimer’s Association
2016 Alzheimer’s Statistics – Alzheimer’s.net
World Alzheimer Report 2016 – Alzheimer’s Society
What Is Alzheimer’s – Alzheimer’s Association
Is Alzheimer’s Disease Genetic? – WebMed
Genetics of dementia – Alzheimer’s Society

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