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Alzheimer Gene

Summarized by PlexPage
Last Updated: 22 September 2020

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General | Latest Info

Alzheimer's Disease is a degenerative disease of the brain that causes dementia, which is gradual loss of memory, judgment, and ability to function. This disorder usually appears in people older than age 65, but less common forms of disease appear earlier in adulthood. Memory loss is the most common sign of Alzheimer's Disease. Forgetfulness may be subtle at first, but loss of memory worsens over time until it interferes with most aspects of daily living. Even in familiar settings, person with Alzheimer's Disease may get lost or become confused. Routine tasks such as preparing meals, doing laundry, and performing other household chores can be challenging. Additionally, it may become difficult to recognize people and name objects. Affected people increasingly require help with dressing, eating, and personal care. As the disorder progresses, some people with Alzheimer's Disease experience personality and behavioral changes and have trouble interacting in a socially appropriate manner. Other common symptoms include agitation, restlessness, withdrawal, and loss of language skills. People with this disease usually require total care during advanced stages of disease. Affected individuals usually survive 8 to 10 years after appearance of symptoms, but the course of disease can range from 1 to 25 years. Survival is usually shorter in individuals diagnosed after age 80 than in those diagnosed at a younger age. Death usually results from pneumonia, malnutrition, or general body wasting. Alzheimer's Disease can be classified as early - onset or late - onset. Signs and symptoms of early - onset form appear between person's thirties and mid - sixties, while late - onset form appear during or after person's mid - sixties. The early - onset form is much less common than the late - onset form, accounting for less than 10 percent of all cases of Alzheimer's Disease. Some cases of early - onset Alzheimer's Disease are caused by gene mutations that can be passed from parent to child. This results in what is known as early - onset familial Alzheimer's Disease. Researchers have found that this form of disorder can result from mutations in APP, PSEN1, or PSEN2 genes. When any of these genes is alter, large amounts of 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's Disease. Buildup of toxic amyloid beta peptide and amyloid plaques may lead to death of nerve cells and progressive signs and symptoms of this disorder. Other cases of early - onset Alzheimer's Disease may be associated with changes in different genes, some of which have not been identify. Some evidence indicates that people with Down syndrome have an increased risk of developing Alzheimer's Disease. Down syndrome, condition characterized by intellectual disability and other health problems, occurs when a person is born with 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.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Genetics and Alzheimers

In order to understand the genetics of Alzheimer's disease, it is first necessary to understand the basics of genetics. Most cells of the body have 46 chromosomes, grouped into 23 pairs. One member of each chromosome pair is inherited from each parent. Each chromosome is composed of deoxyribonucleic acid, genetic material that provides instructions for how the body grows and functions. Genes are segments of DNA found on each of our chromosomes. Each gene provides instructions for specific protein with a specific function. Certain variations within genes may lead to differences in individual traits. Other variations in gene sequence may be disease - causing. When a gene variant causes disease, it is often referred to as a mutation. Many studies have been carried out to identify gene variants associated with increased risk for developing AD. Two different types of variants have been identify: disease - causing mutations in individuals with early - onset familial AD and susceptibility variants in individuals with late - onset AD. Those with early - onset familial AD are likely to develop AD before the age of 65 and are likely to have family members who also have early - onset AD. These individuals account for less than 5% of all AD cases. Those with late - onset AD account for the vast majority of AD cases. Those with late - onset AD may or may not have a similar affect on family members. Mutations in three different genes have been identified in some individuals with early - onset familial AD. These genes are called amyloid precursor protein, presenilin 1, and presenilin 2. Mutations in these genes are inherited in autosomal dominant manner. A person who carries 1 copy of AD - related mutation in one of these genes has a 50% chance of passing it on to each of their children. A person who inherits a mutation in one of these genes will develop early - onset AD, most frequently before the age of 65 and sometimes as early as 30 years of age. Individuals who do not inherit mutation would not be expected to develop early - onset AD. However, they would continue to have the same risk of developing late - onset AD as anyone else in the general population. Approximately 1 in 9 adults over the age of 65 will develop late - onset AD, unrelated to mutation in APP, PSEN1, or PSEN2 genes. The vast majority of people diagnosed with AD have onset after the age of 65 years. These late - onset cases of AD are less likely to be caused by mutation in sequence of APP, PSEN1, or PSEN2 genes. Rather, individuals who develop AD later in life are more likely to have developed disease due to a combination of genetic and environmental risk factors. One gene, term apolipoprotein E, has been found to be an important risk factor for late - onset AD. Specific variants in this gene increase persona risk of developing AD; it does not guarantee that a person will develop the condition. Therefore, APOE is often referred to as a susceptibility gene.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Do Genes Cause Diseases?

Genetic mutations can cause diseases. If a person inherits a genetic mutation that causes a certain disease, then he or she will usually get the disease. Sickle cell anemia, cystic fibrosis, and some cases of Early - onset Alzheimer's disease are examples of inherited genetic disorders. Other changes or differences in genes, called genetic variants, may increase or decrease a person's risk of developing a particular disease. When a genetic variant increases disease risk but does not directly cause disease, it is called genetic risk factor. Identifying genetic variants may help researchers find the most effective ways to treat or prevent diseases such as Alzheimer's in individual. This approach, called precision medicine, takes into account individual variability in genes, environment, and lifestyle for each person. Expression of geneswhen they are switched on or offcan be affect, positively and negatively, by environmental and lifestyle factors, such as exercise, diet, chemicals, or smoking. The field of epigenetics is studying how such factors can alter cell's DNA in ways that affect gene activity.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Genes and Alzheimer's Disease

The vast majority of people with Alzheimer's Disease do not inherit it from parents as single - gene mutation with simple inheritance pattern. Instead, inheritance follows a more complex pattern. Disease might skip generation,sss affect people on both sides of the family, appear seemingly from nowhere or not be passed on at all. More than 20 gene variants have now been identified which affect - to different degrees - the chances of person developing Alzheimer's Disease. The effects of these genes are subtle. Different variants act to slightly increase or decrease the risk of person developing Alzheimer's Disease, but do not directly cause it. These risk genes interact with each other and with other factors, such as age and lifestyle, to influence someone's overall risk of getting disease.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Genetic Testing for Alzheimer's Disease

A Blood Test can identify which APOE alleles a person has, but results cannot predict who will or will not develop Alzheimer's disease. Currently, APOE testing is used primarily in research settings to identify study participants who may have increased risk of developing Alzheimer's. This knowledge helps scientists look for early brain changes in participants and compare the effectiveness of possible treatments for people with different APOE profiles. Genetic testing is also used by physicians to help diagnose early - onset Alzheimers disease and to test people with strong family history of Alzheimers or related brain disease. Genetic testing for APOE or other genetic variants cannot determine individuals ' likelihood of developing Alzheimer's diseasejust, which risk factor genes a person has. It is unlikely that genetic testing will ever be able to predict disease with 100 percent accuracy, researchers believe, because too many other factors may influence its development and progression. Some people learn their APOE status through consumer genetic testing or think about getting this kind of test. They may wish to consult a doctor or genetic counselor to better understand this type of test and their test results. General information about genetic testing can be found at:

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Alzheimer's Genetics Research

Genes can play a role in the development of dementia. However, their effects are complicated and how and whether dementia is passed down - patterns of inheritance - vary considerably. The importance of genes in different dementias varies considerably. For example, role of genes in frontotemporal dementia seems to be much greater than in vascular dementia. We all know how children often take after their parents or grandparents. This is in part because some things - physical characteristics, for example - are passed down to us from our parents in the form of about 20 000 different genes. It is important to understand that genes are only part of the picture. Whatever genes you may have inherit, most people can significantly reduce their chances of getting dementia through simple lifestyle choices.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Familial Alzheimer's disease

In just over 600 families worldwide, studies reveal many close family members who are affected by Alzheimer's Disease across successive generations. This pattern of familial clustering of Alzheimer's Disease suggests there is mutation within a single gene that causes disease. In these cases, mutation is being passed down in DNA from parent to child, across several generations. People with one of these extremely rare mutations tend to develop Alzheimer's Disease early, in their 30s, 40s or 50s. This is much young than the majority of people who develop disease. Studies of affected families show that their Alzheimer's Disease is usually caused by mutation in one of just three genes:

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Genes and Late-Onset Alzheimeras Disease

How could this happen to Bill? * Bills wife wipes her eyes with one hand as she recounts the history of her husband's slow cognitive decline. At age 73, having sold his small business and made plans for comfortable retirement, he started to show increased difficulty when trying to recall recent events. Finding the right word, too, became more of a problem and one day he had trouble finding his way home from an unfamiliar location. His wife insisted that he be evaluated for neurocognitive impairment. A Diagnosis of major neurocognitive disorder with probable Alzheimers disease was make. Bill and his wife told me that his mother had been diagnosed with Alzheimer's disease in her 70s. Is this a genetic disease? * Vignettes are fictionalized to protect the confidentiality of individuals whose stories inspire them. Bill was offered further evaluation and the findings of neurological examination, blood tests, and neuroimaging were consistent with the diagnosis of LOAD. A trial of cognitive enhancer medication was prescribe, and a program of diet, exercise, cognitive stimulation, and meaningful activity was plan. Late - onset suggests that testing for EOAD genes should be informative. Testing for APOE versions, which Bills ' wife request, is not generally recommended in absence of clear linked therapeutic consequence, but Bill later obtained this test on his own through a popular internet - based genetic testing service. He learnt that he Do indeed carry one E4 version and he encouraged his children to reduce their risk of cognitive decline through adopting a brain - healthy lifestyle.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Continued

Another strong risk factor is family history. Those who have parent,s brother or sister with Alzheimer's are more likely to develop the disease. The risk increases if more than one family member has an illness. When diseases tend to run in families, either heredity, environmental factors, or both, may play a role. Learn More: What does Alzheimer's do to the Brain? During the 1960s and 1970s, aluminum emerged as a possible suspect in causing Alzheimer's disease. This suspicion leads to concerns about everyday exposure to aluminum through sources such as cooking pots, foil, beverage cans, antacids and antiperspirants. Since then, studies have failed to confirm any role of aluminum in causing Alzheimers. Almost all scientists today focus on other areas of research, and few experts believe that everyday sources of aluminum pose any threat.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

EVALUATION STRATEGY

Three - generation family history with close attention to the history of individuals with dementia should be obtain. For each affected individual, age of onset of dementia should be NOTE. Generally, individuals with onset before age 65 years are considered to have early - onset AD and those with onset after age 65 years are considered to have late - onset AD. Medical records of affected family members, including reports of neuroimaging studies and autopsy examinations, should be obtain. Diagnosis of EOFAD is made in families with multiple cases of AD in which the mean age of onset is before age 60 - 65 years. Diagnosis of late - onset FAD is made in families with multiple cases of AD in which the mean age of onset is after age 60 - 65 years.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

Sources

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions.

* Please keep in mind that all text is machine-generated, we do not bear any responsibility, and you should always get advice from professionals before taking any actions

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