Rare Endocrinology News

Disease Profile

Alzheimer disease

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

Unknown

Age of onset

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ICD-10

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Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

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Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Summary

Alzheimer disease (AD) is a degenerative disease of the brain that causes gradual loss of memory, judgment, and the ability to function socially. Alzheimer disease currently affects about 5 million people.[1] About 75 percent of Alzheimer disease cases are classified as sporadic, which means they occur in people with no history of the disorder in their family. Although the cause of these cases is unknown, genetic changes are likely to play a role. Virtually all sporadic cases of Alzheimer disease begin after age 65, and the risk of developing this condition increases as a person gets older.[2]

AD can be subdivided into two groups based on the age of onset:[3]
(1) Early-onset (1%-6% of the cases) which start in people younger than 6065 years of age
(2) Late-onset, which starts in people older than 65 years old.

In about 25% of cases, AD is familial (2 or more people in a family have AD). For more information, please visit GARD's familial Alzheimer disease Web page.

Organizations

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Learn more

    These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

    Where to Start

    • Mayo Clinic has an information page on Alzheimer disease.
    • Genetics Home Reference (GHR) contains information on Alzheimer disease. This website is maintained by the National Library of Medicine.
    • The National Institute on Aging (NIA) leads a national program of research on the biomedical, social, and behavioral aspects of the aging process; the prevention of age-related diseases and disabilities; and the promotion of a better quality of life for all older Americans. Click on the link to view information on this topic.
    • The National Institutes of Health (NIH) has developed a fact sheet on Alzheimer's disease. To view this fact sheet, click on the link above.

      In-Depth Information

      • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
      • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
      • PubMed is a searchable database of medical literature and lists journal articles that discuss Alzheimer disease. Click on the link to view a sample search on this topic.

        References

        1. Alzheimer Disease. Genetics Home Reference. May, 2013; https://ghr.nlm.nih.gov/condition=alzheimerdisease. Accessed 9/30/2015.
        2. Alzheimer's Facts and Figures. Alzheimer's association. 2015; https://www.alz.org/alzheimers_disease_facts_figures.asp. Accessed 9/30/2015.
        3. Alzheimer Disease Overview. GeneReviews. September 24, 2015; https://www.ncbi.nlm.nih.gov/books/NBK1161/. Accessed 9/30/2015.