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Disease Profile

Lewy body dementia

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.



US Estimated


Europe Estimated

Age of onset





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


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.


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.


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


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.


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.


Not applicable


Other names (AKA)

Lewy body disease; DLB; Diffuse Lewy body disease;


Lewy body dementia is one of the most common forms of progressive dementia. People affected by this condition may experience a variety of symptoms such as changes in alertness and attention; hallucinations; problems with movement and posture; muscle stiffness; confusion; and/or memory loss. Although the exact cause of Lewy body dementia is poorly understood, symptoms are thought to result when clumps of a protein called alpha-synuclein ("Lewy bodies") accumulate in the brain. Lewy body dementia usually occurs sporadically in people with no family history of the condition. Rarely, more than one family member may be affected. There is currently no cure for Lewy body dementia; however, medications may be available to help manage the associated symptoms.[1][2][3]


This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance
Dementia, progressive
Progressive dementia

[ more ]

Fluctuations in consciousness
Lewy bodies
Visual hallucinations


The exact underlying cause of Lewy body dementia is poorly understood. The symptoms of the condition are thought to occur when clumps of a protein called alpha-synuclein accumulate in the regions of the brain involved in thinking, memory and movement. The build-up of these clumps (which are called "Lewy bodies") appears to be associated with a loss of certain neurons (nerve cells) in the brain that produce two important neurotransmitters (chemicals that act as messengers between brain cells). The neurotransmitter, acetylcholine, is important for memory and learning. The other, dopamine, plays an important role in behavior, cognition, movement, motivation, sleep, and mood.[4]

Although Lewy body dementia usually occurs sporadically, more than one family member can rarely be affected. Studies of these families suggest that there may be a genetic component to the condition in some cases. For example, copy number variants or changes (mutations) in the SNCA gene have been reported in a few affected families.[5][6] The APOE ε4 allele and mutations in the GBA gene have been associated with an increased risk of Lewy body dementia and the APOE ε2 allele with a decreased risk.[5][7][2]


Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.


    The Lewy Body Dementia Association offers detailed and up-to-date information regarding the treatment and management of Lewy body dementia. Please click on the link to access this resource.


    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 Lewy body dementia.
      • MedlinePlus was designed by the National Library of Medicine to help you research your health questions, and it provides more information about this topic.
      • The National Institute of Neurological Disorders and Stroke (NINDS) collects and disseminates research information related to neurological disorders. Click on the link to view information on this topic.
      • 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.

        In-Depth Information

        • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
        • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
        • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
        • PubMed is a searchable database of medical literature and lists journal articles that discuss Lewy body dementia. Click on the link to view a sample search on this topic.


          1. Dementia With Lewy Bodies Information Page. National Institute of Neurological Disorders and Stroke (NINDS). November 2015; https://www.ninds.nih.gov/Disorders/All-Disorders/Dementia-Lewy-Bodies-Information-Page.
          2. Crystal HA. Dementia With Lewy Bodies. Medscape Reference. April 2014; https://emedicine.medscape.com/article/1135041-overview#a4.
          3. Lewy Body Disease. MedlinePlus. October 2015; https://www.nlm.nih.gov/medlineplus/lewybodydisease.html.
          4. Lewy Body Dementia: Information for Patients, Families, and Professionals. National Institute on Aging. September 2015; https://www.nia.nih.gov/alzheimers/publication/lewy-body-dementia/introduction.
          5. DEMENTIA, LEWY BODY. OMIM. December 2012; https://www.omim.org/entry/127750.
          6. Farlow MR. Epidemiology, pathology, and pathogenesis of dementia with Lewy bodies. UpToDate. January 2015; https://www.uptodate.com/contents/epidemiology-pathology-and-pathogenesis-of-dementia-with-lewy-bodies.
          7. Dementia with Lewy body. Orphanet. December 2012; https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=1648.

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