Oct 28, 2011

Alzheimer’s and Relationship to Other Diseases

Alzheimer's Reading Room


Is there a correlation between Alzheimer’s and Parkinson’s disease? Lewy Body disease?

Lewy body disease involves the abnormal accumulation of a different protein in the brain called alpha-synuclein, which also accumulates in the brains of Parkinson’s patients.

Often the alph-synuclein lesions called Lewy bodies are observed along with A-beta deposits, e.g. plaques and tangles in Alzheimer’s disease.

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What is the link between Diabetes and Alzheimer’s?

Type 2 diabetes and AD share a broad array of disease features and a large body of evidence accrued over the last 60 years suggests the pathologies of these two disorders are strongly linked. However, as yet no common molecular mechanism has been identified that can explain the epidemiological commonalities between diabetes and AD. The link between the two diseases was made even stronger when in 1987 the death of pancreatic islet cells (the cells that make insulin) was associated with amyloid deposition. Thus, both diabetes and AD are amyloid diseases. However, the amyloid in diabetic pancreas is not made from A-beta but another peptide called amylin. There are striking similarities between amylin and Abeta. Despite the discovery of amylin, the specific disease mechanisms common to these two epidemic diseases remains elusive.

Given the link between Alzheimer’s and diabetes, should this connection become better known as we work to reduce Type 2 Diabetes? Isn’t this a major public health issue?

Huge public health issue. We know that factors affecting the onset of diabetes are increasing the prevalence of the disease, and to the extent that this exacerbates or accelerates any relationship to Alzheimer’s disease, the implications are truly frightening on a societal basis. As learn more about the inter-relationship of these diseases and how behavior can affect their onset, public health/awareness campaigns on the level of the “Stop Smoking” efforts are certainly warranted.

Given the link between diabetes and Alzheimer’s, is there a higher prevalence of Alzheimer’s in certain populations? E.g. African Americans have a higher incidence of diabetes; does that population therefore have a higher incidence of Alzheimer’s disease?

This suggested link had not been established in published data.

Down Syndrome

Can you comment on how Alzheimer’s disease correlates with Down Syndrome? Do individuals with Down Syndrome have more A-beta genes located on the Trisomy 21 gene?

Down's syndrome involves an extra copy of the APP gene- as would be predicted if A-beta is the culprit in AD, a dose response is observed for Down's patients with all showing early AD pathology- with the exception of a rare form in which the part of chromosome 21 containing the APP gene is not duplicated. These Downs patients do not show AD pathology. This is good evidence of the key role of A-beta in AD.

Source Cure Alzheimer's Fund Taking Control of Alzheimer’s Through Research

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Original content Bob DeMarco, the Alzheimer's Reading Room