Gene Linking Cataracts and Alzheimer's Disease Identified

A gene linking age-related cataracts and Alzheimer's disease has been identified in a recent study by researchers at Boston University Schools of Medicine (BUSM) and Public Health (BUSPH).

The findings, published online in PLoS ONE, contribute to the growing body of evidence showing that these two diseases, both associated with increasing age, may share common etiologic factors.

Gyungah Jun, PhD, from the departments of medicine, ophthalmology and biostatistics at BUSM and BUSPH, served as the study's lead author. Lindsay A. Farrer, PhD, professor of medicine, neurology, ophthalmology, genetics & genomics, epidemiology and biostatistics and chief of the Biomedical Genetics Section at BUSM, was the study's senior author.

Using the Framingham Offspring Eye Study cohort, investigators looked at brain MRI findings on or after 10 years from the original eye exam and concluded that there was a significant correlation between a quantitative measure of cortical cataract and several Alzheimer's disease-related measures of brain degeneration, in particular volume of the temporal horn which is a brain structure that is progressively enlarged in patients with Alzheimer's disease. Another strong correlation in these same individuals, between cortical cataract formation and poorer performance on several cognitive tests administered at the time of the MRI scan, further supports this link.

With such a link not confounded by age or sex, the investigators then performed a genome-wide association study looking at nearly 190,000 single-nucleotide polymorphisms (SNPs), or DNA sequence variations. Three intronic (non-coding) SNPs in the gene encoding δ-catenin came to the fore. This protein is a key component in cell adherence and formation of cell junctional structures. Previously, δ-catenin was also implicated in brain and eye development, but not directly in either cataracts or Alzheimer's disease. To establish a more direct link of δ-catenin to Alzheimer's disease, the researchers transfected into neuronal cells δ-catenin bearing a mutation near the location of the top-associated SNPs and observed a significant and specific increase in the toxic form of amyloid β, the protein that aggregates in Alzheimer brains and thought to be central to development of the disorder. In addition, the researchers found increased deposits of δ-catenin in lens tissue obtained from autopsy-confirmed Alzheimer's cases but not from subjects lacking Alzheimer's-associated neuropathology.

"Though much work remains to be done, a link between cataracts and Alzheimer's disease supports the idea of a systemic rather than brain-limited focus for processes leading to Alzheimer's disease," said Farrer. "This study gives hope that we are moving toward earlier diagnosis and new treatment targets for this debilitating disease."

Source: Eurekalert

Alzheimers Disease

Alzheimer's disease is a progressive neurodegenerative disease affecting memory and thinking and making the person increasingly dependent on others.

Diseases Related to Old Age

Ageing is referred to the accumulation of changes that brings a person closer to death.

Caring for Alzheimers disease patients

Alzheimer's disease is a complex brain disorder that triggers the most common form of dementia. The slide show will show how patients need support and care as dementia progresses.

Cataract

A cataract is cloudiness in the crystalline lens of the eye that results in a gradually progressive painless diminution of vision.

Cataract in Detail

Encyclopedia section of medindia gives general info about Cataract

Clear the Blur-Tips to Boost Your Eye-Q

Eye problems may present as blurry vision or simply a minor headache, but they can affect your life in more ways than one. Here's a comprehensive yet compact guide to boost your eye-Q.

Creutzfeldt-Jakob Disease

Creutzfeldt-Jakob disease (CJD) is a rare form of degenerative brain disorder, or brain damage that leads to a rapid decrease of mental function and movement.

Diet and Alzheimer´s Disease

Alzheimer''s begins with forgetfulness, but over time affects speech and coordination along with drastic behavioral changes. The right diet may lower your risk by 40%. So isn''t a diet change worth it?

DNA Finger Printing

DNA fingerprinting is a technique which helps forensic scientists and legal experts solve crimes, identity thefts, legal suits and terrorism cases.

Genetics of Alzheimer´s disease

There are numerous genes that have been discovered that are associated with Alzheimer’s disease and indicate increased risk, aiding genetic counseling and better care.