Recently, scientists have discovered a new form of cataracts that can be linked to the development of amyloid plaques in the brain. Cataracts are formed by abnormal proteins on the lens, which is responsible for focusing light on the retina. These new cataracts may be useful for designing new tests to diagnose Alzheimer's disease.
Amyloid Identification
Amyloid is the term for an abnormal structure that some proteins can develop. The structure and shape of proteins is critical for their function. Not only does the amyloid conformation cause protein dysfunction, this abnormal shape causes proteins to become insoluble in the body, resulting in the abnormal proteins becoming deposited in tissues in the form of plaques. These plaques can cause cellular damage and can also cause other nearby proteins to also adopt an amyloid shape.
Beta-Amyloid
Although amyloid is implicated in many different diseases, it is a main focus of Down's syndrome and Alzheimer's disease. Both of these conditions are marked by the development of amyloid plaques in the brain and blood vessels that contain the protein beta-amyloid, the American Health Assistance Foundation explains. People with Down's syndrome have an extra copy of the gene that makes beta-amyloid, and changes in the production of beta-amyloid can also lead to Alzheimer's disease, though researchers are still studying how these plaques develop in Alzheimer's patients.
Amyloid Plaques and Cataracts
Recently researchers have discovered that people with Down's syndrome develop cataracts made of beta-amyloid, Science Daily reports. These cataracts develop early in the course of Down's syndrome and can be found in some children with this disorder. These same cataracts can also be found in people with Alzheimer's disease, the Alzheimer's Association notes. Notably, these cataracts differ from those formed by age-related cataracts and do not cause any problems with vision, because they are located on a different spot on the lens of the eye.
Significance
The identification of cataracts associated with Down's syndrome and Alzheimer's disease is significant because it may allow researchers to develop tests to diagnose Alzheimer's disease earlier. Currently, a definitive diagnosis of Alzheimer's disease requires examining brain tissue under a microscope. The discovery of beta-amyloid cataracts could allow researchers to develop tests that look for the presence of this abnormal protein before other signs of Alzheimer's become apparent. This would allow for the earlier diagnosis and treatment of this incurable form of dementia.
