The plaque-forming protein found in the brains of Alzheimer’s suffers also accumulates in the eyes of people with Down syndrome and this discovery may lead to innovative eye tests for early detection of Alzheimer’s pathology in both disorders.
Down syndrome karyotype showing an extra gene on chromosome 21
Amyloid-β is a toxic protein that forms plaques in the brains of those with Alzheimer’s and researchers from Boston University have discovered that this same protein also causes cataracts in the lens of the eye of children with Down syndrome.
“The lens provides a window to the brain,” said Juliet A. Moncaster, co-author of the study, “The lens can’t clear protein deposits the way the brain does. Our findings show that the same amyloid-β protein that aggregates in the brain also accumulated in the lens and leads to these unusual cataracts in Down syndrome.”
People with Down syndrome often develop symptoms of Alzheimer’s-type dementia by the age of 30 because they have an extra copy of the key gene that leads to increased amyloid-β accumulation in the brain, said lead author Lee E Goldstein. Researchers discovered that this protein accumulated very early in the lens – even in children.
“The results are striking,” said David G Hunter, ophthalmologist at the Children’s Hospital Boston, “We have known that these cataracts are prevalent in people with Down syndrome and are sometimes seen at birth, but we never knew they were related to the disorder.”
Goldstein said they are now developing an eye scanner to measure amyloid-β in the lens. “This approach may provide a way for early detection and monitoring of related pathology in the brain. Effective treatments for the brain disease in Down syndrome and Alzheimer’s disease are on the horizon, and early detection is the key for successful intervention.”