Scientists move closer to Alzheimer’s treatment

People with a genetic predisposition to developing Alzheimer’s disease could show signs of the condition up to 25 years before it actually sets in, scientists have found.

By Yasmin Noone

People with a genetic predisposition to Alzheimer’s disease could now be given up 25 years warning as to when they will develop the disease, if at all, thanks to new international research findings.

Using changes in the brain and spinal fluid, scientists will be able to detect Alzheimer’s disease in people who have inherited the disease gene mutation from their parents, according to an international study published in the New England Journal of Medicine last week.

Neuroscience Research Australia (NeuRA) was one of 10 site-partners which participated in the Dominantly Inherited Alzheimer Network (DIAN) study.

Co-author of the paper and NeuRA executive director, Prof Peter Schofield, said the study provided researchers with the first ever chance to look for Alzheimer’s disease-related changes in living people who they know will develop the disease.

“There is currently no cure for Alzheimer’s disease and available treatments target symptoms of this disease only,” said Prof Schofield.

“By looking at changes in people before they show clinical signs of the disease, we will be able to develop more targeted treatments and identify the best window in which, one day, we may be able to prevent this disease altogether.”

The researchers identified a number of major landmarks in the way Alzheimer’s disease progresses. They found that levels of a protein called beta amyloid declines in cerebrospinal fluid around 25 years before Alzheimer’s disease symptoms are expected.

Fifteen years before the onset of Alzheimer’s disease abnormal deposits of beta amyloid and increased levels of another protein, tau, appear in the brain and sections of the brain begin to die.

Patients start to experience memory problems five years later, and show the range of symptoms needed to diagnose Alzheimer’s disease just three years after that.

Familial Autosomal Dominant Alzheimer’s Disease (FAD) is a rare form of Alzheimer’s disease, which experts say accounts for approximately five to 10 per cent of all cases.

Known to be inherited, the disease will occur if the disease gene is present and can be passed directly from one generation to another through a dominant inheritance pattern in certain families.

Therefore, a child will have a 50 per cent chance of inheriting the disease gene and developing Alzheimer’s disease in adulthood if one parent is affected.

Up until now, scientists have been able to predict the age at which Autosomal dominant Alzheimer’s disease will set in but have known little about the order and magnitude of its pathologic processes.

This study found that autosomal dominant Alzheimer’s disease was associated with a series of pathophysiological changes over decades in CSF biochemical markers of Alzheimer’s disease, brain amyloid deposition, and brain metabolism as well as progressive cognitive impairment.

“…Our findings indicate that the Alzheimer’s disease process begins more than 20 years before the clinical onset of dementia,” the paper states.

“Treatment and prevention trials can incorporate these pathophysiological changes to gauge the likelihood of future clinical success.

“Secondary prevention trials that are designed to prevent or delay cognitive and clinical impairment may ultimately test the amyloid hypothesis, just as the cholesterol hypothesis of heart disease was tested three decades ago.”

Tags: alzheimers, dian, dominantly-inherited-alzheimer-network, neura, new-england-journal-of-medicine,

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