Scientists at the Australian National University have discovered a network of nine genes that they say would help them develop new treatments to delay the onset of Alzheimer's, the disease that causes degeneration of the brain with age. The study appears online in the 1 December issue of the journal Molecular Psychiatry.

Lead researcher Mauricio Arcos-Burgos and his team studied a family of 5,000 people in Columbia having a history of hereditary Alzheimer's. The family's genetic tendency to Alzheimer's was traced back to a founder mutation in one individual who came to the region about 500 years ago. Researchers identified a total of nine genes associated with the disease in the family.

Out of the nine genes involved in Alzheimer's, some were involved in delaying the onset of the disease by up to 17 years, while others advanced its progress. Researchers believe delaying the onset of the disease will eventually reduce the number of cases.

"I think it will be more successful to delay the onset of the disease than to prevent it completely. Even if we delay the onset by on average one year, that will mean nine million fewer people have the disease in 2050," Burgos said in a statement. "If you can work out how to decelerate the disease, then you can have a profound impact."

People suffering from Alzheimer's have short-term memory loss, apathy and depression in the early stages. The disease causes decline in most cognitive functions in later stages, according to the university. Alzheimer's is the most common form of dementia, leading to impairment of brain functions including language, memory, perception, personality and cognitive skills.

It affects up to 35 million people around the world and is predicted to affect one in 85 people globally by 2050. Older people with dementia, especially women, are the most affected. Low education, obesity in mid-life, diabetes, depression, high cholesterol levels, traumatic brain injury, smoking, low social engagement and exposure to pesticides are some of the other risk factors.

"The brain cells eventually die and this means that information cannot be recalled or assimilated. As Alzheimer's disease affects each area of the brain, certain functions or abilities are progressively lost," researchers noted.