The discovery of a rare genetic mutation that protects a minority of people against Alzheimer`s disease and a general loss of brain function in old age has raised fresh hopes for treating the condition.
Scientists at the Icelandic genetics firm, deCODE, spotted the mutation in about 1% of 1,795 Icelanders who took part in a study reported on Wednesday in the journal Nature.
Though rare in the populace, the mutation appears to have a substantial protective effect against the neurodegenerative disorder. Scientists behind the discovery estimate that carriers have a 47% greater chance of reaching the age of 85 than the majority of people who lack the mutation. Writing in the journal, the researchers say the DNA sequence is the first mutation known to confer "strong protection against Alzheimer`s disease". In a series of follow-up studies, including one on people aged 80 and over who carried the mutation, the researchers found evidence that the DNA sequence also protects against the general decline in brain performance that is common in old age. The finding suggests that Alzheimer`s and age-related cognitive problems belong to a continuum of disorders and share an underlying cause.
Alzheimer`s is the most common form of dementia and affects about half a million people in the UK. In the early stages of the disease, people can experience memory loss, mood swings and become isolated and withdrawn. The disease is progressive and many patients eventually become reliant on careers for their daily tasks.