Researchers have identified two people from the same Colombian community with genes that both promote and prevent early onset Alzheimer’s disease – a discovery that could lead to new treatments
By Clare Wilson
15 May 2023
Someone with Alzheimer’s walks with his daughter in Yarumal, Colombia, in 2014
RAUL ARBOLEDA/AFP/Getty Images
A few people with partial resistance to Alzheimer’s disease are causing a rethink of the condition’s biological causes that could lead to new treatments.
Their experience suggests that a protein called tau, which builds up inside brain cells in people with Alzheimer’s, could be as crucial, if not more so, than the current chief suspect, a protein called beta-amyloid.
Drugs are in development that aim to reduce the memory loss and confusion of Alzheimer’s by lowering levels of amyloid, but their effects are very small – so small, in fact, they may not be approved for use in countries with more cost-conscious health services.
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The people with partial resistance to Alzheimer’s are part of a community living in Colombia with high levels of a risky gene variant called PSEN1-280A, discovered in the 1980s. The variant is thought to have been introduced by a Spanish conquistador in the 17th century. Those with it live in an isolated region of the Andes mountains, spread across about 25 families.
The gene encodes an enzyme involved in making amyloid and people with one copy of the risky variant were thought to inevitably develop Alzheimer’s in their 40s.
But in 2019, a woman was discovered who, as well as carrying the harmful mutation, also has two copies of a second rare variant, called Christchurch, of a different gene, which gave partial protection against what otherwise would have been her genetic fate of early-onset Alzheimer’s. Instead, she didn’t develop the dementia until her 70s.