Five major findings of dementia research

Amyloid is a protein which builds up in the brain in Alzheimer’s disease. The discovery of amyloid in Alzheimer’s disease was made possible by scientists who worked with families who had a strong family history of dementia in their 40s and 50s going back generations.

A lady named Carol Jennings saw changes in her father in his 50s and noticed that several family member’s on her father’s side also developed similar symptoms around the same age. This family pattern and her father’s Alzheimer’s diagnosis led to Carol writing to scientist Professor John Hardy and clinician Professor Martin Rossor.

In 1991, they discovered that a faulty gene was causing young onset Alzheimer’s disease in Carol’s family. This gene was called Amyloid Precursor Protein (APP) which causes amyloid to malfunction and build up in the brain. The discovery of this faulty gene led Professor Hardy to set out a theory. He suggested that a build-up of amyloid plays a key role in a chain of biological changes in the brain leading to Alzheimer’s. These changes cause progressive damage to our brain cells over time, resulting in symptoms like memory loss and confusion.

Not only did this work help scientists identify a rare, inherited form of Alzheimer’s, but it helped them understand the changes in the brain that happen in more common forms of Alzheimer’s too.

This ‘amyloid theory’ changed the course of dementia research. Since then scientists all around the world have developed Alzheimer’s treatments that target amyloid in the brain. Without the discovery of amyloid, we wouldn’t have such promising treatments for Alzheimer’s on the horizon today.

Lecanemab and donanemab are two new treatments that can slow down the progression of early stage Alzheimer’s disease by around 30%. They are not yet available on the NHS, but are available privately in Great Britain, and have been licensed for use in several countries including the USA and Japan.

These drugs are designed to clear amyloid build-up from the brain. In Alzheimer’s disease, amyloid builds up in the space between different cells in our brain forming plaques which cause damage to brain cells. Clearing amyloid helps reduce this damage to brain cells that are responsible for our memory and thinking. This then reduces the decline in memory and thinking for people with early stage Alzheimer’s disease, enabling them to live independently for longer. This process can be seen in the diagram below.

While only available privately in the UK for the time being, the licensing of the first treatments to tackle the underlying disease gives hope that we are at the tipping point. In the years to come we hope that there will be effective treatments that target the underlying causes of diseases like Alzheimer’s.

You can learn more about other types of treatments currently being researched here.

We now know that 45 in 100 cases of dementia worldwide could be prevented or delayed if, at a population level, we could eliminate 14 factors that increase our risk of developing dementia.

Large scale research studies comparing different groups of people and their dementia risk has helped scientists identify what factors are linked to an increased likelihood of developing dementia. The 2024 Lancet Commission, which Alzheimer’s Research UK helped fund, reviewed the latest research studies and concluded there are 14 factors linked to an increased risk of developing dementia.

The diagram below shows the different factors that affect our dementia risk throughout our life.

You can read about dementia risk factors and steps we can take to reduce our risk here.

Advancements in gene technologies over the past three decades have enabled scientists to identify over 75 genes that can affect our risk of developing Alzheimer’s disease. Some of these genes increase our risk but others may decrease our risk too. It is important to note that having a dementia risk gene doesn’t directly cause a disease like Alzheimer’s. Most cases of dementia are caused by a mixture of factors such as our age, lifestyle, medical history, environment as well as our genes.

The discovery of risk genes has helped scientists understand what goes wrong in different types of dementia and identify targets to develop new treatments.

In 2012 an Alzheimer’s Research UK funded study led to the discovery of a risk gene called ‘TREM2’. This paved the way for a new area of research and hundreds of studies into the role our immune system plays in the development of Alzheimer’s. Identifying TREM2 has influenced the work of over 1,000 research teams across the world and led to new Alzheimer’s drugs being tested in clinical trials today.

Research is now showing inflammation caused by our immune system, to be a key early feature of Alzheimer’s and this is a major focus at the Alzheimer’s Research UK Drug Discovery Alliance.

You can read more about how genes affect our dementia risk here.

Early and accurate diagnosis of dementia is crucial. It means people can access the right treatments, care and support, plan for the future and take part in medical research. Currently people are waiting 18 months on average for a dementia diagnosis in the UK.

Research over the last decade has helped identify different markers in our blood that can be used to diagnose different types of dementia. One of these biological markers is called ‘p-tau 217’, which is a marker for the protein tau, which builds up in the brain in Alzheimer’s disease.

Traces of p-tau 217 can be detected in the blood of people living with the disease. Scientists have found that a simple blood test used to detect p-tau 217 is just as accurate as ‘gold standard’ methods such as PET scans or lumbar punctures.

Currently only 2% of people with a dementia diagnosis have a lumbar puncture or PET scan, which are the only current methods to diagnose the type of dementia someone has with certainty. This is due to lack of availability of these tests as part of diagnostic services. A blood test for dementia would provide a cheaper, easier and quicker way to diagnose the diseases that cause dementia.

Crucially when we look at the development of new lifechanging dementia treatments, we need earlier and accurate diagnosis. This is because these treatments, like lecanemab and donanemab, work best for people in the earliest stage of the disease.

Alzheimer’s Research UK, alongside Alzheimer’s Society, The National Institute for Health and Care Research and Gates Ventures, are funding the Blood Biomarker Challenge. The research studies involved in this project hope to bring blood tests for diagnosing Alzheimer’s and other forms of dementia to the NHS within five years.