Gene Variants Linked To At Least 7 In 10 Alzheimer’s Cases, Study Suggests

Care professionals across the UK may need to reconsider their understanding of genetic risk factors for Alzheimer’s disease, following the publication of significant new research that challenges previous assumptions about the APOE gene.

The study, published in npj Dementia by researchers at University College London, analysed health data from over 450,000 individuals and found that two variants of the APOE gene – APOE3 and APOE4 – could account for more than 70% of Alzheimer’s cases. The research also suggests these genetic variants may be linked to approximately 45% of all dementia cases.

Understanding APOE Variants

Most people carry two copies of the APOE gene, which exists in several different versions. The most common variants are APOE2, APOE3, and APOE4. Until now, APOE4 has been recognised as the strongest genetic risk factor for late-onset Alzheimer’s disease, which typically develops after age 65. APOE3, by contrast, was generally considered to have a neutral effect on dementia risk.

The new findings suggest that APOE3 may actually contribute to Alzheimer’s and dementia risk more significantly than previously thought – a revelation that could have important implications for care planning and understanding disease progression in residential settings.

What This Means for Care Homes

Dr Sheona Scales, Director of Research at Alzheimer’s Research UK, emphasised that whilst the research provides important insights, it’s crucial to understand that not everyone with these gene variants will develop dementia. “There’s a complex relationship between genetics and other risk factors for dementia,” she explained.

Lead researcher Dr Dylan Williams highlighted the importance of modifiable risk factors, noting that research indicates nearly half of global dementia cases could potentially be prevented or delayed by addressing factors such as social isolation and managing conditions like high cholesterol.

This finding holds particular relevance for care professionals, who are uniquely positioned to support residents in maintaining social connections and managing health conditions that may influence dementia risk.

Current Limitations and Future Research

The study focused primarily on data from people of European ancestry, meaning further research is needed to understand how these genetic variants affect other ethnic groups – an important consideration given the diverse populations many care homes serve.

Notably, despite APOE’s strong connection to Alzheimer’s, very few treatments currently in clinical trials target this gene directly. Researchers suggest this could represent a promising avenue for future treatment and prevention strategies.

Testing and Prevention

APOE testing is not currently available through the NHS for individuals concerned about their future dementia risk. This is largely due to the complexity of Alzheimer’s risk factors – having one or more copies of APOE3 or APOE4 does not guarantee someone will develop the disease, and people with other APOE variants can still develop dementia.

Dr Scales offered reassurance: “We cannot change which variants of APOE we have, but there are still steps we can all take to lower our dementia risk as much as possible. It is never too late to start making positive changes to protect our brain health.”