ANXA11 – another gene closer to understanding ALS

A new research paper has been published today in the Science Translational Medicine journal, describing a new gene implicated in developing MND. What is this gene and why is it important for our fight against MND?

Although they are not the sole cause of MND, genes play a big role in someone’s probability of developing the disease. A number of such genes that make a person susceptible to developing MND have already been identified, with most of them causing the rarer, inherited form of the disease.

A new addition to a list of genes that are related to development of ALS, the most common form of MND, has been discovered by researchers from King’s College London. Dr Bradley Smith and colleagues screened genetic data of an unusually high number of people of European origin: 751 with inherited – familial – ALS (fALS) and 180 with non-inherited – sporadic – ALS (sALS). Detailed analysis of this data found that specific mutations in the ANXA11 gene are associated with around 1% of all fALS and 1.7% of all sALS cases. Continue reading

Do retroviruses contribute to the common, sporadic form of MND?

New research from scientists at the American National Institute of Neurological Disorders and Stroke in Bethesda suggest that they might. In a research paper published in Science Translational Medicine yesterday, Li, Nath and colleagues proposed that sporadic MND may be linked to an endogenous retrovirus called ‘HERV-K’. So they conducted a series of experiments to investigate their ideas further.

What are endogenous retroviruses?
These are viruses that are our body’s equivalent of fossil – a left over from our evolution many thousands of years ago. Everyone has them but they are normally in an inactive state.

They are a bit like a family heirloom, lets say a vase. You might walk past the vase every day without really noticing it until one day the cat knocks it off and it smashes onto the floor in front of you.

What did the researchers do?
First, they compared brain tissue of 10 people who died from the sporadic form of MND to brain tissue of 10 people who died from Alzheimer’s Disease. They found proteins made by the virus in MND brain tissue but not in Alzheimer’s Disease brain tissue. Next, studying one of these proteins (called ‘env’) in more detail, they found it was toxic to motor neurones.

Li and colleagues then took a step back and asked ‘what triggered HERV-K to become active in the first place?’. (In other words, going back to my analogy, what caused the vase to fall on to the floor?). They found that the trigger was activation by a protein called ‘TDP-43’ – and this protein is already linked MND.

So what does this really mean?
In a comment article giving a wider perspective on the research study, Professors Bob Brown and MND Association grantee Ammar Al-Chalabi concluded:

The exciting observations of Li, Nath and colleagues will provoke further follow up studies that will illuminate the interplay between the biology of endogenous retroviruses and seemingly impenetrable neurodegenerative disorders like ALS”.

So while this study in itself might not give us the answer, its an exciting step forward in understanding the most common form of MND, that other researchers around the world will build on.

Li et al Human endogenous retrovirus-K contributes to motor neurone disease Sci Transl Med 7 307ra153 (2015)

Brown and Al-Chalabi Endogeneous retroviruses in ALS: a reawakening? Sci Transl Med 7 307fs40 (2015)

‘Dormant viruses may cause MND when awoken’ article in The Guardian