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Tau protein clumped in a neuron

Frontotemporal dementia

What is frontotemporal dementia? 

Frontotemporal dementia (FTD), also commonly known as Pick's disease, is an umbrella term for a group of dementias that mainly affect the front and sides of the brain (the frontal and temporal lobes), which are responsible for personality, behaviour, language and speech. 

It is an uncommon type of dementia that affects around one in 20 people with a dementia diagnosis1. Unlike other types of dementia, memory loss and concentration problems are less common in the early stages.

There are three main types of frontotemporal dementia: the behavioural variant of frontotemporal dementia (bvFTD), semantic variant primary progressive aphasia (svPPA) and non-fluent variant primary progressive aphasia (nfvPPA). The latter two sub-types both primarily affect language but in different ways.

In clinical terms, there is also a lot of overlap between these main variants of frontotemporal dementia and motor neuron disease (MND) – meaning the conditions are quite similar in many ways.

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Frequently asked questions

How common is frontotemporal dementia?
What are the signs and symptoms of frontotemporal dementia?
How is frontotemporal dementia diagnosed?
What treatments are available for frontotemporal dementia?
How can I get involved in research and trials for frontotemporal dementia?
Support for frontotemporal dementia

What are the causes of frontotemporal dementia?

During frontotemporal dementia, clumps of abnormal protein, including tau, TDP-43 and FUS form inside brain cells. These are thought to damage the cells and stop them working properly. This causes the connections between the cells and other parts of the brain to break down. The levels of chemical messengers in the brain also reduce over time. These messengers allow nerve cells to send signals to each other and the rest of the body. The proteins mainly build up in the frontal and temporal lobes of the brain at the front and sides. These are important for controlling language, behaviour, and the ability to plan and organise. As more and more nerve cells are damaged and die, the brain tissue in the frontal and temporal lobes starts to get smaller.

It is not fully understood why this happens, but in around 30-40% of cases, a person with frontotemporal dementia has a family history of the condition in which a parent or sibling has been affected2. In these cases, the cause of frontotemporal dementia is likely to be genetic. However, most cases of frontotemporal dementia do not have a genetic basis.

There is a lot of research being done to try to improve understanding of the causes of frontotemporal dementia so that treatments can be found. Many of our UK DRI researchers who work on frontotemporal dementia also work on MND/ALS, because they share the most commonly found genetic mutation.

Frontotemporal dementia and motor neuron disease (MND)/amyotrophic lateral sclerosis (ALS) are clinically distinct neurodegenerative diseases, but the discovery that they share a common cause – an expansion of a six-letter DNA sequence within the C9orf72 gene – is helping to revolutionise our understanding of the diseases. 

Scientists are studying the biological impact of the faulty version of the C9orf72 gene to work out the mechanisms that lead to frontotemporal dementia and MND/ALS, including how the resulting protein may not function properly and/or could be toxic to neurons.

For example, Prof Adrian Isaacs is investigating the underlying molecular mechanisms behind C9orf72-related frontotemporal dementia and MND/ALS using a variety of experimental techniques and model systems. He is also developing high-throughput screening approaches to identify genes and small molecules that modulate C9orf72 and other frontotemporal dementia/MND/ALS genes. The ultimate goal is to develop innovative treatment strategies – such as novel gene therapies.

Tau protein clumped in a neuron

Clumps of abnormal protein (in blue), including tau, TDP-43 and FUS form inside neurons during frontotemporal dementia. Credit: NIH.