Rare causes of dementia

The 29 February marks Rare Disease Day, and the main objective of the day is to raise awareness about rare diseases and their impact on people’s lives.

A rare disease is defined by the World Health Organisation as one that affects less than 10 per 10,000 people in the general population.

The word ‘dementia’ describes symptoms that occur when brain cells stop working properly. This is caused by different brain diseases that can affect how you think, remember or communicate. Alzheimer’s disease is the most common cause of dementia, but there are several rarer conditions that can lead to dementia or dementia-like problems. Around 35,000 people in the UK are thought to be affected by these.

We provide free health information about the most common causes of dementia, such as Alzheimer’s diseases, vascular dementia, dementia with Lewy bodies and some less common causes like primary progressive aphasia and post cortical atrophy.

But we’ve recently added information about rare causes of dementia to the About dementia section of our website, as well as information about more common causes of symptoms similar to those seen in dementia, but that are not caused by progressive degenerative conditions.

To mark Rare Disease Day we will discuss some of the rarer causes of dementia, providing information about what causes them and how they can be diagnosed.

Progressive supranuclear palsy (PSP)

PSP is thought to affect over 4,000 people in the UK. It’s caused by an abnormal build-up of tau protein, which is also one of the proteins involved in Alzheimer’s disease. Over time this damages and disrupts the way brain cells function, ultimately causing the cells to die.

In PSP, this progressive damage happens to the areas of the brain that control movement and thinking. Problems with balance and walking are therefore common symptoms. Eye movement can also be affected, where people struggle to look downwards, and get double or blurred vision.

Some people with PSP experience personality changes, have difficulty swallowing and develop problems with speech and memory. These symptoms commonly overlap with frontotemporal dementia which is also caused by a build-up of tau.

PSP can be difficult to diagnose because the early symptoms can be similar to other conditions, such as Parkinson’s disease. There is no specific test for PSP, but doctors may use brain scans and memory and thinking tests to help make a diagnosis.

Corticobasal syndrome (CBS)

Corticobasal syndrome is also caused by a build-up of tau in the brain. Like PSP, CBS causes movement problems, muscle stiffness, difficulties with speech and changes in personality. These changes progress and become worse over time as more brain cells are affected.

CBS is thought to affect about 10,000 people living in the UK, and most commonly people between the ages of 50 and 70.

Unfortunately, there are currently no treatments available that can slow down the progression of CBS or PSP. People can experience symptoms in different ways, so the management and treatment of these conditions may include some or all of the following:

  • Medication that helps with the muscle stiffness and tremors, and some medications for mood, pain and sleep may also be beneficial. 
  • Physiotherapy may be prescribed to help people manage their movement and balance symptoms.
  • Speech and language therapy can help with swallowing, speech and communication difficulties.
  • Occupational therapy helps support people to improve the skills and abilities needed for daily activities at home.

Due to the similarities between CBS and progressive supranuclear palsy (PSP), the PSP Association provides advice and support for people with both PSP and CBS. They have a national helpline 0300 0110 122 and can be contacted on email via [email protected]

Huntington’s disease

Huntington’s disease is caused by a faulty gene. People who inherit the directly from an affected parent will develop the condition, and their children have a 50% chance of developing it too. It is thought that around 12 people in every 100,000 are living with the condition in the UK, and it usually affects people between the ages of 30 and 55.

The brain changes that occur in Huntington’s disease can cause dementia. Early on symptoms tend to be physical, and include uncontrolled movements, personality changes, and mood swings. These symptoms will get worse over time, and memory, attention and problem-solving skills are eventually affected too.

For further information the Huntington’s Disease Association provides help and support to via telephone 0151 331 5444 or email [email protected]

Are memory problems always caused by dementia?

There are many reasons why someone might experience memory and thinking problems that we often associate with dementia. Often there are reasons other than diseases like Alzheimer’s or vascular dementia that cause someone to experience these. For example, thyroid disorders, vitamin deficiencies and infections can cause memory and thinking problems, mood changes and confusion. When someone is experiencing such symptoms and they go to see their doctor, the doctor will first run some blood tests to rule out these treatable conditions first.

You can find out more information about other conditions that can cause dementia symptoms here.

Watch our helpful animation to find out how dementia is diagnosed, and what to do if you are concerned about your memory.

If you have questions about dementia, how it is diagnosed or treated, or are worried about symptoms you can contact our Dementia Research Infoline on 0300 111 5111 (9-5pm Monday to Friday) or by email [email protected]

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About the author

Katie Puckering

Team: Information services