Rare types of dementia include frontotemporal dementia, posterior cortical atrophy, progressive supranuclear palsy, corticobasal syndrome, CADASIL, Creutzfeldt-Jakob disease, Huntington's disease, and normal pressure hydrocephalus. These rare forms of dementia can be harder to diagnose and may progress differently from more common conditions like Alzheimer's disease or vascular dementia.
In the UK, almost a million people live with dementia, and around 1 in 20 people have a rare dementia. Globally, rare forms of dementia are thought to account for about 5 to 10 per cent of all forms of dementia, yet they are often misunderstood or missed altogether. This blog will explain the main rare dementia types, how they differ from the most common type of dementia, Alzheimer’s disease, and why diagnoses are often delayed. It will also discuss how dementia care at home can support people affected by rare types of dementia.
Most people have heard of Alzheimer's disease, which is the most common cause of dementia, and vascular dementia, which is often seen as the second most common type. These are the common forms of dementia that many GPs talk about first when explaining types of dementia to patients. However, there are many rarer types where changes in brain cells and brain function begin in different areas of the brain or follow different patterns.
Rare types of dementia can:
A person with a rarer type of dementia might have different symptoms, especially during the early stages. They may show early signs such as mood shifts, unusual decision making, or clumsiness, which can look like depression, anxiety, burnout, or another rare condition rather than dementia.
Some rarer diseases that cause dementia are linked to infections, such as certain prion diseases or HIV associated dementia, or to a faulty gene that runs in families. Other rarer causes include alcohol related brain damage, long-term autoimmune disease, or conditions where brain tissue or nerve cells are no longer working properly.
Here are some of the main rare dementia types you might come across if your loved one has a less typical diagnosis or unusual dementia like symptoms:
Frontotemporal dementia is a rare dementia that primarily affects the frontal and temporal lobes of the brain. These areas are involved inpersonality, planning, and language, so the first symptoms of FTD are behavioural changes and personality changes, not memory loss.
FTD can affect younger people. In fact, most patients are diagnosed before the age of 65. In the UK, frontotemporal dementia accounts for fewer than one in 20 dementia cases, yet it can have a huge impact on families. Subtypes of FTD include Pick’s disease, where a buildup of abnormal protein called Pick bodies is seen in brain cells, and Primary Progressive Aphasia, a form of FTD characterised by a progressive decline in language abilities.
In some families, a faulty gene increases the risk that someone will develop dementia due to FTD. Not everyone with these genes will develop FTD, but a clear family history can help doctors decide which tests and treatment options to consider.
Posterior cortical atrophy is a progressive condition where brain cells at the back of the brain are gradually damaged. This part of the brain helps us process visual information and space. People with PCA may struggle with reading, judging distances, or coping with glare and bright lights, even when their eyes are healthy.
PCA often leads to cognitive impairment in visual and spatial skills before memory is affected. It is considered one of the rare forms of dementia and can sometimes be linked to changes similar to Alzheimer's disease in brain tissue. In the early stages, families may notice that their loved one struggles with simple tasks such as pouring a drink, climbing the stairs, or finding items.
Because these symptoms can look like eye problems, stress, or anxiety, getting correctly diagnosed with PCA can take time. A detailed brain scan and neuropsychological tests often help to confirm the diagnosis.
Progressive supranuclear palsy is a rare condition that affects the nervous system and movement, as well as thinking and memory. People may have problems with balance, falls, and moving their eyes, which can make reading or focusing difficult.
Over time, PSP can cause muscle weakness, stiffness, and slowed movements that may look like Parkinson’s disease. It can also lead to symptoms such as slowed thinking and cognitive impairment. PSP is one of the types of dementia where both movement and thinking change together.
Because PSP affects how people control movement, they often need support with walking, transfers, and daily activities. Home care services can help make the environment safer and give family members more confidence in supporting their loved one.
Corticobasal syndrome is another movement-related dementia that can affect younger people, usually those between 50 and 80. It causes stiffness, rigidity, and jerkiness in one limb or one side of the body. Visuospatial skills are also affected, so judging distance and position becomes harder.
Families may see behavioural changes, language problems, or subtle personality changes alongside movement issues. Over time, corticobasal syndrome can severely affect both physical independence and communication. Because these symptoms overlap with other conditions, there is no single test for CBS, and diagnosis relies on careful assessment of early symptoms and changes over time.
CADASIL stands for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. It is the most common genetic cause of stroke and vascular dementia in adults. CADASIL is caused by a faulty gene that affects blood vessels in the brain, which can lead to repeated mini strokes and gradual cognitive impairment.
People with CADASIL may experience:
Over time, CADASIL can lead to vascular dementia as a result of repeated subcortical infarcts. There is no cure, but knowing about the condition can guide treatment options to reduce stroke risk and support day-to-day life.
Creutzfeldt-Jakob disease CJD is a very rare and rapidly progressive dementia linked to misfolded proteins called prions. In CJD, an abnormal protein misfolds and triggers more misfolding, which causes brain cell death and spongy changes in brain tissue. This group of prion diseases includes conditions seen in animals such as bovine spongiform encephalopathy, sometimes known as mad cow disease.
Types of CJD include sporadic CJD, which occurs without a known cause, usually in a person’s 60s, and accounts for 85% of cases. Familial CJD is linked to a faulty gene, and iatrogenic CJD is caused by medical procedures, such as tissue transplants and contaminated surgical instruments in brain surgery. Acquired CJD occurs when someone comes into contact with an abnormal prion protein, for example, from infected meat. These conditions are the rarest form of dementia that most families will ever hear about.
CJD causes rapidly worsening memory problems, confusion, and difficulty with movement. It’s always life-limiting. There is no cure, and care focuses on comfort and quality of life. The National CJD Research and Surveillance Unit carries out monitoring, supports families, and works to raise awareness of these rarer types of dementia.
Huntington's disease is a genetic condition caused by a faulty gene that leads to both movement problems and changes in thinking. It affects people in midlife, often between 30 and 50, and every child of an affected parent has a 50 per cent chanceof inheriting the gene. Over time, many people with Huntington's disease develop dementia alongside involuntary movements and mood changes.
Huntington’s disease often causes:
Because of the strong family history, families may know about the condition long before early symptoms appear. Home care can support both the person and their relatives through the physical and emotional changes that follow.
Normal pressure hydrocephalus is a treatable condition in which cerebrospinal fluid accumulates in the brain. This buildup puts pressure on the brain and causes dementia-like symptoms such as memory loss, movement problems, and incontinence. However, the fluid pressure in the brain is normal or only slightly elevated, distinguishing the condition from other forms of hydrocephalus.
Dementia symptoms in NPH include memory problems and difficulties with thinking and managing tasks. Interestingly, memory problems may show up later than problems with walking or daily tasks. Doctors may arrange a lumbar puncture to drain spinal fluid, and if this helps, a shunt can be placed to drain excess cerebrospinal fluid over time. If NPH is diagnosed and treated early, before brain tissue has been damaged, the symptoms can be significantly improved or even entirely reversed.
Because NPH has similar symptoms to other types of dementia, it is easy to miss. A careful assessment, including a brain scan and possibly a trial of fluid drainage, can help decide the best treatment options.
Families often ask what types of dementia are there beyond Alzheimer's disease, because their loved one’s changes do not fit the picture they expected. Rare types of dementia may begin with subtle changes in mood, language, or movement, rather than clear memory problems.
There is no single test that confirms or excludes every rare dementia type. Dementia diagnosis usually involves:
Dementia can also be a symptom of other disorders. Around 65 per cent of people with multiple sclerosis have mild thinking changes, and some people with multiple sclerosis develop dementia. People affected by MS are also more likely to have depression, which can make dementia symptoms worse.
Around 4 out of every 5 people with Parkinson’s disease will develop dementia over time, due to a build-up of abnormal clumps of protein, called Lewy bodies, in brain cells. Lewy bodies are also seen in dementia with Lewy bodies, a type of dementia that causes visual and auditory hallucinations, sleep disturbances, and movement difficulties such as stiffness and shaking similar to Parkinson’s disease. Doctors distinguish Parkinson’s dementia and dementia with Lewy bodies by the chronology of symptoms. In Parkinson’s disease, movement symptoms appear first, and cognitive changes, including hallucinations, which are often less severe, occur later, often years later. In dementia with Lewy bodies, motor symptoms develop after or alongside cognitive problems.
Other rare causes of rare dementia include alcohol related brain damage, which can lead to Wernicke-Korsakoff syndrome. Korsakoff's syndrome, a key part of this condition, is caused by a lack of thiamine (vitamin B1), whichoften affects people who drink heavily.
At home, sensitive and reliable dementia care can give your loved one stability while also giving you breathing space as a family. Home care cannot treat or cure rare forms of dementia, but it can make daily life safer, calmer, and more manageable for everyone.
Personal care support can help your loved one wash and dress in a way that protects their dignity and comfort. A care assistant can adapt routines if movement problems, muscle weakness, or visual problems make tasks harder. This is especially important in conditions like PSP, corticobasal syndrome, normal pressure hydrocephalus, and Parkinson’s dementia, where control of movement changes over time.
Home carers can prompt and support with medicines prescribed by a doctor. They can never prescribe or adjust medication themselves, but they can remind your loved one to take prescribed tablets or follow therapies safely. This can be helpful for conditions where brain function is affected by different forms of dementia, rare dementia types, or by linked conditions such as multiple sclerosis or human immunodeficiency virus (HIV).
Meal preparation support can help when planning, shopping, and cooking become difficult. A care assistant can prepare balanced meals, help with fluids, and support any special diets recommended by a GP or a dietitian. This is especially important if there is a history of heavy drinking, alcohol related brain damage, Wernicke's encephalopathy, or Korsakoff's syndrome.
Many rare types of dementia involve changes in movement, balance, and strength. A care assistant can encourage and assist with exercises prescribed by a physiotherapist or occupational therapist. This can help in conditions such as PSP, corticobasal syndrome, CADASIL, NPH, and after subcortical infarcts.
Home care can help your loved one attend medical and other appointments, visit support groups, or take short outings. This might mean helping them cope with busy environments and bright lights, which can be challenging in conditions such as PCA or Dementia with Lewy bodies. Knowing that someone is there to guide, reassure, and keep them safe can make a big difference to confidence.
Support with light housework, laundry, and shopping can lift a real weight off your shoulders. It also helps the person with dementia stay in a clean, calm space that feels familiar. This can be especially important in the later stages of rare dementia, when energy may be low and symptoms more complex.
Perhaps most importantly, a regular care assistant becomes a familiar person in your loved one’s daily life. This sense of continuity is valuable across all types of dementia, from common forms such as Alzheimer's disease to rare dementia types like PCA, PSP, CADASIL, or CJD. It also gives you someone to talk to when t you notice your loved one’s symptoms change, so you are not carrying your concerns alone.
Rare forms of dementia can be complex, fast-changing, and deeply emotional for families. They include conditions linked to faulty gene changes, infections like HIV associated dementia, prion diseases such as Creutzfeldt-Jakob disease, and movement-related syndromes like PSP, PCA, and corticobasal syndrome. While there is no cure for many of these forms of dementia, early recognition, clear information, and thoughtful home support can protect quality of life for both the person and the family around them.
Tiggo Care organises dementia care at home for people living with both common types of dementia and rare types of dementia. Our care assistants follow personalised care plans, support daily routines, and work alongside NHS services, always respecting that doctors lead on diagnosis, medical advice, and treatment options. If you would like to explore how home care could support your loved one, you can contact Tiggo Care to discuss a tailored package that fits your situation and keeps your loved one in the comfort of their own home for as long as possible.
Some of the rarest forms of dementia are prion diseases, such as Creutzfeldt-Jakob disease, which are caused by misfolded proteins in the brain and lead to a very rapid decline. These conditions are extremely rare compared with Alzheimer's disease and vascular dementia, and many families will never meet anyone with them. If your loved one has been diagnosed with one of these rare forms of dementia, specialist clinics and, in the case of Creutzfeldt-Jakob disease, the National CJD Research and Surveillance Unit can offer information and support.
Yes, many people with rare types of dementia can be supported at home, especially in the early stages of the disease and in later stages when routines are clear and the environment is familiar. Home care focuses on maintaining their safety and comfort at home rather than medical treatment, which remains the role of doctors and hospital teams.
Beyond Alzheimer's disease, there are many types of dementia, including frontotemporal dementia, vascular dementia, Dementia with Lewy bodies, CADASIL, corticobasal syndrome, PSP, PCA, NPH, and conditions linked to infections or faulty gene changes. These rare dementia types often involve different parts of the brain, from the frontal and temporal lobes to deep structures affected by strokes or subcortical infarcts.
Behaviour and personality changes can be some of the hardest parts of rare dementia for families to cope with, especially in conditions like frontotemporal dementia or Huntington's disease. Families often find it helpful to learn about the condition, connect with support groups, and arrange home care so they are not responding alone when behavioural changes or similar symptoms appear.
Yes, many rare types of dementia can affect people under 65, particularly frontotemporal dementia, which accounts for around one in 20 dementia cases. Corticobasal syndrome, which causes muscle stiffness and language difficulties, tends to affect people aged 50 to 70. Unlike typical Alzheimer’s, some rare dementias may progress much faster. How do rare dementias differ from more common types? Some rare dementia types develop quickly, while Alzheimer’s disease usually causes a more gradual decline. Rare dementias also affect different parts of the brain, producing symptoms that aren’t associated with Alzheimer’s disease and that families may not immediately associated with dementia including movement difficulties, hallucinations, and sleep disturbances. For example, posterior cortical atrophy (PCA) first affects vision and spatial awareness, while CADASIL causes migraines with aura and stroke-like episodes.
For most rare types of dementia there are no cures and treatment focuses on managing symptoms and improving quality of life. Treatment options vary depending on the diagnosis, so doctors will guide you based on your loved one’s specific condition. However, one rare type of dementia, normal pressure hydrocephalus (NPH), is treatable and even reversible in some patients. In these cases, a lumbar puncture can drain fluid from the brain, and if symptoms improve, a shunt is placed to relieve the pressure.
Get in touch with Tiggo Care today to see how we can help you or your loved one.
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