Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia

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Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are diseases that affect the neurological system. Research has found that the genes and genetic components that play a role in both conditions are similar.

This article discusses the connection between ALS and FTD, the risks associated with developing both conditions simultaneously, and what medical providers can do to help manage the comorbidity in patients with both. 

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Connection Between ALS and Frontotemporal Dementia

ALS and FTD are considered neurodegenerative diseases. That means that the neurological system and neurons (nerve cells) are affected. Both conditions develop because motor neurons, the cells that aid in movement, become damaged or destroyed.

In the case of ALS, motor neurons found in the frontal cortex, brainstem, and spinal cord are affected. In FTD, the motor neurons in the frontal and temporal lobes of the brain are damaged.

Researchers have examined why the overlap exists between the two conditions and found that it all comes down to genetics. People with ALS or FTD seem to have genetic changes in specific genes, such as:

  • C9ORF72
  • TARDBP
  • FUS
  • CHCHD10
  • TBK1
  • VCP
  • SQSTM1

All of these genes provide specific instructions to cells in the body to create the appropriate proteins that aid in bodily functions. When those cells experience changes or mutations, the guidance given to cells is skewed.

The most notable gene association is the C9ORF72 gene. It gives cells the information they need to create a protein found in nerve cells, the same nerve cells that are negatively affected by both ALS and FTD.

Symptoms

Having both conditions can make day-to-day life that much more challenging. People with ALS tend to lose their mobility due to muscle weakness, tightness, stiffness, cramps, speech difficulties, and muscle twitches. These symptoms worsen over time because it is a progressive and fatal disease.

However, it is not always common for those with ALS to experience cognitive changes that occur in FTD, such as:

  • Dramatic behavioral and personality changes
  • Impulsive or repetitive behaviors that are inappropriate
  • Apathy and lack of empathy
  • A decrease in self-awareness
  • Impaired judgment
  • Loss of interest, motivation, and social needs
  • Inability to speak or understand when spoken to
  • Talking less or feeling hesitant to speak
  • Getting distracted easily and having difficulty with organization and planning
  • Mood changes, including agitation

Because of that, experiencing mobility symptoms as well as cognitive symptoms at the same time can be highly debilitating for people who develop ALS and FTD simultaneously.  

Do ALS and FTD Share Any Symptoms?

If a person has only one of the two conditions, they are unlikely to experience the same symptoms. ALS affects movement, speech, and breathing, whereas FTD affects cognitive function. It is only when a person experiences both that they develop mental and mobility issues.

Risks

Though ALS and FTD are connected, researchers have yet to determine if having one puts a person at a higher risk of developing the other. The two simply share a genetic risk factor.

That said, research has determined that as many as 50% of people with ALS will also develop FTD-based cognitive impairment, and 30% of people with FTD will develop the same motor dysfunction symptoms found in ALS. When people have both conditions, it is referred to as ALS-FTD.

Does Having ALS Make FTD Worse or Vice Versa?

Unlike ALS, FTD isn’t fatal, and people can live with the disease for years. However, they will likely need round-the-clock care as it worsens, and they can no longer care for themselves. With ALS, life expectancy shortens drastically. Though it's unclear if people with ALS who also develop FTD have worsened outcomes, they are likely to see their disease progression speed up.

Treatment and Management

Because FTD and ALS are considered neurodegenerative, treatment and management of the diseases focus on slowing down the damage to the affected neurons. That said, there are limited options for people with both.

Research has found that the typical medications for managing FTD and similar diseases that affect the frontotemporal lobes of the brain, such as antidepressants, antipsychotics, and cholinesterase inhibitors, show minimal promise in reducing symptoms. New therapeutic options, such as disease-modifying drugs, are being explored as a possible FTD treatment.

Riluzole is a disease-modifying medication that can help slow the progression of ALS. Still, it is not yet determined whether it can help reduce the symptoms of FTD. Other than that, speech therapy can help with both conditions.

Studies have explored lithium's effects on ALS and FTD and found that it could be a viable treatment option for those with both conditions.   

Monitoring for Concurrent Conditions

If you have ALS or FTD, monitoring your symptoms is essential. Because developing both is somewhat common, paying as much attention as possible is best so that if new symptoms arise, you can contact your healthcare provider immediately. 

Summary

ALS and FTD are both neurodegenerative diseases that affect motor neurons. However, the area where those motor neurons are found differs between the two conditions, which is why the symptoms present so differently.

Though it’s unclear whether having one makes it more likely to have the other, 30–50% of people with ALS or FTD will develop both conditions. Researchers have found that the connection between the two, besides the neurological link, comes down to genetics.

Specific gene changes in ALS are also found in FTD, which can explain why the motor neurons are targeted in both conditions. When a person has both, the best thing they can do is find proper treatment. Many medications are available for FTD, but they are not always effective. The options for ALS are also limited, but ongoing research continues to search for better therapies to slow the progression of ALS and reduce symptoms of FTD in people with both diseases.

Frequently Asked Questions

  • Can you get ALS and FTD at the same time?

    ALS and FTD are both neurodegenerative disorders. However, they cause vastly different symptoms. Although not everyone with ALS will develop FTD and vice versa, roughly 30–50% of people with the disease will end up with both at some point in their lives.

  • Why are ALS symptoms differ from those of FTD?

    ALS and FTD are similar in terms of epidemiology. However, even though the two diseases have a genetic link, the area where the affected neurons are located differs. Because of that, the symptoms present differently.

  • How do you treat ALS and FTD at the same time?

    Treating both conditions simultaneously is often difficult. This is because no one drug can treat both. However, new research is exploring options for medications, such as lithium, which may help decrease symptoms in people who have both conditions at the same time.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Johns Hopkins Medicine. Frontotemporal dementia.

  3. Ferrari R, Kapogiannis D, Huey ED, Momeni P. FTD and ALS: a tale of two diseases. Curr Alzheimer Res. 2011 May;8(3):273-94. doi:10.2174/156720511795563700

  4. The Association for Frontotemporal Degeneration. ALS and frontotemporal degeneration.

  5. Limanaqi F, Biagioni F, Ryskalin L, et al. Molecular mechanisms linking ALS/FTD and psychiatric disorders, the potential effects of lithium. Front Cell Neurosci. 2019 Oct 4;13:450. doi:10.3389/fncel.2019.00450

By Angelica Bottaro
Angelica Bottaro is a professional freelance writer with over 5 years of experience. She has been educated in both psychology and journalism, and her dual education has given her the research and writing skills needed to deliver sound and engaging content in the health space.