Huntington’s disease and ALS both affect your muscles. But while ALS causes muscle weakness and paralysis, Huntington’s is an inherited condition that causes uncontrolled movements and psychiatric symptoms.

Amyotrophic lateral sclerosis (ALS) and Huntington’s disease are two progressive neurological disorders that cause problems with movement.

While they share some symptoms, they’re very different conditions. One of the main differences is that Huntington’s disease is inherited, while ALS is not.

This article explores key differences between ALS (formerly known as Lou Gehrig’s disease) and Huntington’s disease.

Huntington’s disease and ALS both affect movement. But Huntington’s disease is associated with involuntary twitching called chorea, while ALS is more likely to cause muscle weakness (atrophy) and paralysis.

Over time, both conditions lead to difficulties with:

  • walking
  • chewing
  • swallowing
  • speaking
  • breathing

However, Huntington’s is more likely to cause a broader range of symptoms.

In addition to movement, Huntington’s impairs memory, concentration, and decision-making. It can also cause mood swings, personality changes, and depression.

While the cognitive and psychiatric symptoms listed above are possible with ALS, they’re much less common and appear later. With Huntington’s disease, psychiatric symptoms typically appear early, often before motor symptoms.

Huntington’s disease results from a genetic mutation that runs in families. It’s an autosomal dominant condition, which means when one parent has it, their child has a 50% chance of getting it too.

The cause of ALS isn’t as clear. While it has a genetic component, exposure to environmental toxins, a history of head injuries, and smoking also factor into who gets it.

Huntington’s and ALS have distinctive risk factors outlined in the chart below.

Risk factorHuntington’s diseaseALS
AgeThe genetic mutation is present at birth, but symptoms usually appear in people between the ages of 30 and 50 years.Symptoms usually appear in people between the ages of 55 and 75 years.
Family historyPeople who have a parent with Huntington’s disease have a 50-50 chance of also developing symptoms.People who have a family history of ALS are at an increased risk, but only slightly.
SexAffects males and females equally.Males are slightly more likely to develop ALS.
Race/ethnicityAffects all races and ethnicities equally.White people and non-Hispanic people are at an increased risk.

The diagnostic tests for Huntington’s disease and ALS are similar. A doctor will conduct a physical exam and discuss your symptoms and medical history. Additional tests can include:

Huntington’s disease may be easier to diagnose than ALS since most people with Huntington’s also have a parent who has it. Doctors can use genetic testing to confirm a Huntington’s disease diagnosis.

An ALS diagnosis can take 10–16 months, as several other conditions can resemble ALS.

Treatment for both Huntington’s disease and ALS aims to improve symptoms and quality of life.

For Huntington’s disease, doctors often prescribe tetrabenazine (Xenazine) and deutetrabenazine (Austedo) to help with chorea. Antipsychotic drugs, antidepressants, and anti-anxiety medications may improve psychiatric symptoms.

Doctors commonly prescribe riluzole (Riluetk) for people with ALS as it helps to slow the progression of the illness. In 2022, the Food and Drug Administration also approved Relyvrio for ALS.

Medications to treat muscle spasms include gabapentin (Neurontin), baclofen, and tizanidine (Zanaflex).

Other forms of therapy for people with either Huntington’s or ALS can include physical therapy, speech therapy, and psychotherapy.

Huntington’s disease and ALS are both progressive and fatal, which means symptoms get worse and ultimately lead to death.

But Huntington’s disease progresses more gradually than ALS. It’s possible to live with symptoms of Huntington’s for 15–20 years.

In contrast, the typical life expectancy for people with ALS is 3–5 years after they first start having symptoms. However, for 30% of people with ALS, this can be more than 5 years.

What diseases does Huntington’s disease mimic?

Huntington’s disease can resemble other neurodegenerative disorders that affect movement, such as Parkinson’s disease.

What is ALS commonly misdiagnosed for?

ALS may be misdiagnosed for other motor neuron disorders, including spinal muscular atrophy or progressive muscular atrophy.

Is there a cure for Huntington’s disease or ALS?

There is no cure for Huntington’s disease or ALS. In both cases, treatments focus on making people with the condition more comfortable.

ALS and Huntington’s disease both affect movement. But Huntington’s disease is more likely to cause unintentional movements, while ALS usually causes weakness.

Another key difference is that Huntington’s is inherited, while ALS has several potential causes. Huntington’s may also be simpler to diagnose since it can show up in a genetic test.