Spinocerebellar Ataxia vs. Friedreich Ataxia: Differences and More

“Ataxia” refers to problems with balance, coordination, and movement. It’s not a single disease. Instead, it describes a group of conditions with different causes, including inherited gene mutations (changes), injuries, and vitamin deficiencies.

Two of the most common inherited types of ataxia are spinocerebellar ataxia (SCA) and Friedreich ataxia. Both conditions are caused by gene mutations, affect movement and coordination, and tend to worsen over time. However, even with these similarities, spinocerebellar and Friedreich ataxia have some important differences.

This article compares these two types of ataxia. We’ll explain what they have in common and the key differences that can affect diagnosis, treatment, and daily life.

How Are Spinocerebellar Ataxia and Friedreich Ataxia Similar?

Spinocerebellar ataxia and Friedreich ataxia are both inherited ataxias. They’re passed down through families because of gene changes that affect how the nervous system works.

These inherited ataxias are neurodegenerative genetic conditions, meaning they slowly damage the brain and nervous system over time. As nerve cells in the brain stop working properly, problems with movement, balance, and coordination gradually get worse.

Both conditions especially affect the cerebellum, the part of the brain that helps control balance, coordination, and smooth movement.

Over time, these gene changes disrupt communication in the nervous system. This can lead to increasing difficulty with walking, coordination, and other motor functions.

Similar Symptoms

Early on, many symptoms overlap, such as:

• Difficulty walking and maintaining balance
• Dysarthria (slurred or slow speech)
• Poor hand coordination
• Unusual eye movements

These symptoms develop because the brain can’t properly control and coordinate body movements. As symptoms get worse, people may also notice fatigue, trouble with fine motor tasks, or difficulty with daily activities like writing or buttoning clothes.

Worsening Over Time

Both spinocerebellar and Friedreich ataxia are progressive conditions, meaning symptoms get worse over time. The rate of progression varies widely. Some people have slow changes over decades, while others may experience a faster decline depending on the subtype or severity.

Impact on Daily Life

Over time, both conditions can affect independence and daily function, including walking, speaking, and fine motor tasks.

Emotional and social impacts are also common. Adjusting to physical changes can take time and support from a care team of specialists.

How Are Spinocerebellar Ataxia and Friedreich Ataxia Different?

Friedreich ataxia is the most common inherited ataxia, although it’s still rare. It affects an estimated 15,000 people worldwide.

Spinocerebellar ataxias are a group of rare disorders within hereditary cerebellar ataxia. Each subtype affects a relatively small number of people. Because spinocerebellar ataxia includes many overlapping subtypes, diagnosis can be difficult and may be delayed without genetic testing.

Genetic Cause and Inheritance Pattern

Friedreich ataxia is caused by mutations in the FXN gene on chromosome 9, which affects a protein needed for energy production in mitochondria (the parts of cells that create energy). It follows an autosomal recessive inheritance pattern, meaning both copies of the gene — one from each parent — must be affected. Parents can be carriers without having symptoms.

Spinocerebellar ataxias are caused by mutations in several different genes, depending on the subtype. Most SCAs follow an autosomal dominant pattern, meaning one copy of the mutation can cause disease.

Age of Onset

Friedreich ataxia usually begins in childhood or adolescence, often between ages 10 and 15. Early onset can affect school, development, and independence at a young age.

Spinocerebellar ataxia most often begins in adulthood, commonly in a person’s 20s or 30s, as in the case of spinocerebellar ataxia type 1 (SCA1) or Machado-Joseph disease (SCA3). Because SCA usually starts later in life, people may first notice symptoms while working or raising families.

Heart Complications

Heart disease, especially hypertrophic cardiomyopathy (thickening of the heart muscle), is common in people with Friedreich ataxia. These heart changes may not cause symptoms at first, which is why regular monitoring is important.

Heart involvement is uncommon in most forms of SCA, although some subtypes can affect the heart.

Other Symptoms

Friedreich ataxia often affects multiple body systems, including the heart, spine, endocrine system, hearing, and vision. Common features include scoliosis (sideways curvature of the spine) and diabetes. These complications may require care from several healthcare specialists.

Spinocerebellar ataxia symptoms are usually more focused on the cerebellum and coordination, although symptoms vary by subtype.

Early Symptoms

Friedreich ataxia often starts with walking and balance problems, along with sensory neuropathy (nerve damage that can cause numbness, tingling, pain, or reduced sensation).

Spinocerebellar ataxia may begin more gradually with coordination and balance problems, speech changes, or unusual eye movements.

These differences can affect how quickly someone seeks medical care.

Disease Severity and Progression

Friedreich ataxia often leads to significant disability, and many people need wheelchairs within 10 to 20 years.

The progression of spinocerebellar ataxia varies widely by subtype. Some forms remain mild for many years, while others progress more quickly.

Treatment Approaches

There’s no cure for either condition, and treatment focuses on symptom management and supportive care.

Omaveloxolone (Skyclarys) can be prescribed in the United States and Europe for people ages 16 and older with Friedreich ataxia. Clinical trial data suggests it may help slow disease progression.

Care for Friedreich ataxia often includes heart monitoring and treatment for complications that affect multiple parts of the body. This may include checking heart, spine, and metabolic health, along with movement symptoms.

For both conditions, treatment may include:

• Physical therapy — Helps maintain balance and strength
• Occupational therapy — Supports daily activities
• Speech therapy — Can be useful if speech or swallowing becomes difficult

Walkers or wheelchairs are often introduced gradually as part of long-term care planning. These can help support independence and reduce the risk of falls.

How Do Doctors Tell These Forms of Ataxia Apart?

Diagnosis usually starts with a neurological exam to check coordination, reflexes, and eye movements.

Genetic testing is the main way doctors confirm the diagnosis. Testing the FXN gene confirms Friedreich ataxia, while genetic panels can identify spinocerebellar ataxia subtypes such as SCA1, SCA2, and SCA3.

MRI scans and heart tests may also help guide diagnosis and treatment for Friedreich ataxia. MRI scans can sometimes show atrophy (shrinkage) of the cerebellum and other parts of the brain in people with ataxia.

Because hereditary ataxias can have overlapping symptoms but different genetic causes, doctors often use symptoms, imaging, and genetic testing to confirm the diagnosis.

Join the Conversation

On MyAtaxiaTeam, people share their experiences with ataxia, get advice, and find support from others who understand.

Have you or a loved one been diagnosed with either of these types of hereditary ataxia? Let others know in the comments below.