Friedreich’s ataxia is a rare, inherited disease that progressively damages the nervous system and the heart. It affects roughly 1 in 50,000 people in the United States and is most common in people of Western European descent. Symptoms typically appear in late childhood or adolescence, and the condition gradually worsens over time, eventually affecting coordination, mobility, speech, and heart function.
What Causes Friedreich’s Ataxia
The disease is caused by a mutation in a gene called FXN, which provides instructions for making a protein called frataxin. Frataxin is essential for mitochondria, the structures inside your cells that produce energy. In healthy people, a short stretch of DNA in this gene repeats fewer than 36 times. In people with Friedreich’s ataxia, this same stretch repeats anywhere from 66 to over 1,300 times.
These extra repeats act like a roadblock. They prevent the gene from being read properly, which means cells produce far less frataxin than they need. Without enough frataxin, mitochondria can’t generate energy efficiently, and toxic byproducts of metabolism build up inside cells. The tissues that need the most energy, particularly nerve cells and heart muscle, are hit hardest.
Friedreich’s ataxia follows an autosomal recessive pattern, meaning a person must inherit a faulty copy of the FXN gene from both parents to develop the disease. People who carry only one faulty copy are carriers and typically have no symptoms.
Early Symptoms and How It Progresses
The classic form of Friedreich’s ataxia appears before age 25, with symptoms most often starting in the early to mid-teen years. The first sign is almost always difficulty with balance and coordination while walking. This unsteadiness comes from a combination of damage to the cerebellum (the brain’s coordination center), the spinal cord pathways that carry movement signals, and the sensory nerves that help you know where your body is in space.
As the disease progresses, additional symptoms develop:
- Slurred speech (dysarthria), which worsens gradually over years
- Loss of vibration and position sense in the legs, making it harder to feel where your feet are without looking
- Muscle weakness in the legs, eventually spreading to the arms
- Absent reflexes at the ankles and knees
- Scoliosis, or curvature of the spine
Friedreich’s ataxia is relatively slow-moving compared to some neurological diseases. On average, it takes about 10 years from the first symptoms to the point where a person needs a wheelchair for mobility. Balance problems are noticeably worse in the dark or with eyes closed, because the brain can no longer rely on damaged sensory nerves and compensates heavily through vision.
A smaller group of people develops symptoms after age 25. This late-onset form tends to progress more slowly, though it eventually causes many of the same problems.
Heart Disease: The Most Serious Complication
Friedreich’s ataxia is not just a neurological condition. Heart failure from cardiomyopathy is the leading cause of death, responsible for roughly 60% of fatalities. More than 92% of patients develop a detectable cardiomyopathy at some point during the disease.
The heart muscle thickens (a pattern called hypertrophic cardiomyopathy), and over time, scarring and stiffness develop. The heart can usually maintain its pumping ability for years, but eventually it begins to fail. About 30% of patients who die from the disease have congestive heart failure, and nearly 20% experience severe, sometimes fatal, heart rhythm abnormalities. Electrocardiograms are abnormal in over 90% of cases, often showing changes in the electrical patterns of the heartbeat even before symptoms appear.
Beyond the heart, people with Friedreich’s ataxia face an increased risk of problems with blood sugar regulation and lipid metabolism, because energy-starved cells struggle to process fats and glucose normally.
How It’s Diagnosed
Diagnosis begins when a young person shows progressive balance problems, especially combined with absent knee and ankle reflexes and reduced sensation in the legs. These findings together are unusual enough to raise suspicion, since most conditions that cause absent reflexes don’t also cause the type of nerve-tract damage seen in Friedreich’s ataxia.
A genetic test confirms the diagnosis. The test looks for expanded GAA repeats in both copies of the FXN gene. Normal alleles carry 5 to 33 repeats. Repeats of 66 or more on both copies confirm the disease. An intermediate zone of 34 to 65 repeats exists, where the gene is potentially unstable and could expand in future generations, but this range alone does not cause the disease.
Treatment and Day-to-Day Management
In 2023, the FDA approved the first medication specifically for Friedreich’s ataxia: a drug sold under the brand name Skyclarys, for adults and adolescents 16 and older. It works by activating a cellular defense pathway involved in managing oxidative stress, the kind of damage that accumulates when frataxin levels are low. The medication is taken as three capsules once daily on an empty stomach. While it doesn’t cure the disease, it targets one of the core problems at the cellular level.
Beyond medication, management relies on a coordinated team approach. Physical therapy and occupational therapy help maintain strength, flexibility, and independence for as long as possible. They’re valuable both for day-to-day function and for recovery after acute events like illness or surgery. Speech therapy becomes important as dysarthria progresses, and it also addresses swallowing difficulties that can develop later in the disease.
Scoliosis is managed similarly to how it’s treated in the general population: core-strengthening exercises, bracing during growth, and surgery if the curvature becomes severe (generally above 45 degrees). Doctors try to time any surgical correction after the skeleton has finished growing, though that decision is individualized. Heart function requires regular monitoring with imaging and electrocardiograms, since changes can occur well before a person feels cardiac symptoms.
Life Expectancy and Outlook
Friedreich’s ataxia shortens life expectancy, primarily because of heart complications. Many people with the classic form live into their 30s, 40s, or beyond, depending on the severity of cardiac involvement and the number of GAA repeats they carry (longer repeats generally correlate with earlier onset and faster progression). People with late-onset forms tend to have a longer life expectancy.
The treatment landscape is changing. Gene therapy trials are underway, with the most advanced candidate (LX2006) currently in Phase I/II testing, and another program (SGT-212) expected to enter early-stage trials in late 2025. These approaches aim to deliver a working copy of the FXN gene directly to affected cells, which could address the root cause rather than just managing symptoms.