What Is Late-Onset Friedreich Ataxia (LOFA) in Adults?

Yes, while Friedreich ataxia (FA) is most often diagnosed in childhood or early adolescence, it is entirely possible to first develop symptoms as an adult. This is known as late-onset Friedreich ataxia (LOFA) or very late-onset Friedreich ataxia (VLOFA), depending on your exact age when symptoms begin ^[1]. You do not “catch” the disease as an adult; rather, the underlying genetic cause was present from birth, but it took longer for the neurological symptoms to appear.

Defining LOFA and VLOFA

Doctors often use specific categories based on the age when symptoms—such as balance issues or clumsiness—first become noticeable, though identifying the exact start of subtle symptoms can be difficult. These are commonly used research categories, and cutoffs can vary:

• Late-onset Friedreich ataxia (LOFA): Symptoms first appear between the ages of 25 and 39 ^[1][2].
• Very late-onset Friedreich ataxia (VLOFA): Symptoms first appear at age 40 or older ^[1].

Adult-onset balance or coordination problems have many possible causes. Diagnosis requires a thorough neurologic evaluation and genetic testing to confirm the presence of disease-causing mutations in both copies of the FXN gene ^[2].

The Genetic Connection

FA is an autosomal recessive condition caused by an extra-long repeated DNA sequence, known as a GAA repeat expansion, in the FXN gene. This expansion limits the body’s ability to produce a vital protein called frataxin ^[3]. Because it is a recessive condition, people with FA inherit one mutated gene copy from each parent; those parents are typically healthy carriers, meaning a family history of the disease is often absent.

Most people with FA have GAA expansions in both of their FXN gene copies (alleles), though a small number have one expansion and a different type of mutation in the other copy ^[3].

People who develop FA in adulthood typically have shorter GAA repeat lengths—specifically, a shorter expansion on the smaller of their two FXN alleles ^[1][4]. A shorter repeat is associated with the body producing slightly more frataxin protein, which is associated with later symptom onset ^[1][3]. However, repeat lengths are not a crystal ball: they show an average tendency but cannot predict your exact individual progression, cardiac risk, or when you might need mobility assistance.

How Adult-Onset FA is Different

Because of the delayed onset and shorter genetic repeats, LOFA and VLOFA often look different from classic childhood FA. This can sometimes cause diagnostic confusion, as adult-onset symptoms can resemble other causes of ataxia, neuropathy, or spasticity ^[5].

• Slower Average Progression: On average, adult-onset FA progresses more slowly than childhood-onset FA. People with LOFA or VLOFA typically experience a longer period of time between their first symptoms and choosing to use mobility aids for safety and independence ^[1][6]. However, progression varies widely, and some adults still experience substantial mobility changes.
• Fewer Non-Neurological Symptoms (But Screening is Still Vital): The complications that affect the rest of the body are usually less frequent in adults. For example, in one Brazilian cohort study, scoliosis (curvature of the spine) affected only 22% of people with LOFA compared to 61% of those with classic FA ^[5]. Cardiomyopathy (disease of the heart muscle) and diabetes are also seen less frequently in late-onset cases ^[1][5]. Importantly, lower risk does not mean no risk. Cardiac disease in FA can be silent, and you still need ongoing, guideline-based cardiac, glucose, and orthopedic assessments customized by your care team ^[7].
• Different Neurological Signs: In classic childhood FA, tapping the knee with a reflex hammer usually gets no response (absent reflexes). In contrast, adults with LOFA may have preserved or brisk reflexes (hyperreflexia), and some may experience spasticity (increased muscle tone and stiffness) ^[1][5]. Additionally, speech difficulties (dysarthria) may be less prominent or appear much later in the disease course ^[2][5].

Receiving a later-than-usual diagnosis can be confusing, but understanding how LOFA differs from classic FA helps your care team tailor your symptom management. A genetic counselor can also help you understand what your diagnosis means for your siblings, partner, or other relatives.