GNE myopathy is a rare inherited disorder that causes progressive muscle weakness and disability. Currently there is no cure. Mutations in the GNE gene reduce the activity of an enzyme needed to produce sialic acid, a sugar important for normal cell function. Reduced sialic acid is thought to contribute to muscle damage, although the precise mechanism remains uncertain.

Symptoms usually appear between ages 20 and 40, often affecting work and family life. The disease progresses slowly over years or decades and varies considerably. Some people walk with assistive devices for many years, while others require a wheelchair earlier. There is no known way to reverse the muscle loss at this time.

GNE myopathy occurs worldwide but is more common in certain populations. The true prevalence remains unknown, partly because many cases go undiagnosed. A 2024 study of population genetic data estimated approximately 18 to 95 cases per million people, but that may be an underestimate.

Symptoms usually begin in young adulthood. The most common first sign is foot drop, weakness in the muscles that lift the front of the foot, causing the toes to catch or drag when walking.

Common Early Symptoms:

One distinctive feature of GNE myopathy is that the quadriceps, the large muscles at the front of the thigh, are usually spared for far longer than other muscles. This pattern is one of the things that helps a neurologist recognize the disease, and it is the reason for one of its older names, quadriceps-sparing myopathy.

These symptoms overlap with many other conditions. Only genetic testing can confirm GNE myopathy.

Diagnosis requires a confirmed genetic test. Your symptoms, a neurological exam, blood work, an MRI, and even a muscle biopsy can point toward GNE myopathy, but only a genetic test identifies it definitively. Testing can be done from a blood draw or a saliva swab.

If you have symptoms like these, ask to be referred to a neurologist specializing in neuromuscular disease, or to a medical genetics clinic. Ask specifically for GNE gene testing, performed by a CLIA-certified laboratory.

If a family member has already been diagnosed, you can be tested directly. Contact a genetics specialist and tell them which mutations have been identified in your family. This information should make the test faster and cheaper.

Securing a diagnosis often takes time. Many of our community members waited years or even decades, sometimes receiving misdiagnoses such as limb-girdle muscular dystrophy, peripheral neuropathy, or spinal muscular atrophy. If you are in the midst of this struggle, it is neither your imagination nor your fault. It is simply what happens with a rare disease most doctors will never see. Keep advocating for yourself. Finding the correct diagnosis for your condition is worth the push and genetic testing can yield the answer.

GNE myopathy progresses slowly and unevenly, and the course is different from one person to another, even between siblings who carry exactly the same mutation.

Broadly, weakness that begins in the lower legs spreads over years to the thighs, hips, hands, and shoulders. Most people move through a sequence of mobility supports: ankle-foot orthoses, then a cane, then a walker, then a wheelchair or power chair for longer distances. Hand and grip weakness usually arrives later than leg weakness and is, for many people, the harder adjustment.

GNE myopathy is highly unpredictable, and it is impossible to give an exact timeline for how your condition will progress. Published research shows that your specific genetic mutations explain only about 20% of how the disease presents. The remaining 80% of the variation is unique to each individual and is not yet fully understood by science.

What we can tell you is that physical and occupational therapy, appropriate assistive devices, and avoiding over-exercise all appear to matter. Several people in our community have described losing muscle faster after aggressive exercise programs. Work with a physical therapist who understands neuromuscular disease, not a general fitness trainer.

GNE myopathy is autosomal recessive, meaning a person develops the disease only if they inherit a mutated copy of the GNE gene from both parents. Someone with one mutated copy and one working copy is a carrier. Carriers do not develop GNE myopathy and have no symptoms. Most carriers never know.

When both parents are carriers, in each pregnancy there is:

• a 25% chance the child will have GNE myopathy

• a 50% chance the child will be a carrier, like the parents, without the disease

• a 25% chance the child will inherit neither mutated copy

This is why GNE myopathy often appears in several siblings at once while being absent from earlier generations. Several families in a community could have four or five affected siblings.

A simple cheek swab or saliva sample can tell you whether you carry a GNE mutation. It is most useful before a pregnancy, when it gives couples the fullest range of options.

While carrier rates are higher among individuals of Persian Jewish, Middle Eastern, South Asian, East Asian, and certain European descents, GNE myopathy affects people of every ethnic background. Ancestry alone should not determine whether you get tested.

Because the disease is recessive, it is enough for one partner to be screened first. If that result is positive, the other partner should be screened.

Have results reviewed by a genetic counselor. A positive carrier result is not an emergency, and a counselor can explain what it does and does not mean for your family.

At-home and laboratory options:

• JScreen offers a comprehensive at-home saliva screening program reviewed by a genetic counselor.

• Firma Lab, directed by Dr. Valles, offers domestic and international testing. Mention the Neuromuscular Disease Foundation when ordering to qualify for a discount.

[Find a genetic counselor] → [https://www.nsgc.org/About/International-Genetic-Counseling-Organization-Directory]

As understanding of this disease has grown, its name has changed several times. If you were diagnosed some years ago, or in another country, you may have been given one of these diagnoses: