GNE Myopathy

What Is GNE Myopathy?

GNE Myopathy (GNEM) is a severe muscle disease that affects adults.

A deficiency of an enzyme (GNE/MNK) causes GNE Myopathy. In people with this deficiency, their bodies cannot complete the first step of sialic acid biosynthesis needed for the modification of proteins and fats. 

The first symptom of GNEM is often foot drop, which is when lifting the front part of the foot becomes difficult, so the front of the foot is dragged on the ground when walking. As additional muscles become affected by GNE Myopathy this leads to difficulties climbing stairs or getting up from a sitting position, and weakness of the hands and shoulder muscles. People with GNEM typically start to show muscle weaknesses around 20 to 30 years of age. Over the following 10 to 20 years, many people with GNEM progressively lose muscle abilities and may eventually require a wheelchair.  

GNE Myopathy is also known as Hereditary Inclusion Body Myopathy (HIBM), Distal Myopathy with Rimmed Vacuoles (DMRV) or Nonaka Myopathy.


Currently, there are no approved treatments for GNE Myopathy. Clinical studies are investigating potential treatments. These investigational treatments aim to provide a replacement for the sialic acid that is deficient because of the missing enzyme.

In a preliminary study (Phase 2), aceneuramic acid (sialic acid) extended release (ER), an investigational product, slowed upper extremity disease progression and appeared generally safe and well-tolerated, with no treatment-related serious adverse events observed to date. The most common adverse events were procedural pain related to muscle biopsy and were gastrointestinal-related.

Patient Support

Neuromuscular Disease Foundation


Sephardic Health Organization for Referral and Education (SHORE)

Patients Association for Distal Myopathies

Muscular Dystrophy Association

If you are a member of a GNE Myopathy patient organization and would like to be listed here, please contact us.

Current Activities

Ultragenyx is sponsoring several studies aceneuramic acid extended release, an investigational product, in GNE Myopathy.

A Phase 3 clinical study is enrolling patients and a Phase 2 clinical study is ongoing. For additional information on the Phase 3 study, please see the study brochure.

All patients are invited to participate in a registry and natural history study, called the GNEM Disease Monitoring Program (GNEM-DMP). The online registry collects information from GNE myopathy patients worldwide to track the progression of the disease at several points (at registration, six months, 12 months and yearly up to 15 years). Participating in this study will help physicians understand more about how GNE myopathy affects the body and quality of life over time. It will also help researchers develop potential treatments. 

For more information and to join the registry, visit The study is also listed at

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