GNE myopathy is a genetic disease that affects a specific enzyme important for making sialic acid, a vital component for cell movement, attachment, and signaling.
People with GNE myopathy experience a gradual weakening of their legs and arms. Typically, these symptoms start in late teens or early twenties and almost always before age 40. Usually, within 20 years of symptom onset, individuals lose their ability to walk. The muscles in the lower legs are usually the first to be affected, making walking progressively harder and changing the way they walk. This weakness spreads to the thighs, hand muscles, and specific muscles in the shoulders and neck. Some may also experience weakness in facial muscles, although the thigh muscles are often unaffected until later stages of the disease. Interestingly, a few individuals with GNE mutations don’t show any symptoms, though we’re not entirely sure why this happens. Unfortunately, there’s currently no cure or treatment available to reverse or slow down the muscle weakness in GNE myopathy. However, neurologists, rehabilitation specialists, and physical and occupational therapists can help manage the symptoms as they arise.
GNE myopathy is caused by pathogenic (disease-causing) variants in the GNE gene and exhibits autosomal recessive inheritance. This means that both parents must be carriers to have a 25% chance to have a child with the condition. The risk of being a carrier is based on a person’s ancestry or ethnic background. For example, individuals of Sephardic Jewish descent have a 1 in 10 chance to be a carrier.
Other names for this condition are distal myopathy with rimmed vacuoles, hereditary inclusion body myopathy, inclusion body myopathy, quadriceps-sparing, Nonaka myopathy, and rimmed vacuole myopathy.