FAQs
INDEX
+ What are the symptoms of GNE Myopathy?
+ How do the symptoms progress?
+ What can I do to manage the symptoms of GNE Myopathy?
+ What does it mean that GNE myopathy is a genetic or inherited disorder?
+ Is there likely to be a treatment for GNE myopathy soon?
+ What is the test I need to get done to get a diagnosis for GNE Myopathy?
+ Is GNE Myopathy the same as muscular dystrophy?
+ How come I have GNE Myopathy when no one else in my family has it?
+ How long before one becomes wheelchair bound?
+ Where can I read more in detail?
1.
Bilateral foot drop or difficulty in lifting the front part of the foot.
2.
Early-stage muscle weakness includes inability to walk properly, lack of stability, difficulty doing day to day activities like running, climbing stairs, and getting up from a seated position.
3.
Within 10-20 years of the onset, one can expect incapacitation.
Stage 1
Lower limb muscles are typically affected first.
Stage 2
In the 2nd stage, individuals experience progressive weakness and loss of the upper limb muscles.
Stage 3
Individuals begin to experience weaker neck muscles. If disease continues to progress beyond this stage, there is a
possibility of complete loss of skeletal muscle function.
1.
Annual visits with a Neuromuscular specialist.
2.
Physical therapy sessions help to slow down muscle wasting.
3.
Occupational therapy treats patients through the therapeutic use of everyday activities.
4.
Hydrotherapy or exercising in water is gentle on muscles and allows for greater movement.
5.
Benefit from consuming food rich in Sialic acid, commonly found in dairy products like goat milk and proteins.
Q4. What does it mean that GNE myopathy is a genetic or inherited disorder?
A genetic disorder is a disease caused by defects (or mutations) in any of our genes. Genes are passed down to children from their parents. Each gene exists in pairs—one from each parent. GNE myopathy is caused by mutations in the GNE gene. If one GNE gene in the pair is normal, there is no disease symptom, and the defective gene is said to be "recessive". Genes control all the functions of our body, and so if a gene is defective, the function it controls can be lost. The function of the GNE gene is to instruct our body to make a sugar called Sialic acid, which is required by our cells to perform functions. Mutations in the GNE gene result in Sialic acid deficiency, which affects our muscles.
Q5. Is there likely to be a treatment for GNE myopathy soon?
Research is underway worldwide to find treatments for rare genetic diseases, including GNE myopathy. However, numerous studies are conducted in labs before a treatment can be deemed effective and fit for humans. This is a time-consuming process. Hence, it is difficult to predict when we can expect an effective treatment. Currently, the National Institutes of Health (NIH) in the USA is conducting a clinical trial to assess the efficacy of N-acetyl-D-monoamine (ManNAc) to slow the progression of GNE myopathy. ManNAc is a precursor of sialic acid, which could help raise the levels of sialic acid in the body, thereby relieving the symptoms.
Q6. What is the test I need to get done to get a diagnosis for GNE myopathy?
The most definitive test for GNE myopathy is the DNA test to detect any mutation in the GNE gene. This can be done through the "Clinical Exome" test or "Whole Genome Sequencing." A number of companies in India offer these tests. One can also approach government hospitals and institutes that perform these tests.
For example: AIIMS, New Delhi; NIMHANS, Bengaluru; IGIB, New Delhi; CDFD, Hyderabad; CCMB, Hyderabad, etc.
Q7. Is GNE myopathy the same as muscular dystrophy?
Muscular dystrophy is a broad term. It includes many different diseases caused by defects in different genes. For example, in Duchene Muscular Dystrophy (DMD), one of the most common muscular dystrophies, the GNE gene is normal but the dystrophin gene is mutated. The progression of muscle weakening is a common feature of all muscular dystrophies, regardless of which gene is mutated. However, each disease has its own special features. For example, symptoms of GNE myopathy appear only in adulthood, while those of DMD appear in childhood and affect not only the muscles of the limbs but also the heart and diaphragm. In GNE myopathy, the heart and diaphragm muscles are not known to be affected.
Q8. How come I have GNE myopathy when no one else in my family has it?
If one GNE gene in the pair is normal and the other is defective, there is no disease, as the normal copy can perform the GNE function. Hence, parents can be normal as they have one normal copy, but the child, having inherited defective copies from both parents, catch the disease.
1.
Children inheriting either the normal gene copy from both parents or the defective gene from a single parent do not show disease symptoms. Hence, it is possible for other family members to have no symptoms, although they may be "carriers" of the gene mutation.
2.
There's a possibility for other family members to have no disease because the mutation has arisen for the first time in the affected individual, which is called a "sporadic" gene mutation.
Q9. How long before one becomes wheelchair bound?
If one GNE gene in the pair is normal and the other is defective, there is no disease, as the normal copy can perform the GNE function. Hence, parents can be normal as they have one normal copy, but the child, having inherited defective copies from both parents, catch the disease.
Disease onset
- Tripping
- Change in gait
- Bilateral foot drop
- Inability to stand on toes
- Inability to walk on heels
Within 5 years of onset
- Complete loss of ankle dorsiflexion strength
- Difficulty in bending knees backwards with hamstrings
- Reduced strength in lifting arms
- Steppage gait
- Some difficulty climbing stairs
- Decreased balance
- Requiring the use of ankle-foot orthoses (AFOs)
5 to 10 years after onset
- Loss of strength in bending knee backwards using hamstrings
- Worsening gait
- Increased risk of falling
- Poor balance, requiring the use of assistive walking devices
- Difficulty moving from a sitting position to a standing position
- Significant difficulty climbing stairs
- Difficulty performing tasks that involve raising arms above head
- Initial difficulty with hand function
- Decreased shoulder movement, forearm, wrist, and hand strength
Ten to 20 years after onset
- Loss of strength in hip extensors used to lift knees when walking
- Quadriceps may be affected
- The use of a wheelchair may be needed
- Significant difficulty with shoulder movement and fine motor (i.e., hand) tasks
- Increasing dependence for assistance with activities of daily living.
In advanced stages
- The neck, core, and respiratory muscles can be affected.