Nonaka myopathy

=Nonaka Myopathy = Nonaka Myopathy, also known as GNE myopathy or hereditary inclusion body myopathy (HIBM), is a rare genetic disorder characterized by progressive muscle weakness. It is a type of distal myopathy, primarily affecting the muscles of the lower limbs.

Clinical Features

Nonaka Myopathy typically presents in early adulthood, often between the ages of 20 and 40. The initial symptoms usually include weakness in the anterior compartment of the lower legs, leading to foot drop and difficulty with dorsiflexion. As the disease progresses, muscle weakness may extend to the upper limbs and other muscle groups.

Symptoms

• Progressive muscle weakness
• Foot drop
• Difficulty walking
• Muscle atrophy

Genetic Basis

Nonaka Myopathy is caused by mutations in the GNE gene, which encodes the enzyme UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase. This enzyme is crucial for the biosynthesis of sialic acid, an important component of glycoproteins and glycolipids.

Inheritance Pattern

The condition is inherited in an autosomal recessive manner, meaning that an individual must inherit two copies of the mutated gene, one from each parent, to be affected by the disease.

Diagnosis

Diagnosis of Nonaka Myopathy is based on clinical evaluation, family history, and genetic testing. Muscle biopsy may show characteristic features such as rimmed vacuoles and inclusion bodies.

Diagnostic Tests

• Genetic testing for GNE mutations
• Muscle biopsy
• Electromyography (EMG)

Treatment

Currently, there is no cure for Nonaka Myopathy. Treatment focuses on managing symptoms and improving quality of life. Physical therapy and occupational therapy can help maintain muscle function and mobility.

Management Strategies

• Physical therapy
• Orthotic devices for foot drop
• Occupational therapy

Research and Future Directions

Research is ongoing to better understand the pathophysiology of Nonaka Myopathy and to develop potential therapies. Gene therapy and enzyme replacement therapy are areas of active investigation.

See Also

• Distal myopathy
• Muscle weakness
• Genetic disorders

,

 Hereditary inclusion body myopathy: A review, 
 Journal of Neurology, 
 2000, 
 Vol. 247(Issue: 9), 
 pp. 625-632,

,

 Muscle Diseases: Pathology and Genetics, 
  
 Springer, 
 2015,

NIH genetic and rare disease info

• NIH info on Nonaka myopathy

Nonaka myopathy is a rare disease.