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GTR Home > Tests > Neuromuscular Disorders NGS Panel

Indication

This is a clinical test intended for Help: Diagnosis

Clinical summary

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Imported from GeneReviews

Myotonia congenita is characterized by muscle stiffness present from childhood; all striated muscle groups including the extrinsic eye muscles, facial muscles, and tongue may be involved. Stiffness is relieved by repeated contractions of the muscle (the "warm-up" phenomenon). Muscles are usually hypertrophic. Whereas autosomal recessive (AR) myotonia congenita is often associated with more severe manifestations (such as progressive minor distal weakness and attacks of transient weakness brought on by movement after rest), autosomal dominant (AD) myotonia congenita is not. The age of onset varies: in AD myotonia congenita onset is usually in infancy or early childhood; in AR myotonia congenita the average age of onset is slightly older. In both AR and AD myotonia congenita onset may be as late as the third or fourth decade of life.

Clinical features

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Imported from Human Phenotype Ontology (HPO)

  • Dysphagia
  • Muscle weakness
  • Muscle stiffness
  • Myalgia
  • Lid lag on downgaze
  • Myotonia
  • Percussion myotonia
  • Muscle hypertrophy of the lower extremities
  • Skeletal muscle hypertrophy
  • Myotonia with warm-up phenomenon
  • EMG: myotonic runs
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Conditions tested

Target population

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Not provided

Clinical validity

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Not provided

Clinical utility

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Not provided

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