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Condition report · Musculoskeletal

SCN4A-Related Congenital Myopathy

A rare inherited muscle condition causing weakness and low muscle tone from before or at birth, sometimes with breathing difficulties. It is caused by changes in both copies of SCN4A, the gene for the main sodium channel in skeletal muscle.

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The condition we analyse

SCN4A-Related Myopathy, Autosomal Recessive

Autosomal recessive

Caused by changes in both copies of SCN4A that reduce the function of the skeletal muscle sodium channel, so muscle fibres cannot fire properly. Different, single-copy SCN4A changes cause dominant conditions such as periodic paralysis and myotonia.

Signs and symptoms

Low muscle tone, respiratory distress and delayed motor development from birth have been reported. Reduced fetal movement can occur before birth, and weakness can progress later in life.

What a diagnosis changes

Respiratory and feeding support, physiotherapy and orthopaedic care, with neuromuscular follow-up. Genetic counselling explains the recessive inheritance, and carrier and prenatal testing are available for families.

Genes analysed

Also known as

congenital myopathy with "corona" fibers, selective muscle atrophy, and craniosynostosis; congenital myopathy with severe fetal hypokinesia; congenital myopathy with severe foetal hypokinesia; myopathy with ptosis and mild dystrophic pattern

Includes 1 related subtype ↓
  • congenital myasthenic syndrome 16
MONDO:0100121Sources: [2][4][5][1]

References

  1. SCN4A gene. MedlinePlus Genetics
  2. Chan TY, Hung LY, Lam TY, Sheng B, Leung FY, Lee HH, 2024. SCN4A-related congenital myopathy in a Han Chinese patient: A case report and literature review. Heliyon
  3. Stunnenberg BC, LoRusso S, Arnold WD, Barohn RJ, Cannon SC, Fontaine B et al., 2020. Guidelines on clinical presentation and management of nondystrophic myotonias. Muscle & nerve
  4. Waldrop M, Amornvit J, Pierson CR, Boue DR, Sahenk Z, 2020. A Novel De Novo Heterozygous SCN4a Mutation Causing Congenital Myopathy, Myotonia and Multiple Congenital Anomalies. Journal of neuromuscular diseases
  5. Ohno K, Ohkawara B, Shen XM, Selcen D, Engel AG, 2023. Clinical and Pathologic Features of Congenital Myasthenic Syndromes Caused by 35 Genes-A Comprehensive Review. International journal of molecular sciences

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