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GTR Home > Conditions/Phenotypes > Werdnig-Hoffmann disease

Summary

Excerpted from the GeneReview: Spinal Muscular Atrophy
Spinal muscular atrophy (SMA) is characterized by muscle weakness and atrophy resulting from progressive degeneration and irreversible loss of the anterior horn cells in the spinal cord (i.e., lower motor neurons) and the brain stem nuclei. The onset of weakness ranges from before birth to adulthood. The weakness is symmetric, proximal > distal, and progressive. Before the genetic basis of SMA was understood, it was classified into clinical subtypes based on maximum motor function achieved; however, it is now apparent that the phenotype of SMN1-associated SMA spans a continuum without clear delineation of subtypes. With supportive care only, poor weight gain with growth failure, restrictive lung disease, scoliosis, and joint contractures are common complications; however, newly available targeted treatment options are changing the natural history of this disease.

Genes See tests for all associated and related genes

  • Also known as: BCD541, GEMIN1, SMA, SMA1, SMA2, SMA3, SMA4, SMA@, SMN, SMNT, T-BCD541, TDRD16A, SMN1
    Summary: survival of motor neuron 1, telomeric

Clinical features

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Suggested reading

Practice guidelines

  • ACMG ACT, 2020
    American College of Medical Genetics and Genomics, Newborn Screening ACT Sheet, Exon 7 Deletion (Pathogenic Variant) in Survival Motor Neuron Gene (SMN1), Spinal Muscular Atrophy (SMA), 2020
  • ACMG ACT, 2018
    ACMG Carrier Screening ACT Sheet Spinal Muscular Atrophy (SMA)
  • EuroGenetest, 2012
    Clinical utility gene card for: proximal spinal muscular atrophy.

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