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GTR Home > Conditions/Phenotypes > Spinal muscular atrophy, type II

Spinal muscular atrophy, type II

Synonyms
Muscular atrophy, spinal, infantile chronic form; Muscular atrophy, spinal, intermediate type; SMA 2; SMA II; Spinal muscular atrophy type 2
Modes of inheritance
Autosomal recessive inheritance (Orphanet)

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 greater than 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 the disease.
Full text of GeneReview (by section):
Summary
GeneReview Scope
Diagnosis
Clinical Characteristics
Genetically Related (Allelic) Disorders
Differential Diagnosis
Management
Genetic Counseling
Resources
Molecular Genetics
Chapter Notes
References
Authors:
Thomas W Prior
Meganne E Leach
Erika L Finanger
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Available tests

32 tests are in the database for this condition.

Check Related conditions for additional relevant tests.

Clinical tests (32 available)

Molecular Genetics Tests

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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Imported from Human Phenotype Ontology (HPO)

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Reviews

Clinical resources

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.

Molecular resources

Consumer resources

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