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Interfamilial phenotypic heterogeneity in SMARD1

S Joseph1, S A Robb, S Mohammed

  • 1Department of Neurology, Evelina Children's Hospital, Lambeth Palace Road, London SE1 7EH, UK. sonia.joseph@luht.scot.nhs.uk

Neuromuscular Disorders : NMD
|January 23, 2009
PubMed

Insights

Spinal muscular atrophy with respiratory distress (SMARD1) shows varied symptoms even with the same genetic mutation. This suggests other factors influence the disease, impacting its presentation and progression.

Area of Science:

  • Genetics
  • Neurology
  • Pediatrics

Background:

  • Spinal muscular atrophy with respiratory distress (SMARD1) is a severe genetic disorder.
  • It is caused by mutations in the IGHMBP2 gene.
  • SMARD1 typically presents before 13 months with respiratory failure and limb weakness.

Observation:

  • This case report details two siblings with identical SMARD1 mutations.
  • One sibling experienced fatal respiratory failure at 6 months.
  • The other sibling, aged 12, exhibits limb weakness and mild sleep hypoventilation.

Findings:

  • The identical genetic mutation resulted in significantly different clinical outcomes.
  • Phenotype variability in SMARD1 is more pronounced than previously understood.
  • This suggests the influence of modifying genes or environmental factors.

Implications:

  • SMARD1 should be considered in atypical spinal muscular atrophy cases, even without clear diaphragmatic weakness.
  • Understanding phenotype variability can improve diagnostic approaches and patient management.
  • Further research into compensatory mechanisms in SMARD1 is warranted.

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