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Early infantile form of spinal muscular atrophy (Werdnig-Hoffmann disease) with prolonged survival

Janina Borkowska1, Sabine Rudnik-Schoneborn, Irena Hausmanowa-Petrusewicz

  • 1Neuromuscular Unit, Medical Research Centre, Polish Academy of Sciences, Warszawa. neurmyol@cmdik.pan.pl

Folia Neuropathologica
|July 18, 2002
PubMed

Insights

Spinal muscular atrophy (SMA) type I patients can survive past age five, challenging traditional classification systems. Survival may depend on resilience to respiratory issues rather than solely on disease onset or severity.

Area of Science:

  • Neurology
  • Genetics
  • Pediatrics

Background:

  • Traditional classification systems define Spinal Muscular Atrophy (SMA) type I by early onset (<6 months), severe immobility, and a fatal prognosis before age 4.
  • This classification has historically excluded patients with prolonged survival despite severe symptoms.

Observation:

  • A study identified 36 out of 349 (10%) SMA type I patients who survived past age five.
  • These individuals exhibited early onset (<6 months) and never achieved the ability to sit unsupported, alongside frequent respiratory infections.

Findings:

  • The data suggest that age at death is not a suitable criterion for classifying SMA type I.
  • Within the prolonged survival subgroup of SMA type I, the age of symptom onset (at birth, before 3 months, or after 3 months) did not significantly impact lifespan.
  • Discordant ages of death within sibships with similar neuromuscular compromise suggest individual resilience to respiratory insults influences lifespan.

Implications:

  • These findings support revising SMA classification systems to better reflect the spectrum of disease progression and survival.
  • The study highlights the potential overlap between SMA type I and SMA type II phenotypes.
  • Further research into factors influencing resilience to respiratory complications in SMA is warranted.

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