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Updated: Aug 19, 2026

Functional and Morphological Assessment of Diaphragm Innervation by Phrenic Motor Neurons
Published on: May 25, 2015
Atypical infantile spinomuscular atrophy presenting as acute diaphragmatic paralysis
1Department of Pathology, Children's Hospital Medical Center, Cincinnati, Ohio 45229.
Insights
Severe diaphragmatic dysfunction in infants with spinal muscular atrophy (SMA) indicates a distinct Werdnig-Hoffmann disease variant. Early neuronal dysfunction and poor prognosis highlight the need for specific diagnostic approaches.
Area of Science:
- Neurology
- Genetics
- Pediatrics
Background:
- Spinal muscular atrophy (SMA) is a severe genetic neuromuscular disorder.
- Werdnig-Hoffmann disease is a common form of SMA, typically presenting in infancy.
- Diaphragmatic dysfunction is a critical complication in SMA, affecting respiratory function.
Abstract:
Two infants with progressive spinomuscular atrophy presented with severe diaphragmatic dysfunction, increasing to 9 the number of cases with this clinically distinctive variant of Werdnig-Hoffmann disease. The anterior horn cell lesion was generalized but was exceptionally severe in the cervical spinal cord of our cases. Fiber size disproportion in serial thigh muscle samples indicated that qualitative neuronal dysfunction preceded appearance of typical denervation. Shoulder girdle muscle biopsy may be more appropriate in these infants, whose prognosis appears to be universally poor.
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