Spinal muscular atrophy (SMA) is a heritable neuromuscular disorder which encompasses a large group of genetic disorders characterized by slowly progressive degeneration of lower motor neurons. The mutation is seen in the SMN1 gene mapped on chromosome 5. Depending on the age of the onset and the degree of severity, SMA has three subtypes. We discuss the autopsy findings in a case of Type 1 SMA also known by the name Werdnig-Hoffmann disease, to highlight the primary changes in the spinal cord, and skeletal muscle with association changes in the liver and terminal respiratory complications.
Gliosis, microvesicular steatosis, neurogenic atrophy, spinal muscular atrophy type I
PowisRA, GillingwaterTH. Selective loss of alpha motor neurons with sparing of gamma motor neurons and spinal cord cholinergic neurons in a mouse model of spinal muscular atrophy. J Anat. 2016;228(3):443-51. [https://doi.org/10.1111/joa.12419]. [PMID:26576026]
JohnsonMA, SideriG, WeightmanD, AppletonD. A comparison of fibre size, fibre type constitution and spatial fibre type distribution in normal human muscle and in muscle from cases of spinal muscular atrophy and from other neuromuscular disorders. J Neurol Sci. 1973;20(4):345-61. [https://doi.org/10.1016/0022-510X(73)90169-X]. [PMID:4272515]
HansonPA, UrizarR. Ultrastructural lesions of muscle and immunofluorescent deposits in vessels in Reye’s syndrome: a preliminary report of serial muscle biopsies. Ann Neurol. 1977;1(5):431-7. [https://doi.org/10.1002/ana.410010506]. [PMID:363044]