14.6 POJA-L6198+6199 ATPase SMA type I skeletal muscle (human)
14.6 POJA-L6198+6199 ATPase SMA type I skeletal muscle (human)
- (Micrographs by courtesy of H. ter Laak PhD Section Neuropathology, retired staff member Department of Pathology, Radboud university medical center, Nijmegen, The Netherlands)
Title: ATPase SMA type I skeletal muscle (human)
Description:
(A): Normal skeletal muscle stained for myosin ATPase at pH 4.3 showing the checkerboard pattern. Type 1 fibres are stained dark brown, type 2 fibres are pink.
(B): Spinal Muscular Atrophy (SMA) type 1, myosin ATPase at pH 4.3. Type 1 myofibres are brown, and type 2 myofibres are pink. The smallest and largest fibres are type 1, and the large type 1 fibres are clustered. These are the characteristic pathologic findings of this disorder.
Background:
Spinal muscular atrophy type I (or Werdnig-Hoffmann disease) is the most common form of the condition. It is a severe form of the disorder with muscle weakness evident at birth or within the first few months of life. Most children with spinal muscular atrophy type I do not survive past early childhood due to respiratory failure. Apart from the clinical features the use of the ATPase reaction in diagnostic pathology is valuable to distinguish between type I and type II fibres in the following neurogenic cases such as SMA I (Werdnig-Hoffmann disease or severe infantile SMA), SMA II (juvenile spinal muscular atrophy) versus SMA III (Kugelberg-Welander disease), motor neurone disease and chronic neuropathy.
In SMA I and II there is large group atrophy, atrophy of both type fibres as well as hypertrophic mostly type I fibres. SMA III is characterised by often hypertrophic fibres type II. Motor neurone disease shows predominance and hypertrophy of type II fibres. Chronic neuropathy presents predominance and hypertrophy of type I fibres.
See also:
Keywords/Mesh: locomotor system, skeletal muscle, striated muscle, neuromuscular disease, myopathy, spinal muscular atrophy, Werdnig-Hoffman disease, atrophy, hypertrophy, ATPase, pathology, POJA collection