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Hematoxylin and eosin stain of quadriceps muscle of an infant with GARS1-iSMA at 4X (A) and 10X (B) magnification showing findings typical of spinal muscular atrophy
A. Low power magnification demonstrates small atrophied fibers with marked variation in fiber size. Inflammatory cells are absent, and there is no increase in endomysial connective tissue.
B. Higher power magnification demonstrates clusters of large hypertrophied muscle fibers among large groups of small often rounded, atrophic muscle fibers.

Distribution of muscle weakness and atrophy in individuals with two major clinical phenotypes of GARS1-associated disease
A. Thenar and first dorsal interosseus muscle wasting with relatively preserved hypothenar in an individual with dSMA-V phenotype
B. Peroneal atrophy, pes cavus, and hammerhead toes in an individual with the CMT2D phenotype; this individual also has a reduction of pinprick, temperature, touch, and vibration sense in stocking distribution.
Reprinted from Sivakumar et al [2005] by permission of Oxford University Press