Sporadic juvenile muscular atrophy of the distal upper extremity or Hirayama's 
disease (HD) and autosomal dominant motor distal neuronopathy/axonopathy 
(CMT2D/dSMA-V), produced by glycyl-tRNA synthetase (GARS) gene mutations, share 
some clinical features including: young age of onset, predilection for the 
distal upper extremity, asymmetry, sparing of proximal muscles and unusual cold 
sensitivity. However, incomplete penetrance of GARS gene mutations may account 
for apparently non-familial cases. In order to inquire whether GARS gene 
mutations are associated with HD we studied seven patients fulfilling the 
clinical and electrodiagnostic criteria for HD. All patients underwent MRI of 
cervical spine that excluded compressive myelopathy in neutral position and 
intramedullary pathology. Each patient was tested for the presence of mutations 
in GARS by sequencing all coding exons amplified from genomic DNA. No pathogenic 
mutations were found, excluding the role of GARS gene as a possible factor in 
the aetiology of HD in this cohort.