INTRODUCTION: Amyotrophic lateral sclerosis (ALS), a degenerative disorder of 
the central nervous system, manifests as progressive weakening of muscles. The 
diagnosis and prognosis of ALS are often unclear, so useful biomarkers are 
needed.
METHODS: Total proteins were extracted from muscle samples from 36 ALS, 17 
spinal muscular atrophy (SMA), and 36 normal individuals. The expression levels 
of 134 proteins and phosphoproteins were assessed using protein pathway array 
analysis.
RESULTS: Seventeen proteins were differentially expressed between ALS and normal 
muscle, and 9 proteins were differentially expressed between ALS and SMA muscle. 
The low-level expression of Akt and Factor XIIIB correlates with unfavorable 
survival, and the risk score calculated based on these proteins predicts the 
survival of each individual patient.
CONCLUSIONS: Some proteins could be selected as clinically useful biomarkers. 
Specifically, Akt and Factor XIIIB were found to be promising biomarkers for 
estimating prognosis in ALS.