SMN1 and amyotrophic lateral sclerosis: The mRNA levels of both apoptosis-related factors (Smn1 and Naip5) correlated with the TDP-43 levels in WBCs and also differed between A382T and G348C, which suggested that each mutation in TARDBP induces distinct RNA metabolism and abnormal RNA metabolism is one of the causes of neuronal cell death in ALS.