Abstract: Neurodegenerative diseases that affect the motor neurons, including amyotrophic lateral sclerosis (ALS), have little treatment options and are generally rapidly fatal (1, 2). We harnessed the power of unbiased, whole transcriptome differential gene expression analysis, utilizing primary patient cells and tissues to discover genes whose expression defines ALS using published data (3, 4). We found significant differential expression of DHRS9, encoding dehydrogenase/reductase 9, in the motor neurons of patients with ALS. DHRS9 was also differentially expressed in the induced pluripotent stem cell (iPSC)-derived motor neurons of patients with ALS. DHRS9 transcript was present at significantly higher levels in ALS patient motor neurons as compared to control motor neurons. These analyses will begin to define the transcriptional landscape of ALS.