HDAC4 and amyotrophic lateral sclerosis: When comparing the gene expression levels between cells from ALS patients and controls at each time point (i.e. expression analysis between matched ALS and control cultures at each single time point), we found significant differences in selected genes: MYOD1, PAX7, PAX3 and MYF5 showed increased levels in ALS patients, compared with controls, while HDAC4, MYOG and MEF2C levels were lower in the ALS group than in controls (Fig. 4A).