RARB and amyotrophic lateral sclerosis: We, for the first time, have discovered that downregulated miR-18b-5p, which may be one of the important pathogenic mechanisms in ALS associated SOD1 mutants (D90A, G17S, G85R, G86S and G93A) is associated with the sequential regulation of Hif1α, Mef2c, miR-206, Mctp1, and Rarb.