MEF2C and amyotrophic lateral sclerosis: Our findings are as follows: (i) downregulated miR-18b-5p post-transcriptionally controls Hif1α expression, (ii) Hif1α increases Mef2c as a transcription factor, (iii) Mef2c highly increases miR-206 levels, (iv) miR-206 simultaneously degrades Mctp1 and Rarb, (v) decreased Mctp1 inhibits calcium signaling, (vi) reduced Rarb impedes neuronal cell differentiation, and (vii) downregulated miR-18b-5p enhances apoptotic cell death in ALS SOD1 mutations.