CLOCK and multiple sclerosis: Indeed, circadian dysregulation has been associated with myelination disorders in the central nervous system, i.e. enhanced risk of multiple sclerosis correlated with mutations in ARNTL/BMAL1 and CLOCK circadian genes (Lavtar et al., 2018), owing to the regulatory role of the ARNTL gene in oligodendrogenesis (Huang et al., 2020).