RPS6KB1 and mucopolysaccharidosis: We also assessed molecular markers that could be responsible for mediating these impairments in MPS; observing decreases in mTOR Ser2448 phosphorylation with 6‐h PB treatment, as well as reduced phosphorylation (i.e. reduced activation) of downstream regulators of translation initiation (p70 S6K1 and 4E‐BP1), which were still impaired after 24 h.