We addressed these issues taking advantage of an in vitro model of HS, represented by human fibroblasts with the mutational features of this mucopolysaccharidosis, through evaluation of the mRNA expression levels of the core clock genes and of a panel of clock controlled genes selected by means of literature-mining [27-30,33] (for a complete list of circadian transcripts refer to: CircaDB at http://circadb.org). The gene discussed is CLOCK; the disease is mucopolysaccharidosis.