GNAS and Hypocalcemia: Conversely, symptomatic hypocalcaemia is the most often presentation in peripubertal and older patients harboring locus imprinting alterations: this genotype might induce a slight impairment of the Gsα activity which, thank to a higher production of PTH, would preserve normocalcaemia until puberty or even adulthood, when the increased calcium requirement makes the resistance clinically evident.