Given the strong influence of a PTH decrease on Ca concentrations and an extreme PTH decrease on the morning after surgery masking the effect of 1,25(OH)2D, the factors defining morning Ca concentrations (Table 5) and hypocalcemia (< 2mmol/L) (Table 6) were analyzed for all enrolled patients in addition to the groups with PTH levels >10 pg/mL or >15 pg/mL. This evidence concerns the gene PTH and Hypocalcemia.