A reduced, yet higher-than-normal value of PTH may be found after surgery, even after successful parathyroidectomies (for up to a 1-year duration), most probably in relation to a vitamin D deficiency or to a certain latency of PTH correction, which is currently less understood, as pointed out in the case of a 11-year-old patient with an ectopic parathyroid tumor resection (if genetic PHP is excluded) [68]. This evidence concerns the gene PTH and vitamin D deficiency.