Initially, the patient had a clinical picture consistent with either mild PHPT or FHH; mild hypercalcemia with high normal/mildly elevated PTH, low urinary calcium but with concomitant vitamin D deficiency, no end organ damage, negative family history, no previous documentation of normal serum calcium level, and negative MIBI scan. This evidence concerns the gene PTH and familial hypocalciuric hypercalcemia.