e agree with Laurent’s first two points, even though hypovitaminosis D may cause hypocalciuria, raising the doubt of familial hypocalciuria hypercalcemia. 1 2 There is much debate around the issue of vitamin D in patients with primary hyperparathyroidism 3 4 ; we believe that calcidiol should be measured because vitamin D insufficiency worsens skeletal involvement, for example. Regarding the third point, we were referring to hypocalciuria and not hypercalcaemia. The thresholds reported are those set for the distinction between primary hyperparathyroidism and familial hypocalciuria hypercalcaemia, an important step to avoid unnecessary operations. The role of magnesium is important, but because of space limitations we did not mention it.