Hypercalcaemia resolved spontaneously over a median of 64 (range, 9-329) days, and the median duration of exclusive breastfeeding was 150 (range, 8-540) days.<h4>Conclusion</h4>Breast milk-associated physiological hypercalcaemia is a benign, PTH-independent condition without clinical symptoms or nephrocalcinosis. This evidence concerns the gene PTH and nephrocalcinosis.