Two months later, she was admitted to our unit for dehydration and hypercalcemia (3.64 mmol/L) with normal 25-OH vitamin D (113.1 nmol/L) and PTH (15 ng/L) levels and high 1,25-dihydroxyvitamin D levels (336 pmol/L), suggesting ectopic 25-hydroxyvitamin D3 1-alpha-hydroxylase activity. Here, CYP27B1 is linked to Hypercalcemia.