On the other hand, in patients with HHRH due to hypophosphatemia, an appropriate elevation in the serum levels of 1,25-dihydroxyvitamin D leading to hypercalciuria, hypercalcemia and decreased serum PTH levels and increased serum ALP activity are noted (5,6). Here, PTH is linked to hereditary hypophosphatemic rickets with hypercalciuria.