Figure 4. Algorithm for differential diagnosis of nephrocalcinosis associated with hypercalciuria. Ca2+ = calcium; UAG = urinary anion gap; dRTA = distal renal tubular acidosis; LMW = low molecular weight; Mg2+ = magnesium; FHHNC = familial hypomagnesemia with hypercalciuria and nephrocalcinosis; PTH = parathormone; PHPT = primary hyperparathyroidism; TmP/GFR = renal tubular maximum reabsorption rate of phosphate to glomerular filtration rate; ADHH = autosomal dominant hypocalcemia with hypercalciuria. *Nephrocalcinosis rarely occurs in the initial presentation of ADHH, being observed specially after the treatment of hypocalcemia with calcitriol and calcium. **NaPi mutations may also present with hypercalcemia.
