SLC13A2 and Hypercalciuria: Interaction of inhibition of the NaDC-1 citrate transporter by the oxalate transporter slc26a6 in the absence of hypercalciuria and/or calcium sensor receptor alteration may be an answer to the question of whether stone-free or stone-recurrence in OC will occur and explain some of our outliers and extremes [40,41,42].