Genetic defects of NaPi2A and NaPi2C result in renal phosphate wasting, causing hypophosphatemia and nephrocalcinosis, also known as idiopathic infantile hypercalcemia (IIH) and hypophosphatemic rickets with hypercalciuria (HHRH), respectively [13–15]. The gene discussed is SLC34A3; the disease is hypophosphatemia.