SLC34A1 and Hypercalciuria: Homozygous loss-of-function mutations of the SLC34A1 gene have been reported to cause vitamin D-resistant hypophosphatemic rickets, associated with renal Fanconi syndrome, elevated serum 1,25(OH)2D (stimulated by hypophosphatemia), and subsequent hypercalciuria (40, 41) due to enhanced intestinal calcium absorption (42, 43).