- Hereditary hypophosphatemic rickets with hypercalciuria is not caused by mutations in the Na/Pi cotransporter NPT2 gene. Jones, A., Tzenova, J., Frappier, D., Crumley, M., Roslin, N., Kos, C., Tieder, M., Langman, C., Proesmans, W., Carpenter, T., Rice, A., Anderson, D., Morgan, K., Fujiwara, T., Tenenhouse, H. J. Am. Soc. Nephrol. (2001)