SLC20A1 and hereditary hypophosphatemic rickets with hypercalciuria: Our Pit1 and Pit2 three allele knockout mice may be a good model to separate effects of hypophosphatemia from effects caused by adaptive hormonal changes as a result of hypophosphatemia and improve our understanding of the pathophysiology of the myopathy seen in hypophosphatemic disorders such as HHRH or XLH59.