SLC34A1 and Hypercalcemia: While other patients with hypercalcemia related to vitamin D possess normal ratios, such as patients with SLC34A1 mutation, hypervitaminosis D patients, and certain Williams syndrome patients, it should not be overlooked that measurement of other vitamin D metabolites and attention to absolute concentrations point to distinct metabolite profiles in each of these cases, suggesting that measurement of the complete vitamin D metabolome can aid in the differential diagnosis of vitamin D–related hypercalcemia.