Although these observations do not establish causation, we interpret these remarkable findings to mean that canines may be highly sensitive to PTH-induced hypercalcemia, in contrast to other large animal models (i.e. rhesus monkeys that tolerate 25 μg/kg/day PTH(1–84) for 16 months [35]), and further high dose studies with this formulation of rPTH in dogs should be pursued with caution. The gene discussed is PTH; the disease is Hypercalcemia.