a form of diabetes in which the kidneys are unable to produce a normal concentration of urine because the kidney tubules do not respond to vasopressin produced by the pituitary gland. Individuals with this disorder drink enormous amounts of water and excrete large volumes of dilute urine. The disorder can be critical in infants, who cannot communicate their thirst and therefore suffer water depletion, which may lead to brain damage and intellectual disability before the cause can be diagnosed.