Congenital central diabetes insipidus in two sibling Afghan hound pups.

Congenital central diabetes insipidus was determined to be the cause of polydipsia and polyuria in sibling pups. Both pups were lacking adequate plasma arginine vasopressin concentration, compared with that in control dogs. Microscopic abnormalities were confined to the brain and pituitary gland in one pup. Without breeding trials of these dogs or their relatives, it cannot be determined whether the cause was familial.