Introduction
By definition vasopressin-resistant diabetes insipidus is characterized by the following features: (a) polyuria; (b) polydipsia; (c) decreased renal concentrating ability; (d) absence of demonstrable organic renal, pituitary, or hypothalamic lesions; (e) familial nature, and (f) resistance to treatment with vasopressin. Forssman,1 who was one of the first to describe this clinical entity, published a pedigree of five generations, in which there were nine males who were definitely affected and one male who was probably affected. Because all of these males appeared to inherit their condition from a normal female he suggested that the disease was transmitted by a sex-linked recessive gene. In 1947, Williams and Henry2 described five generations of a family in which seven males suffered from polyuria and polydipsia which were resistant to treatment with vasopressin. Again, they inherited their abnormal condition from apparently normal females. These authors also stated that the disease was inherited