Abstract
Congenital nephrogenic diabetes insipidus (renal diabetes insipidus) is a rare hereditarydisease caused by insensitivity of the renal tubules to antidiuretic hormone, leading to a decrease in the ability of the kidneys to concentrate urine by water absorption. Hereditary forms of nephrogenic insipid diabetes are caused by mutations in the AVPR2 gene (90%, X-linked recessive form-I), or in the APQ2 gene (10%, autosomal form-type II).
We present two case reports of families where a pathogenic variant was found that allowed the diagnosis to be confirmed. Families carried out testing of the proband's relatives as well as genetic counseling and testing of partners in family planning.
The case reports also illustrate the importance of long-term monitoring of families with genetic diseases and careful updating of genealogical data in next genetic consultations.