[New phenomena from a genealogical study of Balkan endemic nephropathy in Bulgaria].

The concepts "export" and "import" of BEN are introduced for the first time, admitting to be the ways of spread and expanding the parameters of disease effect -- by marriages of sick, from affected families, with healthy subjects -- from healthy families and settlement. The occurrence of new BEN cases in those families and settlements is explained by the "import of genetic information for BEN." The phenomenon "obviation" of BEN from the families could be of great importance for the medical-genetic consultation, with a view to the prophylaxis of the disease.