Heredity and origin of duplication of the pelvicalyceal collecting system

The present study was undertaken in an effort to prove the significance of genetic factors and their role in the origin of one of the most commonly occurring anomaly, i.e. the duplication of the pelvicalyceal collecting system. Our aim was to test foreign data on autosomal dominant inheritance of low penetrance in this anomaly and to try to find whether a preventive examination of the kidneys and urinary tract (sonography or intravenous urography) can be justified in 1st degree relatives. On intravenous urography made in 44.4% of 1st degree relatives a pathological finding was seen in 20%, one half of which having been estimated as serious requiring further examination and therapy. The above mentioned data in principle coincide with reports in literature abroad. Drawing on the results obtain the pediatrician or urologist can be advised to send the family, in which the pelvis et ureter duplex was discovered, to the genetic consulting centre. Here the 1st degree relatives could be recommended for the examination of their kidneys and urinary tracts on the evidence of the family tree and discussion with parents. The literature assumption that this anomaly is an autosomal dominant defect could not be quite confirmed. The fact that the defect was found in 10.7% of parents and 15% siblings indicates that it could represent the autosomal dominant trait type of low penetrance. An exact definition of the inheritance type is influenced by impossibility of examining the children' grandparents and by retrospective selection of the group. Although the type of heredity cannot be accurately stated yet, we believe the main contribution of our results to consist in the discovered importance of preventive examinations of the urinary tract in 1st degree relatives.