Editorial: Vesicoureteral reflux and its familial distribution.

Abstract

The genitourinary tract is one of the commonest sites of congenital malformation, and several anomalies may coexist in one individual: for instance, primary vesicoureteral reflux due to a short intramural ureter may be associated with dysplasticl 2 or with duplex kidneys.3 4 Since Stephens et a15 observed reflux and megaureter in identical twins there have been many reports of familial reflux, and over 80 families have now been described. Vesicoureteral reflux has been found in up to five members of a family6 and spanning one to four generations.7 In one family reflux or other renal tract anomalies were found in eight first-or second-degree relatives.8Though this familial aggregation suggests a hereditary basis for at least some types of primary vesicoureteral reflux, there is no uniform pattern of inheritance. In one group of families it seems that the patients are almost exclusively male.7 9 Those described in detail have had severe reflux and extensive renal damage of the obstructive atrophy type; there has been little evidence of urinary tract infection. In one of this group of families the pedigree strongly suggests an X-linked mode of genetic transmission9 and in another autosomal dominant inheritance of the trait with incomplete penetrance. 7 In the other, more heterogeneous group both sexes are affected, but females more than males,6 8-13 and reflux may often be shown without any coexisting renal damage-for example, in a grandmother of 72 with presumed lifelong reflux6 and in a 23-year-old mother of three girls, all four with reflux.°0 Repeated urinary tract infection is common in affected members of these families, and has occurred in all the patients with renal scarring, which is generally of the classical, coarse pyelonephritic type.6 811 The inheritance of reflux in these families is less clear, but Burger6 14 suggests a multifactorial genetic basis acting at the vesicoureteral junction and subject to environmental factors such as age, infection, and pressure.These observations are important in piecing together the modes of inheritance of vesicoureteral reflux, but widespread radiological investigation for this purpose alone is scarcely justified, and the pattern will be clarified as more family studies emerge in the course ofroutine care.A more practical application of the findings might be in the early identification of infants or children with vesicoureteral reflux, since reflux is of considerable importance in the pathogenesis of kidney damage associated with infection, which is likely to start at an early age.'5 Reports of individual families with reflux give no indication of the risk of finding it in the relatives of an isolated affected patient, but Burger calculated14 that in a family with at least two affected members the risk of finding reflux in further members was 13.6%. The incidence of reflux in the population is not known, but it probably occurs at some time in at least 0O5-1-0% of girls.The implications of these studies are that the clinician should be aware that vesicoureteral reflux...