Abstract

A family study of perinatally lethal renal disease (PLRD) was undertaken in the State of Victoria, Australia, for the years 1961 to 1980. A total of 221 cases was ascertained through hospital and necropsy records and confirmed by necropsy findings. There were 134 cases of bilateral renal agenesis (BRA), 34 cases of unilateral agenesis with dysplasia of the other kidney (URA/RD), 42 cases of bilateral renal dysplasia (BRD), and 11 cases of renal aplasia. Parents of 131 babies were interviewed and 153 parents from 82 families had a renal ultrasound examination. In the period of best ascertainment (1975 to 1980) the frequency of PLRD was 0.27 per 1000 and of BRA 0.16 per 1000. There were 10 cases of sirenomelia, a frequency of 0.008 per 1000. For all families of PLRD, 15 of 423 (3.6%) sibs and three of 1579 (0.2%) first cousins were affected. One family had three sibs with BRA and four had two sibs with BRA. One pair of sibs and two first cousins had BRA in one and URA/RD in the other affected. One baby had BRD with an affected first cousin. The nature of the renal lesion was not established. When the index case had BRA, 14 in 283 (5.6%) sibs had PLRD. Where the index case had BRA and urogenital defects, but no birth defects in other organs, 12 of 148 sibs (8%) were affected. None of the sibs had BRA when the index case had BRA as part of a multiple malformation complex. In the multiple malformation group, however, five of 40 (12.5%) sibs had similar patterns of malformations. Renal ultrasound abnormalities were no more frequent in parents of two affected babies (one of 18) than in the other parents (nine of 135). Our findings confirm that BRA and URA are genetically related. There are a number of conclusions which are important for genetic counselling. There is a high likelihood of recurrence (8%) in sibs when the index case has BRA and urogenital abnormalities alone. When BRA is part of a multiple malformation complex, the risk of recurrence of multiple malformations is significant (12.5%), but risk recurrence of BRA is low. The finding of renal ultrasound abnormalities in the parents was not informative.