[Hereditary renal agenesis . Report of a case]

Renal agenesis is thought to result from a lack of induction of the metanephric blastema by the ureteral bud. Bilateral renal agenesis/dysgenesis (BRA/D) is rare, occurring in only one or two per 10,000 births. Despite its being moreover a sporadic event, there is a male to female ratio of 2.5 to 1 and approximately 20-36% of BRA/D present a familial recurrence, for genetic transmission most probably autosomal dominant with incomplete penetrance and variable expression, termed hereditary renal adysplasia (HRA). A case of prenatal diagnosis by ultrasound of renal agenesis/dysgenesis (left renal agenesis and severe right multicystic dysplastic kidney) is described here. A woman in the 32nd week of pregnancy, who has never undergone any clinical and medical examination, presents at the ultrasound control. A male fetus was born from breech delivery at 34 weeks gestation, weighted 1950 g died after two hours because of severe pulmonary hypoplasia. Autopsy confirmed the antenatal diagnosis of left renal agenesis and right multicystic dysplastic kidney, that measured 42 x 31 x 25 mm, with bilateral complete absence of ureters and renal vessels. No other malformations were present. The infant's chromosomes were normal (46 XY). No specific chromosomal anomaly was identified in either parents. Both the parents had normal genitourinary ultrasound findings. In the wife's family pedigree, a sibling had asymptomatic unilateral renal agenesis, found at ultrasonography, and one maternal aunt had unilateral multicystic kidney and bicornuate uterus. Moreover one maternal uncle died at birth after preterm delivery from respiratory failure, unfortunately kidneys were never examined. Instead, no renal anomaly was identified in the husband's family history. The parents must be made aware not only of the inevitable fatal outcome for the fetus but also of the increased risk of recurrence in a subsequent pregnancy. On the basis of the literature, (of which this case is a further confirmation) it is underlined the necessity that all families of bilateral renal agenesis/dysgenesis patients-should have a detailed evaluation, including a detailed family history and ultrasound study of the kidneys and uterus; in fact all first-degree relatives have an increased risk of having silent genitourinary malformations.