VP12.07: Unilateral and bilateral fetal renal abnormalities in our centre

Unilateral renal agenesis is defined as the absence of one kidney with visible bladder and normal amniotic fluid. Differential diagnosis should be done with ectopic kidney, defined as the visualisation of the kidney in a different location than the renal fossa. Bilateral renal agenesis is defined as the absence of both kidneys and bladder with anhydramnios from 17 weeks of pregnancy. The objective was to describe the association between unilateral, bilateral renal agenesis, and ectopic kidney with other major abnormalities or genetic alterations. We performed a retrospective observational study. A review of the ultrasound database identified fetuses with unilateral, bilateral renal agenesis and ectopic kidney from 2011 to 2020. Genetic alterations were collected. Neonatal records, postnatal imaging studies and autopsies were reviewed to identify anomalies not diagnosed prenatally. We identified 19 cases of unilateral renal agenesis, 68% were left-sided and 65% were male fetuses. In 7 cases, extra-renal malformations were described, the most common were cardiac malformations. We performed 11 invasive tests and 2 genetic alterations were found in isolated unilateral agenesis (2/8) and 1 in a fetus with other abnormalities (1/3). In another case with other abnormalities and no previous prenatal test, a postnatal study was performed due to ADHD and dyslexia, and a genetic alteration was found. We had 1 bilateral renal agenesis case, without a genetic alteration. 11 ectopic kidneys were described, 46% of the cases were right-sided and 27% were left-sided and 27% were bilateral. In 64% cases were male fetuses. We performed 5 invasive tests with no genetic alteration. In one of the cases, a postnatal exploration was required due to abnormal phenotype and was diagnosed with Pierre-Robin sequence. Our results are similar to the literature. Patients should be aware of the possibility that other major abnormalities or genetic syndromes could be associated. So, an invasive test should be offered, especially if another fetal abnormality is found.