Insights into the pathogenesis and natural history of fetuses with multicystic dysplastic kidney disease

To better delineate the natural history of multicystic displastic kidney disease (MCDKD) and provide insights into the pathogenesis of this condition, we report our experience in 102 prenatally detected cases. MCDKD is most commonly an incidental finding on prenatal ultrasound examination. The abnormality may be unilateral (76 per cent) or bilateral (24 per cent). In unilateral cases, abnormality of the contralateral kidney is common (33 per cent). Associated non-renal abnormalities occur frequently with both unilateral (26 per cent) and bilateral (67 per cent) MCDKD, and increase the risk for an abnormal chromosome study. Males are more likely to be affected than females with a ratio of 2.4:1, but females are twice as likely to have bilateral MCDKD and associated non-renal abnormalities, and four times more likely to have an abnormal chromosome study. We suggest that the option of chromosomal analysis should be discussed with all patients diagnosed with MCDKD in their fetus, if there is bilateral renal involvement or if an associated non-renal abnormality is present. Unilateral MCDKD without associated renal or non-renal abnormalities was not associated with an abnormal chromosome study, and resulted in favourable outcomes. While unilateral MCDKD, lack of associated anomalies, normal chromosome study and adequate amniotic fluid are all reassuring findings, a complete neonatal urologic work-up should be performed in all newborns. We believe the evaluation should include voiding cystourethrography to rule out vesicoureteral reflux. Our findings allow more precise counselling of patients regarding prognosis, and subsequent management of the fetus found to have MCDKD.