Familial renal abnormalities associated with the oligohydramnios tetrad secondary to renal agenesis and dysgenesis.

Thirty-four families of index cases with the oligohydramnios tetrad secondary to renal agenesis/dysgenesis were screened for renal abnormalities using Real Time ultrasonography. The index cases were separated into two groups. Group 1 consisted of cases of perinatally lethal renal disease and Group 2 of cases of renal dysgenesis secondary to the urethral obstruction malformation. Renal ultrasound screenings of 23 families in Group 1 demonstrated two previously unidentified cases of unilateral renal agenesis in siblings. Screening of 11 families in Group 2 revealed one sibling with a hydronephrotic kidney and one parent with an ectopic pelvic kidney. There is a recurrence risk of 3.5-5% in families with perinatal lethal renal disease and an increased risk of silent renal anomalies in first degree family members. The recurrence risk is low in families of infants with renal dysgenesis secondary to the urethral obstruction malformation, but immediate family members are at increased risk of structural and functional urinary anomalies. Routine renal ultrasound screening of first degree relatives of infants with lethal renal agenesis and dysgenesis is recommended.