DISCUSSION / CONCLUSION
Our case provides further evidence that oligohydramnios is an early US sign of malfunctioning kidneys in a fetus affected with RCS. Both the mother and her child were affected, and we saw that the low levels of amniotic fluid throughout the second trimester indicated kidney malfunction, despite renal structure initially appearing grossly normal as seen with the baby girl. For both patients, the amniotic fluid volume normalized in the early third trimester without intervention. Given the maternal personal history, the couple elected to continue their pregnancy as they were confident that the fluid levels would normalize and pulmonary insufficiency seemed unlikely. With this decision, we were able to document a two-generation history of self-resolving oligohydramnios as an early US sign of RCS.
This case also highlights how an RCS diagnosis through the CAKUT sequencing panel has impacted management for the mother who required an eye examination prior to her delivery. This molecular diagnosis prompted the nephrology team to closely monitor the newborn girl. Through this monitoring, we were able to see early signs of renal failure in the baby girl, with suspected bilateral kidney dysplasia on postnatal US, not noted until recently at almost 2 years of age.
Given the mother’s RCS diagnosis and past medical, obstetrical, and surgical history, it puts her at high risk for obstetrical care. Shortly after giving birth, the mother returned to the high-risk obstetrical clinic with her second pregnancy. Amniotic fluid levels were always normal in that subsequent pregnancy. Reassured, the couple deferred molecular testing for the PAX2 variant until after delivery. The mother was able to successfully, without complication, deliver a second daughter who was not affected by the PAX2 mutation.
In this case, the collection of a detailed medical and family history, and subsequent genetic analysis related to the patient’s history, led to a better understanding of the US anomalies seen during pregnancy and greatly impacted neonatal care.