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.