Liver and Brain Iron Deficiency in Newborn Infants with Bilateral Renal Agenesis (Potter's Syndrome)

Abstract

Significant changes in fetal iron status potentially occur in pregnancies in which reduced fetal nutrient delivery is severe enough to result in intrauterine growth retardation (IUGR), particularly if chronic fetal hypoxia is also present and increases fetal iron demand for hemoglobin synthesis. Neonates rarely die following IUGR secondary to maternal preeclampsia, but bilateral renal agenesis, which is also characterized by reduced maternal-fetal blood flow, late gestation placental failure, and IUGR, is uniformly fatal. We measured neonatal liver iron concentration, as an assessment of fetal storage iron status, and heart and brain iron concentrations, as assessments of nonheme tissue iron status, in 11 infants who died in the neonatal period of bilateral renal agenesis, and compared them with values for gestational age-matched control infants whose gestation was not complicated by fetal growth retardation or hypoxia. Stainable nonheme iron in the hepatocytes was significantly reduced in all and completely absent in 8 of the 11 cases of renal agenesis (P < .001 compared with control). The mean ± SEM liver iron concentration of the bilateral renal agenesis group (999 ± 218 μg/g dry tissue weight) was 26% of the control value (3894 ± 548 μg/g dry tissue weight; P < .001). Brain iron concentration was also lower in the group with bilateral renal agenesis (109 ± 17 vs. 161 ± 19; P = .015) and was correlated with liver iron concentration (r = .47; P = .03). Heart iron concentrations were similar in the two groups. Nine of the subjects with bilateral renal agenesis had placental weights below the fifth percentile for gestational age. The bilateral renal agenesis group had a lower mean birth weight (P < .001) and had a higher prevalence of fetal growth retardation (55% vs. 0%; P < .001). We conclude that infants with bilateral renal agenesis are at risk for severe iron deficiency of storage and nonstorage tissues. Liveborn infants with nonfatal fetal conditions characterized by significant restriction of maternal-fetal blood flow may also be at significant risk for postnatal iron deficiency.

Key Words:

• brain
• growth retardation
• iron
• liver
• newborn
• renal agenesis