A Case of Nonimmune Hydrops Fetalis With a Duct-Dependent Systemic Circulation and a Novel Mutation of Kabuki...

Nonimmune hydrops fetalis (NIHF) has numerous etiologies, the most common of which are cardiac anomalies and fetal infection. However, genetic disorders are also being increasingly recognized as a cause of NIHF. Here, we report a case of a neonate presenting with polyhydramnios, NIHF, structural heart disease, and diaphragmatic defect who was found to have a previously unreported mutation in the KMT2D gene.

A female neonate with antenatally detected NIHF was born at 35 weeks of gestation via cesarean section. At birth, she was noted to have dysmorphic features, scoliosis, and a single umbilical artery. Further investigations revealed a left-sided obstructive cardiac lesion and a right-sided Morgagni hernia. She required invasive ventilation, inotropes, and prostaglandin E1 for preductal coarctation of the aorta with hypoplastic left heart syndrome. Genetic analysis was warranted due to multiple anomalies in the neonate. Whole exome sequencing (WES) showed a previously unreported truncating mutation in the KM2TD gene, confirming the diagnosis of Kabuki syndrome type 1.

Kabuki syndrome is rare, and its presentation with hydrops is extremely rare. Our case presented with polyhydramnios, antenatal hydrops, hypoplastic left heart, right-sided Morgagni hernia, and scoliosis with a novel mutation, thus potentially expanding the genotype-phenotype spectrum of this syndrome. This case highlights that a pediatrician should have a high index of suspicion for inherited genetic syndromes in a case of nonimmune hydrops with multiple congenital anomalies. Genetic tests are valuable for identifying rare syndromes and novel mutations.