Prenatal case of RIT1 mutation associated Noonan syndrome by whole exome sequencing (WES) and review of the literature

Objective: We aimed to identify the genetic cause of one hydrops fetalis with Noonan syndrome (NS) manifestations including increased nuchal translucency (INT) and ascites through prenatal whole exome sequencing (WES). Case report: The case is a gestational age (GA) 18 fetus of two healthy parents with a normal child. We proceeded the genomic DNA from both fetus amniotic cells and parents to WES and identified a RIT1 mutation (c.268A>G) as the pathogenic cause of the hydrops fetalis by automatic prioritization algorithm after array-comparative genomic hybridization results showing negative. Conclusion: Mutations in RIT1 have been reported as the causes for different fetus structural abnormities in the recent years. This case contributes to the summary delineations of the prenatal NS phenotypes related to RIT1 mutation. In addition, the fast WES application, in this case, has demonstrated its advantage in prenatal disorder diagnosis when conventional karyotyping or chromosomal microarray testing result is negative.