Brain malformations have been reported in RASopathies, including postnatal external hydrocephalus, a nonobstructive form of cerebrospinal fluid accumulation around the brain. It was described in a few patients with mutations of other genes than PTPN11, such as SOS1 and SHOC2 and never in prenatal diagnosis. The aim of this case report is to describe the prenatal presentation of a fetus with Noonan syndrome (NS) and external hydrocephalus.

中文翻译：

---

外部脑积水作为努南综合征的产前特征

在 RASopathies 中已经报道了脑畸形，包括出生后外部脑积水，脑周围脑脊液积聚的一种非阻塞性形式。它在少数具有除PTPN11以外的其他基因突变的患者中被描述，例如SOS1和SHOC2，并且从未在产前诊断中被描述过。本病例报告的目的是描述患有 Noonan 综合征 (NS) 和外部脑积水的胎儿的产前表现。