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Front. Genet. | doi: 10.3389/fgene.2019.00817

A Novel Silent Mutation in the L1CAM Gene causing Fetal Hydrocephalus detected by Whole Exome Sequencing

 Yixi Sun1, Yanfeng Li1,  Min Chen1, Yuqin Luo1, Yeqing Qian1,  Yanmei Yang1, Hong Lu1, Fenlan Lou1 and  Minyue Dong1*
  • 1Zhejiang University, China

X-linked hydrocephalus (XLH), a genetic disorder, has an incidence of 1/30,000 male births. The great proportion of XLH is ascribed to loss of function mutations of L1 cell adhesion molecule gene (L1CAM), but silent mutations in L1CAM with pathogenic potential were rare, and were usually ignored especially in WES detection. In the present study, we describe a novel silent L1CAM mutation in a Chinese pregnant woman reporting continuous five times pregnancies with fetal hydrocephalus. After fetal blood sampling, we found c.453G>T (p.Gly151=) in L1CAM gene of the fetus by whole exome sequencing (WES), RT-PCR of the mRNA from cord blood mononuclear cells and subsequent sequence analysis identified the mutation created a potential 5' splice site consensus sequence, which would result in an in-frame deletion of 72 bp from exon 5 and 24 amino acids of the L1CAM protein. Heterozygous mutations were confirmed in analyzing DNA and mRNA from peripheral blood mononuclear cells of the woman, and, a severe L1 syndrome was confirmed by fetal ultrasound scan and MRI. Our study first indicated c.453G>T (p.Gly151=) in L1CAM could be disease causing for hydrocephalus, which would aid in genetic counseling for the prenatal diagnosis of hydrocephalus. Meanwhile, it suggested some silent mutations detected in WES should not be ignored, splicing predictions of these mutations were necessary.

Keywords: Hydrocephalus, L1CAM, whole exome sequencing, Silent mutation, splicing mutation

Received: 08 Jun 2019; Accepted: 07 Aug 2019.

Copyright: © 2019 Sun, Li, Chen, Luo, Qian, Yang, Lu, Lou and Dong. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Mx. Minyue Dong, Zhejiang University, Hangzhou, 310058, Zhejiang Province, China, dongmy@zju.edu.cn