Identification of rare missense mutations in NOTCH2 and HERC2 associated with familial central precocious puberty via whole-exome sequencing

Abstract

Objective: Genetic factors play a critical role in pubertal progression; however, mutations associated with central precocious puberty (CPP) have been reported only in four genes: KISS1, KISS1R, DLK1, and MKRN3. This study aimed to identify novel, potentially pathogenic variants in patients with familial CPP via whole-exome sequencing (WES).

Methods: WES analysis was applied in 28 patients (25 girls and three boys) belonging to 14 families, wherein all siblings were diagnosed with CPP. Data analysis aimed to select only very rare variants (minor allele frequency <1%). Nonsense, splice-site, and frameshift variants were considered the most ideal candidate variants. Additionally, non-synonymous missense variants predicted as being deleterious using in silico analysis tools were further considered.

Results: The analysis of exome sequencing data resulted in the identification of rare mutations in two promising candidate genes (NOTCH2 and HERC2) in a family. Siblings with CPP exhibited two heterozygous missense mutations (p. Leu15Phe in NOTCH2 and p. Arg4081His in HERC2). Moreover, their parents without history of CPP had a missense variant in either NOTCH2 or HERC2.

Conclusions: We identified new candidate genes with potential roles in pubertal development. Digenic inheritance of the two genetic mutations associated with the Notch signaling pathway may have a synergistic effect resulting in CPP.

摘要

目的：遗传因素在青春期发育中起着关键作用, 然而, 与中枢性性早熟（CPP）相关的突变只在KISS1、KISS1R、DLK1和MKRN3四个基因中被报道。本研究旨在通过全外显子组测序（WES）鉴定家族性CPP患者新的潜在的致病性基因突变。

方法：对来自于14个家庭的28名患者（25名女孩和3名男孩）进行了WES分析, 他们的所有的兄弟姐妹都被诊断为CPP。数据分析旨在选择非常罕见的基因变异（次要等位基因频率<1%）。无义、剪接位点和移码突变被认为是最理想的突变。此外, 我们进一步考虑到了在硅分析工具中被预测的有害的非同义错义突变。

结果：全外显子组测序数据分析出一个家族中两个基因（NOTCH2和HERC2）的罕见突变。患有CPP的兄弟姐妹表现出两个杂合子错义突变(p. Leu15Phe in NOTCH2 and p. Arg4081His in HERC2)。此外, 他们的父母没有CPP病史, 但在NOTCH2和HERC2中都有一个错义突变。

结论：我们发现了在青春期发育过程中新的潜在致病基因。两个基因突变的双基因遗传与Notch信号通路相关, 他们之间的协同作用导致了CPP。

The Chinese abstracts are translated by Prof. Dr. Xiangyan Ruan and her team: Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing 100026, China.

Keywords:

• Whole exome sequencing
• precocious puberty
• genes
• genetic etiology

Acknowledgements

The authors gratefully acknowledge the support of the patients in this study.

Ethics approval

Clinical and genetic studies were approved by the Institutional Review Board of the Ajou University Hospital (AJIRB-BMR-GEN-16-210). All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration. All participants provided written informed consent prior to study participation. Our datasets were obtained from subjects who consented to the use of their individual clinical and genetic data for biomedical research. Informed and written consent was obtained for publication.

Author contributions

HS Lee and JS Hwang designed the study. HS Lee, HR Jeong, and JS Hwang collected the samples and clinical information. KH Kim and HS Lee performed the laboratory experiments and data analysis. HS Lee was responsible for the pipeline. SY Jeong, DW Kim and JY Cheong performed the in silico analysis and data interpretation. HS Lee drafted the manuscript, and HS Lee and JS Hwang refined the final approved version of the paper. All authors have discussed the data and provided some advice. All authors read and approved the final manuscript.

Disclosure statement

None of the authors have any conflict of interest to disclose. We confirm that we have read the Journal’s position on issues involved in ethical publication and affirm that this report is consistent with those guidelines.

Additional information

Funding

This study was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (Grant number: NRF-2016R1C1B2015718).