Background Premature ovarian insufficiency (POI) is a common disease in women that leads to a reduced reproductive lifespan. The aetiology of POI is genetically heterogeneous, with certain double-strand break (DSB) repair genes being implicated in POI. Although non-homologous end joining (NHEJ) is an efficient DSB repair pathway, the functional relationship between this pathway and POI remains unknown.
Methods and results We conducted whole-exome sequencing in a Chinese family and identified a rare heterozygous loss-of-function variant in non-homologous end joining factor 1 (NHEJ1): c.532C>T (p.R178*), which co-segregated with POI and irregular menstruation. The amount of NHEJ1 protein in the proband was half of the normal level, indicating a link between NHEJ1 haploinsufficiency and POI. Furthermore, another rare heterozygous NHEJ1 variant c.500A>G (p.Y167C) was identified in one of 100 sporadic POI cases. Both variants were predicted to be deleterious by multiple in silico tools. In vitro assays showed that knock-down of NHEJ1 in human KGN ovarian cells impaired DNA repair capacity. We also generated a knock-in mouse model with a heterozygous Nhej1 variant equivalent to NHEJ1 p.R178* in familial patients. Compared with wild-type mice, heterozygous Nhej1-mutated female mice required a longer time to first birth, and displayed reduced numbers of primordial and growing follicles. Moreover, these mice exhibited higher sensitivity to DSB-inducing drugs. All these phenotypes are analogous to the progressive loss of ovarian function observed in POI.
Conclusions Our observations in both humans and mice suggest that NHEJ1 haploinsufficiency is associated with non-syndromic POI, providing novel insights into genetic counselling and clinical prevention of POI.
- DNA repair
- genetic variation
- high-throughput nucleotide sequencing
- reproductive medicine
Data availability statement
All data relevant to the study are included in the article or uploaded as supplementary information.
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GL, XY and LW contributed equally.
Contributors FZ, XiZ, YaW, GL, XY and LW designed the study. XiZ, QC, XuZ and YiW provided patients’ data and performed clinical assessments. GL, XY, LW, YP, SC, LS, YZ, YuW, YiW, LZ and ZZ conducted experiments. GL, XY, LW, JL, LZ, LJ, YaW, XiZ and FZ analysed data. GL, YaW, XY and FZ wrote the manuscript. FZ, XiZ and YaW supervised the study.
Funding This work was supported by National Key Research and Development Program of China (2017YFC1001100), National Natural Science Foundation of China (31625015 and 31521003), Shanghai Municipal Science and Technology Major Project (2017SHZDZX01), Natural Science Foundation of Shanghai (20ZR1407000), State Key Laboratory of Reproductive Medicine (SKLRM-K202002), Science and Technology Major Project of Inner Mongolia Autonomous Region of China (zdzx2018065) and Innovative Research Team of High-level Local Universities in Shanghai (SSMU-ZLCX20180500).
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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