A novel loss-of-function SYCP2 variant causes asthenoteratozoospermia in infertile males

Background:Infertility is a multiplex disorder in the reproductive system. Unexplained infertility affects 2%-3% of reproductive-aged couples. Male factors contribute to about half of all infertility cases. About 15% of these cases are predicted to have a genetic etiology. With the wide application...

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Main Authors: Cong Liu, Yinfeng Zhang, Youming Zhao, Haining Luo
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-05-01
Series:Frontiers in Genetics
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Online Access:https://www.frontiersin.org/articles/10.3389/fgene.2025.1595720/full
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author Cong Liu
Cong Liu
Cong Liu
Yinfeng Zhang
Yinfeng Zhang
Yinfeng Zhang
Youming Zhao
Youming Zhao
Youming Zhao
Haining Luo
Haining Luo
Haining Luo
author_facet Cong Liu
Cong Liu
Cong Liu
Yinfeng Zhang
Yinfeng Zhang
Yinfeng Zhang
Youming Zhao
Youming Zhao
Youming Zhao
Haining Luo
Haining Luo
Haining Luo
author_sort Cong Liu
collection DOAJ
description Background:Infertility is a multiplex disorder in the reproductive system. Unexplained infertility affects 2%-3% of reproductive-aged couples. Male factors contribute to about half of all infertility cases. About 15% of these cases are predicted to have a genetic etiology. With the wide application of whole exome sequencing (WES), more and more variations in male infertility have been identified.Methods:A patient diagnosed with asthenoteratozoospermia was involved in this study. WES was performed in the patient, and Sanger sequencing was used to confirm the variation. Mini-gene splicing assays were performed to validate the effect on the alternative splicing of the variation.Results:A novel heterozygous splice variant was identified in SYCP2 (c.2600+ 5G>C) in the patient ,which inherited from his phenotypically normal mother. SYCP2 encodes a protein critical for the synapsis of homologous chromosomes during meiosis I, and its disruption can impair spermatogenesis. Mini-gene splicing assays confirmed that this splicing variant impacted alternative splicing and that the stop codon appeared early, which was very likely to result in the loss of function of the protein and lead to the occurrence of male infertility.Conclusion:Our results suggested that the c.2600+5G>C variation in SYCP2 might be the genetic etiology for male infertility in this pedigree. This finding expanded the known genotype spectrum of male infertility and provided new etiological information for male infertility.
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spelling doaj-art-388673238aaf43a59f5fbb71ec24e4372025-08-20T02:57:29ZengFrontiers Media S.A.Frontiers in Genetics1664-80212025-05-011610.3389/fgene.2025.15957201595720A novel loss-of-function SYCP2 variant causes asthenoteratozoospermia in infertile malesCong Liu0Cong Liu1Cong Liu2Yinfeng Zhang3Yinfeng Zhang4Yinfeng Zhang5Youming Zhao6Youming Zhao7Youming Zhao8Haining Luo9Haining Luo10Haining Luo11Department of Center for Reproductive Medicine, Tianjin Central Hospital of Gynaecology Obsterics, Tianjin, ChinaTianjin Institute of Gynaecology Obsteric, Tianjin Central Hospital of Gynaecology Obsterics, Tianjin, ChinaTianjin Key Laboratory of Human Development and Reproductive Regulation, Tianjin Central Hospital of Gynaecology Obsterics, Tianjin, ChinaDepartment of Center for Reproductive Medicine, Tianjin Central Hospital of Gynaecology Obsterics, Tianjin, ChinaTianjin Institute of Gynaecology Obsteric, Tianjin Central Hospital of Gynaecology Obsterics, Tianjin, ChinaTianjin Key Laboratory of Human Development and Reproductive Regulation, Tianjin Central Hospital of Gynaecology Obsterics, Tianjin, ChinaDepartment of Center for Reproductive Medicine, Tianjin Central Hospital of Gynaecology Obsterics, Tianjin, ChinaTianjin Institute of Gynaecology Obsteric, Tianjin Central Hospital of Gynaecology Obsterics, Tianjin, ChinaTianjin Key Laboratory of Human Development and Reproductive Regulation, Tianjin Central Hospital of Gynaecology Obsterics, Tianjin, ChinaDepartment of Center for Reproductive Medicine, Tianjin Central Hospital of Gynaecology Obsterics, Tianjin, ChinaTianjin Institute of Gynaecology Obsteric, Tianjin Central Hospital of Gynaecology Obsterics, Tianjin, ChinaTianjin Key Laboratory of Human Development and Reproductive Regulation, Tianjin Central Hospital of Gynaecology Obsterics, Tianjin, ChinaBackground:Infertility is a multiplex disorder in the reproductive system. Unexplained infertility affects 2%-3% of reproductive-aged couples. Male factors contribute to about half of all infertility cases. About 15% of these cases are predicted to have a genetic etiology. With the wide application of whole exome sequencing (WES), more and more variations in male infertility have been identified.Methods:A patient diagnosed with asthenoteratozoospermia was involved in this study. WES was performed in the patient, and Sanger sequencing was used to confirm the variation. Mini-gene splicing assays were performed to validate the effect on the alternative splicing of the variation.Results:A novel heterozygous splice variant was identified in SYCP2 (c.2600+ 5G>C) in the patient ,which inherited from his phenotypically normal mother. SYCP2 encodes a protein critical for the synapsis of homologous chromosomes during meiosis I, and its disruption can impair spermatogenesis. Mini-gene splicing assays confirmed that this splicing variant impacted alternative splicing and that the stop codon appeared early, which was very likely to result in the loss of function of the protein and lead to the occurrence of male infertility.Conclusion:Our results suggested that the c.2600+5G>C variation in SYCP2 might be the genetic etiology for male infertility in this pedigree. This finding expanded the known genotype spectrum of male infertility and provided new etiological information for male infertility.https://www.frontiersin.org/articles/10.3389/fgene.2025.1595720/fullmale infertilitywhole exome sequenceSYCP2gene variationmini-gene splicing assay
spellingShingle Cong Liu
Cong Liu
Cong Liu
Yinfeng Zhang
Yinfeng Zhang
Yinfeng Zhang
Youming Zhao
Youming Zhao
Youming Zhao
Haining Luo
Haining Luo
Haining Luo
A novel loss-of-function SYCP2 variant causes asthenoteratozoospermia in infertile males
Frontiers in Genetics
male infertility
whole exome sequence
SYCP2
gene variation
mini-gene splicing assay
title A novel loss-of-function SYCP2 variant causes asthenoteratozoospermia in infertile males
title_full A novel loss-of-function SYCP2 variant causes asthenoteratozoospermia in infertile males
title_fullStr A novel loss-of-function SYCP2 variant causes asthenoteratozoospermia in infertile males
title_full_unstemmed A novel loss-of-function SYCP2 variant causes asthenoteratozoospermia in infertile males
title_short A novel loss-of-function SYCP2 variant causes asthenoteratozoospermia in infertile males
title_sort novel loss of function sycp2 variant causes asthenoteratozoospermia in infertile males
topic male infertility
whole exome sequence
SYCP2
gene variation
mini-gene splicing assay
url https://www.frontiersin.org/articles/10.3389/fgene.2025.1595720/full
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