Novel homozygous CFAP69 mutations in humans and mice cause severe asthenoteratospermia with multiple morphological abnormalities of the sperm flagella
Novel homozygous CFAP69 mutations in humans and mice cause severe asthenoteratospermia with multiple morphological abnormalities of the sperm flagella
复制标题
人类和小鼠中新型纯合 CFAP69 突变导致严重的弱精子症，并伴有精子鞭毛的多种形态异常
DOI：
10.1136/jmedgenet-2018-105486
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发表时间：
2019-02-01
影响因子：
4
通讯作者：
Cao, Yunxia
中科院分区：
文献类型：
--
作者：
He, Xiaojin;Li, Weiyu;Cao, Yunxia
研究背景男性不育是人类生殖健康的重大问题。弱精子症可损害精子活力，导致男性不育。弱精子症伴多发鞭毛形态异常(MMAF)表现为精子异常，鞭毛缺失、弯曲、卷曲、短小和/或口径不规则。以往对纤毛相关基因(如AKAP4、DNAH1、CFAP43、CFAP44和CFAP69)的研究表明，纤毛相关基因的遗传缺陷是导致MMAF的主要原因。然而，已知的MMAF相关基因只占人类病例的大约30%到50%。我们进一步调查了MMAF病例，以寻找在这种情况下发生突变的其他基因。方法和结果我们对一个血缘关系密切的汉族人MMAF男性个体进行了全外显子组测序。对其他患有MMAF的个体也进行了Sanger测序。有趣的是，在编码CFAP69(纤毛和鞭毛相关蛋白69)的基因中发现了一个纯合子移码突变(p.Leu357Hisfs*11)，该基因在睾丸中高度表达。随后对另外34名MMAF患者的CFAP69编码区进行了Sanger测序，发现1例CFAP69纯合子无义突变(p.Trp216*)。这两个CFAP69功能缺失突变都没有出现在1000基因组计划和ExAC数据库中存档的人类群体基因组数据中，也没有出现在两个汉族对照群体的875个个体中。此外，我们使用CRISPR-Cas9技术在小鼠同源基因Cfap69中建立了基因敲除模型。值得注意的是，雄性Cfap69基因敲除小鼠表现出MMAF表型。结论我们的实验结果表明，CFAP69纯合功能缺失突变可导致人和小鼠的MMAF弱精子畸形。
Background Male infertility is a major issue of human reproduction health. Asthenoteratospermia can impair sperm motility and cause male infertility. Asthenoteratospermia with multiple morphological abnormalities of the flagella (MMAF) presents abnormal spermatozoa with absent, bent, coiled, short and/or irregular-calibre flagella. Previous studies on MMAF reported that genetic defects in cilia-related genes (eg, AKAP4, DNAH1, CFAP43, CFAP44 and CFAP69) are the major cause of MMAF. However, the known MMAF-associated genes are only responsible for approximately 30% to 50% of human cases. We further investigated the cases with MMAF in search of additional genes mutated in this condition. Methods and results We conducted whole exome sequencing in a male individual with MMAF from a consanguineous Han Chinese family. Sanger sequencing was also conducted in additional individuals with MMAF. Intriguingly, a homozygous frameshift mutation (p.Leu357Hisfs*11) was identified in the gene encoding CFAP69 (cilia and flagella-associated protein 69), which is highly expressed in testis. The subsequent Sanger sequencing of the CFAP69 coding regions among 34 additional individuals with MMAF revealed a case with homozygous nonsense mutation (p.Trp216*) of CFAP69. Both of these CFAP69 loss-of-function mutations were not present in the human population genome data archived in the 1000 Genomes Project and ExAC databases, nor in 875 individuals of two Han Chinese control populations. Furthermore, we generated the knockout model in mouse orthologue Cfap69 using the CRISPR-Cas9 technology. Remarkably, male Cfap69-knockout mice manifested with MMAF phenotypes. Conclusion Our experimental findings elucidate that homozygous loss-of-function mutations in CFAP69 can lead to asthenoteratospermia with MMAF in humans and mice.