Research Core Facility of West China Hospital, Sichuan University, Chengdu Sichuan 610041, China; Department of Obstetrics/Gynecology, Joint Laboratory of Reproductive Medicine (SCU-CUHK), Key Laboratory of Obstetric, Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu 610041, China.
Research Core Facility of West China Hospital, Sichuan University, Chengdu Sichuan 610041, China.
Reprod Biomed Online. 2021 Nov;43(5):920-930. doi: 10.1016/j.rbmo.2021.07.005. Epub 2021 Jul 22.
Male infertility is a widespread symptom in patients with primary ciliary dyskinesia (PCD). PCD-related male infertility is often caused by asthenozoospermia, with barely normal sperm morphology. Multiple morphological abnormalities of the sperm flagella (MMAF) are a major cause of asthenozoospermia, characterized by various malformed morphologies of sperm flagella. To date, a limited number of genes have been suggested to be involved in the pathogenesis of both PCD and MMAF. What other genes associated with both PCD and MMAF are waiting to be discovered?
Whole-exome sequencing (WES) was performed to identify the pathogenic mutation associated with MMAF in a PCD patient. Peripheral venous blood and semen samples were collected from the PCD patient. Transmission electron microscopy (TEM), immunofluorescence staining and western blotting were conducted to confirm the pathogenicity of the identified mutation.
A novel homozygous mutation in CCDC39, c.983 T>C (p. Leu328Pro), was identified in two PCD-affected siblings of a consanguineous family showing a typical PCD phenotype, while the proband was infertile, which is associated with characterized MMAF. Furthermore, TEM revealed the abnormal ultrastructure of the patient's sperm flagella. Moreover, immunofluorescence staining revealed that CCDC39 was almost undetectable in the spermatozoa, which was further confirmed by western blotting. The outcome of intracytoplasmic sperm injection (ICSI) in the patient with the CCDC39 mutation was also favourable.
This study demonstrates that a novel loss-of-function mutation of CCDC39 is involved in the pathogenesis of PCD and MMAF and initially reported that ICSI treatment has a good outcome. Therefore, the novel variant of CCDC39 contributes to the genetic diagnosis, counselling and treatment of male infertility in PCD patients with MMAF phenotype.
原发性纤毛运动障碍（PCD）患者普遍存在男性不育症状。PCD 相关的男性不育症通常由弱精症引起，精子形态几乎正常。精子鞭毛多种形态异常（MMAF）是弱精症的主要原因，其特征是精子鞭毛的各种畸形形态。迄今为止，已有少数基因被认为与 PCD 和 MMAF 的发病机制有关。还有哪些与 PCD 和 MMAF 都相关的基因有待发现？
对一名 PCD 患者进行全外显子组测序（WES），以鉴定与 MMAF 相关的致病突变。从 PCD 患者采集外周静脉血和精液样本。进行透射电子显微镜（TEM）、免疫荧光染色和 Western blot 以确认鉴定出的突变的致病性。
在一个表现出典型 PCD 表型的近亲结婚的 PCD 患者的两个受影响的兄弟姐妹中发现了 CCDC39 中的一个新的纯合突变，c.983 T>C（p.Leu328Pro），而先证者不育，这与特征性的 MMAF 有关。此外，TEM 显示患者精子鞭毛的异常超微结构。此外，免疫荧光染色显示 CCDC39 在精子中几乎无法检测到，Western blot 进一步证实了这一点。该患者接受了胞浆内单精子注射（ICSI）的治疗，结果也很理想。
本研究表明，CCDC39 的一个新的功能丧失突变参与了 PCD 和 MMAF 的发病机制，并首次报道 ICSI 治疗有良好的效果。因此，CCDC39 的新变异有助于对具有 MMAF 表型的 PCD 患者的男性不育症进行遗传诊断、咨询和治疗。
