CCDC151基因新型纯合移码突变导致一个中国家庭原发性纤毛运动障碍并伴无精子症

文献信息

中文摘要

背景： CCDC151对外动力蛋白臂（ODA）的对接和组装至关重要，其功能丧失会损害黏液纤毛清除功能，导致原发性纤毛运动障碍（PCD）。CCDC151的致病性变异鲜有报道，而与CCDC151相关PCD伴随的无精子症仍特征不明。
方法： 采用全外显子组测序（WES）和Sanger测序鉴定一个患有PCD的中国家系中的疾病相关基因。应用结构域分析预测该变异对CCDC151的潜在影响。通过高速视频显微镜分析（HSVA）、透射电子显微镜（TEM）和免疫荧光（IF）染色检查呼吸道上皮多纤毛细胞，以评估所鉴定变异的结构和功能后果。在HEK293T细胞中进行功能实验，评估所鉴定变异对mRNA和蛋白表达的影响。
结果： 我们描述了一名40岁男性，表现为反复呼吸道感染、慢性鼻窦炎、弥漫性双侧支气管扩张和无精子症。WES鉴定出CCDC151中一个既往未报道的纯合移码变异（NM_145045.5:c.986dupT; p. Gln330ThrfsTer40），预测会导致蛋白质提前截断。IF染色显示呼吸道上皮纤毛中ODA组分DNAH5和DNAI1完全缺失，TEM证实纤毛轴丝中ODA缺失。一致地，HSVA显示纤毛完全不动。功能实验显示野生型和突变型构建体之间mRNA水平相当，Western blotting在突变型转染细胞中检测到约41 kDa的截短蛋白，证实c.986dupT变异产生稳定的截短CCDC151蛋白。这些发现支持该新型CCDC151变异的致病性。我们进一步回顾了已发表的CCDC151相关PCD病例，强调了该亚型的罕见性和等位基因异质性。
结论： 我们在一名患有PCD和无精子症的患者中鉴定出一个新型纯合移码CCDC151变异，扩展了CCDC151相关PCD的突变谱和表型谱，并支持CCDC151功能障碍与无精子症之间的关联。

英文摘要

BACKGROUND: CCDC151 is essential for outer dynein arms (ODA) docking and assembly, and loss of its function impairs mucociliary clearance, leading to primary ciliary dyskinesia (PCD). Pathogenic variants in CCDC151 have been reported rarely, and azoospermia associated with CCDC151-related PCD remains poorly characterized.
METHODS: Whole exome sequencing (WES) and sanger sequencing were used to identify disease-related genes in a Chinese family with PCD. Domain analysis was applied to predict the potential impact of the variant on CCDC151. Respiratory multiciliated cells were examined by high speed video microscopy analysis (HSVA), transmission electron microscopy (TEM), and immunofluorescence (IF) staining to assess the structural and functional consequences of the identified variant. Functional assays in Human embryonic kidney 293 T (HEK293T) cells were performed to assess the impact of the identified variant on mRNA and protein expression.
RESULTS: We described a 40-year-old man with recurrent respiratory infections, chronic sinusitis, diffuse bilateral bronchiectasis, and azoospermia. WES identified a previously unreported homozygous frameshift variant in CCDC151 (NM_145045.5:c.986dupT; p. Gln330ThrfsTer40), predicted to result in premature protein truncation. IF staining showed complete loss of the ODA components DNAH5 and DNAI1 from respiratory cilia, and TEM confirmed absence of ODA in the cilia axonemes. Consistently, HSVA revealed complete ciliary immotility. Functional assays revealed comparable mRNA levels between wild-type and mutant constructs, and western blotting detected a truncated protein of approximately 41 kDa in mutant-transfected cells, confirming that the c.986dupT variant produces a stable truncated CCDC151 protein. These findings support the pathogenicity of this novel CCDC151 variant. We further reviewed published cases of CCDC151-related PCD, highlighting the rarity and allelic heterogeneity of this subtype.
CONCLUSION: We identified a novel homozygous frameshift CCDC151 variant in a patient with PCD and azoospermia, expanding the mutational and phenotypic spectra of CCDC151-related PCD and supporting an association between CCDC151 dysfunction and azoospermia.