CCDC40 mutation as a cause of primary ciliary dyskinesia: a case report and review of literature

A novel homozygous LRRC6 mutation causes male infertility with asthenozoospermia and primary ciliary dyskinesia in humans

BACKGROUND

Dysfunction of motile cilia, including respiratory cilia and sperm flagella, typically leads to primary ciliary dyskinesia and male infertility or low fertility in humans. Genetic defects of LRRC6 have been associated with primary ciliary dyskinesia and asthenozoospermia due to abnormal ultrastructure of ciliated axonemes.

OBJECTIVES

To identify novel mutations of the LRRC6 gene related to multiple morphological abnormalities of the sperm flagella and male infertility and investigate the underlying molecular mechanisms involved.

MATERIALS AND METHODS

The LRRC6 mutations were identified by whole exome sequencing and confirmed with Sanger sequencing. Papanicolaou staining, scanning, and transmission electron microscopy were performed to investigate the morphological and ultrastructural characteristics of spermatozoa. Further tandem mass tagging proteomics analyses were performed to explore the effect of mutations and confirmed by immunostaining and western blotting. Intracytoplasmic sperm injection was applied for the assisted reproductive therapy of males harboring biallelic LRRC6 mutations.

RESULTS

In this study, we identified a novel homozygous LRRC6 mutation in a consanguineous family, characterized by asthenozoospermia and primary ciliary dyskinesia. Further Semen parameter and morphology analysis demonstrate that the novel LRRC6 mutation leads to a significant reduction in sperm flagella length, a decrease in sperm progressive motility parameters, and abnormalities of sperm ultrastructure. Specifically, the absence of outer dynein arms and inner dynein arms, and incomplete mitochondrial sheath in the flagellar mid-piece were observed by transmission electron microscopy. In addition, tandem mass tagging proteomics analysis revealed that spermatozoa obtained from patients harboring the LRRC6 mutation exhibited a significant decrease in the expression levels of proteins related to the assembly and function of dynein axonemal arms. Functional analysis revealed that this novel LRRC6 mutation disrupted the function of the leucine-rich repeat containing 6 protein, which in turn affects the expression of the dynein arm proteins and leucine-rich repeat containing 6-interacting proteins CCDC40, SPAG1, and ZMYND10. Finally, we reported a successful pregnancy through assisted reproductive technology with intracytoplasmic sperm injection in the female partner of the proband.

DISCUSSION AND CONCLUSION

This study highlights the identification of a novel homozygous LRRC6 mutation in a consanguineous family and its impact on sperm progressive motility, morphology, and sperm kinetics parameters, which could facilitate the genetic diagnosis of asthenozoospermia and offer valuable perspectives for future genetic counseling endeavors.

Identification of a Homozygous Mutation of CCDC40 in a Chinese Infertile Man with MMAF and PCD-like Phenotypes

Aims: Asthenozoospermia is the most common factor of male infertility, mainly caused by multiple morphological abnormalities of the sperm flagella (MMAF) and primary ciliary dyskinesia (PCD). Previous studies have shown that genetic factors may contribute to MMAF and PCD. The study aimed to identify novel potentially pathogenic gene mutations in a Chinese infertile man with MMAF and PCD-like phenotypes. Methods: A Chinese infertile man with MMAF and PCD was enrolled in this study. Whole exome sequencing and Sanger sequencing were performed to identify potential causative genes and mutations. Results: A novel homozygous missense mutation (c.1450G>A; p.E484K) of CCDC40 was finally identified and Sanger sequencing confirmed that the patient carried the homozygous mutation, which was inherited from his parents. We reported the first homozygous missense CCDC40 mutation in infertile men with MMAF but had other milder PCD symptoms. Conclusion: Our findings not only broaden the disease-causing mutation spectrum of CCDC40 but also provide new insight into the correlation between CCDC40 mutations and MMAF.

Regulatory network and targeted interventions for CCDC family in tumor pathogenesis

CCDC (coiled-coil domain-containing) is a coiled helix domain that exists in natural proteins. There are about 180 CCDC family genes, encoding proteins that are involved in intercellular transmembrane signal transduction and genetic signal transcription, among other functions. Alterations in expression, mutation, and DNA promoter methylation of CCDC family genes have been shown to be associated with the pathogenesis of many diseases, including primary ciliary dyskinesia, infertility, and tumors. In recent studies, CCDC family genes have been found to be involved in regulation of growth, invasion, metastasis, chemosensitivity, and other biological behaviors of malignant tumor cells in various cancer types, including nasopharyngeal carcinoma, lung cancer, colorectal cancer, and thyroid cancer. In this review, we summarize the involvement of CCDC family genes in tumor pathogenesis and the relevant upstream and downstream molecular mechanisms. In addition, we summarize the potential of CCDC family genes as tumor therapy targets. The findings discussed here help us to further understand the role and the therapeutic applications of CCDC family genes in tumors.

Ccdc57 is required for straightening the body axis by regulating ciliary motility in the brain ventricle of zebrafish

Recently, cilia defects have been proposed to contribute to scoliosis. Here, we demonstrate that coiled-coil domain-containing 57 (Ccdc57) plays an essential role in straightening the body axis of zebrafish by regulating ciliary beating in the brain ventricle (BV). Zygotic ccdc57 (Zccdc57) mutant zebrafish developes scoliosis without significant changes in their bone density and calcification, and the maternal-zygotic ccdc57 (MZccdc57) mutant embryos display curved bodies since the long-pec stage. The expression of ccdc57 is enriched in ciliated tissues and immunofluorescence analysis reveals colocalization of Ccdc57-HA with acetylated α-tubulin, implicating it in having a role in ciliary function. Further examination reveals that it is the coordinated cilia beating of multiple cilia bundles (MCB) in the MZccdc57 mutant embryos that is affected at 48 hours post fertilization, when the compromised cerebrospinal fluid flow and curved body axis have already occurred. Either ccdc57 mRNA injection or epinephrine treatment reverses the spinal curvature in MZccdc57 mutant larvae from ventrally curly to straight or even dorsally curly and significantly upregulates urotensin signaling. This study reveals the role of ccdc57 in maintaining coordinated cilia beating of MCB in the BV.

Clinical and genetic spectrum of primary ciliary dyskinesia in Chinese patients: a systematic review

Background

Primary ciliary dyskinesia (PCD) represents a highly heterogenous disorder with extensive clinical and genetic patterns among populations of different geographic location and ethnic origin. However, data about Chinese patients are limited. We aimed to summarize the clinical and genetic spectrum of Chinese PCD patients based on all available literatures.

Methods

We searched Embase, Pubmed, Web of Science and Chinese databases including CNKI, SinoMed and Wanfang from 1981 to 2021, to identify articles reporting patients with PCD in China, which had included information about transmission electron microscopy and/or genetic testing.

Results

A total of 244 Chinese PCD patients in 52 articles were included. Of these patients, the mean age was 13.1 years, and 55 patients (22.5%) were diagnosed with PCD after 18 years old. Compared with patients diagnosed with PCD in childhood or infancy, patients diagnosed with PCD in adulthood had a higher prevalence of chronic wet cough, sinusitis, Pseudomonas aeruginosa (PA) isolation and radiological bronchiectasis as well as worse lung function. 25 PCD-related genes were identified in 142 patients, and DNAH5, DNAH11, CCDC39 and CCDC40 were the most frequently detected mutations. More than half of genetic variants were loss-of-function mutations, and the majority of these variants were seen only once. Correlations between PCD phenotype, genotype and ciliary ultrastructure were also evidenced.

Conclusions

Diagnostic delay and under-recognition of PCD remain a big issue in China, which contributes to progressive lung disease and PA infection indicating worse outcome. Specialist equipment and expertise are urgently required to facilitate the early diagnosis and treatment of PCD.

Trial registry

PROSPERO; No.: CRD42021257804; URL:www.crd.york.ac.uk/prospero/

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02427-1.

Comparative Proteomic Analyses of Poorly Motile Swamp Buffalo Spermatozoa Reveal Low Energy Metabolism and Deficiencies in Motility-Related Proteins

The acquisition of mammalian sperm motility is a main indicator of epididymal sperm maturation and helps ensure fertilization. Poor sperm motility will prevent sperm cells from reaching the fertilization site, resulting in fertilization failure. To investigate the proteomic profiling of normal and poorly motile buffalo spermatozoa, a strategy applying liquid chromatography tandem mass spectrometry combined with tandem mass targeting was used. As a result, 145 differentially expressed proteins (DEPs) were identified in poorly motile spermatozoa (fold change > 1.5), including 52 upregulated and 93 downregulated proteins. The upregulated DEPs were mainly involved in morphogenesis and regulation of cell differentiation. The downregulated DEPs were involved with transport, oxidation-reduction, sperm motility, regulation of cAMP metabolism and regulation of DNA methylation. The mRNA and protein levels of PRM1 and AKAP3 were lower in poorly motile spermatozoa, while the expressions of SDC2, TEKT3 and IDH1 were not correlated with motility, indicating that their protein changes were affected by transcription or translation. Such changes in the expression of these proteins suggest that the formation of poorly motile buffalo spermatozoa reflects a low efficiency of energy metabolism, decreases in sperm protamine proteins, deficiencies in motility-related proteins, and variations in tail structural proteins. Such proteins could be biomarkers of poorly motile spermatozoa. These results illustrate some of the molecular mechanisms associated with poorly motile spermatozoa and provide clues for finding molecular markers of these pathways.

Novel Compound Heterozygous Variants in CCDC40 Associated with Primary Ciliary Dyskinesia and Multiple Morphological Abnormalities of the Sperm Flagella

Primary ciliary dyskinesia (PCD) is a rare genetic disease caused by mutations of genes coding motile-cilia-related proteins. CCDC40 variants can cause PCD via disrupting the assembling of inner dynein and dynein regulating complex in cilia and flagella, but none has been reported associated with multiple morphological abnormalities of the sperm flagella (MMAF). We identified and validated the disease-causing variants in our patient via whole-exome and Sanger sequencing. We used high-speed video microscopy analysis (HSVA) and immunofluorescence to analyze the functional and structural deficiency of respiratory cilia. Papanicolaou staining and scanning electron microscope was applied to analyze the morphological sperm defects resulted from the PCD associated variants. We identified novel compound variants (c.901C>T, p.(Arg301*); c.2065_2068dup, p.(Ala690Glyfs*67)) in CCDC40 in a male patient with male infertility. HSVA revealed the rigid and stiff ciliary beating pattern. Immunofluorescence indicated loss of inner dynein arm protein DNAH2 both in cilia and the sperms of the patient. Diagnosis of MMAF was confirmed through sperm Papanicolaou staining and scanning electron microscope. We first describe a patient with a combination of PCD and MMAF associated with novel compound heterozygous variants in CCDC40. Our results present initial evidence that CCDC40 associated with MMAF, which expands the genetic spectrum of PCD and MMAF and provides precise clinical genetic counseling to this family.

Syndromic male subfertility: a network view of genome-phenome associations

Background

Male infertility is a disorder of the reproductive system with a highly complex genetic landscape. In most cases, the reason for male infertility remains unknown; however, the importance of genetic abnormalities in the diagnosis of subfertility/infertility is becoming increasingly recognized. Several syndromes include impaired male fertility in the clinical picture, although a comprehensive analysis of genetic causes of the syndromology perspective of male reproduction is not yet available.

Objectives

(1) To develop a catalog of syndromes and corresponding genes associated with impaired male fertility and (2) to visualize an up‐to‐date genome–phenome network of syndromic male subfertility.

Materials and methods

Published literature was retrieved from the Online Mendelian Inheritance in Man, Orphanet, Human Phenotype Ontology and PubMed databases using keywords “male infertility,” “syndrome,” “gene,” and “case report”; time period from 1980 to September, 2021. Retrieved data were organized as a catalog and complemented with identification numbers of syndromes (MIM ID) and genes (Gene ID). The genome–phenome network and the phenome network were visualized using Cytoscape and Gephi software platforms. Protein–protein interaction analysis was performed using STRING tool.

Results

Retrieved syndromes were presented as (1) a catalog containing 63 syndromes and 93 associated genes, (2) a genome–phenome network including CHD7 and WT1 genes and Noonan and Kartagener syndromes, and (3) a phenome network including 63 syndromes, and 25 categories of clinical features.

Discussion

The developed catalog will contribute to the advances and translational impact toward understanding the factors of syndromic male infertility. Visualized networks provide simple, flexible tools for clinicians and researchers to quickly generate hypotheses and gain a deeper understanding of underlying mechanisms affecting male reproduction.

Conclusion

Recognition of the significance of genome–phenome visualization as part of network medicine can help expedite efforts toward unravelling molecular mechanisms and enable advances personal/precision medicine of male reproduction and other complex traits.

CCDC40 mutation as a cause of infertility in a Chinese family with primary ciliary dyskinesia

TRIAL DESIGN

Primary ciliary dyskinesia (PCD) is a genetical disease that inherited in an autosomal-recessive way. Its clinical manifestations (such as male infertility) are mainly caused by defects of motion-related cilia that encoded by mutated genes. Although some mutation has been verified, a number of mutations of PCD remain elusive. The main purpose of this study is to identify mutant genes in a Chinese family with PCD, and to verify the safety and effectiveness of intracytoplasmic sperm injection (ICSI) of infertility caused by PCD.

METHODS

Imaging examination was used to exclude pulmonary inflammation and visceral translocation. Semen analysis was used to assess the quality of the proband's sperm. Transmission electron microscopy (TEM) was conducted to assess the ultrastructure of flagella and cilia. Targeted next generation sequencing and Sanger sequencing and qPCR (real-time quantitative polymerase chain reaction detecting system) were applied to identified mutation of Chinese Family suspected of having PCD. Viable sperm were selected by hypo-osmotic swelling test (HOST) for ICSI.

RESULTS

We report 2 novel mutations in CCDC40 gene (c.1259delA and EX17_20 deletion) resulted in immobility of sperm and infertility of the proband. These mutations were confirmed in the proband's sister (heterozygous) and his parents (recessive carrier) by Sanger sequencing and qPCR. All the spermatozoa from the proband were immotile. Ultrastructural defects were found in flagella and cilia of proband and his sister. Viable sperms were selected by HOST for ICSI and fertilized 9 of 21 eggs. Two frozen embryos were transplanted and a healthy 3500 g boy was delivered at 40 + 4 weeks' gestation. And then, we summarized the genes related to PCD and the mutant sites of CCDC40 gene.

CONCLUSION

We reported 2 novel mutants in CCDC40 gene (c.1259delA and EX17_20 deletion), which could be candidates for genetic diagnosis in PCD patients. The combination of targeted next generation sequencing and Sanger sequencing may be a useful tool to diagnose PCD. ICSI is a considerable method in treatment of infertility caused by PCD.

Molecular genetics of infertility: loss-of-function mutations in humans and corresponding knockout/mutated mice

BACKGROUND

Infertility is a major issue in human reproductive health, affecting an estimated 15% of couples worldwide. Infertility can result from disorders of sex development (DSD) or from reproductive endocrine disorders (REDs) with onset in infancy, early childhood or adolescence. Male infertility, accounting for roughly half of all infertility cases, generally manifests as decreased sperm count (azoospermia or oligozoospermia), attenuated sperm motility (asthenozoospermia) or a higher proportion of morphologically abnormal sperm (teratozoospermia). Female infertility can be divided into several classical types, including, but not limited to, oocyte maturation arrest, premature ovarian insufficiency (POI), fertilization failure and early embryonic arrest. An estimated one half of infertility cases have a genetic component; however, most genetic causes of human infertility are currently uncharacterized. The advent of high-throughput sequencing technologies has greatly facilitated the identification of infertility-associated gene mutations in patients over the past 20 years.

OBJECTIVE AND RATIONALE

This review aims to conduct a narrative review of the genetic causes of human infertility. Loss-of-function mutation discoveries related to human infertility are summarized and further illustrated in tables. Corresponding knockout/mutated animal models of causative genes for infertility are also introduced.

SEARCH METHODS

A search of the PubMed database was performed to identify relevant studies published in English. The term 'mutation' was combined with a range of search terms related to the core focus of the review: infertility, DSD, REDs, azoospermia or oligozoospermia, asthenozoospermia, multiple morphological abnormalities of the sperm flagella (MMAF), primary ciliary dyskinesia (PCD), acephalic spermatozoa syndrome (ASS), globozoospermia, teratozoospermia, acrosome, oocyte maturation arrest, POI, zona pellucida, fertilization defects and early embryonic arrest.

OUTCOMES

Our search generated ∼2000 records. Overall, 350 articles were included in the final review. For genetic investigation of human infertility, the traditional candidate gene approach is proceeding slowly, whereas high-throughput sequencing technologies in larger cohorts of individuals is identifying an increasing number of causative genes linked to human infertility. This review provides a wide panel of gene mutations in several typical forms of human infertility, including DSD, REDs, male infertility (oligozoospermia, MMAF, PCD, ASS and globozoospermia) and female infertility (oocyte maturation arrest, POI, fertilization failure and early embryonic arrest). The causative genes, their identified mutations, mutation rate, studied population and their corresponding knockout/mutated mice of non-obstructive azoospermia, MMAF, ASS, globozoospermia, oocyte maturation arrest, POI, fertilization failure and early embryonic arrest are further illustrated by tables. In this review, we suggest that (i) our current knowledge of infertility is largely obtained from knockout mouse models; (ii) larger cohorts of clinical cases with distinct clinical characteristics need to be recruited in future studies; (iii) the whole picture of genetic causes of human infertility relies on both the identification of more mutations for distinct types of infertility and the integration of known mutation information; (iv) knockout/mutated animal models are needed to show whether the phenotypes of genetically altered animals are consistent with findings in human infertile patients carrying a deleterious mutation of the homologous gene; and (v) the molecular mechanisms underlying human infertility caused by pathogenic mutations are largely unclear in most current studies.

WILDER IMPLICATIONS

It is important to use our current understanding to identify avenues and priorities for future research in the field of genetic causes of infertility as well as to apply mutation knowledge to risk prediction, genetic diagnosis and potential treatment for human infertility.

Clinical and Genetic Spectrum of Children with Primary Ciliary Dyskinesia in China

OBJECTIVE

To report detailed knowledge about the clinical manifestations, ciliary phenotypes, genetic spectrum as well as phenotype/genotype correlation in primary ciliary dyskinesia (PCD) in Chinese children.

STUDY DESIGN

We recruited 50 Chinese children with PCD. Extensive clinical assessments, nasal nitric oxide, high-speed video analysis, transmission electron microscopy, and genetic testing were performed to characterize the phenotypes and genotypes of these patients.

RESULTS

Common clinical features included chronic wet cough (85.4%), laterality defects (70.0%), and neonatal respiratory distress (55.8%). A high prevalence of congenital abnormalities (30.2%, 13/43), observed in patients who underwent comprehensive examination for comorbidities, included thoracic deformity (11.6%, 5/43), congenital heart disease (9.3%, 4/43), and sensorineural deafness (2.3%, 1/43). For 24 children age >6 years, the mean predicted values of forced expiratory volume in 1 second were 87.2%. Bronchiectasis evident on high-resolution computed tomography was reported in 38.1% of patients (16/42). Biallelic mutations (81 total; 57 novel) were identified in 13 genes: DNAAF3, DNAAF1, DNAH5, DNAH11, CCDC39, CCDC40, CCDC114, CCDC103, HYDIN, CCNO, DNAI1, OFD1, and SPAG1. Overall, ciliary ultrastructural and beat pattern correlated well with the genotype. However, variable phenotypes were also observed in CCDC39 and DNAH5 mutant cilia.

CONCLUSIONS

This large PCD cohort in China broadens the clinical, ciliary phenotypes, and genetic characteristics of children with PCD. Our findings are roughly consistent with previous studies besides some peculiarities such as high prevalence of associated abnormalities.

Male Infertility Diagnosis: Improvement of Genetic Analysis Performance by the Introduction of Pre-Diagnostic Genes in a Next-Generation Sequencing Custom-Made Panel

BACKGROUND

Infertility affects about 7% of the general male population. The underlying cause of male infertility is undefined in about 50% of cases (idiopathic infertility). The number of genes involved in human spermatogenesis is over two thousand. Therefore, it is essential to analyze a large number of genes that may be involved in male infertility. This study aimed to test idiopathic male infertile patients negative for a validated panel of "diagnostic" genes, for a wide panel of genes that we have defined as "pre-diagnostic."

METHODS

We developed a next-generation sequencing (NGS) gene panel including 65 pre-diagnostic genes that were used in 12 patients who were negative to a diagnostic genetic test for male infertility disorders, including primary spermatogenic failure and central hypogonadism, consisting of 110 genes.

RESULTS

After NGS sequencing, variants in pre-diagnostic genes were identified in 10/12 patients who were negative to a diagnostic test for primary spermatogenic failure (n = 9) or central hypogonadism (n = 1) due to mutations of single genes. Two pathogenic variants of DNAH5 and CFTR genes and three uncertain significance variants of DNAI1, DNAH11, and CCDC40 genes were found. Moreover, three variants with high impact were found in AMELY, CATSPER 2, and ADCY10 genes.

CONCLUSION

This study suggests that searching for pre-diagnostic genes may be of relevance to find the cause of infertility in patients with apparently idiopathic primary spermatogenic failure due to mutations of single genes and central hypogonadism.

Genetics of male infertility

Male infertility is a multifactorial pathological condition affecting approximately 7% of the male population. The genetic landscape of male infertility is highly complex as semen and testis histological phenotypes are extremely heterogeneous, and at least 2,000 genes are involved in spermatogenesis. The highest frequency of known genetic factors contributing to male infertility (25%) is in azoospermia, but the number of identified genetic anomalies in other semen and aetiological categories is constantly growing. Genetic screening is relevant for its diagnostic value, clinical decision making, and appropriate genetic counselling. Anomalies in sex chromosomes have major roles in severe spermatogenic impairment. Autosome-linked gene mutations are mainly involved in central hypogonadism, monomorphic teratozoospermia or asthenozoospermia, congenital obstructive azoospermia, and familial cases of quantitative spermatogenic disturbances. Results from whole-genome association studies suggest a marginal role for common variants as causative factors; however, some of these variants can be important for pharmacogenetic purposes. Results of studies on copy number variations (CNVs) demonstrate a considerably higher CNV load in infertile patients than in normozoospermic men, whereas whole-exome analysis has proved to be a highly successful diagnostic tool in familial cases of male infertility. Despite such efforts, the aetiology of infertility remains unknown in about 40% of patients, and the discovery of novel genetic factors in idiopathic infertility is a major challenge for the field of androgenetics. Large, international, and consortium-based whole-exome and whole-genome studies are the most promising approach for the discovery of the missing genetic aetiology of idiopathic male infertility.

Clinical and Genetic Analysis of Children with Kartagener Syndrome

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive disorder characterized by dysfunction of motile cilia causing ineffective mucus clearance and organ laterality defects. In this study, two unrelated Portuguese children with strong PCD suspicion underwent extensive clinical and genetic assessments by whole-exome sequencing (WES), as well as ultrastructural analysis of cilia by transmission electron microscopy (TEM) to identify their genetic etiology. These analyses confirmed the diagnostic of Kartagener syndrome (KS) (PCD with situs inversus). Patient-1 showed a predominance of the absence of the inner dynein arms with two disease-causing variants in the CCDC40 gene. Patient-2 showed the absence of both dynein arms and WES disclosed two novel high impact variants in the DNAH5 gene and two missense variants in the DNAH7 gene, all possibly deleterious. Moreover, in Patient-2, functional data revealed a reduction of gene expression and protein mislocalization in both genes' products. Our work calls the researcher's attention to the complexity of the PCD and to the possibility of gene interactions modelling the PCD phenotype. Further, it is demonstrated that even for well-known PCD genes, novel pathogenic variants could have importance for a PCD/KS diagnosis, reinforcing the difficulty of providing genetic counselling and prenatal diagnosis to families.

Compound Heterozygous Variants in the Coiled-Coil Domain Containing 40 Gene in a Chinese Family with Primary Ciliary Dyskinesia Cause Extreme Phenotypic Diversity in Cilia Ultrastructure

Purpose: Primary ciliary dyskinesia (PCD) is a rare genetic disorder manifested with recurrent infections of respiratory tract and infertility. Mutations in more than 20 genes including the Coiled-Coil Domain Containing 40 (CCDC40) gene are associated with PCD. A Chinese proband with a clinical diagnosis of PCD was analyzed for mutations in these genes to identify the genetic basis of the disease in the family. The proband showed altered mucociliary clearance of the airways, various degree of hyperemia and edema of the mucous membrane, left/right body asymmetry, infertility and ultrastructural abnormality of cilia in both sperm and bronchioles. Methods: The DNA from the proband was analyzed for genetic variation in a subset of genes known to cause PCD using targeted next generation sequencing in order to understand the molecular and genetic basis of the PCD in present family. The result of targeted next generation sequencing has been validated by Sanger sequencing and q-PCR. Results: Targeted next-generation sequencing identified two novel mutations (c.1259delA and EX17_20 deletion) in CCDC40 gene that causes abnormal CCDC40 mRNA expression. These two novel variants cause disorganization of axoneme filaments, which resulted in reduction of sperm motility and phenotypic diversity in ultrastructure of cilia in the proband. Conclusion: These findings highlight the significance of the mutations in CCDC40 as novel candidates for genetic testing in PCD patients as well as the key role of ICSI treatment for the families affected by this ciliary dysmotility. Our findings showed that our work enriched the performance of cilia ultrastructure which were not previously reported in PCD patients.

Analyses of Long Non-Coding RNA and mRNA profiling using RNA sequencing in chicken testis with extreme sperm motility

Sperm motility is the most important indicator in evaluating roosters' fecundity. However, the genetic mechanisms underlying chicken sperm motility is not yet clear. Long non-coding RNA (lncRNA) play epigenetic roles in reproduction. In this study, RNA sequencing was employed to profile the testis transcriptome (lncRNA and mRNA) of six Beijing-you cocks divergent in sperm motility. In total, 2,597 lncRNAs were identified in the chicken testis, including 1,267 lincRNAs, 975 anti-sense lncRNAs, and 355 intronic lncRNAs. They shared similar features with previous studies. Of these lncRNAs, 124 were differentially expressed. Among 17,690 mRNAs detected in this study, 544 were differentially expressed, including a bunch of genes with known functions on sperm motility. GO annotation analysis revealed these genes were involved in ATP binding, cilium assembly, and oxidation-reduction processes. Integrating analysis of lncRNA and mRNA profiles predicted 10 lncRNA-gene pairs, including 8 co-regulated and 2 inversely-regulated pairs. To the best of our knowledge, this is the first genome-wide investigation of the lncRNAs in the chicken testis associated with sperm motility. Our results provided a catalog of chicken testis lncRNAs and genes worthy of further studies to understand their roles in cocks' reproductive performance regulation.

The importance of transmission electron microscopy analysis of spermatozoa: Diagnostic applications and basic research

This review is aimed at discussing the role of ultrastructural studies on human spermatozoa and evaluating transmission electron microscopy as a diagnostic tool that can complete andrology protocols. It is clear that morphological sperm defects may explain decreased fertilizing potential and acquire particular value in the field of male infertility. Electron microscopy is the best method to identify systematic or monomorphic and non-systematic or polymorphic sperm defects. The systematic defects are characterized by a particular anomaly that affects the vast majority of spermatozoa in a semen sample, whereas a heterogeneous combination of head and tail defects found in variable percentages are typically non-systematic or polymorphic sperm defects. A correct diagnosis of these specific sperm alterations is important for choosing the male infertility's therapy and for deciding to turn to assisted reproduction techniques. Transmission electron microscopy (TEM) also represents a valuable method to explore the in vitro effects of different compounds (for example drugs with potential spermicidal activity) on the morphology of human spermatozoa. Finally, TEM used in combination with immunohistochemical techniques, integrates structural and functional aspects that provide a wide horizon in the understanding of sperm physiology and pathology.

ABBREVIATIONS

transmission electron microscopy: TEM; World Health Organization: WHO; light microscopy: LM; motile sperm organelle morphology examination: MSOME; intracytoplasmic morphologically selected sperm injection: IMSI; intracytoplasmic sperm injection: ICSI; dysplasia of fibrous sheath: DFS; primary ciliary dyskinesia: PCD; outer dense fibers: ODF; assisted reproduction technologies: ART; scanning electron microscopy: SEM; polyvinylpirrolidone: PVP; tert-butylhydroperoxide: TBHP.

Coiled-coil domain containing 42 (Ccdc42) is necessary for proper sperm development and male fertility in the mouse

Spermiogenesis is the differentiation of spermatids into motile sperm consisting of a head and a tail. The head harbors a condensed elongated nucleus partially covered by the acrosome-acroplaxome complex. Defects in the acrosome-acroplaxome complex are associated with abnormalities in sperm head shaping. The head-tail coupling apparatus (HTCA), a complex structure consisting of two cylindrical microtubule-based centrioles and associated components, connects the tail or flagellum to the sperm head. Defects in the development of the HTCA cause sperm decapitation and disrupt sperm motility, two major contributors to male infertility. Here, we provide data indicating that mutations in the gene Coiled-coil domain containing 42 (Ccdc42) is associated with malformation of the mouse sperm flagella. In contrast to many other flagella and motile cilia genes, Ccdc42 expression is only observed in the brain and developing sperm. Male mice homozygous for a loss-of-function Ccdc42 allele (Ccdc42(KO)) display defects in the number and location of the HTCA, lack flagellated sperm, and are sterile. The testes enriched expression of Ccdc42 and lack of other phenotypes in mutant mice make it an ideal candidate for screening cases of azoospermia in humans.

The "omics" of human male infertility: integrating big data in a systems biology approach

Spermatogenesis is a complex process in which >2300 genes are temporally and spatially regulated to form a terminally differentiated sperm cell that must maintain the ability to contribute to a totipotent embryo which can successfully differentiate into a healthy individual. This process is dependent on fidelity of the genome, epigenome, transcriptome, and proteome of the spermatogonia, supporting cells, and the resulting sperm cell. Infertility and/or disease risk may increase in the offspring if abnormalities are present. This review highlights the recent advances in our understanding of these processes in light of the "omics revolution". We briefly review each of these areas, as well as highlight areas of future study and needs to advance further.