A splice site and copy number variant responsible for TTC25-related primary ciliary dyskinesia

The Odad3 Gene Is Necessary for Spermatozoa Development and Male Fertility in Mice

Odad3 gene loss-of-function mutation leads to Primary Ciliary Dyskinesia (PCD), a disease caused by motile cilia dysfunction. Previously, we demonstrated that knockout of the Odad3 gene in mice replicates several features of PCD, such as hydrocephalus, defects in left-right body symmetry, and male infertility, with a complete absence of sperm in the reproductive tract. The majority of Odad3 knockout animals die before sexual maturation due to severe hydrocephalus and failure to thrive, which precludes fertility studies. Here, we performed the expression analysis of the Odad3 gene during gonad development and in adult testes. We showed that Odad3 starts its expression during the first wave of spermatogenesis, specifically at the meiotic stage, and that its expression is restricted to the germ cells in the adult testes, suggesting that Odad3 plays a role in spermatozoa formation. Subsequently, we conditionally deleted the Odad3 gene in adult males and demonstrated that even partial ablation of the Odad3 gene leads to asthenoteratozoospermia with multiple morphological abnormalities of sperm flagella (MMAF) in mice. The analysis of the seminiferous tubules in Odad3-deficient mice revealed defects in spermatogenesis with accumulation of seminiferous tubules at the spermiogenesis and spermiation phases. Furthermore, analysis of fertility in heterozygous Odad3+/- knockout mice revealed a reduction in sperm count and motility as well as abnormal sperm morphology. Additionally, Odad3+/- males exhibited a shorter fertile lifespan. Overall, these results suggest the important role of Odad3 and Odad3 gene dosage in male fertility. These findings may have an impact on the genetic and fertility counseling practice of PCD patients carrying Odad3 loss-of-function mutations.

Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD) is a rare, genetic disease characterized by dysfunctional motile cilia and abnormal mucociliary clearance, resulting in chronic sino-oto-pulmonary disease, neonatal respiratory distress, subfertility, and organ laterality defects. Over the past 2 decades, research and international collaborations have led to an improved understanding of disease prevalence, classic and variable phenotypes, novel diagnostics, genotype-phenotype correlations, long term morbidity, and innovative therapeutics. However, PCD is often underrecognized in clinical settings and the recent analyses of genetic databases suggest that only a fraction of these patients are being accurately diagnosed. Knowledge of significant advancements, from pathophysiology to the expanded range of clinical manifestations, will have important clinical impacts. These may include increasing disease recognition, improving diagnostic testing and management, and establishing an adequate pool of affected patients to enroll in upcoming clinical therapeutic trials. The objective of this state-of-the-art review is for readers to gain a greater understanding of the clinical spectrum of motile ciliopathies, cutting-edge diagnostic practices, emerging genotype-phenotype associations, and currently accepted management of people with PCD.

First reports of primary ciliary dyskinesia caused by a shared DNAH11 allele in Canadian Inuit

BACKGROUND

Primary ciliary dyskinesia (PCD) is typically an autosomal recessive disease characterized by recurrent infections of the lower respiratory tract, frequent and severe otitis media, chronic rhinosinusitis, neonatal respiratory distress, and organ laterality defects. While severe lower respiratory tract infections and bronchiectasis are common in Inuit, PCD has not been recognized in this population.

METHODS

We report a case series of seven Inuit patients with PCD identified by genetic testing in three Canadian PCD centers.

RESULTS

Patients ranged from 4 to 59 years of age (at time of last evaluation) and originated in the Qikiqtaaluk region (Baffin Island, n = 5), Nunavut, or Nunavik (northern Quebec, n = 2), Canada. They had typical features of PCD, including neonatal respiratory distress (five patients), situs inversus totalis (four patients), bronchiectasis (four patients), chronic atelectasis (six patients), and chronic otitis media (six patients). Most had chronic rhinitis. Genetic evaluation demonstrated that all had homozygous pathogenic variants in DNAH11 at NM_001277115.1:c.4095+2C>A.

CONCLUSIONS

The discovery of this homozygous DNAH11 variant in widely disparate parts of the Nunangat (Inuit homelands) suggests this is a founder mutation that may be widespread in Inuit. Thus, PCD may be an important cause of chronic lung, sinus, and middle ear disease in this population. Inuit with chronic lung disease, including bronchiectasis or laterality defects, should undergo genetic testing for PCD. Consideration of including PCD genetic analysis in routine newborn screening should be considered in Inuit regions.

Novel HYDIN variants associated with male infertility in two Chinese families

INTRODUCTION

Infertility is a major disease affecting human life and health, among which male factors account for about half. Asthenoteratozoospermia accounts for the majority of male infertility. High-throughput sequencing techniques have identified numerous variants in genes responsible for asthenoteratozoospermia; however, its etiology still needs to be studied.

METHOD

In this study, we performed whole-exome sequencing on samples from 375 patients with asthenoteratozoospermia and identified two HYDIN compound heterozygous variants, a primary ciliary dyskinesia (PCD)-associated gene, in two unrelated subjects. H&E staining, SEM were employed to analyze the varies on sperm of patients, further, TEM was employed to determine the ultrastructure defects. And westernblot and immunostaining were chose to evaluate the variation of structural protein. ICSI was applied to assist the mutational patient to achieve offspring.

RESULT

We identified two HYDIN compound heterozygous variants. Patient AY078 had novel compound heterozygous splice variants (c.5969-2A>G, c.6316+1G>A), altering the consensus splice acceptor site of HYDIN. He was diagnosed with male infertility and PCD, presenting with decreased sperm progressive motility and morphological abnormalities, and bronchial dilatation in the inferior lobe. Compared to the fertile control, HYDIN levels, acrosome and centrosome markers (ACTL7A, ACROSIN, PLCζ1, and Centrin1), and flagella components (TOMM20, SEPT4, SPEF2, SPAG6, and RSPHs) were significantly reduced in HYDIN-deficient patients. Using intracytoplasmic sperm injection (ICSI), the patient successfully achieved clinical pregnancy. AY079 had deleterious compound heterozygous missense variants, c.9507C>G (p. Asn3169Lys) and c.14081G>A (p. Arg4694His), presenting with infertility; however, semen samples and PCD examination were unavailable.

DISCUSSION

Our findings provide the first evidence that the loss of HYDIN function causes asthenoteratozoospermia presenting with various defects in the flagella structure and the disassembly of the acrosome and neck. Additionally, ICSI could rescue this failure of insemination caused by immobile and malformed sperm induced by HYDIN deficiency.

Diagnostics and Management of Male Infertility in Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD), a disease caused by the malfunction of motile cilia, manifests mainly with chronic recurrent respiratory infections. In men, PCD is also often associated with infertility due to immotile sperm. Since causative mutations for PCD were identified in over 50 genes, the role of these genes in sperm development should be investigated in order to understand the effect of PCD mutations on male fertility. Previous studies showed that different dynein arm heavy chains are present in respiratory cilia and sperm flagellum, which may partially explain the variable effects of mutations on airways and fertility. Furthermore, recent studies showed that male reproductive tract motile cilia may play an important part in sperm maturation and transport. In some PCD patients, extremely low sperm counts were reported, which may be due to motile cilia dysfunction in the reproductive tract rather than problems with sperm development. However, the exact roles of PCD genes in male fertility require additional studies, as do the treatment options. In this review, we discuss the diagnostic and treatment options for men with PCD based on the current knowledge.