Mutations in CFTR genes are associated with oligoasthenospermia in infertile men undergoing IVF

Genetic syndromes leading to male infertility: a systematic review

Male-factor infertility is a multifactorial, complex, and increasingly common condition, of which genetic factors have more frequently been implicated. Not only are the causal relationships between genetic variation and male infertility phenotypes understudied, but also the differences in frequency of disease-causing genetic alterations within different geographic and ethnic groups. Guidelines remain inconsistent as to recommended genomic testing during the male infertility workup. Our current fund of knowledge limits our diagnostic capability where the etiology of male infertility remains idiopathic in about 40% of patients, despite advances in genomic sequencing and testing.

Identification of deleterious variants associated with male infertility genes in a cohort of idiopathic hypospermatogenesis patients

Introduction

Hypospermatogenesis is a common histopathological subtype of non-obstructive azoospermia and is characterized by a decrease in the total number of germ cells within the seminiferous tubule as a result of spermatogenic failure. Determination of genetic factors before intracytoplasmic sperm injection can prevent the inheritance of these factors, as hypospermatogenesis patients gives high successful sperm retrieval rate. This study aimed to identify the structural variants associated with idiopathic hypospermatogenesis (iHS) by analyzing patient cohorts diagnosed with azoospermia using whole exome sequencing.

Methods

It is a hospital-based observational study in which patients reporting with azoospermia due to spermatogenic failure were recruited prospectively. Comprehensive clinical history, blood samples, semen analysis parameters, and reproductive endocrine evaluation reports of 51 hypospermatogenesis patients were collected. The known genetic causes were investigated using XY fluorescent in situ hybridization and Yq microdeletion for exclusion. Whole exome sequencing was performed, and the data of 42 iHS patients was analyzed to identify single nucleotide variants associated with diagnostically important male infertility genes.

Results

Genomic analysis of SNVs identified rare deleterious candidate variants in CFTR (c.1265C>T; p.Ser422Phe), CYP21A2 (c.955C>T; p.Gln319Glu), SRD5A2 (c.737G>A; p.Arg245Gln), LHCGR (c.378A>C; p.Lys126Asn) and AR (c.2179C>A; p.Arg727Ser) genes associated with 7/42 idiopathic hypospermatogenesis patients. In silico analysis of variants shows deleterious and probably damaging effects on canonical transcripts of the genes.

Discussion

This exploratory genomic analysis conducted on idiopathic hypospermatogenesis patients shows prevalence of rare deleterious candidate variants in genes associated with human male infertility. The candidate variants in idiopathic hypospermatogenesis patients are heterozygous and genotypically associated with syndromic male infertility. The symptomatic heterozygosity leading to mild spermatogenic failure resulting in hypospermatogenesis points towards a multifactorial etiology of the disease. This study justifies the importance of genetic screening of idiopathic hypospermatogenesis patients for the presence of structural variants in known human male infertility genes.

DNA methylation patterns in patients with asthenospermia and oligoasthenospermia

BACKGROUND

Spermatogenesis is a highly regulated and complex process in which DNA methylation plays a crucial role. This study aimed to explore the differential methylation profiles in sperm DNA between patients with asthenospermia (AS) and healthy controls (HCs), those with oligoasthenospermia (OAS) and HCs, and patients with AS and those with OAS.

RESULTS

Semen samples and clinical data were collected from five patients with AS, five patients with OAS, and six age-matched HCs. Reduced representation bisulfite sequencing (RRBS) was performed to identify differentially methylated regions (DMRs) in sperm cells among the different types of patients and HCs. A total of 6520, 28,019, and 16,432 DMRs were detected between AS and HC, OAS and HC, and AS and OAS groups, respectively. These DMRs were predominantly located within gene bodies and mapped to 2868, 9296, and 9090 genes in the respective groups. Of note, 12, 9, and 8 DMRs in each group were closely associated with spermatogenesis and male infertility. Furthermore, BDNF, SMARCB1, PIK3CA, and DDX27; RBMX and SPATA17; ASZ1, CDH1, and CHDH were identified as strong differentially methylated candidate genes in each group, respectively. Meanwhile, the GO analysis of DMR-associated genes in the AS vs. HC groups revealed that protein binding, cytoplasm, and transcription (DNA-templated) were the most enriched terms in the biological process (BP), cellular component (CC), and molecular function (MF), respectively. Likewise, in both the OAS vs. HC and AS vs. OAS groups, GO analysis revealed protein binding, nucleus, and transcription (DNA-templated) as the most enriched terms in BP, CC, and MF, respectively. Finally, the KEGG analysis of DMR-annotated genes and these genes at promoters suggested that metabolic pathways were the most significantly associated across all three groups.

CONCLUSIONS

The current study results revealed distinctive sperm DNA methylation patterns in the AS vs. HC and OAS vs. HC groups, particularly between patients with AS and those with OAS. The identification of key genes associated with spermatogenesis and male infertility in addition to the differentially enriched metabolic pathways may contribute to uncovering the potential pathogenesis in different types of abnormal sperm parameters.

Discovery of a novel miRNA involved in the regulation of male infertility in zebrafish

Azoospermia and asthenospermia are common manifestations of male infertility, but it needs further studies to understand the intrinsic regulation mechanism. As a popular model organism, zebrafish is often used to assess reproductive complications. In this study, by analyzing miRNA transcriptome of the mature triploid zebrafish testis afflicted with spermatogenic dysfunctions, leading to the identification of 36 miRNAs that are differentially expressed in comparison with diploid, which are predicted to target 2737 genes. Subsequent functional annotation of these genes pinpointed two miRNAs might association with spermatogenesis. Inhibitory experiments showed that NC_007115.7.7_998413 inhibited conducts a substantial decline in sperm density, and conducted lower embryo fertilization rate than control. And putative target genes qRT-PCR evaluation showed that spata2 was significant down-regulate upon inhibited NC_007115.7.7_998413. In summary, this research positions newly identified miRNA NC_007115.7.998413 as a regulatory factor in male zebrafish reproductive development, enhancing our comprehension of the molecular regulated pathways involved in spermatogenesis.

One-step NGS molecular analysis of the CFTR gene on newborn dried blood spots gives a higher diagnostic sensitivity in affected and carrier subjects: A pilot study

BACKGROUND

Cystic fibrosis is the most common hereditary recessive disease with an incidence of about 1:2500/3000. It has long been known that the disease is caused by deleterious mutations in the CFTR gene. Conventionally, the disease is diagnosed in several phases. The analysis of all the possible disease-causing molecular alterations is time consuming and may not lead to a definitive diagnosis in several cases. Consequently, we propose, in this paper, a rapid sequencing method that, in a single procedural asset, reveals the presence of small mutations and also the copy number variants (CNVs) from the DNA extracted from the Guthrie Spot.

MATERIALS AND METHODS

We first sequenced 30 blood spots, then we validated the method on 100 spots that underwent both traditional analyses and this complete NGS sequencing, and lastly, we tested the strategy on patients who normally do not reach the molecular sequencing step because of low level of Immune-Reactive Trypsinogen.

RESULTS

Using this procedure, we identified 97 variants in the CFTR gene of our samples and 6 CNVs. Notably, the significant data were obtained in the group of patients with borderline or negative IRT who routinely would not undergo molecular testing. We also identified 6 carriers of "disease-causing" variants.

CONCLUSION

This method is very robust. Indeed, there was a 100% concordance with Sanger sequencing validation, and 6 mutation carriers were identified who normally escaped molecular testing with actual conventional procedure. There were also 3 duplications of almost the entire gene in heterozygosity, which were not seen with traditional methods. Being quick and easy to perform, we suggest that complete sequencing of the CFTR gene, as in this study be considered for all newborns.

Current and emerging treatment options for premature ejaculation

Premature ejaculation (PE) is a prevalent male sexual dysfunction. Current standard treatment regimens include behavioural therapies, topical anaesthetics, dapoxetine and other selective serotonin reuptake inhibitors (SSRIs). Most of the pharmacotherapeutic options target neurotransmitters (such as serotonin and oxytocin) that have a role in the ejaculation mechanism. However, these treatments are mildly effective and only provide a temporary delay in the ejaculation latency time, and PE recurs when the treatment is stopped. Thus, a treatment for PE is urgently needed and research is ongoing to find the ideal PE therapy. The efficacy and safety of topical anaesthetics and SSRIs in delaying ejaculation have been confirmed in many well-designed controlled trials. Both preclinical and clinical studies on new-generation SSRIs are ongoing. Moreover, promising results came from clinical trials in which the efficacy of on-demand PE therapies targeting neurotransmitters other than serotonin, such as α1-adrenoceptor antagonists and oxytocin antagonists, was assessed. Surgical intervention and neuromodulation have been proposed as potential treatment options for PE; however, current PE guidelines do not recommend these treatments owing to safety concerns.