Associations between DNAH1 gene polymorphisms and male infertility: A retrospective study

Identification of high-risk non-synonymous SNPs (nsSNPs) in DNAH1 and DNAH17 genes associated with male infertility: a bioinformatics analysis

Male infertility is a significant reproductive issue affecting a considerable number of couples worldwide. While there are various causes of male infertility, genetic factors play a crucial role in its development. We focused on identifying and analyzing the high-risk nsSNPs in DNAH1 and DNAH17 genes, which encode proteins involved in sperm motility. A total of 20 nsSNPs for DNAH1 and 10 nsSNPs for DNAH17 were analyzed using various bioinformatics tools including SIFT, PolyPhen-2, CADD, PhD-SNPg, VEST-4, and MutPred2. As a result, V1287G, L2071R, R2356W, R3169C, R3229C, E3284K, R4096L, R4133C, and A4174T in DNAH1 gene and C1803Y, C1829Y, R1903C, and L3595P in DNAH17 gene were identified as high-risk nsSNPs. These nsSNPs were predicted to decrease protein stability, and almost all were found in highly conserved amino acid positions. Additionally, 4 nsSNPs were observed to alter post-translational modification status. Furthermore, the interaction network analysis revealed that DNAH1 and DNAH17 interact with DNAH2, DNAH3, DNAH5, DNAH7, DNAH8, DNAI2, DNAL1, CFAP70, DNAI3, DNAI4, ODAD1, and DNAI7, demonstrating the importance of DNAH1 and DNAH17 proteins in the overall functioning of the sperm motility machinery. Taken together, these findings revealed the detrimental effects of identified high-risk nsSNPs on protein structure and function and highlighted their potential relevance to male infertility. Further studies are warranted to validate these findings and to elucidate the underlying mechanisms.

Splicing Mutation in DNALI1 Causes Male Infertility with Severe Oligoasthenoteratozoospermia in Humans

Oligo-astheno-teratozoospermia (OAT), which is a common cause of male infertility, can be caused by genetic factors. This study reports on a case of a male patient suffering from infertility concomitant with OAT. Whole-exome sequencing (WES) confirmed the presence of a homozygous variant (NM_003462: c.464-1G > A) in the DNALI1 gene via Sanger sequencing. Immunofluorescence staining demonstrated that the DNALI1 signal was nearly undetectable in the patient's sperm. Bioinformatics analysis revealed that this mutation could reverse the splicing of the exon 4 acceptor splice site. A minigene experiment was performed to verify the mutation and the results confirmed that the mutation disrupted the splicing. Our findings show that this rare mutation in DNALI1 contributes to male infertility and OAT in humans, thereby expanding our understanding of the causes and pathogenesis of male infertility. This knowledge facilitates genetic counseling, clinical diagnosis, and therapeutic development of male infertility.

Novel biallelic variants in DNAH1 cause multiple morphological abnormalities of sperm flagella with favorable outcomes of fertility after ICSI in Han Chinese males

BACKGROUND

Multiple morphological abnormalities of sperm flagella is an idiopathic asthenoteratozoospermia characterized by absent, short, coiled, angulation, and irregular-caliber flagella. Genetic variants of DNAH1 gene have been identified as a causative factor of multiple morphological abnormalities of sperm flagella and intracytoplasmic sperm injection is an available strategy for infertile males with dynein axonemal heavy chain 1 defects to conceive.

OBJECTIVES

To identify novel variants and candidate mutant hotspots of DNAH1 gene related to multiple morphological abnormalities of sperm flagella and male infertility in humans.

MATERIALS AND METHODS

The DNAH1 variants were identified by whole exome sequencing and confirmed with Sanger sequencing. Papanicolaou staining, scanning and transmission electron microscopy, and immunostaining were performed to investigate the morphological and ultrastructural characteristics of spermatozoa. Intracytoplasmic sperm injection was applied for the assisted reproductive therapy of males harboring biallelic DNAH1 variants.

RESULTS

We identified 18 different DNAH1 variants in 11 unrelated families, including nine missense variants (p.A2564T, p.T3657R, p.G1862R, p.L2296P, p.T4041I, p.L611P, p.A913D, p.R1932Q, p.R2356W) and nine loss-of-function variants (c.2301-1G>T, p.Q1518*, p.R1702*, p.D2845Mfs*2, p.P3909Rfs*33, p.Q4040Dfs*33, p.Q4058*, p.E4060Pfs*61, p.V4071Cfs*54). A total of 66.7% (12/18) of the identified variants were novel. Morphological analysis based on Papanicolaou staining and scanning electron microscopy demonstrated the typical multiple morphological abnormalities of sperm flagella characteristics of dynein axonemal heavy chain 1-deficient spermatozoa. Immunostaining further revealed the absence of inner dynein arms but not outer dynein arms, which induced a general ultrastructural disorganization, such as the loss of central pair and mis-localization of the microtubule doublets and outer dense fibers. To date, seven affected couples have accepted the intracytoplasmic sperm injection treatment, and three of them have given birth to five healthy babies.

DISCUSSION AND CONCLUSION

These findings further expand the variant spectrum of DNAH1 gene related to multiple morphological abnormalities of sperm flagella and male infertility in humans, thus providing new information for the molecular diagnosis of asthenoteratozoospermia. The favorable fertility outcomes of intracytoplasmic sperm injection will facilitate the genetic counseling and clinical treatment of infertile males with multiple morphological abnormalities of sperm flagella in the future.

Identification of novel compound heterozygous variants in the DNAH1 gene of a Chinese family with left-right asymmetry disorder

Most internal organs in humans and other vertebrates exhibit striking left-right asymmetry in position and structure. Variation of normal organ positioning results in left-right asymmetry disorders and presents as internal organ reversal or randomization. Up to date, at least 82 genes have been identified as the causative genetic factors of left-right asymmetry disorders. This study sought to discover potential pathogenic variants responsible for left-right asymmetry disorder present in a Han-Chinese family using whole exome sequencing combined with Sanger sequencing. Novel compound heterozygous variants, c.5690A>G (p.Asn1897Ser) and c.7759G>A (p.Val2587Met), in the dynein axonemal heavy chain 1 gene (DNAH1), were found in the proband and absent in unaffected family members. Conservation analysis has shown that the variants affect evolutionarily conserved residues, which may impact the tertiary structure of the DNAH1 protein. The novel compound heterozygous variants may potentially bear responsibility for left-right asymmetry disorder, which results from a perturbation of left-right axis coordination at the earliest embryonic development stages. This study broadens the variant spectrum of left-right asymmetry disorders and may be helpful for genetic counseling and healthcare management for the diagnosed individual, and promotes a greater understanding of the pathophysiology.

Analysis of 29 Targeted Genes for Non-Obstructive Azoospermia: The Relationship between Genetic Testing and Testicular Histology

PURPOSE

To analyze the presence of potentially pathogenic variants of 29 candidate genes known to cause spermatogenic failure (SPGF) in patients with non-obstructive azoospermia (NOA) who underwent testicular histology.

MATERIALS AND METHODS

Forty-eight patients with unexplained NOA referred to the Department of Transfusion Medicine and Transplantation Biology, University Hospital Center Zagreb, Zagreb, Croatia for testicular biopsy. They were divided into three groups: those who had cryptorchidism (n=9), those with varicocele (n=14), and those with idiopathic NOA (n=25). All included patients underwent blood withdrawal for next-generation sequencing (NGS) analysis and gene sequencing.

RESULTS

We found a possible genetic cause in 4 patients with idiopathic NOA (16%) and in 2 with cryptorchidism (22%). No pathogenic or possibly pathogenic mutations were identified in patients with varicocele. Variants of undetermined significance (VUS) were found in 11 patients with idiopathic NOA (44%), 3 with cryptorchidism (33%), and 8 patients with varicocele (57%). VUSs of the USP9Y gene were the most frequently as they were found in 14 out of 48 patients (29%). In particular, the VUS USP9Y c.7434+14del was found in 11 patients. They showed varied histological pictures, including Sertoli cell-only syndrome, mixed atrophy, and hypospermatogenesis, regardless of cryptorchidism or varicocele. No direct correlation was found between the gene mutation/variant and the testicular histological picture.

CONCLUSIONS

Different mutations of the same gene cause various testicular histological pictures. These results suggest that it is not the gene itself but the type of mutation/variation that determines the testicular histology picture. Based on the data presented above, it remains challenging to design a genetic panel with prognostic value for the outcome of testicular sperm extraction in patients with NOA.

Novel compound heterozygous mutations in DNAH1 cause primary infertility in Han Chinese males with multiple morphological abnormalities of the sperm flagella

This study aimed to identify genetic causes responsible for multiple morphological abnormalities of the sperm flagella (MMAF) in the Han Chinese population. Three primary infertile males with completely immobile sperm and MMAF were enrolled. Whole-exome sequencing and Sanger sequencing were performed to identify disease-causing genes. Subsequently, morphological and ultrastructural analyses of sperm flagella were investigated. The probable impact of genetic variants on protein function was analyzed by online bioinformatic tools and immunofluorescence assay. Three patients with dynein axonemal heavy chain 1 (DNAH1) gene compound heterozygous variations were identified. DNAH1 c.7435C>T, p.R2479X and c.10757T>C, p.F3586S were identified in the patient from Family 1, c.11726_11727delCT, p.P3909fs and c.12154delC, p.L4052fs were found in the patient from Family 2, and c.10627-3C>G and c.11726_11727delCT, p.P3909fs existed in the patient from Family 3. Four of these variations have not been reported, and all the mutations showed pathogenicity by functional effect predictions. The absence of the center pair and disorganization of the fibrous sheath were present in sperm flagella at the ultrastructural level. Moreover, the expression of DNAH1 was absent in spermatozoa from the participants, validating the pathogenicity of the variants. All three couples have undergone intracytoplasmic sperm injection (ICSI), and two couples of them became pregnant after the treatment. In conclusion, the newly identified DNAH1 mutations can expand the mutational and phenotypic spectrum of MMAF genes and provide a theoretical basis for genetic diagnosis in MMAF patients. It is recommended to conduct genetic screening in male infertility patients with MMAF and provide rational genetic counseling, and ICSI might be an optimal strategy to help with fertilization and conception for patients with DNAH1 mutations.

Potential role of dynein-related genes in the etiology of male infertility: A systematic review and a meta-analysis

BACKGROUND

The dynein-related genes may have a role in the etiology of male infertility, particularly in cases of impaired sperm motility.

OBJECTIVES

The goal of this review is to compile a list of the most important dynein-related candidate genes that may contribute to male factor infertility.

MATERIALS AND METHODS

Databases were searched using the keywords "dynein", "male", "infertility" and by applying strict inclusion criteria. A meta-analysis was also performed by using the eligible case-control studies. The odd ratios (OR), the Z-test score, and the level of significance were determined using a fixed model with a p value of 0.05. Funnel plots were used to check for publication bias.

RESULTS

There were 35 studies that met the inclusion criteria. There were a total of fifteen genes responsible for the production of dynein structural proteins, the production of dynein assembling factors, and potentially associated with male infertility. A total of five case-control studies were eligible for inclusion in the meta-analysis. Variants in the dynein-related genes were linked to an increased the risk of male infertility (OR = 21.52, 95% Confidence Interval (CI) 8.34 - 55.50, Z test = 6.35, p < 0.05). The percentage of heterogeneity, I² , was 47.00%. The lack of variants in the dynein genes was an advantage and this was statistically significant.

DISCUSSION

The results from the present review illustrate that pathogenic variants in genes both for dynein synthesis and for dynein assembly factors could be associated with isolated cases of male infertility without any other symptoms.

CONCLUSIONS

The genes addressed in this study, which are involved in both the production and assembly of dynein, could be used as molecular targets for future research into the etiology of sperm motility problems. This article is protected by copyright. All rights reserved.

Genomic analyses of 10,376 individuals in the Westlake BioBank for Chinese (WBBC) pilot project

We initiate the Westlake BioBank for Chinese (WBBC) pilot project with 4,535 whole-genome sequencing (WGS) individuals and 5,841 high-density genotyping individuals, and identify 81.5 million SNPs and INDELs, of which 38.5% are absent in dbSNP Build 151. We provide a population-specific reference panel and an online imputation server ( https://wbbc.westlake.edu.cn/ ) which could yield substantial improvement of imputation performance in Chinese population, especially for low-frequency and rare variants. By analyzing the singleton density of the WGS data, we find selection signatures in SNX29, DNAH1 and WDR1 genes, and the derived alleles of the alcohol metabolism genes (ADH1A and ADH1B) emerge around 7,000 years ago and tend to be more common from 4,000 years ago in East Asia. Genetic evidence supports the corresponding geographical boundaries of the Qinling-Huaihe Line and Nanling Mountains, which separate the Han Chinese into subgroups, and we reveal that North Han was more homogeneous than South Han.

Genetic Variations and mRNA Expression of Goat DNAH1 and Their Associations with Litter Size

Dynein Axonemal Heavy Chain 1 (DNAH1) encodes proteins which provide structural support for the physiological function and motor structure of spermatozoa (hereafter referred to as sperm) and ova. This study found that three single nucleotide polymorphisms (SNPs), the 27-bp insertion/deletion (InDel) mutations and three exonic copy number variations (CNVs) within DNAH1 were significantly associated with litter size of Shaanbei white cashmere goats (n = 1101). Goats with the wildtypes of these three SNPs had higher litter sizes than other carriers (p < 0.05). II genotype of the 27-bp InDel had the highest litter size compared with ID carriers (p = 0.000022). The gain genotype had the largest litter sizes compared with the loss or medium carriers for the three CNV mutations (p < 0.01). Individuals with the AA-TT-CC-II-M1-M2-M3 and AA-TT-CC-II-G1-G2-M3 combination genotypes had larger litter sizes compared with the other genotypes. This study also showed the DNAH1 expression in mothers of multiple kids was higher than mothers of single kids. These three SNPs, the 27-bp InDel and three CNVs in DNAH1 could be used as molecular markers for the selection of goat reproductive traits.

Novel DNAH1 Mutation Loci Lead to Multiple Morphological Abnormalities of the Sperm Flagella and Literature Review

The protein encoded by dynein axonemal heavy chain 1 (DNAH1) is a part of dynein, which regulates the function of cilia and sperm flagella. The mutant of DNAH1 causes the deletion of inner dynein arm 3 in the flagellum, leading to multiple morphological abnormalities of the sperm flagella (MMAF) and severe asthenozoospermia. However, instead of asthenozoospermia and MMAF, the result caused by the mutation of DNAH1 remains unknown. Here we report a male infertility patient with severe asthenozoospermia and teratozoospermia. We found two heterozygous mutations in DNAH1 (c.6912C>A and c.7076G>T) and which were reported to be associated with MMAF for the first time. We next collected and analyzed 65 cases of DNAH1 mutation and found that the proportion of short flagella is the largest, while the bent flagella account for the smallest, and the incidence of head deformity is not high in the sperm of these patients. Finally, we also analyzed 31 DNAH1 mutation patients who were treated with intracytoplasmic sperm injection (ICSI) and achieved beneficial outcomes. We hope our research will be helpful in the diagnosis and treatment of male infertility caused by DNAH1 mutation.

Novel bi-allelic mutations in DNAH1 cause multiple morphological abnormalities of the sperm flagella resulting in male infertility

Background

Male infertility is a major health concern and approximately 10–15% of cases are caused by genetic abnormalities. Defects in the sperm flagella are closely related to male infertility, since flagellar beating allows sperm to swim. The sperm of males afflicted with multiple morphological abnormalities of the flagella (MMAF) possess severe defects of the sperm flagella, may impair sperm motility and lead to male infertility. Currently, known genetic defects only account for MMAF in about 60% of patients and need more intensive efforts to explore the relationship between genes and MMAF.

Methods

The whole-exome sequencing (WES) was performed to analyze the genetic cause of the MMAF patient. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the morphology of sperm cells and to identify the ultrastructural characteristics of the flagella in the patient. The expression of DNAH1 was analyzed by sperm immunofluorescence staining.

Results

We identified the negative effects produced by the DNAH1 mutations c. 8170.C>T (p. R2724*) and c. 4670C>T (p. T1557M) on DNAH1 expression and the development of sperm flagella.

Conclusions

Our findings suggest that DNAH1 is associated with the formation of sperm flagella and homozygous loss-of-function mutations in DNAH1 can impair sperm motility and cause male infertility.

A novel frameshift mutation in ubiquitin-specific protease 26 gene in a patient with severe oligozoospermia

Ubiquitin-specific protease 26 (USP26) encodes a predicted protein containing his- and cys- domains that are conserved among deubiquitinating enzymes. USP26 is specifically expressed in testis tissue and is a potential infertility gene. In the present study, we performed genetic testing related to spermatogenesis impairment in a patient with idiopathic severe oligozoospermia to identify the cause. The patient underwent clinical examination and reproductive hormone testing. Genes associated with male infertility, including USP26, were assessed by targeted exome sequencing. A novel frameshift mutation, c.2195delT (p.Phe732Serfs*14), was identified in USP26. This frameshift mutation was located in residue 732 of USP26 gene, leading to loss of the conserved deubiquitinating enzyme His-domain and producing a truncated protein of 744 amino acids. Bioinformatics analysis revealed this mutation to be pathogenic. A novel framshift mutation c.2195delT (p.Phe732Serfs*14) in USP26 gene was reported to be associated with male infertility in a Chinese patient with severe oligozoospermia.

Novel Loss-of-Function Mutations in DNAH1 Displayed Different Phenotypic Spectrum in Humans and Mice

Male infertility is a prevalent disorder distressing an estimated 70 million people worldwide. Despite continued progress in understanding the causes of male infertility, idiopathic sperm abnormalities such as multiple morphological abnormalities of sperm flagella (MMAF) still account for about 30% of male infertility. Recurrent mutations in DNAH1 have been reported to cause MMAF in various populations, but the underlying mechanism is still poorly explored. This study investigated the MMAF phenotype of two extended consanguineous Pakistani families without manifesting primary ciliary dyskinesia symptoms. The transmission electron microscopy analysis of cross-sections of microtubule doublets revealed a missing central singlet of microtubules and a disorganized fibrous sheath. SPAG6 staining, a marker generally used to check the integration of microtubules of central pair, further confirmed the disruption of central pair in the spermatozoa of patients. Thus, whole-exome sequencing (WES) was performed, and WES analysis identified two novel mutations in the DNAH1 gene that were recessively co-segregating with MMAF phenotype in both families. To mechanistically study the impact of identified mutation, we generated Dnah1 mice models to confirm the in vivo effects of identified mutations. Though Dnah1^{△iso1/△iso1} mutant mice represented MMAF phenotype, no significant defects were observed in the ultrastructure of mutant mice spermatozoa. Interestingly, we found DNAH1 isoform2 in Dnah1^{△iso1/△iso1} mutant mice that may be mediating the formation of normal ultrastructure in the absence of full-length protein. Altogether we are first reporting the possible explanation of inconsistency between mouse and human DNAH1 mutant phenotypes, which will pave the way for further understanding of the underlying pathophysiological mechanism of MMAF.

CHD7 missense variants and clinical characteristics of Chinese males with infertility

Background

Isolated hypogonadotropic hypogonadism (IHH) and Kallmann syndrome (KS) are rare genetic diseases that cause male infertility. The chromodomain helicase DNA‐binding protein 7 (CHD7) gene is commonly associated with KS and IHH. We speculated that CHD7 variants may be associated with male infertility.

Methods

Two hundred males with azoospermia and 120 with oligozoospermia were recruited. The patients underwent clinical examination and reproductive hormone testing. A panel of genes including CHD7 and others related to spermatogenic failure was sequenced by targeted‐gene exome sequencing.

Results

Three patients with severe oligozoospermia had CHD7 variants (a detection rate of 0.94% (3/320)). After prediction software analysis, two of the variants c.3464G>A (p.R1155H) and c.4516G>A (p.G1506S) were predicted to be likely pathogenic. Although predicted to be benign, the variants of c.2824A>G (p.T942A) located in the chromodomain 2 could not be excluded as disease causing. The patients with variants had small testicular volumes. In particular, the testes of the patient with a p.G1506S variant varied in size (left, 8 ml; right, 4.5 ml). Two patients (patients 31 and 120) had low E2 levels and two (patients 83 and 120) had low T levels. Ultimately, these variants were classified as “variants of unknown significant” that may be associated with male infertility.

Conclusions

There may be a relationship between the CHD7 gene missense variants and male infertility. These variants are easier to find in patients with azoospermia and severe oligospermia whose testosterone levels are decreased.

Investigation of the association of endothelial nitric oxide synthase (eNOS)-T786C gene polymorphism with the risk of male infertility in an Iranian population

Recent studies have demonstrated that making the sorts of oxygen reactive, such as nitric oxide, can cause oxidative lipid damage, protein damage, and damage to the DNA of cells. Sperm DNA damage effect on the reduction of sperm mobility and damage of acrosome membrane lead to the inability of sperm to fertilize the oocyte. Increasing expression of endothelial nitric oxide synthase (eNOS) gene is seen in various diseases such as cardiovascular and infertility diseases. This study aimed to assess the association between eNOS gene single nucleotide polymorphism/SNP (rs2070744, T786C) and risk of male infertility and the quality of sperm parameters in an Iranian population. In this case-control study, 100 infertile men were enrolled as a patient group. Control groups consisted of 100 fertile men. T786C genotypes were determined using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results showed that T786C SNP, contained frequent genotype TC (p = 0.000; OR = 0.000; 95% CI = 0.000-0.015), TC + CC genotypes (p = 0.000; OR = 0.000; 95% CI = 0.000-0.015), and C allele (p = 0.000; OR = 0.00; 95% CI = 0.000-0.007), revealed a significant with male infertility. Based on the findings of this study suggested that although T786C SNP could not be applied as an appropriate genetic risk factor for male infertility, it probably may be considered a protective marker for other researchers. However, more comprehensive studies in different populations are required to confirm our data.

Research Progress of Male Reproductive Toxicity of Chinese Materia Medicas

In recent years, as the infertility rate in China has been increasing year by year and semen quality decreasing, male reproductive toxicity of drugs attracts more and more attention. There are many factors that cause male reproductive toxicity, among which Chinese materia medica is an important aspect. This article will introduce the male reproductive toxicity of Chinese materia medicas grouped by different effectivenesses such as immunosuppressant, evacuant, diuretic, cardiotonic, anti-infective drug and analgesic.