Bi-allelic variants in DNHD1 cause flagellar axoneme defects and asthenoteratozoospermia in humans and mice.

Asthenoteratozoospermia, defined as reduced sperm motility and abnormal sperm morphology, is a disorder with considerable genetic heterogeneity. Although previous studies have identified several asthenoteratozoospermia-associated genes, the etiology remains unknown for the majority of affected men. Here, we performed whole-exome sequencing on 497 unrelated men with asthenoteratozoospermia and identified DNHD1 bi-allelic variants from eight families (1.6%). All detected variants were predicted to be deleterious via multiple bioinformatics tools. Hematoxylin and eosin (H&E) staining revealed that individuals with bi-allelic DNHD1 variants presented striking abnormalities of the flagella; transmission electron microscopy (TEM) further showed flagellar axoneme defects, including central pair microtubule (CP) deficiency and mitochondrial sheath (MS) malformations. In sperm from fertile men, DNHD1 was localized to the entire flagella of the normal sperm; however, it was nearly absent in the flagella of men with bi-allelic DNHD1 variants. Moreover, abundance of the CP markers SPAG6 and SPEF2 was significantly reduced in spermatozoa from men harboring bi-allelic DNHD1 variants. In addition, Dnhd1 knockout male mice (Dnhd1‒/‒) exhibited asthenoteratozoospermia and infertility, a finding consistent with the sperm phenotypes present in human subjects with DNHD1 variants. The female partners of four out of seven men who underwent intracytoplasmic sperm injection therapy subsequently became pregnant. In conclusion, our study showed that bi-allelic DNHD1 variants cause asthenoteratozoospermia, a finding that provides crucial insights into the biological underpinnings of this disorder and should assist with counseling of affected individuals.

Bi-allelic mutations of DNAH10 cause primary male infertility with asthenoteratozoospermia in humans and mice.

Multiple morphological abnormalities of the sperm flagella (MMAF)-induced asthenoteratozoospermia is a common cause of male infertility. Previous studies have identified several MMAF-associated genes, highlighting the condition's genetic heterogeneity. To further define the genetic causes underlying MMAF, we performed whole-exome sequencing in a cohort of 643 Chinese MMAF-affected men. Bi-allelic DNAH10 variants were identified in five individuals with MMAF from four unrelated families. These variants were either rare or absent in public population genome databases and were predicted to be deleterious by multiple bioinformatics tools. Morphological and ultrastructural analyses of the spermatozoa obtained from men harboring bi-allelic DNAH10 variants revealed striking flagellar defects with the absence of inner dynein arms (IDAs). DNAH10 encodes an axonemal IDA heavy chain component that is predominantly expressed in the testes. Immunostaining analysis indicated that DNAH10 localized to the entire sperm flagellum of control spermatozoa. In contrast, spermatozoa from the men harboring bi-allelic DNAH10 variants exhibited an absence or markedly reduced staining intensity of DNAH10 and other IDA components, including DNAH2 and DNAH6. Furthermore, the phenotypes were recapitulated in mouse models lacking Dnah10 or expressing a disease-associated variant, confirming the involvement of DNAH10 in human MMAF. Altogether, our findings in humans and mice demonstrate that DNAH10 is essential for sperm flagellar assembly and that deleterious bi-allelic DNAH10 variants can cause male infertility with MMAF. These findings will provide guidance for genetic counseling and insights into the diagnosis of MMAF-associated asthenoteratozoospermia.

Biallelic CFAP61 variants cause male infertility in humans and mice with severe oligoasthenoteratozoospermia.

BACKGROUND: The genetic causes for most male infertility due to severe oligoasthenoteratozoospermia (OAT) remain unclear. OBJECTIVE: To identify the genetic cause of male infertility characterised by OAT. METHODS: Variant screening was performed by whole-exome sequencing from 325 infertile patients with OAT and 392 fertile individuals. In silico and in vitro analyses were performed to evaluate the impacts of candidate disease-causing variants. A knockout mouse model was generated to confirm the candidate disease-causing gene, and intracytoplasmic sperm injection (ICSI) was used to evaluate the efficiency of clinical treatment. RESULTS: We identified biallelic CFAP61 variants (NM_015585.4: c.1654C>T (p.R552C) and c.2911G>A (p.D971N), c.144-2A>G and c.1666G>A (p.G556R)) in two (0.62%) of the 325 OAT-affected men. In silico bioinformatics analysis predicted that all four variants were deleterious, and in vitro functional analysis confirmed the deleterious effects of the mutants. Notably, H&E staining and electron microscopy analyses of the spermatozoa revealed multiple morphological abnormalities of sperm flagella, the absence of central pair microtubules and mitochondrial sheath malformation in sperm flagella from man with CFAP61 variants. Further immunofluorescence assays revealed markedly reduced CFAP61 staining in the sperm flagella. In addition, Cfap61-deficient mice showed the OAT phenotype, suggesting that loss of function of CFAP61 was the cause of OAT. Two individuals accepted ICSI therapy using their own ejaculated sperm, and one of them succeeded in fathering a healthy baby. CONCLUSIONS: Our findings indicate that CFAP61 is essential for spermatogenesis and that biallelic CFAP61 variants lead to male infertility in humans and mice with OAT.

Novel SPEF2 variants cause male infertility and likely primary ciliary dyskinesia.

PURPOSE: This study aimed to identify the genetic causes of male infertility and primary ciliary dyskinesia (PCD)/PCD-like phenotypes in three unrelated Han Chinese families. METHODS: We conducted whole-exome sequencing of three patients with male infertility and PCD/PCD-like phenotypes from three unrelated Chinese families. Ultrastructural and immunostaining analyses of patient spermatozoa and respiratory cilia and in vitro analyses were performed to analyze the effects of SPEF2 variants. Intracytoplasmic sperm injection (ICSI) was administered to three affected patients. RESULTS: We identified four novel SPEF2 variants, including one novel homozygous splicing site variant [NC_000005.10(NM_024867.4): c.4447 + 1G > A] of the SPEF2 gene in family 1, novel compound heterozygous nonsense variants [NC_000005.10(NM_024867.4): c.1339C > T (p.R447*) and NC_000005.10(NM_024867.4): c.1645G > T (p.E549*)] in family 2, and one novel homozygous missense variant [NC_000005.10(NM_024867.4): c.2524G > A (p.D842N)] in family 3. All the patients presented with male infertility and PCD/likely PCD. All variants were present at very low levels in public databases, predicted to be deleterious in silico prediction tools, and were further confirmed deleterious by in vitro analyses. Ultrastructural analyses of the spermatozoa of the patients revealed the absence of the central pair complex in the sperm flagella. Immunostaining of the spermatozoa and respiratory cilia of the patients validated the pathogenicity of the SPEF2 variants. All patients carrying SPEF2 variants underwent one ICSI cycle and delivered healthy infants. CONCLUSION: Our study reported four novel pathogenic variants of SPEF2 in three male patients with infertility and PCD/PCD-like phenotypes, which not only extend the spectrum of SPEF2 mutations but also provide information for genetic counseling and treatment of such conditions.

CFAP65 is required in the acrosome biogenesis and mitochondrial sheath assembly during spermiogenesis.

Asthenoteratospermia is a common cause of male infertility. Recent studies have revealed that CFAP65 mutations lead to severe asthenoteratospermia due to acrosome hypoplasia and flagellum malformations. However, the molecular mechanism underlying CFAP65-associated sperm malformation is largely unclear. Here, we initially examined the role of CFAP65 during spermiogenesis using Cfap65 knockout (Cfap65-/-) mice. The results showed that Cfap65-/- male mice exhibited severe asthenoteratospermia characterized by morphologically defective sperm heads and flagella. In Cfap65-/- mouse testes, hyper-constricted sperm heads were apparent in step 9 spermatids accompanied by abnormal manchette development, and acrosome biogenesis was abnormal in the maturation phase. Moreover, subsequent flagellar elongation was also severely affected and characterized by disrupted assembly of the mitochondrial sheath (MS) in Cfap65-/- male mice. Furthermore, the proteomic analysis revealed that the proteostatic system during acrosome formation, manchette organization and MS assembly was disrupted when CFAP65 was lost. Importantly, endogenous immunoprecipitation and immunostaining experiments revealed that CFAP65 may form a cytoplasmic protein network comprising MNS1, RSPH1, TPPP2, ZPBP1 and SPACA1. Overall, these findings provide insights into the complex molecular mechanisms of spermiogenesis by uncovering the essential roles of CFAP65 during sperm head shaping, acrosome biogenesis and MS assembly.

Identification of novel biallelic LRRC6 variants in male Chinese patients with primary ciliary dyskinesia and infertility.

PURPOSE: The aim of this study is to identify the genetic cause of primary ciliary dyskinesia (PCD) and male infertility in two unrelated Han Chinese families. METHODS: We performed whole-exome sequencing in two unrelated male Han Chinese patients suffering from infertility and PCD to identify the pathogenic variants. Ultrastructural and immunostaining analyses of patient's spermatozoa were performed to characterize the effect of the variants. The pathogenicity of the variants was validated using patient's spermatozoa by western blotting and immunostaining analysis. Intracytoplasmic sperm injection (ICSI) was conducted in the affected families. RESULTS: Three variants in leucine-rich repeat containing 6 (LRRC6) [patient 1(compound heterozygote): NM_012472: c.538C > T, (p.R180*) and c.64dupT, (p.S22Ffs*19); patient 2 (homozygote): c.863C > A, (p.P288H)] were identified in two unrelated patients with PCD and male infertility. These variants were predicated deleterious and were absent or rare in human population genome data. LRRC6-mutant spermatozoa showed a highly aberrant morphology and ultrastructure with lacked inner and outer dynein arms. The LRRC6 protein was present along the normal sperm flagella, and was significantly decreased in the mutated spermatozoa. Interestingly, both patients were able to conceive through ICSI and birthed a healthy baby. CONCLUSION: Our results extend the LRRC6 variant spectrum and provide reproductive guidance to families suffering from PCD-linked infertility caused by LRRC6 variants.

Bi-allelic variants in SHOC1 cause non-obstructive azoospermia with meiosis arrest in humans and mice.

Meiosis is pivotal to gametogenesis and fertility. Meiotic recombination is a mandatory process that ensures faithful chromosome segregation and generates genetic diversity in gametes. Non-obstructive azoospermia (NOA) caused by meiotic arrest is a common cause of male infertility and has many genetic origins, including chromosome abnormalities, Y chromosome microdeletion and monogenic mutations. However, the genetic causes of the majority of NOA cases remain to be elucidated. Here, we report our findings of three Shortage in chiasmata 1 (SHOC1) bi-allelic variants in three NOA patients, of which two are homozygous for the same loss-of-function variant (c.231_232del: p.L78Sfs*9), and one is heterozygous for two different missense variants (c.1978G>A: p.A660T; c.4274G>A: p.R1425H). Testicular biopsy of one patient revealed impairment of spermatocyte maturation. Both germ-cell-specific and general Shoc1-knockout mice exhibited similar male infertility phenotypes. Subsequent analysis revealed comprehensive defects in homologous pairing and synapsis along with abnormal expression of DMC1, RAD51 and RPA2 in Shoc1-defective spermatocyte spreads. These findings imply that SHOC1 may have a presynaptic function during meiotic recombination apart from its previously identified role in crossover formation. Overall, our results provide strong evidence for the clinical relevance of SHOC1 mutations in patients with NOA and contribute to a deeper mechanistic understanding of the role of SHOC1 during meiotic recombination.

Novel homozygous truncating variants in ZMYND15 causing severe oligozoospermia and their implications for male infertility.

Sequence variants of ZMYND15 cause azoospermia in humans, but they have not yet been reported in infertile men with severe oligozoospermia (SO). We performed whole-exome and Sanger sequencing to identify suspected causative variants in 414 idiopathic participating infertile men with SO or azoospermia. Three novel homozygous truncating variants in ZMYND15 were identified in three of the 219 (1.37%) unrelated patients with SO, including c.1209T>A(p.Tyr403*), c.1650delC (p.Glu551Lysfs*75), and c.1622_1636delinsCCAC (p.Leu541Profs*39). In silico bioinformatic analyses as well as in vivo and in vitro experiments showed that the ZMYND15 variants carried by the affected subjects might be the underlying cause for their infertility. One patient accepted intracytoplasmic sperm injection therapy, using his ejaculated sperm, and his wife successfully became pregnant. Our findings expand the disease phenotype spectrum by indicating that ZMYND15 variants cause SO and male infertility and suggest a possible correlation between the severity of male infertility caused by ZMYND15 variants and male age.

Novel mutations in SPEF2 causing different defects between flagella and cilia bridge: the phenotypic link between MMAF and PCD.

Severe asthenozoospermia is a common cause of male infertility. Recent studies have revealed that SPEF2 mutations lead to multiple morphological abnormalities of the sperm flagella (MMAF) without primary ciliary dyskinesia (PCD) symptoms in males, but PCD phenotype was also found in one female individual. Therefore, whether there is a phenotypic continuum ranging from infertile patients with PCD to MMAF patients with no or low noise PCD manifestations remains elusive. Here, we performed whole-exome sequencing in 47 patients with severe asthenozoospermia from 45 unrelated Chinese families. We identified four novel biallelic mutations in SPEF2 (8.9%, 4/45) in six affected individuals (12.8%, 6/47), while no deleterious biallelic variants in SPEF2 were detected in 637 controls, including 219 with oligoasthenospermia, 195 with non-obstructive azoospermia, and 223 fertile controls. Notably, all six patients exhibited PCD-like symptoms, including recurrent airway infections, bronchitis, and rhinosinusitis. Ultrastructural analysis revealed normal 9 + 2 axonemes of respiratory cilia but consistently abnormal 9 + 0 axoneme or disordered accessory structures of sperm flagella, indicating different roles of SPEF2 in sperm flagella and respiratory cilia. Subsequently, a Spef2 knockout mouse model was used to validate the PCD-like phenotype and male infertility, where the subfertility of female Spef2-/- mice was found unexpectedly. Overall, our data bridge the link between MMAF and PCD based on the association of SPEF2 mutations with both infertility and PCD in males and provide basis for further exploring the molecular mechanism of SPEF2 during spermiogenesis and ciliogenesis.

An M1AP homozygous splice-site mutation associated with severe oligozoospermia in a consanguineous family.

Severe oligozoospermia (SO) is an important cause of male infertility. Its etiology and pathogenesis are associated with genetic abnormalities; however, the genetic causes of the majority of idiopathic human SO remain unclear. Here, we report a homozygous splice-site mutation in M1AP (meiosis 1 associated protein; NM_138804, c.1435-1G>A) observed in a patient with SO from a consanguineous Han Chinese family. His parents and fertile brother were heterozygous for the mutation. The splice variant led to a lack of M1AP protein in the patient's spermatozoa. Ultrastructural and immunostaining analyses of patient's spermatozoa showed highly aberrant swollen mitochondrial sheaths with normal axonemal structures. Subsequent mutation screening identified three additional heterozygous M1AP variants in 4/243 subjects with idiopathic SO, but no M1AP variants among 223 fertile subjects. Additionally, a previously study reported that M1ap knock-out mice exhibited SO due to meiotic arrest. Hence, our findings indicate that M1AP mutation might represent novel genetic alteration responsible for human SO.

Biallelic mutations in CFAP65 lead to severe asthenoteratospermia due to acrosome hypoplasia and flagellum malformations.

BACKGROUND: The genetic causes for most male infertility due to severe asthenozoospermia remain unclear. OBJECTIVE: Our objective was to identify unknown genetic factors in 47 patients with severe asthenozoospermia from 45 unrelated Chinese families. METHODS: We performed whole exome sequencing of 47 individuals with severe asthenozoospermia from 45 unrelated families. Mutation screening was performed in a control cohort of 637 individuals, including 219 with oligoasthenospermia, 195 with non-obstructive azoospermia and 223 fertile controls. Ultrastructural and immunostaining analyses of patients' spermatozoa were performed to characterise the effect of variants. RESULTS: One homozygous non-sense mutation (NM_194302, c.G5341T:p.E1781X), two compound heterozygous mutations (c.C2284T:p.R762X and c.1751delC:p.P584fs) and two compound heterozygous mutations (c.5714_5721del:p.L1905fs and c.C3021A:p.N1007K) were identified in CFAP65 of three individuals with completely immotile spermatozoa, respectively. No biallelic deleterious variants of CFAP65 were detected in the control cohort of 637 individuals. Ultrastructural and immunostaining analyses of spermatozoa from two patients showed highly aberrant sperm morphology with severe defects such as acrosome hypoplasia, disruption of the mitochondrial sheath and absence of the central pair complex. CONCLUSION: To the best of our knowledge, we are the first to report that CFAP65 mutations may cause spermatozoa to be completely immotile.

Novel DNAAF6 variants identified by whole-exome sequencing cause male infertility and primary ciliary dyskinesia.

PURPOSE: To identify the genetic cause of patients with primary ciliary dyskinesia (PCD) and male infertility from two unrelated Han Chinese families. METHODS: We conducted whole-exome sequencing of three individuals with PCD and male infertility from two unrelated Chinese families, and performed a targeted look-up for DNAAF6 variants in our previously reported cohort of 442 individuals (219 with isolated oligoasthenospermia and 223 fertile controls). Ultrastructural and immunostaining analyses of patients' spermatozoa were performed. The pathogenicity of the variants was validated using patient's spermatozoa and HEK293T cells. Intracytoplasmic sperm injection (ICSI) treatment was conducted in two patients. RESULTS: We identified one novel hemizygous frameshift variant (NM_173494, c.319_329del: p.R107fs) of DNAAF6 gene (previously named PIH1D3) in family 1 and one novel hemizygous missense variant (c.290G>T: p.G97V) in family 2. No hemizygous deleterious variants in DNAAF6 were detected in the control cohort of 442 individuals. Ultrastructural and immunostaining analyses of patients' spermatozoa showed the absence of outer and inner dynein arms in sperm flagella. Both variants were proven to lead to DNAAF6 protein degradation in HEK293T cells. Both patients carrying DNAAF6 variants underwent one ICSI cycle and delivered one healthy child each. CONCLUSION: We identified novel DNAAF6 variants causing male infertility and PCD in Han Chinese patients. This finding extended the spectrum of variants in DNAAF6 and revealed new light on the impact of DNAAF6 variants in sperm flagella.

[Trigger effect of hMG and hCG in the treatment of unexplainable non-obstructive azoospermia].

OBJECTIVE: To investigate whether the trigger effect of human menopausal gonadotropins (hMG) and human chorionic gonadotropins (hCG) attributes to the treatment of unexplainable non-obstructive azoospermia (NOA). METHODS: We retrospectively analyzed the clinical data about 282 cases of unexplainable NOA treated in the Maternity and Child Health Hospital of Guizhou Province from January 2010 to May 2017. All the patients underwent trigger treatment by intramuscular injection of hMG at 75 IU 3 times a week for 2 weeks, followed by hCG at 2 000 IU twice a week for another 2 weeks, and meanwhile took vitamin E, Levocarnitine and Tamoxifen as an adjunctive therapy. The treatment lasted 3－12 months. RESULTS: Fifty-eight of the 255 patients that completed the treatment were found with sperm in the semen after treatment, all with severe oligoasthenospermia. Forty-seven of the 58 cases received assisted reproductive technology (ART), of which 18 achieved clinical pregnancy. Semen centrifugation revealed no sperm in the other cases, of which 6 were found with epididymal sperm at epididymal and testicular biopsy after treatment and 3 of them achieved clinical pregnancy after ART. Sperm was found in the semen or at epididymal or testicular biopsy in 64 of the patients after treatment, with an effectiveness rate of 25.1%. CONCLUSIONS: Trigger treatment by injection of hMG and hCG combined with adjunctive oral medication has a certain effect on unexplainable NOA.

Novel homozygous variants in TTC12 cause male infertility with asthenoteratozoospermia owing to dynein arm complex and mitochondrial sheath defects in flagella.

Introduction: Tracing the genetic causes for male infertility due to asthenoteratozoospermia has revealed at least 40 causative genes, which provides valuable reference for the genetic testing of asthenoteratozoospermia in clinical practice. To identify deleterious variants in the human tetratricopeptide repeat domain 12 (TTC12) gene in a large cohort of infertile Chinese males with asthenoteratozoospermia. Methods: A total of 314 unrelated asthenoteratozoospermia-affected men were recruited for whole exome sequencing. The effects of the identified variants were evaluated by in silico analysis, and confirmed by in vitro experiments. Intracytoplasmic sperm injection (ICSI) was used to evaluate the efficiency of assisted reproduction technique therapy. Results and Discussion: Novel homozygous TTC12 variants (c.1467_1467delG (p.Asp490Thrfs*14), c.1139_1139delA (p.His380Profs*4), and c.1117G>A (p.Gly373Arg)) were identified in three (0.96%) of the 314 cases. Three mutants were indicated to be damaging using in silico prediction tools, and were further confirmed by in vitro functional analysis. Hematoxylin and eosin staining and ultrastructural observation of the spermatozoa revealed multiple morphological abnormalities of flagella, with the absence of outer and inner dynein arms. Notably, significant mitochondrial sheath malformations were also observed in the sperm flagella. Immunostaining assays indicated that TTC12 is present throughout the flagella, and was strongly concentrated in the mid-piece in control spermatozoa. However, spermatozoa from TTC12-mutated individuals exhibited almost no staining intensity of TTC12 and outer and inner dynein arms components. The three men accepted ICSI treatment using their ejaculated spermatozoa, and two female partners successfully delivered healthy babies. Our findings provide direct genetic evidence that homozygous variants in TTC12 cause male infertility with asthenoteratozoospermia by causing dynein arm complex defects and mitochondrial sheath malformations in the flagellar. We also demonstrated that TTC12 deficiency-mediated infertility could be overcome by ICSI technology.

Novel MEIOB variants cause primary ovarian insufficiency and non-obstructive azoospermia.

Background: Infertility is a global health concern. MEIOB has been found to be associated with premature ovarian insufficiency (POI) and non-obstructive azoospermia (NOA), but its variants have not been reported in Chinese patients. The aim of this study was to identify the genetic aetiology of POI or NOA in three Han Chinese families. Methods: Whole-exome sequencing (WES) was used to identify candidate pathogenic variants in three consanguineous Chinese infertile families with POI or NOA. Sanger sequencing was performed to validate these variants in the proband of family I and her affected family members. In vitro functional analyses were performed to confirm the effects of these variants. Results: Two novel homozygous frameshift variants (c.258_259del and c.1072_1073del) and one novel homozygous nonsense variant (c.814C > T) in the MEIOB gene were identified in three consanguineous Han Chinese families. In vitro functional analyses revealed that these variants produced truncated proteins and affected their function. Conclusion: We identified three novel MEIOB loss-of-function variants in local Chinese patients for the first time and confirmed their pathogenicity using in vitro functional analyses. These results extend the mutation spectrum of the MEIOB gene and have important significance for genetic counselling in these families.

Genetic testing of sperm donors at a human sperm bank in China.

Background: In China, numerous human sperm banks only perform three-generation family history evaluation to exclude genetic diseases with clinical symptoms; therefore, many inherited risks cannot be detected before donor qualification even when a thorough genetic family history evaluation has been performed. Hence, the risk of recessive disease inheritance persists with the current eligibility guidelines in China regarding the donor selection process. Methods: Retrospective study that reviewed the genetic test analyses and clinical outcomes of young adult men who were qualified sperm donors at the Hunan Province Human Sperm Bank of China from January 1, 2018, to May 1, 2021. We included a total of 3231 qualified sperm donors: all donors underwent primary screening for thalassemia and glucose-6-phosphate dehydrogenase (G6PD) deficiency. Whereafter, 278 of donors underwent genetic testing for specific genes, and 43 donors underwent whole exome sequencing. Results: 2.4% of 3231 qualified sperm donors might have thalassemia and 1.4% might have G6PD deficiency. Sperm donors with thalassemia and G6PD deficiency would be eliminated. Specific gene testing identified 7 of the 278 donors (2.5%) as carriers of at least one pathogenic or likely pathogenic variant in a gene, including 1.9% of 154 donors (3/154) as carrier variants in α-Like or ß-Like globin genes, 17.6% of 17 donors (3/17) as carrier variants in GJB2, 12.5% of 8 donors (1/8) as carrier variants in SMN1. In addition, among the 43 sperm donors carrying the 111 pathogenic/likely pathogenic variants, eight (18.6%) were carriers of pathogenic variants of the GJB2 gene. The frequency, therefore, was approximately 1 in 5. Conclusions: The data suggest that used blood routine and RDT can make a preliminary screening of sperm donors, and special gene testing should be performed for sperm donors according to the regional incidence of specific genetic diseases. Meanwhile, whole exome sequencing can be used as a supplementary application in sperm donor genetic testing, and aid a successful and healthy pregnancy. However, industry guidelines must be modified to incorporate its use.

Long Y chromosome is not a fetal loss risk.

PURPOSE: To assess the long Y chromosome genetic effect on human pregnancy outcomes. METHODS: We studied all records of pregnancies by human sperm donors after artificial insemination or in vitro fertilization at the Reproductive and Genetic Hospital of Citic-Xiangya. Fetal losses were compared from two groups of sperm donors: the observation group (with long Y chromosome) and the control group (without long Y chromosome). RESULTS: 2885 pregnancies were achieved with donor sperm by artificial insemination and 1746 by in vitro fertilization. The rates of fetal loss, congenital malformation and donor fecundity in the observation group after both assisted reproductive technique were the same as for the control group. CONCLUSIONS: A long Y chromosome may therefore be considered as a normal variant.

[Karyotype analysis of qualified sperm donors on preliminary screening].

OBJECTIVE: To explore the significance of karyotype analysis in screening sperm donors. METHODS: From January 1, 2004 to December 31, 2008, a total of 2537 potential sperm donors passed our preliminary screening, and all were routinely karyo-typed via peripheral blood. Follow-ups were conducted on the pregnancy outcome and congenital malformation after artificial insemination with the sperm from the qualified donors. RESULTS: Among the 2537 qualified sperm donors, 2362 were of the normal karyotype 46, XY and 135 showed polymorphism. Abnormal karyotype was found in 6 cases, and controversial abnormal karyotype in 34. CONCLUSION: Karyotype analysis can reduce the risk of chromosomal disease in neonates from artificial insemination, and genetic counseling for abnormal karyotype sperm donors may help them solve their future reproductive problems.

TCF3 Regulates the Proliferation and Apoptosis of Human Spermatogonial Stem Cells by Targeting PODXL.

Spermatogonial stem cells (SSCs) are the initial cells for the spermatogenesis. Although much progress has been made on uncovering a number of modulators for the SSC fate decisions in rodents, the genes mediating human SSCs remain largely unclear. Here we report, for the first time, that TCF3, a member of the basic helix-loop-helix family of transcriptional modulator proteins, can stimulate proliferation and suppress the apoptosis of human SSCs through targeting podocalyxin-like protein (PODXL). TCF3 was expressed primarily in GFRA1-positive spermatogonia, and EGF (epidermal growth factor) elevated TCF3 expression level. Notably, TCF3 enhanced the growth and DNA synthesis of human SSCs, whereas it repressed the apoptosis of human SSCs. RNA sequencing and chromatin immunoprecipitation (ChIP) assays revealed that TCF3 protein regulated the transcription of several genes, including WNT2B, TGFB3, CCN4, MEGF6, and PODXL, while PODXL silencing compromised the stem cell activity of SSCs. Moreover, the level of TCF3 protein was remarkably lower in patients with spermatogenesis failure when compared to individuals with obstructive azoospermia with normal spermatogenesis. Collectively, these results implicate that TCF3 modulates human SSC proliferation and apoptosis through PODXL. This study is of great significance since it would provide a novel molecular mechanism underlying the fate determinations of human SSCs and it could offer new targets for gene therapy of male infertility.

A novel homozygous frameshift mutation in MNS1 associated with severe oligoasthenoteratozoospermia in humans.

Oligoasthenoteratozoospermia (OAT) refers to the combination of various sperm abnormalities, including a decreased sperm count, reduced motility, and abnormal sperm morphology. Only a few genetic causes have been shown to be associated with OAT. Herein, we identified a novel homozygous frameshift mutation in meiosis-specific nuclear structural 1 (MNS1; NM_018365: c.603_604insG: p.Lys202Glufs*6) by whole-exome sequencing in an OAT proband from a consanguineous Chinese family. Subsequent variant screening identified four additional heterozygous MNS1 variants in 6/219 infertile individuals with oligoasthenospermia, but no MNS1 variants were observed among 223 fertile controls. Immunostaining analysis showed MNS1 to be normally located in the whole-sperm flagella, but was absent in the proband's sperm. Expression analysis by Western blot also confirmed that MNS1 was absent in the proband's sperm. Abnormal flagellum morphology and ultrastructural disturbances in outer doublet microtubules were observed in the proband's sperm. A total of three intracytoplasmic sperm injection cycles were carried out for the proband's wife, but they all failed to lead to a successful pregnancy. Overall, this is the first study to report a loss-of-function mutation in MNS1 causing OAT in a Han Chinese patient.