Undiagnosed RASopathies in infertile men.

RASopathies are syndromes caused by congenital defects in the Ras/mitogen-activated protein kinase (MAPK) pathway genes, with a population prevalence of 1 in 1,000. Patients are typically identified in childhood based on diverse characteristic features, including cryptorchidism (CR) in >50% of affected men. As CR predisposes to spermatogenic failure (SPGF; total sperm count per ejaculate 0-39 million), we hypothesized that men seeking infertility management include cases with undiagnosed RASopathies. Likely pathogenic or pathogenic (LP/P) variants in 22 RASopathy-linked genes were screened in 521 idiopathic SPGF patients (including 155 CR cases) and 323 normozoospermic controls using exome sequencing. All 844 men were recruited to the ESTonian ANDrology (ESTAND) cohort and underwent identical andrological phenotyping. RASopathy-specific variant interpretation guidelines were used for pathogenicity assessment. LP/P variants were identified in PTPN11 (two), SOS1 (three), SOS2 (one), LZTR1 (one), SPRED1 (one), NF1 (one), and MAP2K1 (one). The findings affected six of 155 cases with CR and SPGF, three of 366 men with SPGF only, and one (of 323) normozoospermic subfertile man. The subgroup "CR and SPGF" had over 13-fold enrichment of findings compared to controls (3.9% vs. 0.3%; Fisher's exact test, p = 5.5 × 10-3). All ESTAND subjects with LP/P variants in the Ras/MAPK pathway genes presented congenital genitourinary anomalies, skeletal and joint conditions, and other RASopathy-linked health concerns. Rare forms of malignancies (schwannomatosis and pancreatic and testicular cancer) were reported on four occasions. The Genetics of Male Infertility Initiative (GEMINI) cohort (1,416 SPGF cases and 317 fertile men) was used to validate the outcome. LP/P variants in PTPN11 (three), LZTR1 (three), and MRAS (one) were identified in six SPGF cases (including 4/31 GEMINI cases with CR) and one normozoospermic man. Undiagnosed RASopathies were detected in total for 17 ESTAND and GEMINI subjects, 15 SPGF patients (10 with CR), and two fertile men. Affected RASopathy genes showed high expression in spermatogenic and testicular somatic cells. In conclusion, congenital defects in the Ras/MAPK pathway genes represent a new congenital etiology of syndromic male infertility. Undiagnosed RASopathies were especially enriched among patients with a history of cryptorchidism. Given the relationship between RASopathies and other conditions, infertile men found to have this molecular diagnosis should be evaluated for known RASopathy-linked health concerns, including specific rare malignancies.

Toward clinical exomes in diagnostics and management of male infertility.

Infertility, affecting ∼10% of men, is predominantly caused by primary spermatogenic failure (SPGF). We screened likely pathogenic and pathogenic (LP/P) variants in 638 candidate genes for male infertility in 521 individuals presenting idiopathic SPGF and 323 normozoospermic men in the ESTAND cohort. Molecular diagnosis was reached for 64 men with SPGF (12%), with findings in 39 genes (6%). The yield did not differ significantly between the subgroups with azoospermia (20/185, 11%), oligozoospermia (18/181, 10%), and primary cryptorchidism with SPGF (26/155, 17%). Notably, 19 of 64 LP/P variants (30%) identified in 28 subjects represented recurrent findings in this study and/or with other male infertility cohorts. NR5A1 was the most frequently affected gene, with seven LP/P variants in six SPGF-affected men and two normozoospermic men. The link to SPGF was validated for recently proposed candidate genes ACTRT1, ASZ1, GLUD2, GREB1L, LEO1, RBM5, ROS1, and TGIF2LY. Heterozygous truncating variants in BNC1, reported in female infertility, emerged as plausible causes of severe oligozoospermia. Data suggested that several infertile men may present congenital conditions with less pronounced or pleiotropic phenotypes affecting the development and function of the reproductive system. Genes regulating the hypothalamic-pituitary-gonadal axis were affected in >30% of subjects with LP/P variants. Six individuals had more than one LP/P variant, including five with two findings from the gene panel. A 4-fold increased prevalence of cancer was observed in men with genetic infertility compared to the general male population (8% vs. 2%; p = 4.4 × 10-3). Expanding genetic testing in andrology will contribute to the multidisciplinary management of SPGF.

Severe sperm DNA fragmentation may persist for up to 3 years after cytotoxic therapy in patients affected by Hodgkin lymphoma and non-Hodgkin lymphoma.

STUDY QUESTION: Does sperm DNA recover from damage in all men after 2 years from the end of cytotoxic treatments? SUMMARY ANSWER: The current indication of 2 years waiting time for seeking natural pregnancy after cytotoxic treatment may not be adequate for all men, since severe sperm DNA damage is present in a proportion of subjects even after this timeframe. WHAT IS KNOWN ALREADY: Data in the literature on sperm DNA fragmentation (SDF) in lymphoma patients after cytotoxic treatments are scarce. The largest longitudinal study evaluated paired pre- and post-therapy (up to 24 months) semen samples from 34 patients while one study performed a longer follow-up (36 months) in 10 patients. The median/mean SDF values >24 months after therapy did not show significant differences but the studies did not explore the proportion of patients with severe DNA damage and the analysis was done on frozen-thawed samples. STUDY DESIGN, SIZE, DURATION: In this study, 53 Hodgkin lymphoma (HL) and 25 non-Hodgkin lymphoma (NHL) post-pubertal patients were included over a recruitment period of 10 years (2012-2022). Among them, 18 subjects provided paired semen samples for SDF analysis at the three time points. SDF was evaluated in patients before (T0) and after 2 (T2) and 3 years (T3) from the end of, cytotoxic treatments (chemotherapy alone or in combination with radiotherapy). A cohort of 79 healthy, fertile, and normozoospermic men >18 years old served as controls (recruited between 2016 and 2019). PARTICIPANTS/MATERIALS, SETTING, METHODS: SDF was evaluated on fresh semen samples (i.e. spermatozoa potentially involved in natural conception) from patients and controls using TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) assay coupled with flow cytometry. SDF median values were compared between groups: (i) HL and NHL patients versus controls at the three time points; (ii) HL versus NHL patients at baseline; and (iii) patients at T0 versus T2 and T3. Severe DNA damage (SDD) was defined for SDF levels above the 95th percentile of controls (50%) and the proportion of patients with SDD at all time points was established. MAIN RESULTS AND THE ROLE OF CHANCE: At T0, patients displayed higher median SDF than controls, reaching statistical significance in the NHL group: 40.5% [IQR: 31.3-52.6%] versus 28% [IQR: 22-38%], P < 0.05. Comparing SDF pre-treatment to that post-treatment, HL patients exhibited similar median values at the three time points, whereas NHL showed significantly lower values at T3 compared to T0: 29.2% [IQR: 22-38%] versus 40.5% [IQR: 31.3-52.6%], P < 0.05. The proportion with SDD in the entire cohort at T2 was 11.6% and 13.3% among HL and NHL patients, respectively. At T3, only one in 16 NHL patients presented SDD. LIMITATIONS, REASONS FOR CAUTION: TUNEL assay requires at least 5 million spermatozoa to be performed; hence, severe oligozoospermic men were not included in the study. Although our cohort represents the largest one in the literature, the relatively small number of patients does not allow us to establish precisely the frequency of SDD at T2 which in our study reached 11-13% of patients. WIDER IMPLICATIONS OF THE FINDINGS: Our data provide further insights into the long-term effects of cytotoxic treatments on the sperm genome. The persistent severe DNA damage after 2 years post-treatment observed in some patients suggests that there is an interindividual variation in restoring DNA integrity. We propose the use of SDF as a biomarker to monitor the treatment-induced genotoxic effects on sperm DNA in order to better personalize pre-conceptional counseling on whether to use fresh or cryopreserved spermatozoa. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by grants from the Istituto Toscano Tumori (ITT), Fondazione Ente Cassa di Risparmio di Firenze, the European Commission-Reproductive Biology Early Research Training (REPROTRAIN). C.K., G.F., V.R., and A.R.-E. belong to COST Action CA20119 (ANDRONET) which is supported by the European Cooperation in Science and Technology (www.cost.eu). The authors declare no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Long-term effect of cytotoxic treatments on sperm DNA fragmentation in patients affected by testicular germ cell tumor.

INTRODUCTION: Testicular germ cell tumor is the most frequent neoplasia in men of reproductive age, with a 5-year survival rate of 95%. Antineoplastic treatments induce sperm DNA fragmentation, especially within the first year post-therapy. Data in the literature are heterogeneous concerning longer follow-up periods, and the large majority is limited to 2 years. OBJECTIVE: To define the timing for the recovery of sperm DNA damage and the proportion of patients with severe DNA damage at 2 and 3 years from the end of therapy. MATERIALS AND METHODS: Sperm DNA fragmentation was evaluated in 115 testicular germ cell tumor patients using terminal deoxynucleotidyl transferase dUTP nick end labeling assay coupled with flow cytometry before (T0 ) and 2 (T2 ) and 3 (T3 ) years post-treatment. Patients were divided based on the type of treatment: carboplatin, bleomycin-etoposide-cisplatin, and radiotherapy. For 24 patients, paired sperm DNA fragmentation data were available at all time-points (T0 -T2 -T3 ). Seventy-nine cancer-free, fertile normozoospermic men served as controls. Severe DNA damage was defined as the 95th percentile in controls (sperm DNA fragmentation = 50%). RESULTS: Comparing patients versus controls, we observed: (i) no differences at T0 and T3 and (ii) significantly higher sperm DNA fragmentation levels (p < 0.05) at T2 in all treatment groups. Comparing pre- and post-therapy in the 115 patients, the median sperm DNA fragmentation values were higher in all groups at T2 , reaching significance (p < 0.05) only in the carboplatin group. While the median sperm DNA fragmentation values were also higher in the strictly paired cohort at T2 , about 50% of patients returned to baseline. The proportion of severe DNA damage in the entire cohort was 23.4% and 4.8% of patients at T2 and T3 , respectively. DISCUSSION: Currently, testicular germ cell tumor patients are advised to wait 2 years post-therapy before seeking natural pregnancy. Our results suggest that this period may not be sufficient for all patients. CONCLUSION: The analysis of sperm DNA fragmentation may represent a useful biomarker for pre-conception counseling following cancer treatment.

Sperm DNA methylome abnormalities occur both pre- and post-treatment in men with Hodgkin disease and testicular cancer.

BACKGROUND: Combination chemotherapy has contributed to increased survival from Hodgkin disease (HD) and testicular cancer (TC). However, questions concerning the quality of spermatozoa after treatment have arisen. While studies have shown evidence of DNA damage and aneuploidy in spermatozoa years following anticancer treatment, the sperm epigenome has received little attention. Our objectives here were to determine the impact of HD and TC, as well as their treatments, on sperm DNA methylation. Semen samples were collected from community controls (CC) and from men undergoing treatment for HD or TC, both before initiation of chemotherapy and at multiple times post-treatment. Sperm DNA methylation was assessed using genome-wide and locus-specific approaches. RESULTS: Imprinted gene methylation was not affected in the sperm of HD or TC men, before or after treatment. Prior to treatment, using Illumina HumanMethylation450 BeadChip (450 K) arrays, a subset of 500 probes was able to distinguish sperm samples from TC, HD and CC subjects; differences between groups persisted post-treatment. Comparing altered sperm methylation between HD or TC patients versus CC men, twice as many sites were affected in TC versus HD men; for both groups, the most affected CpGs were hypomethylated. For TC patients, the promoter region of GDF2 contained the largest region of differential methylation. To assess alterations in DNA methylation over time/post-chemotherapy, serial samples from individual patients were compared. With restriction landmark genome scanning and 450 K array analyses, some patients who underwent chemotherapy showed increased alterations in DNA methylation, up to 2 to 3 years post-treatment, when compared to the CC cohort. Similarly, a higher-resolution human sperm-specific assay that includes assessment of environmentally sensitive regions, or "dynamic sites," also demonstrated persistently altered sperm DNA methylation in cancer patients post-treatment and suggested preferential susceptibility of "dynamic" CpG sites. CONCLUSIONS: Distinct sperm DNA methylation signatures were present pre-treatment in men with HD and TC and may help explain increases in birth defects reported in recent clinical studies. Epigenetic defects in spermatozoa of some cancer survivors were evident even up to 2 years post-treatment. Abnormalities in the sperm epigenome both pre- and post-chemotherapy may contribute to detrimental effects on future reproductive health.

Diverse monogenic subforms of human spermatogenic failure.

Non-obstructive azoospermia (NOA) is the most severe form of male infertility and typically incurable. Defining the genetic basis of NOA has proven challenging, and the most advanced classification of NOA subforms is not based on genetics, but simple description of testis histology. In this study, we exome-sequenced over 1000 clinically diagnosed NOA cases and identified a plausible recessive Mendelian cause in 20%. We find further support for 21 genes in a 2-stage burden test with 2072 cases and 11,587 fertile controls. The disrupted genes are primarily on the autosomes, enriched for undescribed human "knockouts", and, for the most part, have yet to be linked to a Mendelian trait. Integration with single-cell RNA sequencing data shows that azoospermia genes can be grouped into molecular subforms with synchronized expression patterns, and analogs of these subforms exist in mice. This analysis framework identifies groups of genes with known roles in spermatogenesis but also reveals unrecognized subforms, such as a set of genes expressed across mitotic divisions of differentiating spermatogonia. Our findings highlight NOA as an understudied Mendelian disorder and provide a conceptual structure for organizing the complex genetics of male infertility, which may provide a rational basis for disease classification.

Large-scale analyses of the X chromosome in 2,354 infertile men discover recurrently affected genes associated with spermatogenic failure.

Although the evolutionary history of the X chromosome indicates its specialization in male fitness, its role in spermatogenesis has largely been unexplored. Currently only three X chromosome genes are considered of moderate-definitive diagnostic value. We aimed to provide a comprehensive analysis of all X chromosome-linked protein-coding genes in 2,354 azoospermic/cryptozoospermic men from four independent cohorts. Genomic data were analyzed and compared with data in normozoospermic control individuals and gnomAD. While updating the clinical significance of known genes, we propose 21 recurrently mutated genes strongly associated with and 34 moderately associated with azoospermia/cryptozoospermia not previously linked to male infertility (novel). The most frequently affected prioritized gene, RBBP7, was found mutated in ten men across all cohorts, and our functional studies in Drosophila support its role in germ stem cell maintenance. Collectively, our study represents a significant step towards the definition of the missing genetic etiology in idiopathic severe spermatogenic failure and significantly reduces the knowledge gap of X-linked genetic causes of azoospermia/cryptozoospermia contributing to the development of future diagnostic gene panels.

DDB1- and CUL4-associated factor 12-like protein 1 (Dcaf12l1) is not essential for male fertility in mice.

Male infertility is a common condition affecting at least 7% of men worldwide and is often genetic in origin. Using whole exome sequencing, we recently discovered three hemizygous, likely damaging variants in DDB1- and CUL4-associated factor 12-like protein 1 (DCAF12L1) in men with azoospermia. DCAF12L1 is located on the X-chromosome and as identified by single cell sequencing studies, its expression is enriched in human testes and specifically in Sertoli cells and spermatogonia. However, very little is known about the role of DCAF12L1 in spermatogenesis, thus we generated a knockout mouse model to further explore the role of DCAF12L1 in male fertility. Knockout mice were generated using CRISPR/Cas9 technology to remove the entire coding region of Dcaf12l1 and were assessed for fertility over a broad range of ages (2-8 months of age). Despite outstanding genetic evidence in men, loss of DCAF12L1 had no discernible impact on male fertility in mice, as highlighted by breeding trials, histological assessment of the testis and epididymis, daily sperm production and evaluation of sperm motility using computer assisted methods. This disparity is likely due to the parallel evolution, and subsequent divergence, of DCAF12 family members in mice and men or the presence of compounding environmental factors in men.

A systematic review of the validated monogenic causes of human male infertility: 2020 update and a discussion of emerging gene-disease relationships.

BACKGROUND: Human male infertility has a notable genetic component, including well-established diagnoses such as Klinefelter syndrome, Y-chromosome microdeletions and monogenic causes. Approximately 4% of all infertile men are now diagnosed with a genetic cause, but a majority (60-70%) remain without a clear diagnosis and are classified as unexplained. This is likely in large part due to a delay in the field adopting next-generation sequencing (NGS) technologies, and the absence of clear statements from field leaders as to what constitutes a validated cause of human male infertility (the current paper aims to address this). Fortunately, there has been a significant increase in the number of male infertility NGS studies. These have revealed a considerable number of novel gene-disease relationships (GDRs), which each require stringent assessment to validate the strength of genotype-phenotype associations. To definitively assess which of these GDRs are clinically relevant, the International Male Infertility Genomics Consortium (IMIGC) has identified the need for a systematic review and a comprehensive overview of known male infertility genes and an assessment of the evidence for reported GDRs. OBJECTIVE AND RATIONALE: In 2019, the first standardised clinical validity assessment of monogenic causes of male infertility was published. Here, we provide a comprehensive update of the subsequent 1.5 years, employing the joint expertise of the IMIGC to systematically evaluate all available evidence (as of 1 July 2020) for monogenic causes of isolated or syndromic male infertility, endocrine disorders or reproductive system abnormalities affecting the male sex organs. In addition, we systematically assessed the evidence for all previously reported possible monogenic causes of male infertility, using a framework designed for a more appropriate clinical interpretation of disease genes. SEARCH METHODS: We performed a literature search according to the PRISMA guidelines up until 1 July 2020 for publications in English, using search terms related to 'male infertility' in combination with the word 'genetics' in PubMed. Next, the quality and the extent of all evidence supporting selected genes were assessed using an established and standardised scoring method. We assessed the experimental quality, patient phenotype assessment and functional evidence based on gene expression, mutant in-vitro cell and in-vivo animal model phenotypes. A final score was used to determine the clinical validity of each GDR, across the following five categories: no evidence, limited, moderate, strong or definitive. Variants were also reclassified according to the American College of Medical Genetics and Genomics-Association for Molecular Pathology (ACMG-AMP) guidelines and were recorded in spreadsheets for each GDR, which are available at imigc.org. OUTCOMES: The primary outcome of this review was an overview of all known GDRs for monogenic causes of human male infertility and their clinical validity. We identified a total of 120 genes that were moderately, strongly or definitively linked to 104 infertility phenotypes. WIDER IMPLICATIONS: Our systematic review curates all currently available evidence to reveal the strength of GDRs in male infertility. The existing guidelines for genetic testing in male infertility cases are based on studies published 25 years ago, and an update is far overdue. The identification of 104 high-probability 'human male infertility genes' is a 33% increase from the number identified in 2019. The insights generated in the current review will provide the impetus for an update of existing guidelines, will inform novel evidence-based genetic testing strategies used in clinics, and will identify gaps in our knowledge of male infertility genetics. We discuss the relevant international guidelines regarding research related to gene discovery and provide specific recommendations to the field of male infertility. Based on our findings, the IMIGC consortium recommend several updates to the genetic testing standards currently employed in the field of human male infertility, most important being the adoption of exome sequencing, or at least sequencing of the genes validated in this study, and expanding the patient groups for which genetic testing is recommended.

The X chromosome and male infertility.

The X chromosome is a key player in germ cell development, as has been highlighted for males in previous studies revealing that the mammalian X chromosome is enriched in genes expressed in early spermatogenesis. In this review, we focus on the X chromosome's unique biology as associated with human male infertility. Male infertility is most commonly caused by spermatogenic defects to which X chromosome dosage is closely linked; for example, any supernumerary X chromosome as in Klinefelter syndrome will lead to male infertility. Furthermore, because males normally only have a single X chromosome and because X-linked genetic anomalies are generally only present in a single copy in males, any loss-of-function mutations in single-copy X-chromosomal genes cannot be compensated by a normal allele. These features make X-linked genes particularly attractive for studying male spermatogenic failure. However, to date, only very few genetic causes have been identified as being definitively responsible for male infertility in humans. Although genetic studies of germ cell-enriched X-chromosomal genes in mice suggest a role of certain human orthologs in infertile men, these genes in mice and humans have striking evolutionary differences. Furthermore, the complexity and highly repetitive structure of the X chromosome hinder the mutational analysis of X-linked genes in humans. Therefore, we conclude that additional methodological approaches are urgently warranted to advance our understanding of the genetics of X-linked male infertility.

Preconception genome medicine: current state and future perspectives to improve infertility diagnosis and reproductive and health outcomes based on individual genomic data.

BACKGROUND: Our genetic code is now readable, writable and hackable. The recent escalation of genome-wide sequencing (GS) applications in population diagnostics will not only enable the assessment of risks of transmitting well-defined monogenic disorders at preconceptional stages (i.e. carrier screening), but also facilitate identification of multifactorial genetic predispositions to sub-lethal pathologies, including those affecting reproductive fitness. Through GS, the acquisition and curation of reproductive-related findings will warrant the expansion of genetic assessment to new areas of genomic prediction of reproductive phenotypes, pharmacogenomics and molecular embryology, further boosting our knowledge and therapeutic tools for treating infertility and improving women's health. OBJECTIVE AND RATIONALE: In this article, we review current knowledge and potential development of preconception genome analysis aimed at detecting reproductive and individual health risks (recessive genetic disease and medically actionable secondary findings) as well as anticipating specific reproductive outcomes, particularly in the context of IVF. The extension of reproductive genetic risk assessment to the general population and IVF couples will lead to the identification of couples who carry recessive mutations, as well as sub-lethal conditions prior to conception. This approach will provide increased reproductive autonomy to couples, particularly in those cases where preimplantation genetic testing is an available option to avoid the transmission of undesirable conditions. In addition, GS on prospective infertility patients will enable genome-wide association studies specific for infertility phenotypes such as predisposition to premature ovarian failure, increased risk of aneuploidies, complete oocyte immaturity or blastocyst development failure, thus empowering the development of true reproductive precision medicine. SEARCH METHODS: Searches of the literature on PubMed Central included combinations of the following MeSH terms: human, genetics, genomics, variants, male, female, fertility, next generation sequencing, genome exome sequencing, expanded carrier screening, secondary findings, pharmacogenomics, controlled ovarian stimulation, preconception, genetics, genome-wide association studies, GWAS. OUTCOMES: Through PubMed Central queries, we identified a total of 1409 articles. The full list of articles was assessed for date of publication, limiting the search to studies published within the last 15 years (2004 onwards due to escalating research output of next-generation sequencing studies from that date). The remaining articles' titles were assessed for pertinence to the topic, leaving a total of 644 articles. The use of preconception GS has the potential to identify inheritable genetic conditions concealed in the genome of around 4% of couples looking to conceive. Genomic information during reproductive age will also be useful to anticipate late-onset medically actionable conditions with strong genetic background in around 2-4% of all individuals. Genetic variants correlated with differential response to pharmaceutical treatment in IVF, and clear genotype-phenotype associations are found for aberrant sperm types, oocyte maturation, fertilization or pre- and post-implantation embryonic development. All currently known capabilities of GS at the preconception stage are reviewed along with persisting and forthcoming barriers for the implementation of precise reproductive medicine. WIDER IMPLICATIONS: The expansion of sequencing analysis to additional monogenic and polygenic traits may enable the development of cost-effective preconception tests capable of identifying underlying genetic causes of infertility, which have been defined as 'unexplained' until now, thus leading to the development of a true personalized genomic medicine framework in reproductive health.

Correction: gr/gr deletion predisposes to testicular germ cell tumour independently from altered spermatogenesis: results from the largest European study.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Genetic dissection of spermatogenic arrest through exome analysis: clinical implications for the management of azoospermic men.

PURPOSE: Azoospermia affects 1% of men and it can be the consequence of spermatogenic maturation arrest (MA). Although the etiology of MA is likely to be of genetic origin, only 13 genes have been reported as recurrent potential causes of MA. METHODS: Exome sequencing in 147 selected MA patients (discovery cohort and two validation cohorts). RESULTS: We found strong evidence for five novel genes likely responsible for MA (ADAD2, TERB1, SHOC1, MSH4, and RAD21L1), for which mouse knockout (KO) models are concordant with the human phenotype. Four of them were validated in the two independent MA cohorts. In addition, nine patients carried pathogenic variants in seven previously reported genes-TEX14, DMRT1, TEX11, SYCE1, MEIOB, MEI1, and STAG3-allowing to upgrade the clinical significance of these genes for diagnostic purposes. Our meiotic studies provide novel insight into the functional consequences of the variants, supporting their pathogenic role. CONCLUSION: Our findings contribute substantially to the development of a pre-testicular sperm extraction (TESE) prognostic gene panel. If properly validated, the genetic diagnosis of complete MA prior to surgical interventions is clinically relevant. Wider implications include the understanding of potential genetic links between nonobstructive azoospermia (NOA) and cancer predisposition, and between NOA and premature ovarian failure.

Short anogenital distance is associated with testicular germ cell tumour development.

BACKGROUND: Testicular germ cell tumour is a multifactorial disease in which various genetic and environmental factors play a role. Testicular germ cell tumour is part of the testicular dysgenesis syndrome which includes also cryptorchidism, hypospadias, oligo/azoospermia and short anogenital distance. OBJECTIVES: The primary objective was to examine anogenital distance in testicular germ cell tumour cases and healthy fertile controls. The secondary objective was to assess the (CAG)n polymorphism of the Androgen Receptor gene in relationship with anogenital distances and testicular germ cell tumour development. MATERIAL AND METHODS: 156 testicular germ cell tumour patients and 110 tumour-free normozoospermic controls of Spanish origin. All subjects underwent full andrological workup (including semen and hormone analysis) and genetic analysis (Androgen Receptor (CAG)n). The main outcome measures were the anopenile distance (AGDap), the anoscrotal distance (AGDas) and AR(CAG)n. RESULT: We observed significantly shorter anogenital distances in the group of testicular germ cell tumour patients in respect to controls (P < .001) independently from sperm count and testis histology. Threshold values, applicable only to our cohort, were calculated for anogenital distances with the best sensitivity and specificity. Subjects with AGDap and AGDas below threshold showed a significantly increased risk for testicular germ cell tumour (OR = 4.97, 95% CI = 2.01-12.33, P = .001 and OR = 4.11, 95% CI = 1.89-8.92, P ≤ .001, respectively). No significant correlation was observed between AR(CAG)n polymorphism and anogenital distances. The median values of the AR(CAG)n were similar between cases and controls, excluding a major role for this polymorphism in the etiopathogenesis of these testicular dysgenesis syndrome components. CONCLUSIONS: Ours is the first study focusing on anogenital distances in testicular germ cell tumour patients. We identified short anogenital distances (which is a surrogate biomarker of androgen action during foetal life) as a significant risk factor for this disease. After further validation of our preliminary data, anogenital distance measurement could become part of testicular germ cell tumour screening in order to better define those individuals who would benefit from long-term active follow-up.

Monogenic Forms of Male Infertility.

Male infertility is a multifactorial and heterogeneous pathological condition affecting 7% of the general male population. The genetic landscape of male infertility is highly complex as semen and testis histological phenotypes are extremely heterogeneous, and at least 2000 genes are predicted to be involved in spermatogenesis. Genetic factors have been described in each etiological category of male reproductive impairment: (1) hypothalamic-pituitary axis dysfunction; (2) quantitative and qualitative alterations of spermatogenesis; (3) ductal obstruction/dysfunction. In 25% of azoospermic and in 10% of oligozoospermic men, a genetic anomaly can be diagnosed with the current genetic testing. However, up to now, only a relatively low number of monogenic factors have a clear-cut cause-effect relationship with impaired reproductive function. Thanks to the widespread diffusion of Next-Generation Sequencing, a continuously increasing number of monogenic causes of male infertility are being discovered and their validation is currently ongoing. The identification of genetic factors is of outmost clinical importance since there is a risk of transmission of genetic defects through natural or assisted reproductive techniques. The benefit of the genetic diagnosis of infertility has an obvious clinical significance for the patient itself with implications not only for his reproductive health but in many instances also for his general health.

gr/gr deletion predisposes to testicular germ cell tumour independently from altered spermatogenesis: results from the largest European study.

The association between impaired spermatogenesis and TGCT has stimulated research on shared genetic factors. Y chromosome-linked partial AZFc deletions predispose to oligozoospermia and were also studied in TGCT patients with controversial results. In the largest study reporting the association between gr/gr deletion and TGCT, sperm parameters were unknown. Hence, it remains to be established whether this genetic defect truly represents a common genetic link between TGCT and impaired sperm production. Our aim was to explore the role of the following Y chromosome-linked factors in the predisposition to TGCT: (i) gr/gr deletion in subjects with known sperm parameters; (ii) other partial AZFc deletions and, for the first time, the role of partial AZFc duplications; (iii) DAZ gene dosage variation. 497 TGCT patients and 2030 controls from two Mediterranean populations with full semen/andrological characterization were analyzed through a series of molecular genetic techniques. Our most interesting finding concerns the gr/gr deletion and DAZ gene dosage variation (i.e., DAZ copy number is different from the reference sequence), both conferring TGCT susceptibility. In particular, the highest risk was observed when normozoospermic TGCT and normozoospermic controls were compared (OR = 3.7; 95% CI = 1.5-9.1; p = 0.006 for gr/gr deletion and OR = 1.8; 95% CI = 1.1-3.0; p = 0.013 for DAZ gene dosage alteration). We report in the largest European study population the predisposing effect of gr/gr deletion to TGCT as an independent risk factor from impaired spermatogenesis. Our finding implies regular tumour screening/follow-up in male family members of TGCT patients with gr/gr deletion and in infertile gr/gr deletion carriers.

Design, optimization and validation of genes commonly used in expression studies on DMH/AOM rat colon carcinogenesis model.

Colorectal cancer (CRC), also known as colon cancer, is the third most common form of cancer worldwide in men and the second in women and is characterized by several genetic alterations, among them the expression of several genes. 1,2-dimethylhydrazine (DMH) and its metabolite azoxymethane (AOM) are procarcinogens commonly used to induce colon cancer in rats (DMH/AOM rat model). This rat model has been used to study changes in mRNA expression in genes involved in this pathological condition. However, a lack of proper detailed PCR primer design in the literature limits the reproducibility of the published data. The present study aims to design, optimize and validate the qPCR, in accordance with the MIQE (Minimum Information for Publication of Quantitative Real-Time PCR Experiments) guidelines, for seventeen genes commonly used in the DMH/AOM rat model of CRC (Apc, Aurka, Bax, Bcl2, ß-catenin, Ccnd1, Cdkn1a, Cox2, Gsk3beta, IL-33, iNOs, Nrf2, p53, RelA, Smad4, Tnfα and Vegfa) and two reference genes (Actb or ß-actin and B2m). The specificity of all primer pairs was empirically validated on agarose gel, and furthermore, the melting curve inspection was checked as was their efficiency (%) ranging from 90 to 110 with a correlation coefficient of r 2 > 0.980. Finally, a pilot study was performed to compare the robustness of two candidate reference genes.

From exome analysis in idiopathic azoospermia to the identification of a high-risk subgroup for occult Fanconi anemia.

PURPOSE: In about 10% of patients affected by Fanconi anemia (FA) the diagnosis is delayed until adulthood, and the presenting symptom in these "occult" FA cases is often a solid cancer and cancer treatment-related toxicity. Highly predictive clinical parameter(s) for diagnosing such an adult-onset cases are missing. METHODS: (1) Exome sequencing (ES), (2) Sanger sequencing of FANCA, (3) diepoxybutane (DEB)-induced chromosome breakage test. RESULTS: ES identified a pathogenic homozygous FANCA variant in a patient affected by Sertoli cell-only syndrome (SCOS) and in his azoospermic brother. Although they had no overt anemia, chromosomal breakage test revealed a reverse somatic mosaicism in the former and a typical FA picture in the latter. In 27 selected SCOS cases, 1 additional patient showing compound heterozygous pathogenic FANCA variants was identified with positive chromosomal breakage test. CONCLUSION: We report an extraordinarily high frequency of FA in a specific subgroup of azoospermic patients (7.1%). The screening for FANCA pathogenic variants in such patients has the potential to identify undiagnosed FA before the appearance of other severe clinical manifestations of the disease. The definition of this high-risk group for "occult" FA, based on specific testis phenotype with mild/borderline hematological alterations, is of unforeseen clinical relevance.

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.

Testing for genetic contributions to infertility: potential clinical impact.

INTRODUCTION: Male infertility affects about 7% of the general male population, and it is a multifactorial, polygenic pathological condition. Known genetic factors, accounting for about 20-25% of male factor infertility, are present in each etiological category: i) hypothalamic-pituitary axis dysfunction; ii) quantitative and qualitative alterations of spermatogenesis; iii) ductal obstruction/dysfunction. Areas covered: All routinely available genetic tests are described. Indication for testing for chromosomal anomalies and Y chromosome microdeletions is based on sperm count (severe oligozoospermia/azoospermia). Mutation screening in candidate genes is indicated in specific semen/testis phenotypes. In about 40% of infertile patients, the aetiology remains unknown ('idiopathic cases') and whole exome sequencing may reveal novel genetic causes. Expert commentary: Genetic testing is essential for its relevance in clinical decision-making. For instance, it helps to avoid unnecessary surgical or medical treatments and it may provide prediction for testicular sperm retrieval. The highest frequency of genetic anomalies is observed in severe spermatogenic impairment, which can be treated with in vitro fertilization (IVF). Given the risk of transmitting genetic disorders to the future offspring through IVF, the diagnosis of known and the discovery of novel genetic factors in idiopathic infertility is of outmost clinical importance.