Eduard Ruiz-Castañé

Evaluation of 172 candidate polymorphisms for association with oligozoospermia or azoospermia in a large cohort of men of European descent

BACKGROUND In spite of tremendous efforts by a number of groups, the search for single nucleotide polymorphisms (SNPs) strongly associated with male factor infertility by means of gene re-sequencing studies has yielded few likely candidates. A recent pilot, genome-wide SNP association study (GWAS) identified a list of SNPs associated with oligozoospermia and azoospermia. This is an expanded follow-up study of the SNPs identified by the GWAS as well as other SNPs from previously published gene re-sequencing studies. METHODS On the basis of the pilot GWAS and SNPs with published associations with male infertility, 172 SNPs were genotyped in men with idiopathic azoospermia or oligozoospermia using the Illumina BeadXpress platform. RESULTS Several SNPs were identified or confirmed to be significantly associated with oligozoospermia and/or azoospermia. More importantly, this follow-up study indicates that, at least in Caucasian men, no single common SNP accounts for a significant proportion of spermatogenic failure cases. CONCLUSIONS The associations reported in this study are promising, but much larger genome-wide studies will be necessary to confidently validate these SNPs and identify novel SNPs associated with male infertility.

High Resolution X Chromosome-Specific Array-CGH Detects New CNVs in Infertile Males

Context The role of CNVs in male infertility is poorly defined, and only those linked to the Y chromosome have been the object of extensive research. Although it has been predicted that the X chromosome is also enriched in spermatogenesis genes, no clinically relevant gene mutations have been identified so far. Objectives In order to advance our understanding of the role of X-linked genetic factors in male infertility, we applied high resolution X chromosome specific array-CGH in 199 men with different sperm count followed by the analysis of selected, patient-specific deletions in large groups of cases and normozoospermic controls. Results We identified 73 CNVs, among which 55 are novel, providing the largest collection of X-linked CNVs in relation to spermatogenesis. We found 12 patient-specific deletions with potential clinical implication. Cancer Testis Antigen gene family members were the most frequently affected genes, and represent new genetic targets in relationship with altered spermatogenesis. One of the most relevant findings of our study is the significantly higher global burden of deletions in patients compared to controls due to an excessive rate of deletions/person (0.57 versus 0.21, respectively; p = 8.785×10−6) and to a higher mean sequence loss/person (11.79 Kb and 8.13 Kb, respectively; p = 3.435×10−4). Conclusions By the analysis of the X chromosome at the highest resolution available to date, in a large group of subjects with known sperm count we observed a deletion burden in relation to spermatogenic impairment and the lack of highly recurrent deletions on the X chromosome. We identified a number of potentially important patient-specific CNVs and candidate spermatogenesis genes, which represent novel targets for future investigations.

Clinical relevance of Y-linked CNV screening in male infertility: new insights based on the 8-year experience of a diagnostic genetic laboratory

AZF microdeletion screening is routinely performed in the diagnostic work-up for male infertility; however, some issues remain debated. In this study, we provide insights into the sperm concentration cutoff value for routine testing, the predictive value of AZFc deletion for testicular sperm retrieval and the Y-background contribution to the interpopulation variability of deletion frequencies. In the Spanish population, partial AZFc rearrangements have been poorly explored and no data exist on partial duplications. In our study, 27/806 (3.3%) patients carried complete AZF deletions. All were azoo/cryptozoospermic, except for one whose sperm concentration was 2 × 106/ml. In AZFc-deleted men, we observed a lower sperm recovery rate upon conventional TESE (9.1%) compared with the literature (60–80% with microTESE). Haplogroup E was the most represented among non-Spanish and hgr P among Spanish AZF deletion carriers. The analysis of AZFc partial rearrangements included 330 idiopathic infertile patients and 385 controls of Spanish origin. Gr/gr deletion, but not AZFc partial duplications, was significantly associated with spermatogenic impairment. Our data integrated with the literature suggest that: (1) routine AZF microdeletion testing could eventually include only men with ≤2 × 106/ml; (2) classical TESE is associated with low sperm recovery rate in azoospermic AZFc-deleted men, and therefore microTESE should be preferred; (3) Y background could partially explain the differences in deletion frequencies among populations. Finally, our data on gr/gr deletion further support the inclusion of this genetic test in the work-up of infertile men, whereas partial AZFc duplications do not represent a risk for spermatogenic failure in the Spanish population.

Recurrent X chromosome-linked deletions: discovery of new genetic factors in male infertility

Background The role of X-linked genes and copy-number variations (CNVs) in male infertility remains poorly explored. Our previous array-CGH analyses showed three recurrent deletions in Xq exclusively (CNV67) and prevalently (CNV64, CNV69) found in patients. Molecular and clinical characterisation of these CNVs was performed in this study. Methods 627 idiopathic infertile patients and 628 controls were tested for each deletion with PCR+/−. We used PCR+/− to map deletion junctions and long-range PCR and direct sequencing to define breakpoints. Results CNV64 was found in 5.7% of patients and in 3.1% of controls (p=0.013; OR=1.89; 95% CI 1.1 to 3.3) and CNV69 was found in 3.5% of patients and 1.6% of controls (p=0.023; OR=2.204; 95% CI 1.05 to 4.62). For CNV69 we identified two breakpoints, types A and B, with the latter being significantly more frequent in patients than controls (p=0.011; OR=9.19; 95% CI 1.16 to 72.8). CNV67 was detected exclusively in patients (1.1%) and was maternally transmitted. The semen phenotype of one carrier (11-041) versus his normozoospermic non-carrier brother strongly indicates a pathogenic effect of the deletion on spermatogenesis. MAGEA9, an ampliconic gene reported as independently acquired on the human X chromosome with exclusive physiological expression in the testis, is likely to be involved in CNV67. Conclusions We provide the first evidence for X chromosome-linked recurrent deletions associated with spermatogenic impairment. CNV67, specific to spermatogenic anomaly and with a frequency of 1.1% in oligo/azoospermic men, resembles the AZF regions on the Y chromosome with potential clinical implications.

Comprehensive investigation in patients affected by sperm macrocephaly and globozoospermia

The aim of this study was to provide a comprehensive genetic/phenotypic characterization of subjects suffering infertility owing to sperm macrocephaly (n = 3) or globozoospermia (n = 9) and to investigate whether the patients’ genetic status was correlated with the alteration of various sperm parameters. AURKC was sequenced in case of sperm macrocephaly while the DPY19L2 status has been analyzed by multiple approaches including a novel qPCR–based copy number assay in case of globozoospermia. Globozoospermic patients were also analyzed for SPACA1, a novel candidate gene herein tested for the first time in humans. The effect of the patients’ genetic status was interrogated by implementing the molecular screening with the characterization of several sperm parameters: (i) routine sperm analysis, integrated with transmission electron microscopy; (ii) sperm fluorescent in situ hybridization (FISH) analysis; (iii) sperm DNA fragmentation (DF) analysis. Moreover, for the first time, we performed microsatellite instability analysis as a marker of genome instability in men with sperm macrocephaly and globozoospermia. Finally, artificial reproductive technology (ART) history has been reported for those patients who underwent the treatment. Macrocephalic patients had an AURKC mutation and >89% tetraploid, highly fragmented spermatozoa. DPY19L2 was mutated in all patients with >80% globozoospermia: the two homozygous deleted men and the compound heterozygous showed the severest phenotype (90–100%). The newly developed qPCR method was fully validated and has the potential of detecting also yet undiscovered deletions. DPY19L2 status is unlikely related to FISH anomalies and DF, although globozoospermic men showed a higher disomy rate and DF compared with internal reference values. No patient was mutated for SPACA1. Our data support the general agreement on the negative correlation between macro/globozoospermia and conventional intracytoplasmic sperm injection outcomes. Microsatellites were stable in all patients analyzed. The comprehensive picture provided on these severe phenotypes causing infertility is of relevance in the management of patients undergoing ART.

X Chromosome-Linked CNVs in Male Infertility: Discovery of Overall Duplication Load and Recurrent, Patient-Specific Gains with Potential Clinical Relevance

Introduction Spermatogenesis is a highly complex process involving several thousand genes, only a minority of which have been studied in infertile men. In a previous study, we identified a number of Copy Number Variants (CNVs) by high-resolution array-Comparative Genomic Hybridization (a-CGH) analysis of the X chromosome, including 16 patient-specific X chromosome-linked gains. Of these, five gains (DUP1A, DUP5, DUP20, DUP26 and DUP40) were selected for further analysis to evaluate their clinical significance. Materials and Methods The copy number state of the five selected loci was analyzed by quantitative-PCR on a total of 276 idiopathic infertile patients and 327 controls in a conventional case-control setting (199 subjects belonged to the previous a-CGH study). For one interesting locus (intersecting DUP1A) additional 338 subjects were analyzed. Results and Discussion All gains were confirmed as patient-specific and the difference in duplication load between patients and controls is significant (p = 1.65×10−4). Two of the CNVs are private variants, whereas 3 are found recurrently in patients and none of the controls. These CNVs include, or are in close proximity to, genes with testis-specific expression. DUP1A, mapping to the PAR1, is found at the highest frequency (1.4%) that was significantly different from controls (0%) (p = 0.047 after Bonferroni correction). Two mechanisms are proposed by which DUP1A may cause spermatogenic failure: i) by affecting the correct regulation of a gene with potential role in spermatogenesis; ii) by disturbing recombination between PAR1 regions during meiosis. This study allowed the identification of novel spermatogenesis candidate genes linked to the 5 CNVs and the discovery of the first recurrent, X-linked gain with potential clinical relevance.

ESR1 promoter polymorphism is not associated with nonsyndromic cryptorchidism

The ESR1 promoter microsatellite (TA)n was reported as a potential functional polymorphism. In a case-control study, we were unable to demonstrate any association between (TA)n and nonsyndromic cryptorchidism in Italian and Spanish study populations.

Whole exome sequencing in non-obstructive azoospermia allows the identification of a high-risk subgroup of infertile men for undiagnosed Fanconi Anemia, a cancer-prone disease

Whole exome sequencing in non-obstructive azoospermia allows the identification of a high-risk subgroup of infertile men for undiagnosed Fanconi Anemia, a cancer-prone disease A. RIERA-ESCAMILLA, C. CHIANESE, D. MORENO-MENDOZA, O. RAJMIL, E. CASAMONTI, E. RUIZ-CASTA~ NE, J. SURRALL ES AND C. KRAUSZ Andrology Department, Fundaci o Puigvert, Universitat Aut onoma de Barcelona, IIB-Sant Pau, Barcelona, Catalonia, Spain; Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, Centre of Excellence DeNothe, University of Florence, Florence, Italy; Genetics Department and Biomedical Research Institute, Hospital de Sant Pau, Center for Biomedical Research on Rare Diseases (CIBERER), and Department of Genetics and Microbiology, Universitat Aut onoma de Barcelona, Barcelona, Catalonia, Spain Background: The etiology of non-obstructive azoospermia (NOA) remains unknown in about 40% of cases and genetic factors are likely to be involved in a large proportion of them. Gene mutations involved in stem cell proliferation and DNA repair may cause isolated NOA or be responsible for syndromic diseases, such as Fanconi Anemia (FA). Although the most frequent presenting symptom in FA is bone marrow failure in childhood, in about 10% of cases the diagnosis is delayed until adulthood and in these late-onset cases the presenting syndrome is frequently a malignant tumor. Methods: An idiopathic NOA patient (index case) with consanguineous parents was subjected to Whole-Exome Sequencing (WES) with the purpose to identify the etiology of NOA. In the second part of the study, two-steps Sanger sequencing of the Fanconi Anemia Complementation Group A gene (FANCA) in the brother of the index case and in 27 selected NOA patients was performed. DEB-induced chromosome breakage test was carried out to confirm the FA diagnosis. Results: Through WES we identified a rare pathogenic homozygous FANCA variant (c.2639G>A) in the index case, affected by NOA due to Sertoli Cell only syndrome (SCOS). The patient’s brother (also affected by NOA) has been found to be a homozygous carrier of the same mutation. The two brothers did not manifest overt anemia, though chromosomal breakage test revealed a reverse somatic mosaicism in the index case and a typical FA picture in the brother. Following this incidental finding of FA, we selected 27 NOA patients with similar testicular phenotype and borderline/mild hematological alterations. Sanger sequencing of the FANCA gene in this selected group of patients allowed the identification of one additional NOA patient with SCOS showing compound heterozygous variants (c.3788_3790delTCT and c.3913C>T). Following our investigation, the three subjects with FANCA mutations are now receiving specific medical attention including strict follow-up by oncohematologists. Conclusion: Our study reports an unexpectedly high frequency of occult FA in a specific subgroup of NOA patients with mild or borderline hematological alterations (2/28; 7.1%). The screening for FANCA mutations in such patients may allow the identification of undiagnosed FA before the appearance of other severe clinical manifestations (cancer, bone marrow failure etc.) of the disease. Our finding highlights the importance to introduce the systematic evaluation of hematological parameters into the routine andrological workup in NOA patients. Moreover, corroborates previous epidemiological observations reporting a higher risk of morbidity (including cancer) and a lower life expectancy in infertile men in respect to fertile, normozoospermic men. Based on our data, we propose a novel genetic link between idiopathic NOA and a chronic, cancer-prone disease. Funding: Instituto Carlos III (FIS/FEDER: PI14/01250; PI17/01822) and Ente Cassa di Risparmio di Firenze.