Genetic Causes Of Male Infertility Research Articles

Современные возможности и подходы к диагностике генетических нарушений фертильности у мужчин

Рассмотрены современные возможности медико-генетического обследования мужчин с нарушением фертильности, а также приведены показания и алгоритмы диагностики генетических причин мужского бесплодия, связанного с различными формами патозооспермии. The current possibilities of a genetic examination of infertile men, as well as indications and diagnostic algorithms for the genetic causes of male infertility associated with various forms of pathozoospermia are presented.

Y CHROMOSOME MICRODELETION AND PHENOTYPE CORRELATES WITH MALE INFERTILITY IN GUJARATI POPULATION

Background: Y chromosome microdeletions are one of the genetic causes of male infertility. Evaluation of this is important clinically to assist couple with such genetic defects using polymerase chain reaction-based sequence-targeted-site (STS). Objective: The objective of the study was to evaluate Yq microdeletion in suspected infertile male patients referred to our genetic center. Materials and Methods: European Association of Andrology STS markers for azoospermia factor (AZF) region were used to analyze these anomalies. In addition to semen analysis, cytogenetic, and hormonal studies have also been carried out using respective techniques. Results: Three of 41 cases (7.3%) included in our study had Yq microdeletion, of which one case was of azoospermia and two cases of severe oligozoospermia in AZFa and AZFc subregions were detected. Hormonal levels and karyotypes were unchanged. Conclusion: Yq microdeletion in our study exhibited is similar to Maharashtra, but it varies region-wise and ethnicity, including across Indian populations. Such couples require counseling before opting assisted reproductive technologies.

Possible misdiagnosis of 46,XX testicular disorders of sex development in infertile males.

Objectives: The 46,XX disorders of sex development (DSD) is a rare genetic cause of male infertility and possible misdiagnosis of this condition has never been reported. We aim to investigate clinical characteristics and laboratory results of infertile males with possibly misdiagnosed 46,XX DSD.Methods: Between January 2008 and December 2017, a retrospective case series study was performed involving sixteen 46,XX DSD males without azoospermia factor (AZF) deletion. Demographics, clinical features, laboratory results and assisted reproductive technology (ART) outcomes of these patients were depicted, and the underlying accurate diagnosis was also discussed.Results: The mean age was 30.06 ± 5.40 years old. Thirteen patients (81.25%) merely obtained secondary school education. Gynaecomastia occurred in one case, and cryptorchidism appeared in two cases. Testicular volumes were equal to 15 mL on two sides in one patient who had severe asthenozoospermia. Thirteen patients (81.25%) had bilateral atrophic testes which were below 5 mL. The majority of patients were observed with elevated levels of gonadotropic hormones and decreased testosterone values. Neither AZF region nor sex-determining region Y gene was absent among all patients. Twelve patients had normal ejaculatory function, whereas four were diagnosed with ejaculatory dysfunction. Eleven patients (68.75%) were diagnosed with azoospermia. Testicular sperm aspiration was performed in six subjects (37.50%). The pathological results showed that Leydig cell hyperplasia with spermatic failure was found in each case, and no sperm was found in testicular tissue. ART with donor sperm was conducted in 15 patients. Live birth was achieved in three cases through artificial insemination by donor and in one case using in-vitro fertilization by donor.Conclusions: Chromosomal analysis rarely yields 46,XX karyotype combined with no deletion of AZF in infertile males. Under this condition, molecular analysis should be conducted to avoid potential misdiagnosis and false interpretation of other findings.

Современные возможности генетической диагностики мужского бесплодия

Тяжелые формы мужского и женского бесплодия, привычного невынашивания беременности, аномалий формирования пола часто обусловлены генетическими причинами или связаны с генетическими факторами. Медико-генетическое обследование и консультирование пациентов с нарушением репродукции зачастую ограничивается использованием стандартных рутинных исследований, поэтому не позволяет выявить многие наследственные формы репродуктивной патологии. Методы геномного анализа позволяют повысить эффективность диагностики генетически обусловленных нарушений репродукции, вызванных генными мутациями и вариациями числа копий (CNV), но их пока широко не используют в практическое медицине. В статье рассмотрены современные возможности медико-генетического обследования мужчин с нарушением фертильности, а также приведены показания и алгоритмы диагностики генетических причин мужского бесплодия, связанного с различными формами патозооспермии. Evere forms of male and female infertility, recurrent miscarriage, abnormalities in disorders of sex development are often due to genetic causes or are associated with genetic factors. Genetic examination and counseling of patients with reproductive problems is often limited to the use of standard routine techniques, therefore, it is not possible to identify many hereditary forms of reproductive pathology. Genomic analysis methods can improve the diagnosis of genetic reproductive disorders caused by gene mutations and copy number variations (CNVs), but they are not yet widely used in practical medicine. The article discusses the modern possibilities of medical-genetic examination of infertile men with, as well as the indications and diagnostic algorithms for the genetic causes of male infertility associated with various forms of pathozoospermia.

FOXP3 pathogenic variants cause male infertility through affecting the proliferation and apoptosis of human spermatogonial stem cells.

Genetic causes of male infertility that is associated with aging are largely unknown. This study was designed to identify novel pathogenic variants of FOXP3 gene causing azoospermia. One homozygous (c.155 G > T) pathogenic variant of FOXP3 was identified in nine non-obstructive azoospermia patients, and one heterozygous (c.691 C > A) of FOXP3 was found in one non-obstructive azoospermia patient. Pedigrees studies indicated that the homozygous (c.155 G > T) FOXP3 pathogenic variant was inherited, while heterozygous (c.691 C > A) FOXP3 pathogenic variant was acquired. Human testis carrying pathogenic variant exhibited abnormal spermatogenesis. FOXP3 protein was expressed at a lower level or undetected in spermatocytes of mutant testis of non-obstructive azoospermia patients compared to obstructive azoospermia patients. FOXP3 stimulated the proliferation and inhibited the apoptosis of human spermatogonial stem cells, and we further analyzed the targets of FOXP3. We have identified two new pathogenic variants of FOXP3 in non-obstructive azoospermia patients with high incidence, and FOXP3 silencing inhibits the proliferation and enhances the apoptosis of human spermatogonial stem cells. This study provides new insights into the etiology of azoospermia and offers novel pathogenic variants for gene targeting of male infertility.

Genetics of male infertility and related genes within Y chromosome

Objective: The infertility is a reproductive health problem that affects nearly 7% of all couples in the human population. It has been estimated that nearly 50% of infertility cases are due to genetic defects. Male infertility may be contributory to 30 - 40 % of infertile couples. Male infertility focuses on genetic factors impairing spermatogenesis and structural abnormalities such as Y chromosome microdeletions. The Y chromosome microdeletions are the most frequent genetic cause of male infertility. In this review article, we will focus on the structural abnormality and related gene functions on infertility.

The Male Fertility Gene Atlas – A web tool for collecting and integrating data about epi-/genetic causes of male infertility

The Male Fertility Gene Atlas – A web tool for collecting and integrating data about epi-/genetic causes of male infertility

Частота выявления делеций AZF, мутаций CFTR и длинных аллелей CAG-повтора AR при первичной лабораторной диагностике в гетерогенной группе пациентов с мужским бесплодием

microdeletions in the AZF region of Y-chromosome, compound heterozygotes of severe and mild CFTR mutations, and long CAG-repeats in the androgen receptor gene (AR) as marker of predisposition are frequently studied as genetic causes of male infertility. A simultaneously testing of the panel including biochemical, immunological, cyto- and molecular genetic markers is often performed during the complex laboratory diagnostics in infertile men. The aim of our work was to identify molecular genetic alterations, which are advisable for simultaneously testing in a man with currently uncertain form of infertility, to increase the informativeness of laboratory diagnostics. a retrospective study of 885 infertile men was conducted. AZF deletions were determined by multiplex PCR using 10 STS-markers (sY83, sY84, sY86, sY127, sY134, sY143, sY152, sY157, sY254, sY255) and two control loci SRY and AMEL with detection in polyacrylamide gel. Mutations in the CFTR gene (F508del, CFTRdel2.3(21kb), I507del, 1677delTA, 2143delT, 2184insA, 394delTT, W1282X, G542X, N1303K, R334W and 5T) were detected by PCR and SNaPshot. For determination of length of the AR CAG-repeat a fragment analysis of fluorescently labeled PCR products on the 3500xl capillary sequencer was performed. AZF deletions were detected in 8.2% of cases. The largest number of deletions was found in the AZFc subregion (58.9%), while a frequency of deletion in AZFa, AZFb or combined deletions of two and three subregions was 5.5%, 12.3% and 23.3%, respectively. Heterozygous carriage of severe CFTR mutations was detected in 4.7% patients. The most frequent mutation was F508del (83.3%), followed by CFTRdel21kb (7.1%) and W1282X (4.8%). The frequency of the mild splicing 5T mutation was 5.3%, and its incidence was significantly higher than in the previously published control group (p=0.002). AR genotyping revealed that the most prevailing allele was 21 (CAG) (21.5%). Long alleles with 27 or more CAG-trinucleotides were identified in 7.5% of the tested cases. In addition, 7 CAG heterozygotes with Kleinfelter syndrome were found. during primary complex laboratory diagnostics in a heterogeneous group of infertile men, it is advisable to detect AZF deletions and the most frequent CFTR mutations, including F508del, CFTRdel21kb, 1677delTA, 2143delT, W1282X and 5T. The more comprehensive analysis of CFTR mutations is justified only in patients with verified obstructive infertility. Sequencing of panels associated with infertility genes using NGS technology is promising.

SUN-208 Rare Case of 47XXY/46XX Mosaic Klinefelter Syndrome

Introduction: Klinefelter syndrome (KS) is the most common X chromosome abnormality and genetic cause of male infertility. Nondisjunction of paired X chromosomes during meiosis or gametogenesis gives rise to the karyotype 47XXY seen in 80 % of cases. The most common form of mosaicism results from post-fertilization nondisjunction of the XXY zygote in two cell lines 47XXY/46XY in 15-20 % of KS. The 47XXY/46XX mosaic form is very rare with only 20-25 cases described in the literature to date. Phenotype varies with distribution of the two cell lineages in developing embryo tissues, including KS male, true hermaphroditism, ovarian hypoplasia and normal female. Only 10 cases have been reported of 47XXY/46XX mosaic KS male phenotype . Our case is the 11th. Case: A 39 year old male presented with fatigue, weight gain, poor concentration and loss of libido. He reported no secondary sexual development during puberty, including hair, muscle mass, penis and testicles, and minimal erections. On exam, both testes were less than 2 cm with a normal penis. He had abdominal obesity, reduced muscle mass, and gynecomastia, as well as male pattern frontal baldness. Total testosterone (T) was 125 ng/dl (250-1100), Free T was 16 ng/dl (46-224), albumin was 3.9, FSH was 25 mIU/ml, and LH was 15.9 mIU/ml. Chromosome analysis: 25/30 (83%) cells 47XXY and 5/30 (17 %) cells 46XX. FISH study on 100 peripheral blood cells showed 87 % 47XXY and 14 % 46XX. The patient did not desire fertility and started testosterone replacement. Conclusion: Our case demonstrated the common features of 47XXY/46XX mosaic KS, including small testes, gynecomastia, hypergondotropic hypogonadism, and normal IQ. Interestingly, our patient had male pattern baldness, which was also common in his family. The average age of diagnosis for cases reported to date was 12-62 years, similar to ours, suggesting a delay in diagnosis, as can occur in many KS cases. Distribution of cell lines can vary between different tissues, but the presence of a Y chromosome in the gonad determines the phenotype. Mediastinal germ cell tumor, testicular teratoma, and radioulnar synostosis have been noted in 3 cases but not in this case. Mosaic cases tend to be more androgenic, and are more likely to have spermatogenesis than non-mosaic KS. This along with the failure to detect the 46XX cell line in routine blood cytogenetic tests (as opposed to gonadal tissue) is the reason for delayed detection in many cases. KS mosaicism should be considered in all cases of male infertility.

A novel homozygous FBXO43 mutation associated with male infertility and teratozoospermia in a consanguineous Chinese family

To identify the genetic causes of male infertility characterized by teratozoospermia. Genetic studies. Medical university. Two infertile brothers with teratozoospermia in a consanguineous Chinese family, another 124 sporadic infertile male patients presenting with teratozoospermia, and 200 male controls with normal fertility. None. Whole exome sequencing and genotype analysis to identify the potential pathogenic mutation, Sanger sequencing to validate the mutation in family members, in silico structural modeling to predict the functional consequences of mutation, and targeted next-generation sequencing to validate the mutation in sporadic cases. A novel homozygous nonsynonymous mutation (C1991T, p.G664D) in FBXO43 (F-box only protein 43) was observed in two brothers from a consanguineous Chinese family. The mutation was segregated with the disease phenotype and was predicted to be a disease causing protein by SIFT, PolyPhen-2, and Mutation Taster. An in silico mutant FBXO43 model predicts that the mutation p.G664D causes shortening of two β-sheets, an additional α-helix, and change in loops, which may result in loss of function of the protein. The homozygous mutation of FBXO43 was absent in the 1000 Genomes Project (1000G) and the Exome Aggregation Consortium (ExAC) databases. Subsequent mutation screening of FBXO43 in a cohort of 124 cases identified four additional cases with heterozygous FBXO43 mutations. No mutations were found in FBXO43 in 200 fertile controls. The mutation in FBXO43 is a causative factor of male infertility and teratozoospermia.

A systematic review and standardized clinical validity assessment of male infertility genes.

STUDY QUESTIONWhich genes are confidently linked to human monogenic male infertility?SUMMARY ANSWEROur systematic literature search and clinical validity assessment reveals that a total of 78 genes are currently confidently linked to 92 human male infertility phenotypes.WHAT IS KNOWN ALREADYThe discovery of novel male infertility genes is rapidly accelerating with the availability of next-generating sequencing methods, but the quality of evidence for gene–disease relationships varies greatly. In order to improve genetic research, diagnostics and counseling, there is a need for an evidence-based overview of the currently known genes.STUDY DESIGN, SIZE, DURATIONWe performed a systematic literature search and evidence assessment for all publications in Pubmed until December 2018 covering genetic causes of male infertility and/or defective male genitourinary development.PARTICIPANTS/MATERIALS, SETTING, METHODSTwo independent reviewers conducted the literature search and included papers on the monogenic causes of human male infertility and excluded papers on genetic association or risk factors, karyotype anomalies and/or copy number variations affecting multiple genes. Next, the quality and the extent of all evidence supporting selected genes was weighed by a standardized scoring method and used to determine the clinical validity of each gene–disease relationship as expressed by the following six categories: no evidence, limited, moderate, strong, definitive or unable to classify.MAIN RESULTS AND THE ROLE OF CHANCEFrom a total of 23 526 records, we included 1337 publications about monogenic causes of male infertility leading to a list of 521 gene–disease relationships. The clinical validity of these gene–disease relationships varied widely and ranged from definitive (n = 38) to strong (n = 22), moderate (n = 32), limited (n = 93) or no evidence (n = 160). A total of 176 gene–disease relationships could not be classified because our scoring method was not suitable.LARGE SCALE DATANot applicable.LIMITATIONS, REASONS FOR CAUTIONOur literature search was limited to Pubmed.WIDER IMPLICATIONS OF THE FINDINGSThe comprehensive overview will aid researchers and clinicians in the field to establish gene lists for diagnostic screening using validated gene–disease criteria and help to identify gaps in our knowledge of male infertility. For future studies, the authors discuss the relevant and important international guidelines regarding research related to gene discovery and provide specific recommendations for the field of male infertility.STUDY FUNDING/COMPETING INTEREST(S)This work was supported by a VICI grant from The Netherlands Organization for Scientific Research (918-15-667 to J.A.V.), the Royal Society, and Wolfson Foundation (WM160091 to J.A.V.) as well as an investigator award in science from the Wellcome Trust (209451 to J.A.V.).PROSPERO REGISTRATION NUMBERNone.

Genetic causes of male infertility: snapshot on morphological abnormalities of the sperm flagellum

Male infertility due to Multiple Morphological Abnormalities of the sperm Flagella (MMAF), is characterized by nearly total asthenozoospermia due to the presence of a mosaic of sperm flagellar anomalies, which corresponds to short, angulated, absent flagella and flagella of irregular calibre. In the last four years, 7 novel genes whose mutations account for 45% of a cohort of 78 MMAF individuals were identified: DNAH1, CFAP43, CFAP44, CFAP69, FSIP2, WDR66 (CFAP251), AK7. This successful outcome results from the efficient combination of high-throughput sequencing technologies together with robust and complementary approaches for functional validation, in vitro, and in vivo using the mouse and unicellular model organisms such as the flagellated parasite T. brucei. Importantly, these genes are distinct from genes responsible for Primary Ciliary Dyskinesia (PCD), an autosomal recessive disease associated with both respiratory cilia and sperm flagellum defects, and their mutations therefore exclusively lead to male infertility. In the future, these genetic findings will definitely improve the diagnosis efficiency of male infertility and might provide genotype-phenotype correlations, which could be helpful for the prognosis of intracytoplasmic sperm injection (ICSI) performed with sperm from MMAF patients. In addition, functional study of these novel genes should improve our knowledge about the protein networks and molecular mechanisms involved in mammalian sperm flagellum structure and beating.

The Association of Partial Azoospermia Factor C Deletions and Male Infertility in Northwestern China

Background: Male infertility is a major health issue worldwide. Y chromosome microdeletions are well-characterized genetic causes of male infertility. The association of partial AZFc deletions (gr/gr, b2/b3, and b1/b3) with male infertility is not well confirmed in diverse populations. The purpose of the present study was to investigate the frequency of partial AZFc deletions and their association with male infertility in a population from Northwestern China. Methods: Multiplex polymerase chain reaction was used to detect partial AZFc deletions in 228 infertile patients. We analyzed 141 cases of azoospermia (AS), 87 cases of oligozoospermia (OS), and 200 fertile controls. Results: Our data showed that the frequency of a b2/b3 deletion in infertile men, men with AS, men with OS, and controls was 3.51, 2.13, 5.75, and 0.00%, respectively. The frequency of this deletion was significantly different between the infertile group and the control group (3.51 vs. 0.00%, respectively, p = 0.021) and between the OS group and the control group (5.75 vs. 0.00%, respectively, p = 0.003). The frequency of a gr/gr deletion in each group was 11.84, 9.22, 16.09, and 7.50%, respectively. The frequency of a gr/gr deletion was significantly different between the OS group and the control group (16.09 vs. 7.50%, respectively, p = 0.026) but not between the infertile group and the control group (11.84 vs. 7.50%, p = 0.132) or the AS group and the control group (9.22 vs. 7.50%, p = 0.569). The frequency of a b1/b3 deletion was 0.44, 0.71, 0.00, and 3.00%, respectively. For this deletion, there was no significant difference between the infertile (0.44 vs. 3.00%, p = 0.089), AS (0.71 vs. 3.00%, p = 0.276), and OS groups (0.00 vs. 3.00%, p = 0.236) and the control group. Conclusions: Our results suggest that the b2/b3 deletion might be associated with male infertility and that the gr/gr deletion might be associated with spermatogenic failure in men with OS in Northwestern China (Ningxia).

Chromosomal translocations and semen quality: A study on 144 male translocation carriers.

Chromosomal translocations are known genetic causes of male infertility. Are certain translocations or chromosomal regions more directly associated with sperm defects? Is there a threshold of sperm impairment that can be relevant for detection of translocations? This is a monocentric retrospective observational study covering a 10-year period. Eighty-one patients carrying a reciprocal translocation (RCT) and 63 carrying a Robertsonian translocation (ROBT) were compared with 105 fertile patients. Semen quality before and after sperm migration was compared. The aims were to define whether a threshold based on sperm analysis could be proposed for detection of translocations and to identify whether some redundant chromosomal regions might be associated with sperm quality defects. The number of progressive spermatozoa retrieved after sperm preparation (NPS-ASP) was altered in both RCT and ROBT carriers compared with controls, with a stronger alteration in ROBT. Based on the NPS-ASP results in this large group of translocation carriers, a relatively robust threshold, fixed at less than 5 million, may be proposed for detection of translocations. The alteration of NPS-ASP was independent of the chromosome involved in ROBT, while in RCT, four redundant chromosomal regions (1q21, 6p21, 16q21, 17q11.2) were associated with poor or very poor NPS-ASP. The NPS-ASP appears to be a good parameter to assess sperm function and would be a useful tool to detect chromosomal translocations. Four redundant regions have been identified on four chromosomes, suggesting that they may contain genes of interest to study sperm functions.

Chromosome positioning and male infertility: it comes with the territory.

The production of functional spermatozoa through spermatogenesis requires a spatially and temporally highly regulated gene expression pattern, which in case of alterations, leads to male infertility. Changes of gene expression by chromosome anomalies, gene variants, and epigenetic alterations have been described as the main genetic causes of male infertility. Recent molecular and cytogenetic approaches have revealed that higher order chromosome positioning is essential for basic genome functions, including gene expression. This review addresses this issue by exposing well-founded evidences which support that alterations on the chromosome topology in spermatogenetic cells leads to defective sperm function and could be considered as an additional genetic cause of male infertility.

Ccdc87 is critical for sperm function and male fertility.

Male infertility has become an increasingly common health concern in recent years. Apart from environmental factors, nutrition, lifestyle, and sexually transmitted diseases, genetic defects are important causes of male infertility. Many genes have been demonstrated to be associated with male infertility. However, the roles of some functional genes in infertility, especially those that are specifically expressed in the reproductive system, remain to be elucidated. Here, we demonstrated that the testis-specific gene coiled-coil domain-containing 87 (Ccdc87) is critical for male fertility. Reverse-transcriptase polymerase chain reaction and western blot analyses revealed that the Ccdc87 mRNA and protein were only expressed in mouse testis. Ccdc87 expression first appeared at postnatal day 14 and remained at a relatively high level until adulthood. Male mice lacking Ccdc87 gene (Ccdc87-/-) were found to be subfertile. Approximately 20% of Ccdc87-null sperm from the testis and epididymis displayed severe abnormity of acrosome and cell nucleus. Sperm isolated from the cauda epididymides of Ccdc87-/- mice exhibited decreased initial motility but did not show any change in capacitation. Additionally, Ccdc87 disruption led to the impotency of sperm spontaneous and progesterone-induced acrosome reaction. Moreover, in vitro fertilization assays indicated that the fertilizing capacity of Ccdc87-/- sperm was significantly reduced. Taken together, these findings provide a new clue to understand the genetic causes of male infertility.

AZF-deletion – one of the genetic causes of male infertility

The possibility of investigating the causes of infertility in men increased significantly thanks to the human genome, the sequencing of the Y-chromosome, and the introduction of modern molecular techniques in medical practice. We conducted a survey of 80 men with idiopathic infertility, which included clinical and urological examination: complete blood count, urinalysis, Wassermann, blood sugar, blood biochemical examination, hormonal examination (testosterone, LH, FSH, prolactin), karyotyping, ultrasound examination of the scrotum and prostate, microscopic and bacteriological examination of ejaculate, a study on sexually transmitted infections. 68 patients with the concentration of sperm in the ejaculate <5*106/ml conducted a genetic blood test for the presence of deletions in the AZF locus Y-chromosome. Isolation and purification of DNA from whole venous blood passes through a standard method of precipitation of nucleic acids. For the analysis of the variations of the gene regions of AZF deletions specific DNA amplification was carried out in vitro. In the study group (68 patients) in the locus AZF deletions were detected in 6 patients (8.8%). According to the world of literature and the results of his observations is obvious need for research azoospermia factor for all men with azoospermia/oligozoospermia severe.

Disorders of spermatogenesis: Perspectives for novel genetic diagnostics after 20years of unchanged routine.

Infertility is a common condition estimated to affect 10–15% of couples. The clinical causes are attributed in equal parts to the male and female partners. Diagnosing male infertility mostly relies on semen (and hormone) analysis, which results in classification into the two major phenotypes of oligo- and azoospermia. The clinical routine analyses have not changed over the last 20 years and comprise screening for chromosomal aberrations and Y‑chromosomal azoospermia factor deletions. These tests establish a causal genetic diagnosis in about 4% of unselected men in infertile couples and 20% of azoospermic men. Gene sequencing is currently only performed in very rare cases of hypogonadotropic hypogonadism and the CFTR gene is routinely analysed in men with obstructive azoospermia. Still, a large number of genes have been proposed to be associated with male infertility by, for example, knock-out mouse models. In particular, those that are exclusively expressed in the testes are potential candidates for further analyses. However, the genome-wide analyses (a few array-CGH, six GWAS, and some small exome sequencing studies) performed so far have not lead to improved clinical diagnostic testing. In 2017, we started to routinely analyse the three validated male infertility genes: NR5A1, DMRT1, and TEX11. Preliminary analyses demonstrated highly likely pathogenic mutations in these genes as a cause of azoospermia in 4 men, equalling 5% of the 80 patients analysed so far, and increasing the diagnostic yield in this group to 25%. Over the past few years, we have observed a steep increase in publications on novel candidate genes for male infertility, especially in men with azoospermia. In addition, concerted efforts to achieve progress in elucidating genetic causes of male infertility and to introduce novel testing strategies into clinical routine have been made recently. Thus, we are confident that major breakthroughs concerning the genetics of male infertility will be achieved in the near future and will translate into clinical routine to improve patient/couple care.

Development and implementation of a novel panel consisting 20 markers for the detection of genetic causes of male infertility.

Azoospermia factor (AZF) genes are involved in spermatogenesis. Deletions in the region of these genes have been recognised as a major genetic cause of infertility due to defects in spermatogenesis. Klinefelter syndrome (KS) is the other main cause of male infertility. This study was performed to establish a novel method for the detection of genetic causes of infertility in males and also to investigate the prevalence, extent and position of Y chromosome microdeletions in Iranian infertile men. We developed a newly designed panel of fluorescent multiplex-PCR method to amplify 20 markers (15 sequence-tagged sites (STSs) markers which are placed in the Y chromosome AZF region, 2 short tandem repeats (STRs) and 3 segmental duplications (SDs)). This multifunctional method is for the simultaneous detection of Y chromosome microdeletions and KS. Among 149 studied infertile men, one was detected to suffer from KS and seven (4.7%) were detected with the presence of one or more deleted STS loci. The main cause of infertility for the remaining patients would be nongenetic factors. This strategy is represented as a fast and accurate method to determine the frequencies of different AZF microdeletions which are suitable for use in clinical purposes.

Validation and application of a novel integrated genetic screening method to a cohort of 1,112 men with idiopathic azoospermia or severe oligozoospermia.

Microdeletions of the Y chromosome (YCMs), Klinefelter syndrome (47,XXY), and CFTR mutations are known genetic causes of severe male infertility, but the majority of cases remain idiopathic. Here, we describe a novel method using single molecule Molecular Inversion Probes (smMIPs), to screen infertile men for mutations and copy number variations affecting known disease genes. We designed a set of 4,525 smMIPs targeting the coding regions of causal (n=6) and candidate (n=101) male infertility genes. After extensive validation, we screened 1,112 idiopathic infertile men with non-obstructive azoospermia or severe oligozoospermia. In addition to five chromosome YCMs and six other sex chromosomal anomalies, we identified five patients with rare recessive mutations in CFTR as well as a patient with a rare heterozygous frameshift mutation in SYCP3 that may be of clinical relevance. This results in a genetic diagnosis in 11-17 patients (1%-1.5%), a yield that may increase significantly when more genes are confidently linked to male infertility. In conclusion, we developed a flexible and scalable method to reliably detect genetic causes of male infertility. The assay consolidates the detection of different types of genetic variation while increasing the diagnostic yield and detection precision at the same or lower price compared with currently used methods.