Genetic screening in couples experiencing recurrent assisted procreation failure

Infertility is a major health problem affecting about 10-20% of couples in the reproductive age group. Male factor is assumed to be responsible in about 50% cases of infertility. The origin of reduced testicular sperm function is unknown in about 50-70% of cases and for such couples assisted reproduction techniques (ART) are a boon. Male infertility is often due to poor semen quality and may be associated with genetic defects. ART has revolutionized management of infertility and intracytoplasmic sperm injection (ICSI) is the ART procedure of choice in 60-80% cases. Despite major technological advancements and professional expertise in ART, the success rate and carry-home live birth rate of ICSI is low (18-25%). This study was aimed to understand the genetic etiopathology of recurrent ART failure. For this, 110 couples with 3 or more failed ART cycles were recruited. A detailed history was taken and only idiopathic ART failure cases were enrolled for this study. They were subjected to cytogenetic and Yq microdeletion analysis. Genetic abnormalities were detected in 19 couples. Since a large number (18.2%) cases harboured genetic abnormalities, it is important for all couples opting for ART to undergo a thorough genetic analysis to prevent recurrent emotional, physical and financial stress.     

Necessity of nuclear and mitochondrial genome analysis prior to assisted reproductive techniques/intracytoplasmic sperm injection

Assisted reproductive technique (ART) has revolutionized the management of severe male factor infertility and in some countries 5% babies are conceived through ART/intra cytoplasmic sperm injection (ICSI). However, the carry-home live birth rate after several ART cycles is low (18-25%) and this is financially, physically and emotionally crippling for the couples. Genetic factors could lead to pre or post-implantation failure and thus explain for low ART success rate. Thus, this study was planned to understand, if infertile men harbour genetic abnormalities which may be iatrogenically transmitted by ART and adversely affect growth potential of embryo. Ninety infertile men underwent semen, cytogenetic, Yq microdeletion and mitochondrial mutation analysis. Of these, 14.4% cases harboured cytogenetic abnormality, and 8.89% Yq microdeletions. A high frequency of mitochondrial mutations was found in 23 men with asthenospermia. It is important to understand that through ART genetic abnormalities are transmitted to offspring, resulting in impaired growth and development potential of embryo and poor take-home live birth rate. Thus, genetic analysis is strongly recommend in all men with idiopathic infertility who opt for ART to counsel couples and provide them with most adapted therapeutics.     

Health of children born after the infertility treatment with Assisted Reproduction Technology

Since the birth of Louise Brown in July 1978 and the birth of the first intracytoplasmic sperm injection (ICSI) child in January 1992 many couples with female-factor or male-factor infertility can be helped to overcome their infertility resulting in a delivery and birth of a child. Over a million children have been born from assisted conception worldwide. Newer techniques being introduced appear less and less 'natural', such as intracytoplasmic sperm injection (ICSI), but there is little information on these children beyond the neonatal period. This risk varied according to the patient's age, the type of ART procedure performed, the number of embryos transferred, and embryo availability. ART is associated with low increase risk of congenital malformations, major birth defects and genetic and imprinting disorders.     

Current trends in evaluation of sperm function: in vitro selection and manipulation of male gametes for assisted conception

With increasing medical utilization of assisted reproductive technology (ART), scientists and clinicians have been able to study extensively multiple cell functions operating synchronously and flawlessly during the events preceding, before and after fertilization. Critical evaluation of the functional status of spermatozoa for in vitro techniques such as sperm-mucus interaction, acrosome reaction status, sperm-zona pellucida binding and penetration tests, hyaluronic acid binding assay, and computer assisted semen analysis etc. can direct a male partner of an infertile couple to more aggressive forms of treatments. In vitro selection of functionally competent sperm cells is a pre-requisite for successful outcome in in vitro fertilization or in intracytoplasmic sperm injection (ICSI). Direct injections of acrosome-intact spermatozoa into oocyte during ICSI bypassing the normal events of sperm oocyte interaction and fusion events have raised concerns with regard to fertilization abnormalities and genetic issues. The present communication briefly reviews the sperm function tests with emphasis on its correlation with fertility outcome, and the currently employed sperm selection and manipulation procedures which may have implications in assisted conception programs.     

Bilan des examens chromosomiques de 277 couples candidats à l’injection intracytoplasmique de spermatozoïde

In these study the frequency of congenital chromosomal aberrations was assessed in a sample of 277 couples included in a intracytoplasmic sperm injection (ICSI) program. A total of 7 aberrant karyotypes were diagnosed, corresponding to an abnormality rate of 1.3% per individual and 2.6% per couple. The following types of abnormalities were observed: reciprocal translocations (n=2), Robertsonian translocations (n=2), pericentral inversion (n=1), sex chromosomal mosaicism (n=1), marker chromosome (n=1). Surprisingly, 71% (5/7) of all abnormal karyotypes were contributed by the female partner of ICSI patients. These data confirm the higher incidence of chromosomal aberration in infertile couples compared with the baseline population risk. It also confirms that not only the male, but also the female should be routinely karyotyped prior to ICSI, and then receive appropriate genetic counselling.     

Chromosomal Abnormality and Y Chromosome Microdeletion in Chinese Patients with Azoospermia or Severe Oligozoo-spermia

Chromosomal abnormality and Y chromosome microdeletion are regarded as two frequent genetic causes associated with spermatogenic failure in Caucasian population. To investigate the distribution of the two genetic defects in Chinese patients with azoospermia or severe oligozoospermia, karyotype analysis by G-banding was carried out in 358 idiopathic infertile men, including 256 patients with azoospermia and 102 patients with severe oligozoospermia, and screening of AZF region microdeletion of Y chromosome by multiplex PCR was performed in those patients without detectable chromosomal abnormality and 100 fertile controls. Of 358 patients, 39(10.9%) were found to have chromosomal abnormalities in which Klinefelters syndrome (47, XXY) was the most common chromosomal aberration. The incidence of sex chromosomal abnormality in patients with azoospermia was significantly higher than that in patients with severe oligozoospermia (12.1% vs 1%). Among the rest of the 319 patients with normal karyotype, 46 (14.4%) were found to have microdeletions in AZF region. The prevalence rates of AZF microdeletion was 15% and 13.1% in patients with azoospermia and severe oligozoospermia respectively. The microdeletion in AZFc was the most frequent deletion and all the microdeletions in AZFa were found in azoospermic patients. No microdeletion in AZF region was detected in fertile controls. In conclusion, chromosomal abnormality and AZF region microdeletion of Y chromosome might account for about 25% of Chinese infertile patients with azoospermia or severe oligozoospermia, suggesting the two abnormalities are important genetic etiology of spematogenic failure in Chinese population and it is essential to screen them during diagnosis of male infertility before in vitro assisted fertilization by introcytoplasmic sperm injection.     

中国无精症、严重寡精症患者的染色体异常和Y染色体微缺失

染色体异常和Y染色体微缺失被认为是两个白种人群中常见的生精障碍相关遗传因素。为了解中国无精症、严重寡精症患者中的染色体异常和Y染色体微缺失,运用染色体G显带技术,在358个原发无精症（256人）和严重寡精症（102人）不育患者中进行染色体核型分析;同时运用多重PCR技术,在核型正常的患者和100个正常生育男性中,对Y染色体AZF区微缺失进行筛查。在358个患者中,39人（10．9％）发现有染色体异常,Klinefelter（47,XYY）最为常见。无精症患者性染色体异常频率明显高于严重寡精症患者（12．1％VS1％）。在319个核型正常的患者中,46（14．4％）发现有AZF区微缺失,无精症和寡精症患者中Y染色体微缺失频率分别为15％和13．1％,AZFc区的微缺失最为常见,AZFa区的微缺失只见于无精症患者,正常生育男性中未发现AZF区的微缺失。结果显示,在中国无精症、严重寡精症患者中,大约25％的患者有染色体异常或Y染色体AZF区微缺失,提示这两种遗传异常是中国人群生精障碍的重要相关遗传病因,有必要在男性不育的诊断以及利用细胞浆内精子注射技术进行辅助生育时,对患者的这些遗传异常进行筛查。     

Chromosome abnormalities in sperm from infertile men with normal somatic karyotypes: oligozoospermia

Recently, intracytoplasmic sperm injection (ICSI) has been extremely successful for the treatment of male infertility. However, transmission of cytogenetic defects to offspring is a great concern. There are two types of cytogenetic problems in patients seeking ICSI; one is the transmission of genetic defects from patients with constitutional chromosomal abnormalities and the second is the generation of de novo defects in infertile men. Generally about 5.1% of infertile men have chromosomal abnormalities. Among such infertile men, men with severe spermatogenesis defects, including oligozoospermia and azoospermia, are subjects for ICSI. Therefore it is very important to obtain cytogenetic information in these infertile patients. Furthermore, oligozoospermic men with a normal somatic karyotype also have increased frequencies of sperm chromosome abnormalities. Oligozoospermia is usually associated with other sperm alterations, for example oligoasthenozoospermia, oligoteratozoospemia and oligoasthenoteratozoospermia. In this review, the relationship between sperm concentration and sperm aneuploidy frequencies has been analyzed. The inverse correlation between the frequency of sperm aneuploidy and concentration has been reported in extensive studies. Especially in severe oligozoospermia, a significantly higher frequency of sex chromosome aneuploidy has been observed and this has been corroborated in recent clinical outcome data of ICSI.     

A cytogenetic study of Kuwaiti couples with infertility and reproductive disorders: short arm deletion of chromosome 21 is associated with male infertility

Chromosomal anomalies may be a reason for both male and female infertility. The aim of this study was to investigate the contribution of chromosomal abnormalities in sterile couples from Kuwait. A total of 118 patients with clinical diagnosis of infertility was analyzed using cytogenetic banding techniques. Common chromosomal abnormalities were detected in 12 patients. We describe here one new case of an infertile male with the karyotype 46,XY, del(21)(pter;q11.2). The overall incidence of 11% abnormality indicates that routine chromosome analysis of infertile couples in Kuwait should be considered before the planning of intracytoplasmic sperm injection.     

Chromosomal evaluation in a group of Tunisian patients with non-obstructive azoospermia and severe oligozoospermia attending a Tunisian cytogenetic department

Male infertility is the cause in half of all childless partnerships. Numerous factors contribute to male infertility, including chromosomal aberrations and gene defects. Few data exist regarding the association of these chromosomal aberrations with male infertility in Arab and North African populations. We therefore aimed to evaluate the frequency of chromosomal aberrations in a sample of 476 infertile men with non-obstructive azoospermia (n = 328) or severe oligozoospermia (n = 148) referred for routine cytogenetic analysis to the department of cytogenetics of the Pasteur Institute of Tunis. The overall incidence of chromosomal abnormalities was about 10.9%. Out of the 52 patients with abnormal cytogenetic findings, sex chromosome abnormalities were observed in 42 (80.7%) including Klinefelter syndrome in 37 (71%). Structural chromosome abnormalities involving autosomes (19.2%) and sex chromosomes were detected in 11 infertile men. Abnormal findings were more prevalent in the azoospermia group (14.02%) than in the severe oligozoospermia group (4.05%). The high frequency of chromosomal alterations in our series highlights the need for efficient genetic testing in infertile men, as results may help to determine the prognosis, as well as the choice of an assisted reproduction technique. Moreover, a genetic investigation could minimize the risk of transmitting genetic abnormalities to future generations.     

Panorama de l’infertilité masculine

This paper reviews new epidemiological, etiological and therapeutic aspects of male infertility. Because of the great improvement in the efficacy of assisted reproductive techology due to ICSI, the recently discovered genetic causes of male infertility have to be considered. While studies concerning the role of xenobiotics in disrupting endocrine regulation of testicular functions are in progress, genetic causes of male infertility has been discovered. Microdeletions of the long arm of the Y chromosome account for a substantial part of unexplained spermatogenic failures. Mutations of CFTR gene are involved in bilateral agenesis of vas deferens. This condition might be considered as a mild form of cystic fibrosis. These genetic defects together with chromosmal abnormalities, which are known to be responsible for spermatogenic failures, should be considered as potential sources of reproductive abnormalities of more global pathology transmissible to children who can be obtained by ICSI with ejaculated, epididymal or testicular sperm.     

Génétique et infertilité masculine: données actuelles

Intracytoplasmic sperm injection (ICSI) and testicular biopsies (TESE) have revolutionized the treatment of male infertility, introducing a risk of an increased frequency of genetic defects in the offspring. These risks and their consequences must therefore be evaluated when proposing ICSI to an infertile man. Karyotype and molecular analysis should be performed to detect any genetic defects responsible for male infertility. Y microdeletion screening is important, not only to define the aetiology of spermatogenic failure, but also to provide information allowing a more appropriate management of both the infertile male and his future male child. Genetic counselling is then advised before deciding to attempt ICSI.     

Cytogenetic abnormalities in 222 infertile men with azoospermia and oligospermia in Iran: Report and review

BACKGROUND:

Infertility affects approximately 10%-15% of couples in reproductive age. In half of the couples, causes are male-related, associated with impaired spermatogenesis. There is a complex correlation between genetics and infertility. Several factors affect on gametogenesis, from which factors that lead to chromosomal abnormalities are one of the best known. The aim of this study was to determine type and rate of chromosomal abnormalities in infertile azoospermic and oligospermic males in Iranian population.

MATERIALS AND METHODS:

The records of a total of 222 participants were evaluated retrospectively.

RESULTS:

As a whole we observed 13.96% chromosomal abnormality, from which 12.15% showed numerical and 1.8% showed structural abnormalities.

CONCLUSION:

Comparison of our results with the review of the literature shows a higher incidence (4- fold) of gonosomal, in particular, numerical gonosomal, chromosomal anomalies. Cytogenetic analysis is strongly suggested for infertile men, particularly in those who suffer from azoospermia.     

Chromosome analysis by spectral karyotyping of spermatozoa from an oligoasthenozoospermic carrier of a 10; 21 reciprocal translocation

Cytogenetic analysis of germ-line cells prior to intracytoplasmic sperm injection (ICSI) treatment is thought to be necessary for infertile males with an identified chromosomal abnormality. We analyzed the chromosomal karyotype of human spermatozoa from an oligoasthenozoospermic carrier of a reciprocal translocation t(10; 21). Cytogenetic analysis of 39 spermatozoa was performed by spectral karyotyping (SKY) and by ICSI into mouse oocytes. The motile morphologically normal spermatozoa were injected into mouse oocytes. Of these spermatozoa, 38 (97.4%) were activated. Twenty-one (53.8%) of the activated oocytes formed two pronuclei. Metaphase chromosome spreads from 13 spermatozoa were analyzed. Only one spermatozoon was normal and 2 spermatozoa exhibited balanced translocation. Nine and one spermatozoa showed abnormalities related and unrelated to the translocation, respectively. The numbers of normal/balanced spermatozoa were lower than those in previous reports analyzing reciprocal translocations using a previously described technique involving penetrated golden hamster oocytes. After genetic counseling with the carrier and his partner, ICSI treatment was performed. Healthy female and male infants were delivered at 37 weeks gestation via a Caesarean section. The female infant was a carrier of the reciprocal translocation and the male infant was confirmed normal on prenatal diagnosis at 16 weeks gestation. For genetic counseling prior to ICSI treatment, the incidence of unbalanced type spermatozoa after swim-up or Percoll gradient treatment should be investigated and discussed with couples having fertility problems related to oligozoospermia autosomal structural abnormalities.     

Sperm nuclear transfer and transgenic production in the fish medaka

Sperm nuclear transfer or intracytoplasmic sperm injection (ICSI) is a powerful assisted reproductive technology (ART) for treating human male infertility. Controversial reports of increased birth defects have raised concerns about the ART's safety. The cause for birth defects, however, has remained elusive for analysis in human because of the sample size, male infertility genetics, physiological heterogeneity and associated procedures such as embryo manipulations. Animal models are required to evaluate factors leading to the increased birth defects. Here we report the establishment of medakafish model for ICSI and transgenic production. This small laboratory fish has high fecundity and easy embryology. We show that ICSI produced a 5% high percentage of fertile animals that exhibited both paternal and maternal contribution as evidenced by the pigmentation marker. Furthermore, when sperm were pre-incubated with a plasmid ubiquitously expressing RFP and subjected to ICSI, 50% of sperm nuclear transplants showed germline transmission. We conclude that medaka is an excellent model for ICSI to evaluate birth defects and that sperm nuclear transfer can mediate stable gene transfer at high efficiency. Although more demanding for experimentation, sperm-mediated transgenesis should be particularly applicable for aquaculture species with a lengthy generation time and/or a large adult body size.     

When should a mare go for assisted reproduction?

The use of assisted reproductive techniques (ART) has helped owners to produce offspring from valuable mares that were considered infertile using standard breeding techniques. Before referring a mare for an ART, the practitioner should be able to identify the underlying cause of subfertility of the mare. The objective of this review is to provide information regarding embryo transfer, oocyte transfer and intracytoplasmic sperm injection, the three most common ART used in equine practice. Knowing the complexity as well as the risks of these techniques, enables practitioners to refer a subfertile mare to the least complex and most appropriate and successful ART that can overcome specific causes of infertility.     

The Use of In Vitro Fertilization in the Management of Male Infertility: What the Urologist Needs to Know

Infertility affects approximately 10% to 20% of reproductive-age couples, many of whom may present initially to a urologist. Some couples may be treated medically to increase spontaneous conception rates; however, many will require more aggressive management with in vitro fertilization (IVF) and/or intracytoplasmic sperm injection (ICSI). IVF involves ovarian stimulation, oocyte retrieval, and fertilization outside of the body; ICSI involves injecting one sperm into the oocyte to promote fertilization. Here we provide a brief overview of IVF and ICSI along with a discussion of the risks involved to facilitate the counseling and care of the infertile couple.Key words: Intracytoplasmic sperm injection, Male infertilityInfertility, defined as the inability to conceive within 12 months of unprotected intercourse, affects approximately 10% to 20% of reproductive-age couples.¹ As couples defer childbearing until later ages and as the obesity epidemic grows, the incidence of infertility is likely to continue to rise.^2,3 Male factor infertility is estimated to contribute to two-thirds of all cases. Of men seeking care for infertility, 18.1% reported being diagnosed with male factor infertility and 13.7% with a sperm or semen problem.⁴The evaluation for male infertility includes a thorough history and physical examination, and the mainstay of diagnostic testing continues to be the semen analysis. If abnormalities are noted on semen analysis, further testing is warranted to evaluate for possible etiologies. Where applicable, treatment is initiated with the goal of improving semen quality and male fertility. Previously, in cases in which semen quality remained profoundly impaired, the successful treatment for male factor infertility was once limited to donor insemination.The development of in vitro fertilization (IVF) revolutionized the management of female infertility. As powerful a tool as this proved to be, however, IVF fertilization rates remained poor in the presence of compromised semen parameters. A significant breakthrough in the treatment of severe male infertility was the development of intracytoplasmic sperm injection (ICSI) in 1992.⁵ By allowing the injection of a single sperm into each oocyte, ICSI provides the possibility of genetic offspring to men who have very scant numbers of motile sperm on semen analysis or who require surgical harvesting.From its inception, assisted reproduction has involved a gynecologist and an embryologist. The urologist is a critical collaborator for the treatment of couples with male factor infertility. Sperm harvested by microsurgical epididymal sperm aspiration, testicular sperm aspiration, or biopsy can be used to fertilize harvested oocytes by ICSI. The urologist may be the first to evaluate a couple for infertility, and will certainly be involved if sperm harvesting is indicated. Therefore, this article reviews the process of assisted reproduction by IVF/ICSI for urologists who may be seeing patients with infertility issues.     

Value of chromosome tests in genetic counseling of infertile couples

A cytogenetic analysis of more than 7000 subjects has been performed in the aetiological screening of infertile couples. This study revealed that infertile couples can be divided into three groups: those with one or more spontaneous abortions before 13 weeks of gestations, those with primary sterility (no gestation for at least 24 months) or those with secondary sterility (after one or more children, no further gestation for at least 24 months). The frequency of chromosomal abnormalities observed in this population is 2,9%, i.e. 1/17 couple. The results, according to sex of subjects bearing the chromosomal abnormality, were then analysed in each of the three groups. From this study, the authors insist on the advantage of systematically performing a chromosome analysis in the case of infertile couples for two main reasons: frequency of chromosomal abnormalities is relatively high in this population, detection of such abnormalities enables some couple to be rapidly directed to other solutions (Artificial Insemination), and others, due to prenatal chromosomal diagnosis, to have offspring in safety.