TESE–ICSI in patients with non-mosaic Klinefelter syndrome: a comparative study

Sperm extraction in nonmosaic Klinefelter syndrome patients: A case series and literature review of sperm extraction in Klinefelter syndrome patients

Objectives

Klinefelter syndrome (KF) is a group of chromosomal disorders with at least one extra X chromosome in male individuals that leads to infertility and diminished hair growth in affected males. In this study, we present a case series of 16 nonmosaic KF and an extensive literature review.

Patients and Methods

This is a retrospective study including 16 nonmosaic Klinefelter Syndrome patients that underwent micro-testicular sperm extraction (m-TESE) at our center between January 2016 and December 2022. Frequencies and percentages were used to present categorical variables, whereas continuous variables were presented as the median and interquartile range (IQR). The sperm retrieval rate (SRR) was assessed using a one-sample proportions test with continuity correction. Fisher's exact test was to assess the differences between patients with negative and positive retrieval in terms of the categorical variables. A Wilcoxon rank-sum test was applied to explore the between-group differences in the numerical variables. A literature search was performed for additional publications of discussing m-TESE among KF patients.

Results

The median (IQR) age of patients was 40.0 years (34.5-47.0). All of the patients had nonobstructive azoospermia, and the majority of them (93.8%) had primary infertility. The most common histopathological findings were atrophic tubules (57.1%), followed by Sertoli cell-only (28.6%). Sperm retrieval was positive for two patients with a rate of 12.5% (95% confidence interval 2.2 to 39.6). Patients with positive sperm retrieval were significantly younger than their peers with negative retrieval (median = 28.0, IQR = 27.5 to 28.5 vs. median = 41.5, IQR = 35.8 to 47.0, P = 0.031). The successful conception rate was 100% (n = 2) using intracytoplasmic sperm injection with a birth rate of 100% (n = 2).

Conclusion

Our observed SRR among nonmosaic KF patients was marginally lower than the reported literature. Younger-age patients were significantly more likely to benefit from the procedure.

The Klinefelter Syndrome and Testicular Sperm Retrieval Outcomes

Klinefelter syndrome (KS), caused by the presence of an extra X chromosome, is the most prevalent chromosomal sexual anomaly, with an estimated incidence of 1:500/1000 per male live birth (karyotype 47,XXY). High stature, tiny testicles, small penis, gynecomastia, feminine body proportions and hair, visceral obesity, and testicular failure are all symptoms of KS. Endocrine (osteoporosis, obesity, diabetes), musculoskeletal, cardiovascular, autoimmune disorders, cancer, neurocognitive disabilities, and infertility are also outcomes of KS. Causal theories are discussed in addition to hormonal characteristics and testicular histology. The retrieval of spermatozoa from the testicles for subsequent use in assisted reproduction treatments is discussed in the final sections. Despite testicular atrophy, reproductive treatments allow excellent results, with rates of 40–60% of spermatozoa recovery, 60% of clinical pregnancy, and 50% of newborns. This is followed by a review on the predictive factors for successful sperm retrieval. The risks of passing on the genetic defect to children are also discussed. Although the risk is low (0.63%) when compared to the general population (0.5–1%), patients should be informed about embryo selection through pre-implantation genetic testing (avoids clinical termination of pregnancy). Finally, readers are directed to a number of reviews where they can enhance their understanding of comprehensive diagnosis, clinical care, and fertility preservation.

Delaying testicular sperm extraction in 47,XXY Klinefelter patients does not impair the sperm retrieval rate, and AMH levels are higher when TESE is positive

STUDY QUESTION

Should testicular sperm extraction (TESE) in non-mosaic 47,XXY Klinefelter syndrome (KS) patients be performed soon after puberty or could it be delayed until adulthood?

SUMMARY ANSWER

The difference in sperm retrieval rate (SRR) in TESE was not significant between the 'Young' (15-22 years old) cohort and the 'Adult' (23-43 years old) cohort of non-mosaic KS patients recruited prospectively in parallel.

WHAT IS KNOWN ALREADY

Several studies have tried to define predictive factors for TESE outcome in non-mosaic KS patients, with very heterogeneous results. Some authors have found that age was a pejorative factor and recommended performing TESE soon after puberty. To date, no predictive factors have been unanimously recognized to guide clinicians in deciding to perform TESE in azoospermic KS patients.

STUDY DESIGN, SIZE, DURATION

Two cohorts (Young: 15-22 years old; Adult: 23-43 years old) were included prospectively in parallel. A total of 157 non-mosaic 47,XXY KS patients were included between 2010 and 2020 in the reproductive medicine department of the University Hospital of Lyon, France. However 31 patients gave up before TESE, four had cryptozoospermia and three did not have a valid hormone assessment; these were excluded from this study.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Data for 119 patients (61 Young and 58 Adult) were analyzed. All of these patients had clinical, hormonal and seminal evaluation before conventional TESE (c-TESE).

MAIN RESULTS AND THE ROLE OF CHANCE

The global SRR was 45.4%. SRRs were not significantly different between the two age groups: Young SRR=49.2%, Adult SRR = 41.4%; P = 0.393. Anti-Müllerian hormone (AMH) and inhibin B were significantly higher in the Young group (AMH: P = 0.001, Inhibin B: P < 0.001), and also higher in patients with a positive TESE than in those with a negative TESE (AMH: P = 0.001, Inhibin B: P = 0.036). The other factors did not differ between age groups or according to TESE outcome. AMH had a better predictive value than inhibin B. SRRs were significantly higher in the upper quartile of AMH plasma levels than in the lower quartile (or in cases with AMH plasma level below the quantification limit): 67.7% versus 28.9% in the whole population (P = 0.001), 60% versus 20% in the Young group (P = 0.025) and 71.4% versus 33.3% in the Adult group (P = 0.018).

LIMITATIONS, REASONS FOR CAUTION

c-TESE was performed in the whole study; we cannot rule out the possibility of different results if microsurgical TESE had been performed. Because of the limited sensitivity of inhibin B and AMH assays, a large number of patients had values lower than the quantification limits, preventing the definition a threshold below which negative TESE can be predicted.

WIDER IMPLICATIONS OF THE FINDINGS

In contrast to some studies, age did not appear as a pejorative factor when comparing patients 15-22 and 23-44 years of age. Improved accuracy of inhibin B and AMH assays in the future might still allow discrimination of patients with persistent foci of spermatogenesis and guide clinician decision-making and patient information.

STUDY FUNDING/COMPETING INTEREST(S)

The study was supported by a grant from the French Ministry of Health D50621 (Programme Hospitalier de Recherche Clinical Régional 2008). The authors have no conflicts of interest to disclose.

TRIAL REGISTRATION NUMBER

NCT01918280.

Reproductive Chances of Men with Azoospermia Due to Spermatogenic Dysfunction

Non-obstructive azoospermia (NOA), or lack of sperm in the ejaculate due to spermatogenic dysfunction, is the most severe form of infertility. Men with this form of infertility should be evaluated prior to treatment, as there are various underlying etiologies for NOA. While a significant proportion of NOA men have idiopathic spermatogenic dysfunction, known etiologies including genetic disorders, hormonal anomalies, structural abnormalities, chemotherapy or radiation treatment, infection and inflammation may substantively affect the prognosis for successful treatment. Despite the underlying etiology for NOA, most of these infertile men are candidates for surgical sperm retrieval and subsequent use in intracytoplasmic sperm injection (ICSI). In this review, we describe common etiologies of NOA and clinical outcomes following surgical sperm retrieval and ICSI.

ART strategies in Klinefelter syndrome

PURPOSE

Patients with Klinefelter syndrome (KS) who receive assisted reproductive technology (ART) treatment often experience poor pregnancy rates due to decreased fertilization, cleavage, and implantation rates and even an increased miscarriage rate. Mounting evidence from recent studies has shown that various technological advances and approaches could facilitate the success of ART treatment for KS patients. In this review, we summarize the methods for guiding KS patients during ART and for developing optimal strategies for preserving fertility, improving pregnancy rate and live birth rate, and avoiding the birth of KS infants.

METHODS

We searched PubMed and Google Scholar publications related to KS patients on topics of controlled ovarian stimulation protocols, sperm extraction, fertility preservation, gamete artificial activation, round spermatid injection (ROSI), and non-invasive prenatal screening (PGD) methods.

RESULTS

This review outlines the different ovulation-inducing treatments for female partners according to the individual sperm status in the KS patient. We further summarize the methods of retrieving sperm, storing, and freezing rare sperm. We reviewed different methods of gamete artificial activation and discussed the feasibility of ROSI for sterile KS patients who absolutely lack sperm. The activation of eggs in the process of intracytoplasmic sperm injection and non-invasive PGD are urgently needed to prevent the birth of KS infants.

CONCLUSION

The integrated strategies will pave the way for the establishment of ART treatment approaches and improve the clinical outcome for KS patients.

Sperm recovery and ICSI outcomes in men with non-obstructive azoospermia: a systematic review and meta-analysis

BACKGROUND

Factor affecting sperm retrieval rate (SRR) or pregnancy rates (PR) after testicular sperm extraction (TESE) in patients with non-obstructive azoospermia (NOA) have not been systematically evaluated. In addition, although micro-TESE (mTESE) has been advocated as the gold standard for sperm retrieval in men with NOA, its superiority over conventional TESE (cTESE) remains conflicting.

OBJECTIVE AND RATIONALE

The objective was to perform a meta-analysis of the currently available studies comparing the techniques of sperm retrieval and to identify clinical and biochemical factors predicting SRR in men with NOA. In addition, PRs and live birth rates (LBRs), as derived from subjects with NOA post-ICSI, were also analysed as secondary outcomes.

SEARCH METHODS

An extensive Medline, Embase and Cochrane search was performed. All trials reporting SRR derived from cTESE or mTESE in patients with NOA and their specific determinants were included. Data derived from genetic causes of NOA or testicular sperm aspiration were excluded.

OUTCOMES

Out of 1236 studies, 117 studies met the inclusion criteria for this study, enrolling 21 404 patients with a mean age (± SD) of 35.0 ± 2.7 years. cTESE and mTESE were used in 56 and 43 studies, respectively. In addition, 10 studies used a mixed approach and 8 studies compared cTESE with mTESE approach. Overall, a SRR per TESE procedure of 47[45;49]% (mean percentage [95% CI]) was found. No differences were observed when mTESE was compared to cTESE (46[43;49]% for cTESE versus 46[42;49]% for mTESE). Meta-regression analysis demonstrated that SRR per cycle was independent of age and hormonal parameters at enrolment. However, the SRR increased as a function of testis volume. In particular, by applying ROC curve analysis, a mean testis volume higher than 12.5 ml predicted SRR >60% with an accuracy of 86.2% ± 0.01. In addition, SRR decreased as a function of the number of Klinefelter's syndrome cases included (S = -0.02[-0.04;-0.01]; P < 0.01. I = 0.12[-0.05;0.29]; P = 0.16). Information on fertility outcomes after ICSI was available in 42 studies. Overall, a total of 1096 biochemical pregnancies were reported (cumulative PR = 29[25;32]% per ICSI cycle). A similar rate was observed when LBR was analysed (569 live births with a cumulative LBR = 24[20;28]% per ICSI cycle). No influence of male and female age, mean testis volume or hormonal parameters on both PR and LBR per ICSI cycle was observed. Finally, a higher PR per ICSI cycle was observed when the use of fresh sperm was compared to cryopreserved sperm (PR = 35[30;40]%, versus 20[13;29]% respectively): however, this result was not confirmed when cumulative LBR per ICSI cycle was analysed (LBR = 30[20;41]% for fresh versus 20[12;31]% for cryopreserved sperm).

WIDER IMPLICATIONS

This analysis shows that cTESE/mTESE in subjects with NOA results in SRRs of up to 50%, with no differences when cTESE was compared to mTESE. Retrieved sperms resulted in a LBR of up to 28% ICSI cycle. Although no difference between techniques was found, to conclusively clarify if one technique is superior to the other, there is a need for a sufficiently powered and well-designed randomized controlled trial to compare mTESE to cTESE in men with NOA.

Sperm retrieval success and testicular histopathology in idiopathic nonobstructive azoospermia

Prior studies have investigated sperm retrieval rates in men with nonobstructive azoospermia (NOA) secondary to specific etiologies, yet most cases of NOA are idiopathic. We compared sperm retrieval rates and testicular histopathology in idiopathic NOA (iNOA) and nonidiopathic NOA (niNOA). We performed a retrospective review of men with NOA who underwent microdissection testicular sperm extraction (microTESE) between 2000 and 2016. Men with no history of malignancy or cryptorchidism and negative genetic evaluation were considered idiopathic. Multivariable regression determined the association between idiopathic etiology and primary outcomes of sperm retrieval and active spermatogenesis on histopathology. Among 224 men, 86 (38.4%) were idiopathic, 75 (33.5%) were nonidiopathic, and 63 (28.1%) did not undergo genetic testing. Median age and serum testosterone were higher among iNOA or no testing versus niNOA. Median follicle-stimulating hormone (FSH) was lower among iNOA or no testing versus niNOA. A higher proportion of iNOA or no testing versus niNOA had a clinical varicocele. Sperm retrieval rates were similar between iNOA, niNOA, and no testing (41.8% vs 48.0% vs 55.6%, respectively; P = 0.255). Active spermatogenesis was seen in a higher proportion of iNOA or no testing versus niNOA (31.4% and 27.0% vs 16.0%, P = 0.073). On multivariable analysis, iNOA was not associated with sperm retrieval or spermatogenesis (P = 0.430 and P = 0.078, respectively). Rates of sperm retrieval and spermatogenesis on testis pathology were similar in men with iNOA and niNOA. These data will be useful to clinicians in preoperative counseling for men with NOA and negative genetic evaluation.

Sperm retrieval by microdissection testicular sperm extraction and intracytoplasmic sperm injection outcomes in nonobstructive azoospermic patients with Klinefelter syndrome

Klinefelter syndrome is the most frequent chromosomal abnormality in patients with nonobstructive azoospermia. The development of advanced assisted reproductive techniques, such as testicular sperm extraction and intracytoplasmic sperm injection, has provided the possibility of biological fathering in nonobstructive azoospermic patients with Klinefelter syndrome. We aimed to evaluate our sperm retrieval rate by microdissection testicular sperm extraction and to analyse the intracytoplasmic sperm injection outcomes in these patients. Medical records of 110 nonobstructive azoospermic patients with Klinefelter syndrome were retrospectively reviewed. We found that the sperm retrieval rate by microdissection testicular sperm extraction is lower than published reports on other types of secretory azoospermia. The statistical analyses yielded that age, FSH and testosterone levels as predictive factors for successful sperm retrieval.

Sperm recovery and ICSI outcomes in Klinefelter syndrome: a systematic review and meta-analysis

BACKGROUND

Specific factors underlying successful surgical sperm retrieval rates (SRR) or pregnancy rates (PR) after testicular sperm extraction (TESE) in adult patients with Klinefelter syndrome (KS) have not been completely clarified.

OBJECTIVE AND RATIONALE

The aim of this review was to meta-analyse the currently available data from subjects with KS regarding SRRs as the primary outcome. In addition, when available, PRs and live birth rates (LBRs) after the ICSI technique were also investigated as secondary outcomes.

SEARCH METHODS

An extensive Medline, Embase and Cochrane search was performed. All trials reporting SRR for conventional-TESE (cTESE) or micro-TESE (mTESE) and its specific determinants without any arbitrary restriction were included.

OUTCOMES

Out of 139 studies, 37 trials were included in the study, enrolling a total of 1248 patients with a mean age of 30.9 ± 5.6 years. The majority of the studies (n = 18) applied mTESE, 13 applied cTESE and in one case testicular sperm aspiration (TESA) was used. Additionally, four studies used a mixed approach and in one study, the method applied for sperm retrieval was not specified. Overall, a SRR per TESE cycle of 44[39;48]% was detected. Similar results were observed when mTESE was compared to cTESE (SRR 43[35;50]% vs 45[38;52]% for cTESE vs micro-TESE, respectively; Q = 0.20, P = 0.65). Meta-regression analysis showed that none of the parameters tested, including age, testis volume and FSH, LH and testosterone (T) levels at enrollment, affected the final SRR. Similarly, no difference was observed when a bilateral procedure was compared to a unilateral approach. No sufficient data were available to evaluate the effect of previous T treatment on SRR. Information on fertility outcome after ICSI was available for 29 studies. Overall a total of 218 biochemical pregnancies after 410 ICSI cycles were observed (PR = 43[36;50]%). Similar results were observed when LBR was analyzed (LBR = 43[34;53]%). Similar to what was observed for SRR, no influence of KS age, mean testis volume, LH, FSH or total T levels on either PR and LBR was observed. No sufficient data were available to test the effect of the women's age or other female fertility problems on PR and LBR. Finally, no difference in PR or LBR was observed when the use of fresh sperm was compared to the utilization of cryopreserved sperm.

WIDER IMPLICATIONS

The present data suggest that performing TESE/micro-TESE in subjects with KS results in SRRs of close to 50%, and then PRs and LBRs of close to 50%, with the results being independent of any clinical or biochemical parameters tested.

Sperm Retrieval in Patients with Klinefelter Syndrome: A Skewed Regression Model Analysis

BACKGROUND

The most common chromosomal abnormality due to non-obstructive azoospermia (NOA) is Klinefelter syndrome (KS) which occurs in 1-1.72 out of 500-1000 male infants. The probability of retrieving sperm as the outcome could be asymmetrically different between patients with and without KS, therefore logistic regression analysis is not a well-qualified test for this type of data. This study has been designed to evaluate skewed regression model analysis for data collected from microsurgical testicular sperm extraction (micro-TESE) among azoospermic patients with and without non-mosaic KS syndrome.

MATERIALS AND METHODS

This cohort study compared the micro-TESE outcome between 134 men with classic KS and 537 men with NOA and normal karyotype who were referred to Royan Institute between 2009 and 2011. In addition to our main outcome, which was sperm retrieval, we also used logistic and skewed regression analyses to compare the following demographic and hormonal factors: age, level of follicle stimulating hormone (FSH), luteinizing hormone (LH), and testosterone between the two groups.

RESULTS

A comparison of the micro-TESE between the KS and control groups showed a success rate of 28.4% (38/134) for the KS group and 22.2% (119/537) for the control group. In the KS group, a significantly difference (P<0.001) existed between testosterone levels for the successful sperm retrieval group (3.4 ± 0.48 mg/mL) compared to the unsuccessful sperm retrieval group (2.33 ± 0.23 mg/mL). The index for quasi Akaike information criterion (QAIC) had a goodness of fit of 74 for the skewed model which was lower than logistic regression (QAIC=85).

CONCLUSION

According to the results, skewed regression is more efficient in estimating sperm retrieval success when the data from patients with KS are analyzed. This finding should be investigated by conducting additional studies with different data structures.

Outcome of intracytoplasmic sperm injection using fresh and cryopreserved-thawed testıcular spermatozoa in 83 azoospermic men with Klinefelter syndrome

AIM

To report the outcome of intracytoplasmic sperm injection (ICSI) cycles using fresh or cryopreserved-thawed testicular spermatozoa of men with Klinefelter syndrome (KS).

METHODS

Medical records of 83 azoospermic men with KS who underwent testicular sperm extraction (TESE) were reviewed. The clinical parameters for predicting sperm retrieval and fertilization, implantation, pregnancy and live birth rates of ICSI cycles in these patients were evaluated.

RESULTS

A total of 88 TESE procedures were performed with sperm retrieval rates of 39.8% per cycle (35/88) and 42.1% per patient (35/83). None of the studied clinical parameters were found to be informative in predicting successful sperm recovery. A total of 41 embryo transfer cycles were carried out using fresh testicular spermatozoa in 30, cryopreserved-thawed spermatozoa in 10 and cryopreserved-thawed embryo replacement in one. The fertilization and clinical pregnancy rates were comparable at 52.7% and 51.6% with fresh and 48.3% and 60% with cryopreserved-thawed testicular spermatozoa groups, respectively. Twenty-two clinical pregnancies were obtained, including 14 singletons, five twins, two triplets and one quadruplet and ended with the delivery of 13 singletons and six twins. In total, out of 25 delivered fetuses, four died (3 female, 1 male) following delivery and 21 newborns (14 female, 7 male) were healthy with a female to male ratio of 2:1. Conclusions We concluded that no clinical or laboratory parameter predicts the presence of spermatozoa in patients with KS, except the TESE procedure itself. The use of fresh or cryopreserved-thawed spermatozoa on ICSI cycle outcomes are equally successful in patients with KS.

Genetic risk of Klinefelter's syndrome in assisted reproductive technology

Aim

The main cause of Klinefelter's syndrome (KS) has been believed to be XY sperm. Accordingly, in the intracytoplasmic sperm injection treatment of patients with KS, hereditary KS has been a concern. Therefore, this study attempted to estimate the risk before and after the assisted reproductive technology.

Methods

First, in order to validate the safety of the gametes of the patients with KS, a fluorescent in situ hybridization (FISH) analysis, following an original cell identification method using 1052 testicular gametes of 30 patients, was conducted. Second, in the resultant 45 babies, cytogenetic and physical-cognitive screening data were analyzed. In addition, a first attempt was conducted to investigate the origin of the extra X chromosome in 11 patients with KS by using 12 X-chromosome short tandem repeat (STR) analysis in order to estimate the paternal contribution to KS.

Results

No sex chromosomally abnormal gamete was found in the FISH analysis and the babies were normal genetically, physically, and cognitively. In the STR, it was confirmed that most (7/11) of the patients with KS resulted from the fertilization of the XX oocytes, suggesting that a baby with KS that had been reported previously might not have resulted from XY sperm.

Conclusion

These results indicate that the risk of assisted reproductive technology for patients with KS is not as high as previously expected.

Testicular function during puberty and young adulthood in patients with Klinefelter's syndrome with and without spermatozoa in seminal fluid

Patients with Klinefelter's syndrome experience progressive testicular degeneration resulting in impaired endocrine function and azoospermia. What proportion of adolescents develop testosterone deficiency during puberty and how many have spermatozoa in their semen is unclear to date. We aimed to investigate testicular function during puberty and young adulthood in patients with Klinefelter's syndrome and to assess testosterone effects in target tissues. The clinical data of 281 patients with non-mosaic Klinefelter's syndrome aged 10-25 years without previous testosterone replacement were reviewed. In late pubertal adolescents, semen analyses were evaluated, and testicular volumes, hormone and haemoglobin (Hb) levels, the number of CAG repeats and final height data were compared to those of 233 age-matched controls with pubertal gynaecomastia. Spontaneous pubertal virilisation to Tanner stages IV-V occurred. Serum T levels ≥10 nmol/L were reached in 62% of patients with Klinefelter's syndrome and in 85% of controls at ages 15-25 (T_KFS : 12.2 ± 5.4 vs. T_C : 16.6 ± 7.2 nmol/L). LH_KFS levels were elevated >10 U/L in 84%, and normal in all controls (LH_KFS : 18.6 ± 12.2 vs. LH_C : 3.5 ± 1.6 U/L). In nine of 130 (7%) adolescents with Klinefelter's syndrome, spermatozoa (oligozoospermia) were found in semen; all had T levels >7 nmol/L and eight of nine had LH levels ≤18 U/L, while their hormone levels, number of CAG repeats and testicular volumes were not different from those of adolescents with azoospermia. Controls had normal sperm concentrations in 73% (46/63). Semen volumes_KFS were normal in 55% vs. 78% in controls; Hb_KFS was normal in 89% (Hb_C : 97%). Mean final height_KFS was 185 ± 8 cm vs. 181 ± 7 cm in controls. Hypergonadotropic hypogonadism develops during early puberty in adolescents with Klinefelter's syndrome and remains compensated in over 60% during ages 15-25, with sufficient testosterone secretion for spontaneous accomplishment of pubertal development. Spermatozoa in semen are rare and associated with T levels >7 nmol/L. Parameters reflecting androgen deficiency in target tissues may help to optimise timing of testosterone substitution, which should preferably not be initiated before fertility status has been clarified.

Klinefelter syndrome and fertility: sperm preservation should not be offered to children with Klinefelter syndrome

STUDY QUESTION

Should fertility preservation be offered to children with Klinefelter syndrome (KS)?

SUMMARY ANSWER

Current evidence shows that fertility preservation should not be offered to adolescents with KS younger than 16 years because of lower retrieval rates for germ cells by testicular sperm extraction (TESE) compared with retrieval rates for adolescents and adults between 16 and 30 years.

WHAT IS KNOWN ALREADY

KS, the most common chromosomal disorder in men leading to non-obstructive azoospermia, is caused by the presence of at least one additional X chromosome. The onset of puberty in adolescents with KS leads to progressive degeneration of the testicular environment. The impact of the subsequent tissue degeneration on fertility potential of patients with KS is unknown, but in previous literature it has been suggested that fertility preservation should be started in adolescents as early as possible. However spermatozoa can be found by TESE in about 50% of adults with KS despite severe testicular degeneration. This review discusses the current evidence for fertility preservation in children and adolescents and possible prognostic markers for fertility treatment in KS.

STUDY DESIGN, SIZE, DURATION

An extensive literature search was conducted, searching Pubmed, Embase, Cinahl and Web of Science from origin until April 2016 for 'Klinefelter syndrome' and 'fertility' and various synonyms. Titles and abstracts have been scanned manually by the authors for eligibility.

PARTICIPANTS/MATERIALS, SETTING, METHODS

In total 76 studies were found to be eligible for inclusion in this review. Information from the papers was extracted separately by two authors.

MAIN RESULTS AND THE ROLE OF CHANCE

Various studies have shown that pre-pubertal children with KS already have a reduced number of germ cells despite a normal hormonal profile during childhood. The presence of spermatozoa in the ejaculate of adolescents with KS is extremely rare. Using TESE, the retrieval rates of spermatozoa for adolescents younger than 16 years old are much lower (0-20%) compared with those for adolescents and young adults between 16 and 30 years old (40-70%). Although spermatogonia can be found by TESE in about half of the peri-pubertal adolescents, there are currently no clinically functional techniques for their future use. Children and adolescents need to be informed that early fertility preservation before the age of 16 cannot guarantee fertility later in life and may even reduce the chances for offspring by removing functional immature germ cells which may possibly develop into spermatozoa after puberty. Furthermore, except for the age of patients with KS, there are no identified factors that can reliably be used as a predictive marker for fertility preservation.

LIMITATIONS, REASONS FOR CAUTION

Most of the evidence presented in this review is based on studies including a small number of adolescents with KS. Therefore, the studies may have been underpowered to detect clinically significant differences for their various outcomes, especially for potential predictive factors for fertility preservation, such as hormone levels. Furthermore, the population of patients with KS diagnosed during childhood might be different from the adult population with KS where the diagnosis is based on infertility. Results based on comparisons between the two groups must be interpreted with caution.

WIDER IMPLICATIONS OF THE FINDINGS

Despite the limitations, this review summarizes the current evidence for managing fertility preservation in patients with KS to provide optimal health care.

STUDY FUNDING/COMPETING INTERESTS

There was no funding for this study. S.F., Y.H., K.D., W.L.M.N., D.S., H.L.C.-v.d.G. and L.R. declare to have no conflicts of interests. D.D.M.B. reports grants from Merck Serono, grants from Ferring and grants from MSD, outside the submitted work. K.F. reports personal fees from MSD (commercial sponsor), personal fees from Ferring (commercial sponsor), grants from Merck-Serono (commercial sponsor), grants from Ferring (commercial sponsor) and grants from MSD (commercial sponsor), outside the submitted work.

Reproductive outcomes in men with karyotype abnormalities: Case report and review of the literature

Reciprocal translocations of autosomal chromosomes are present in about 1/625 men, yet often there are no symptoms except primary infertility. Abnormal segregation during meiosis often produces sperm and subsequent embryos with unbalanced translocations that often ultimately result in spontaneous abortions. We report on a 37-year-old man and his 39-year-old wife who complained of primary infertility. Previous in vitro fertilization (IVF) had resulted in pregnancy, but two spontaneous abortions. Upon chromosomal testing, the man was diagnosed with a reciprocal translocation and his wife was diagnosed with mosaic Turner's syndrome. Through testicular sperm extraction (TESE) and IVF with preimplantation genetic screening (PGS), they succeeded in having two healthy children. Since men with different karyotype abnormalities can have male infertility, we reviewed the literature and summarized the reproductive outcomes for men with both autosome and sex chromosomal karyotype abnormalities.

Ploidy of spermatogenic cells of men with non-mosaic Klinefelter's syndrome as measured by a computerized cell scanning system

PURPOSE

This study aims to characterize the origin of testicular post-meiotic cells in non-mosaic Klinefelter's syndrome (KS).

METHODS

The study included testicular tissue specimens from 11 non-mosaic KS patients, with (6 positive) and without (5 negative) spermatozoa presence. The obtained testicular cells were affixed and stained for morphology followed by fluorescence in situ hybridization (FISH) for centromeric probes X, Y, and 18. We used a computerized automated cell scanning system that enables simultaneous viewing of morphology and FISH in the same cell.

RESULTS

A total of 12,387 cells from the positive cases, 11,991 cells from the negative cases, and 1,711 cells from the controls were analyzed. The majority of spermatogonia were 47, XXY in both the positive and negative KS cases (88.9 ± 4.76 % and 90.6 ± 4.58 %) as were primary spermatocytes (76.8 ± 8.14 % and 79.6 ± 7.30 %). The respective rates of secondary spermatocytes and post-meiotic cells (round, elongating spermatids and sperm cells) were 1.1 ± 1.39 % in the positive cases, 2.9 ± 3.33 % in the negative cases, compared to 67.6 ± 6.22 % in the controls (P < 0.02). Pairing of both 18 and XY homologous chromosomes in 46,XY primary spermatocytes was 2.5 ± 2.31 % and 3.4 ± 2.39 %, respectively, compared to 19.8 ± 8.95 % in the control group (P < 0.02) and in 47,XXY primary spermatocytes in 2.4 ± 3.8 % in the positive group and 3.2 ± 2.26 % in the negative group.

CONCLUSIONS

This study presents data to indicate that the majority of primary spermatocytes in the testes of non-mosaic KS patients are 47,XXY and could possibly develop into post-meiotic cells.

Managing infertility in patients with Klinefelter syndrome

Klinefelter syndrome (KS) is the most frequent chromosomal abnormality with a prevalence of 150 per 100,000 males. It is now well known that the phenotype of Klinefelter adults varies from individual to individual and one registry study indicates that approximately 75% of KS subjects are not diagnosed probably because of very mild phenotypes. Due to seminiferous tubule fibrosis KS patients have small testes and are infertile because of azoospermia (>90%) or severe oligozoospermia (<10%). Adoption or heterologous insemination has been used in the past to achieve paternity. Currently it is well known that with TESE/micro-TESE (TESE = TEsticular Sperm Extraction) spermatozoa can be found in the testes of 28-67% of KS patients. Predictive factors of sperm retrieval success/failure, such as reproductive hormone plasma levels, testis volume and age, have been evaluated without any positive results. By combining TESE/micro-TESE with intracytoplasmic sperm injection an average of 50% of these patients have the possibility of fathering children and the birth of more than 150 children with normal karyotype has been reported in the last 20 years. However couples with a Klinefelter partner must be informed of the increased risk of autosomal/sex chromosomes aberrations in the sperm and embryos and of the possibility of preimplantation genetic diagnosis which is currently suggested by a minority of authors.

Klinefelter syndrome and TESE-ICSI

Until few years ago, Klinefelter syndrome with a homogenous 47,XXY karyotype was considered a model of absolute male sterility. We will discuss first the potential fertility following Testicular Sperm Injection, then the physiopathology of spermatogenic failure and the origin of focal spermatogenesis and risk of aneuploidy in offspring, and third the advantage of searching spermatozoa earlier instead of adult age. The rate of positive sperm extraction seems to be better for younger patients. During childhood, there is a low rate of spermatogonia. The spermagonia, which completes the spermatogenesis, seems resulting from a rare clone of 46,XY gonia, having lost their extra X chromosome. Several arguments suggest that this focal spermatogenesis decreases with age. In addition, androgen treatment, frequently prescribed in case of Klinefelter syndrome, carries a risk of decreasing focal spermatogenesis by lowering gonadotropins. The question arises if it is necessary to expect the sperm cryopreservation before introducing androgen treatment. Further studies are necessary to determine the best age of sperm retrieval in case of Klinefelter syndrome.

Clinical genetic testing for male factor infertility: current applications and future directions

Spermatogenesis involves the aggregated action of up to 2300 genes, any of which, could, potentially, provide targets for diagnostic tests of male factor infertility. Contrary to the previously proposed common variant hypothesis for common diseases such as male infertility, genome-wide association studies and targeted gene sequencing in cohorts of infertile men have identified only a few gene polymorphisms that are associated with male infertility. Unfortunately, the search for genetic variants associated with male infertility is further hampered by the lack of viable animal models of human spermatogenesis, difficulty in robustly phenotyping infertile men and the complexity of pedigree studies in male factor infertility. In this review, we describe basic genetic principles involved in understanding the genetic basis of male infertility and examine the utility and proper clinical use of the proven genetic assays of male factor infertility, specifically Y chromosome microdeletions, chromosomal translocations, karyotype, cystic fibrosis transmembrane conductance regulator mutation analysis and sperm genetic tests. Unfortunately, these tests are only able to diagnose the cause of about 20% of male factor infertility. The remainder of the review will be devoted to examining novel tests and diagnostic tools that have the potential to explain the other 80% of male factor infertility that is currently classified as idiopathic. Those tests include epigenetic analysis of the spermatozoa and the evaluation of rare genetic variants and copy number variations in patients. Success in advancing to the implementation of such areas is not only dependent on technological advances in the laboratory, but also improved phenotyping in the clinic.

[Genetic aspects of fertility disorders]

Genetic disorders of fertility can occur at the level of gonadal differentiation or function, germ cell production or function, and the genital ducts. In gonadal dysgenesis, the differentiation of testes or ovaries is impaired. Gonadal dysgenesis can be caused by chromosome aberrations or monogenetic defects in XY or XX gonadal dysgenesis. For the biosynthesis of sexual hormones, a normal development of the gonads and an intact hypothalamic-pituitary-gonadal axis is necessary. Disorders of steroid hormone synthesis are associated with an increased or diminished production of sexual hormones. Clinical and genetic aspects of adrenogenital syndrome are discussed here. Mutations of the androgen receptor cause a spectrum of androgen insensitivity ranging from women with female external genitalia through patients with genital ambiguity to men with infertility. Disturbed spermatogenesis is heterogeneous and can be the result of chromosome aberrations such as Klinefelter syndrome or structural aberrations as translocations and microdeletions of the Y chromosome. Premature ovarian failure is characterized by amenorrhea and hypergonadotropic hypogonadism before 40 years of age. Beside nongenetic factors, premature ovarian failure can be caused by chromosome aberrations or monogenetic defects. Disorders of the genital ducts such as anomalies of the müllerian ducts in females and of the wolffian ducts in males can be associated with sterility or infertility.

Current issues in medically assisted reproduction and genetics in Europe: research, clinical practice, ethics, legal issues and policy. European Society of Human Genetics and European Society of Human Reproduction and Embryology

In March 2005, a group of experts from the European Society of Human Genetics and European Society of Human Reproduction and Embryology met to discuss the interface between genetics and assisted reproductive technology (ART), and published an extended background paper, recommendations and two Editorials. Seven years later, in March 2012, a follow-up interdisciplinary workshop was held, involving representatives of both professional societies, including experts from the European Union Eurogentest2 Coordination Action Project. The main goal of this meeting was to discuss developments at the interface between clinical genetics and ARTs. As more genetic causes of reproductive failure are now recognised and an increasing number of patients undergo testing of their genome before conception, either in regular health care or in the context of direct-to-consumer testing, the need for genetic counselling and preimplantation genetic diagnosis (PGD) may increase. Preimplantation genetic screening (PGS) thus far does not have evidence from randomised clinical trials to substantiate that the technique is both effective and efficient. Whole-genome sequencing may create greater challenges both in the technological and interpretational domains, and requires further reflection about the ethics of genetic testing in ART and PGD/PGS. Diagnostic laboratories should be reporting their results according to internationally accepted accreditation standards (International Standards Organisation - ISO 15189). Further studies are needed in order to address issues related to the impact of ART on epigenetic reprogramming of the early embryo. The legal landscape regarding assisted reproduction is evolving but still remains very heterogeneous and often contradictory. The lack of legal harmonisation and uneven access to infertility treatment and PGD/PGS fosters considerable cross-border reproductive care in Europe and beyond. The aim of this paper is to complement previous publications and provide an update of selected topics that have evolved since 2005.

Testicular function and fertility in men with Klinefelter syndrome: a review

Klinefelter syndrome, 47,XXY (KS), is the most frequent sex chromosome aberration in males, affecting 1 in 660 newborn boys. The syndrome is characterized by testicular destruction with extensive fibrosis and hyalinization of the seminiferous tubules resulting in small testes, hypergonadotropic hypogonadism, and azoospermia in the majority of cases. Until recently, infertility was considered an untreatable condition in KS. However, with the development of new advanced assisted reproductive techniques such as testicular sperm extraction (TESE) combined with ICSI it seems that KS patients should no longer be labelled as infertile. Especially, microdissection (micro)-TESE has proved to be an advantageous procedure for the identification of testicular spermatozoa in KS. The aim of this review was to describe current knowledge on the testicular changes occurring in KS, the associated changes in reproductive hormones and spermatogenesis, and the existing possibilities of biological fatherhood in 47,XXY patients.

Testicular biopsy: clinical practice and interpretation

Testicular biopsy was considered the cornerstone of male infertility diagnosis for many years in men with unexplained infertility and azoospermia. Recent guidelines for male infertility have limited the indications for a diagnostic testicular biopsy to the confirmation of obstructive azoospermia in men with normal size testes and normal reproductive hormones. Nowadays, testicular biopsies are mainly performed for sperm harvesting in men with non-obstructive azoospermia, to be used for intracytoplasmic sperm injection. Testicular biopsy is also performed in men with risk factors for testicular malignancy. In a subgroup of infertile men, there is an increased risk for carcinoma in situ of the testis, especially in men with a history of cryptorchidism and testicular malignancy and in men with testicular atrophy. Ultrasonographic abnormalities, such as testicular microlithiasis, inhomogeneous parenchyma and lesions of the testes, further increase the risk of carcinoma in situ (CIS) in these men. For an accurate histological classification, proper tissue handling, fixation, preparation of the specimen and evaluation are needed. A standardized approach to testicular biopsy is recommended. In addition, approaches to the detection of CIS of the testis testicular immunohistochemistry are mandatory. In this mini-review, we describe the current indications for testicular biopsies in the diagnosis and management of male infertility.

[Fertility in patients with Klinefelter syndrome (47,XXY)]

In the past 10 years, our knowledge about fertility chances of patients with Klinefelter syndrome (KS, 47,XXY) has changed considerably, especially when regarding the possibility of IVF ICSI treatment (in vitro fertilisation, intracytoplasmic sperm injection) with single testicular spermatozoa. Thus, it is important to take this knowledge into consideration when counselling Klinefelter patients.Germ cell degeneration in the testicles of Klinefelter patients due to their additional X chromosome is an important phenomenon in this disease which is not yet fully understood. When entering puberty, the testicular volume of KS patients increases for a short time with rising testosterone and inhibin B levels at the same time. These decrease, however, and FSH increases during puberty. This seems to indicate a critical point in time when spermatogenetic function of the testicles could still be existent. Thus, in early puberty there could possibly be a time slot when spermatozoa could be detected in the ejaculate or-if not-at least in the testicular tissue. These could be extracted by testicular sperm extraction, cryopreserved and used for intracytoplasmic sperm injection therapy later on. In the literature, a total of 133 births of children from Klinefelter fathers have been reported. This early specific procedure could lead to a better acceptance of their diagnosis and also offer the option of not being incurably infertile.

Consensus statement on diagnosis and clinical management of Klinefelter syndrome

Nearly 70 years after its description, Klinefelter syndrome (KS) remains a largely undiagnosed condition. As its clinical presentation may be subtle, many of those affected may be unaware or diagnosed only during evaluation for hypogonadism and/or infertility. In February 2010 an interdisciplinary panel of specialists met in Abano Terme (Padua, Italy) in a workshop on "Klinefelter Syndrome: diagnosis and clinical management". The main aim of this meeting was to discuss several aspects related to the epidemiology, pathogenesis, and evaluation of KS and to develop a consensus defining its early diagnosis and treatment. In the present consensus we have highlighted the features that may prompt the physicians to look after patients with KS both for the syndrome and correlated diseases. We have provided evidences that, during the different phases of life, there might be some advantages in establishing the diagnosis and starting proper follow-up and treatment. The workshop was carried out under the auspices of the Italian Society of andrology and Sexual Medicine (SIAMS).