Spermatogenesis in Klinefelter syndrome

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.

A dual-center study of predictive factors for sperm retrieval through microdissection testicular sperm extraction and intracytoplasmic sperm injection outcomes in men with non-mosaic Klinefelter syndrome

PURPOSE

This study evaluated the predictors of sperm retrieval (SR) in non-mosaic Klinefelter syndrome (KS) patients undergoing microsurgical testicular sperm extraction (mTESE). The cutoff values of the predictors of SR and overall pregnancy rates after intracytoplasmic sperm injection (ICSI) were analyzed for the positive SR (PSR) cases.

MATERIALS AND METHODS

The study was a dual-center retrospective study. Overall 118 patients with KS underwent mTESE between January 2011 and July 2021. Clinicopathological factors including comorbidities, endocrine profiles, and testicular volumes were analyzed.

RESULTS

A total of 58 patients showed PSR (49.2%) and 60 patients (50.8%) had negative SR (NSR). The mean overall age of the patients was 32.5 years. The NSR patients had a significantly greater prevalence of obesity, diabetes mellitus, and cerebrovascular disease. The PSR group had a significantly higher left testis mean volume (p=0.039). The differences between the two study groups regarding follicular-stimulating hormone, luteinizing hormone, and testosterone variations at 1 and 3 months after mTESE were insignificant. Preoperative mean neutrophil-to-lymphocyte ratio was significantly greater in the NSR group (p=0.011), but the platelet-to-lymphocyte ratio showed no significant difference between the two study groups. A live child birth was achieved in 53.4% of the PSR patients. Multivariate logistic analysis showed that total testicular volume >3.93 mL, left testis volume >1.79 mL, and neutrophil-to-lymphocyte ratio ≤1.82 were significantly associated with PSR.

CONCLUSIONS

mTESE-ICSI is a feasible method for KS patients to have a child, and total testicular volume, left testis volume, and neutrophil-to-lymphocyte ratio might be predictors of successful SR.

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.

Male factor infertility: A contemporary overview of investigation, diagnosis and management

Infertility, defined as the failure to achieve a clinical pregnancy after 1 year of regular, unprotected sexual intercourse, is a public health issue of global concern. It affects up to 12% of couples worldwide. While traditionally, research and treatment have focused on female causes of infertility, male factors contribute to up to 70% of cases and therefore deserve appropriate recognition. The purpose of this comprehensive review is to detail the diagnostic work-up, investigations and management of male factor infertility. We discuss much-debated pathologies, such as varicocele, and novel investigations, including sperm DNA fragmentation and reactive oxygen species.

Level of evidence: Not applicable

A systemic review and meta-analysis exploring the predictors of sperm retrieval in patients with non-obstructive azoospermia and chromosomal abnormalities

To identify the most prevalent chromosomal abnormalities in patients with non-obstructive azoospermia (NOA), consolidate their surgical sperm retrieval (SSR) rates and determine the significant predictors of positive SSR in this patient population. A systematic review and meta-analysis were performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Fifty-three studies including 2965 patients were identified through searching the PubMed database. Klinefelter Syndrome (KS) was the most prevalent chromosomal abnormality reported in 2239 cases (75.5%). Azoospermia factor c (AZFc) microdeletions were the second most common (18.6%), but men with these deletions had higher SSR rates than patients with KS (41.95% with AZFc vs. 38.63% with KS). When examining predictors of SSR in KS patients, younger age was a significant predictor of positive SSR in patients undergoing microsurgical testicular sperm extraction (micro-TESE). Higher testosterone was a favourable predictor in those undergoing micro-TESE and conventional TESE. Lower luteinizing hormone (LH) and follicular stimulating hormone (FSH) values were significantly associated with positive SSR with testicular sperm aspiration (TESA). No parameter predicted SSR rates in patients with AZFc microdeletions. Overall, genetic abnormalities have significant implications on SSR success in patients with NOA.

How Successful Is Surgical Sperm Retrieval in Klinefelter Syndrome?

Klinefelter Syndrome (KS) is characterized by the presence of an extra X chromosome. It was first diagnosed in 1942 in a group of azoospermic men. KS is the most common chromosomal abnormality encountered in infertile men and accounts for more than 10% of the causes of azoospermia. Men who are azoospermic may still father children via testicular sperm extraction followed by intracytoplasmic sperm injection (ICSI). This review article summarizes the success rates of the available techniques for surgical sperm retrieval (SSR) in KS including conventional testicular sperm extraction (cTESE) and micro testicular sperm extraction (mTESE), as well as the risks of these procedures for future fertility. The evidence indicates that the SSR rate is as successful in non-mosaic men with KS as those with normal karyotypes, with retrieval rates of up to 55% reported. The influence of different factors that affect the chances of a successful outcome are discussed. In particular, the impact of aneuploidy rate, physical characteristics, co-morbidities, reproductive endocrine balance and the use of different hormone management therapies are highlighted. Evidence is presented to suggest that the single most significant determinant for successful SSR is the age of the patient. The success of SSR is also influenced by surgical technique and operative time, as well as the skills of the surgeon and embryology team. Rescue mTESE may be used successfully following failed TESE in KS patients in combination with hormone stimulation.

Thoughts on the popularity of ICSI

Purpose

Intracytoplasmic sperm injection (ICSI) is the most widely utilized assisted reproductive technique (ART) worldwide. In this feature, we review the early assisted fertilization attempts that eventually led to the development of ICSI, and discuss its current utilization in cases of male and non-male factor infertility.

Methods

We researched the literature related to the development, indications, and current use of ICSI, such as sperm structural abnormalities, male genetic indications, surgically retrieved sperm, high sperm chromatin fragmentation, oocyte dysmorphism, and preimplantation genetic testing (PGT). We also describe the potential future applications of ICSI.

Results

This review summarizes the early micromanipulation techniques that led to the inception of ICSI. We also explore its current indications, including non-male factor infertility, where its use is more controversial. Finally, we consider the benefits of future advancements in reproductive biology that may incorporate ICSI, such as in vitro spermatogenesis, neogametogenesis, and heritable genome editing.

Conclusion

The versatility, consistency, and reliability of ICSI have made it the most prevalently utilized ART procedure worldwide.

Potential causes of male and female infertility in Qatar

A steady decline in the fertility rate has been observed in Qatar during the past fifty years. Therefore, infertility is considered a national priority in Qatar, a pronatalist society. This review article summarises the potential causes of infertility that are particularly prevalent in the Qatari population. The high rate of consanguinity leading to genetic abnormalities, the high incidence of metabolic disease, environmental contamination due to the rapid urbanization and oil and natural gas extraction procedures are discussed. In addition, the particular lifestyle of the Qatari population and the influence of religion and culture on sexual and reproductive behavior in an Arab/Islamic society are considered. The active response of the state of Qatar in implementing ways to mitigate the effects of these factors to protect fertility are also presented.

Expression profile of microRNAs in the testes of patients with Klinefelter syndrome

Klinefelter syndrome (KS) is the most common sex chromosome aneuploidy. A distinctive characteristic of KS is oligozoospermia. Despite multiple studies that have described the natural history of the degenerative process of germ cells in patients with KS, the molecular mechanisms that initiate this process are not well characterized. MicroRNA (miRNA)-mediated post-transcriptional control mechanisms have been increasingly recognized as important regulators of spermatogenesis; however, only a few studies have evaluated the role of miRNAs in the gonadal failure of these patients. Here, we describe a differential expression profile for the miRNAs in testicular tissue samples taken from KS patients. We analysed testicular tissue samples from 4 KS patients and 5 control patients (obstructive azoospermia) through next-generation sequencing, which can provide information about the mechanisms involved in the degeneration of germ cells. A distinctive differential expression profile was identified for 166 miRNAs in the KS patients: 66 were upregulated, and 100 were downregulated. An interactome analysis was performed for 7 of the upregulated and the 20 downregulated miRNAs. The results showed that the target genes are involved in the development, proliferation, and differentiation processes of spermatogenesis, which may explain their role in the development of infertility. This is the first report of a miRNA expression profile generated from testicular tissue samples of KS patients.

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.

Fertility in Adolescents With Klinefelter Syndrome: A Survey of Current Clinical Practice

CONTEXT

Progress has been made in determining the fertility timeline and potential in adolescents with Klinefelter syndrome; however, medical professionals are currently without protocols to guide treatment.

OBJECTIVE

To evaluate the current practices regarding fertility and andrology care in adolescent males with Klinefelter syndrome.

DESIGN

A 24-question survey was developed to elicit practitioner background/expertise and management practices. This was distributed to members of the Society for the Study of Male Reproduction, the Pediatric Endocrine Society, and the Endocrine Society.

SETTING

N/A.

PATIENTS

Adolescent males with Klinefelter syndrome.

INTERVENTION

None.

MAIN OUTCOME MEASURED

Current practices regarding fertility and andrology care.

RESULTS

232 responses were received from 133 (57%) adult endocrinologists, 60 (26%) pediatric endocrinologists, and 39 (17%) urologists. Among these, 69% of respondents were in academics, 62% practiced for > 10 years, and 65% received formal training in Klinefelter syndrome. All specialties encouraged sperm banking in late puberty, however most disagreed with the practice in early puberty. Seventy-eight percent agreed that testicular biopsy should be offered if no sperm was found in the ejaculate. The perceived optimal age for testicular biopsy varied among specialists. Clinical symptoms of hypogonadism (28%), rising gonadotropin levels (15%), and testosterone levels (15%) were the most commonly cited reasons for initiation of testosterone replacement therapy.

CONCLUSION

Fertility preservation practices in adolescents with Klinefelter syndrome vary greatly within and among the specialties caring for these patients. These findings should guide future research and highlight the importance of establishing clinical practice guidelines.

Relative hyperestrogenism in Klinefelter Syndrome: results from a meta-analysis

OBJECTIVE

Klinefelter Syndrome (KS) is classically described as characterized by hyperestrogenism, although solid evidence is lacking. This study aims to test the hypothesis that men with KS have higher serum estradiol than normal controls.

DESIGN

Meta-analysis of all studies extracted by MEDLINE from 1942 to 31 January 2018. All studies reporting serum estradiol measurement were considered, among them only case-control studies were included in the meta-analysis.

METHODS

Meta-analysis was conducted according to the PRISMA statement using RevMan.

RESULTS

Out of 4120 articles, 23 case-control studies, 14 case series, and 19 case reports reported data on serum estradiol. A total of 707 KS and 1019 controls were included in the meta-analysis. Serum estradiol was slightly, but significantly higher in KS than controls (mean difference 4.25 pg/mL; CI: 0.41, 8.10 pg/mL; p = 0.030). This difference was lost considering only studies using estradiol assays with good accuracy (5.48 pg/mL, CI: -2.11, 13.07 pg/mL; p = 0.160). Serum testosterone and estradiol/testosterone ratio were significantly lower and higher in KS than controls, respectively. Data from KS case series and case reports confirmed that serum estradiol is within the normal ranges.

CONCLUSIONS

Serum estradiol is not increased in KS although slightly higher than controls. However, the meta-analysis that included only studies using a serum estradiol assay with good accuracy showed no difference in serum estradiol between KS and controls. The traditional belief that KS is associated with elevated serum estradiol should be reconsidered. This meta-analysis shows that men with KS have relative hyperestrogenism (increased estradiol/testosterone ratio) compared to controls.

Prevalence of XXY karyotypes in human blastocysts: multicentre data from 7549 trophectoderm biopsies obtained during preimplantation genetic testing cycles in IVF

STUDY QUESTION

Which is the prevalence of a 47,XXY karyotype in human blastocysts biopsied during preimplantation genetic testing for aneuploidies (PGT-A) cycles?

SUMMARY ANSWER

The prevalence of a 47,XXY karyotype amongst male blastocysts without autosomal aneuploides is ~1%.

WHAT IS KNOWN ALREADY

The prevalence of Klinefelter syndrome is estimated as 0.1-0.2% in male newborns. However, the KS phenotype is extremely variable and there are men with a 47,XXY karyotype and less evident signs, who may go undetected. No risk factor for the 47,XXY karyotype in products of conception has been yet clearly defined, and no data are available regarding the prevalence of this karyotype among human preimplantation embryos.

STUDY DESIGN, SIZE, DURATION

This multicentre cohort study involved 7549 blastocysts obtained during 2826 PGT-A cycles performed between April 2013 and September 2017 at six IVF clinics in Italy.

PARTICIPANTS/MATERIALS, SETTING, METHODS

During 2826 PGT-A cycles, 7549 blastocysts underwent trophectoderm biopsy and quantitative-PCR-based comprehensive chromosomal testing to predict the karyotype of the corresponding embryos. The results were also presented according to ranges of maternal and paternal age at oocyte retrieval as well as sperm factor and blastocyst quality. Univariate and multivariate logistic regression analyses were conducted to investigate the correlation of possible confounding factors with the prevalence of 47,XXY karyotype.

MAIN RESULTS, THE ROLE OF CHANCE

Overall, 62 blastocysts were 47,XXY or had an XXY karyotype associated with autosomal aneuploidies. After exclusion of the latter, the prevalence of a 47,XXY karyotype among male blastocysts without autosomal aneuploidies was 0.9% (n = 17/1794). A significant correlation was only found for maternal age and blastocyst quality (OR: 1.20, 95% CI: 1.01-1.42; P = 0.04 and OR: 1.6, 95% CI: 1.13-2.45; P = 0.01).

LIMITATIONS, REASONS FOR CAUTION

These retrospective data have been produced based on a population of infertile couples undergoing IVF and PGT-A, and the women were mainly of advanced maternal age. Moreover, the qPCR technique is validated only to detect full-chromosome uniform aneuploidies in trophectoderm biopsies.

WIDER IMPLICATIONS OF THE FINDINGS

The 0.9% prevalence of the 47,XXY karyotype among male blastocysts, when compared with the 0.1-0.2% prevalence reported in the prenatal and postnatal periods, suggests four possible scenarios that require further investigations: (i) the latter prevalence is underestimated; (ii) 47,XXY blastocysts result in a lower implantation rate than euploid embryos (estimated to be ≈50%); (iii) 47,XXY blastocysts result in a higher early miscarriage rate than euploid embryos (estimated to be ≈10%); or (iv) infertile patients of advanced maternal age and referred to IVF/PGT-A produce a higher rate of 47,XXY blastocysts.

STUDY FUNDING/COMPETING INTEREST(S)

None.

TRIAL REGISTRATION NUMBER

N/A.

Novel insights on testicular volume and testosterone replacement therapy in Klinefelter patients undergoing testicular sperm extraction. A retrospective clinical study

STUDY QUESTION

To investigate whether sperm recovery is related to clinical features, hormone parameters and testosterone replacement therapy (TRT) in patients with Klinefelter syndrome (KS).

SUMMARY ANSWER

This study provides three interesting insights: (i) the probability to retrieve sperm is not related to testicular volume; (ii) TRT does not affect sperm retrieval rate (SRR); and (iii) reduced levels of LH and FSH represent a negative predictor of sperm retrieval in patients with TRT.

WHAT IS KNOWN ALREADY

Classical KS shows a karyotype with one extra X chromosome in all of somatic cells and clinical manifestations characterized by hypergonadotropic hypogonadism and infertility.

STUDY DESIGN, SIZE AND DURATION

We performed a retrospective cohort study. Data from 111 consecutive KS azoospermic patients undergoing testicular sperm extraction (TESE) were collected from 2005 to 2016.

PARTICIPANTS/MATERIALS, SETTING AND METHODS

Data on anthropometric parameters, reproductive hormones and testicular volumes were collected. SRR was related to clinical characteristics and compared between TRT and untreated patients.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 38 patients (34.2%) had successful sperm recovery. The comparison of clinical characteristics did not differ between patients with and without sperm recovery. Sperm retrieval was successful also in subjects with smaller testes. The comparison of SRR in patients with or without TRT was not different (33.3% vs 34.6%). In TRT group, LH and FSH levels were significantly lower in subjects with no sperm retrieval (P values, respectively, <.05 and <.001).

LIMITATIONS AND REASONS FOR CAUTION

Well-designed controlled studies are necessary to confirm these data aimed to set the best therapeutic approach for fertility management in hypogonadal patients with nonmosaic KS.

WIDER IMPLICATIONS OF THE FINDINGS

Age at TESE, anthropometric measures, testis volume, sex hormones levels and semen parameters are not predictive parameters of SRR. Among TRT patients, reduced gonadotropin is related to failure in sperm retrieval.

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.

Distinctive pattern of expression of spermatogenic molecular markers in testes of azoospermic men with non-mosaic Klinefelter syndrome

PURPOSE

Mature sperm cells can be found in testicular specimens extracted from azoospermic men with non-mosaic Klinefelter syndrome (KS). The present study evaluates the expression of various known molecular markers of spermatogenesis in a population of men with KS and assesses the ability of those markers to predict spermatogenesis.

METHODS

Two groups of men with non-obstructive azoospermia who underwent testicular sperm-retrieval procedures were included in the study: 31 had non-mosaic KS (KS group) and 91 had normal karyotype (NK group). Each group was subdivided into mixed atrophy (containing some mature sperm cells) or Sertoli cell only syndrome according to testicular histology and cytology observations. Semi-quantitative histological morphometric analysis (interstitial hyperplasia and hyalinization, tubules with cells and abnormal thickness of the basement membrane) and expression of spermatogenetic markers (DAZ, RBM, BOLL, and CDY1) were evaluated and compared among those subgroups.

RESULTS

Clear differences in the histological morphometry and spermatogenetic marker expression were noted between the KS and NK groups. There was a significant difference in the expression of spermatogenetic markers between the subgroups of the NK group (as expected), while no difference could be discerned between the two subgroups in the KS group.

CONCLUSION

We conclude that molecular spermatogenetic markers have a pattern of expression in men with KS that is distinctively different from that of men with NK, and that it precludes and limits their use for predicting spermatogenesis in the former. It is suggested that this difference might be due to the specific highly abnormal histological morphometric parameters in KS specimens.

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.

Pubertal induction in hypogonadism: Current approaches including use of gonadotrophins

Primary disorders of the gonad or those secondary to abnormalities of the hypothalamic pituitary axis result in hypogonadism. The range of health problems of childhood and adolescence that affect this axis has increased, as most children now survive chronic illness, but many have persisting deficits in gonadal function as a result of their underlying condition or its treatment. An integrated approach to hormone replacement is needed to optimize adult hormonal and bone health, and to offer opportunities for fertility induction and preservation that were not considered possible in the past. Timing of presentation ranges from birth, with disorders of sexual development, through adolescent pubertal failure, to adult fertility problems. This review addresses diagnosis and management of hypogonadism and focuses on new management strategies to address current concerns with fertility preservation. These include Turner syndrome, and fertility presevation prior to childhood cancer treatment. New strategies for male hormone replacement therapy that may impinge upon future fertility are emphasized.

Outcome of testicular sperm extraction in nonmosaic Klinefelter syndrome patients: what is the best approach?

Klinefelter syndrome (KS) is the most common chromosomal disorder associated with male hypogonadism and infertility. Parenthood can be achieved in men with KS by intracytoplasmic sperm injection (ICSI) using testicular spermatozoon. The aim of this study was to evaluate surgical sperm retrieval (SSR) rate in patients with KS and to investigate the approach associated with the highest SSR. This is a retrospective study where all medical records of patients with KS who underwent SSR for ICSI, in our centre in the past 14 years, were reviewed. Forty-three patients were included in this study. Twenty-three underwent conventional testicular sperm extraction (TESE), while 20 patients underwent microsurgical TESE (Micro-TESE). The SSR was significantly higher in the Micro-TESE group when compared with the TESE group (30% versus 0% respectively). In the Micro-TESE group, hormonal stimulation was given to 16 patients, while no treatment was given to four patients. SSR was only successful in hormonally treated patients (6/16). When the type of hormone stimulation was evaluated, SSR was higher in patients receiving aromatase inhibitors (27.8%). SSR in patients with KS is significantly higher when using hormonal stimulation by aromatase inhibitors followed by microsurgical testicular sperm extraction.

[Therapeutic issues concerning male fertility]

Men reproductive health has long been ignored although it is responsible for 50% of couple's infertility. However, in recent years, the understanding of endocrine physiology underlying testis development and spermatogenesis has enabled the development of new therapeutic strategies. Some concern the management of male infertility. Others are dealing with finding an effective male contraceptive. In this review, we first present the management of infertility, in patients with congenital hypogonadotropic hypogonadism. We then describe the major improvements for Klinefelter patient's infertility. Finally, we review the different hormonal and non-hormonal methods for male contraception, currently in development. Efficacy and safety of the some non-hormonal methods remain to be demonstrated so far in humans.

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.

Should repeated TESE be performed following a failed TESE in men with Klinefelter Syndrome?

The main goal of this study was to evaluate the success rate of repeated Testicular Sperm Extraction (TESE) in Klinefelter Syndrome (KS). Eighteen patients with the diagnosis of KS who had undergone micro TESE previously were re-evaluated between May 2007 and May 2012. Testes were measured and testicular volume was calculated by orchidometer and by scrotal ultrasonography in all patients All patients underwent repeated micro TESE. Serum follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone levels and testicular volume of the patients with and without successful sperm retrieval were compared statistically. A p value of less than 0.05 was considered statistically significant. The mean age of the patients was 30.3 years. The mean testicular volume was 2.08 and 2.1 mL for right and left testes respectively. The comparisons of serum FSH, LH, testosterone levels and testicular volume between patients with and without successful sperm retrieval did not show any significant difference. Three of the 18 patients who underwent repeated micro TESE, had successful sperm retrieval and repeated TESE failed in 15 patients. Three patients with successful sperm retrieval underwent intracytoplasmic sperm injection using retrieved testicular spermatozoa. Two embryos for each patient which were determined as healthy were transferred to the wives of the patients. Pregnancy occured in one of them and a healthy female infant was born. We conclude that consideration and hope must be given for a repeated micro TESE in patients with KS, even with a minimal chance of success.

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.

The natural history of endocrine function and spermatogenesis in Klinefelter syndrome: what the data show

Once thought to be a chromosomal aberration associated with absolute sterility, Klinefelter syndrome may now be potentially treatable by testicular sperm retrieval coupled with intracytoplasmic sperm injection. With these therapeutic advances, azoospermic 47,XXY men now may have an opportunity for biological paternity. However, our knowledge of the basic mechanisms underlying germ cell loss and Leydig cell compromise is lagging, and is just now beginning to evolve and provide answers to some of the field's most vexing questions: how to maximize and preserve fertility in Klinefelter males many years or even decades before they wish to actively pursue fatherhood. This article reviews the development of the androgenic and spermatogenic compartments of the Klinefelter testis through puberty, and recommends that it is only with a clear understanding of the basic facts that a rational, considered approach to fertility optimization and preservation can be determined.

The genetic origin of Klinefelter syndrome and its effect on spermatogenesis

Klinefelter syndrome is the most prevalent chromosome abnormality and genetic cause of azoospermia in males. The availability of assisted reproductive technology (ART) has allowed men with Klinefelter syndrome to father their own genetic offspring. When providing ART to men with Klinefelter syndrome, it is important to be able to counsel them properly on both the chance of finding sperm and the potential effects on their offspring. The aim of this review is twofold: [1] to describe the genetic etiology of Klinefelter syndrome and [2] to describe how spermatogenesis occurs in men with Klinefelter syndrome and the consequences this has for children born from men with Klinefelter syndrome.

Klinefelter syndrome: an argument for early aggressive hormonal and fertility management

OBJECTIVE

To investigate the impact of early hormone replacement therapy (HT) on sperm retrieval rates in patients with Klinefelter syndrome (KS).

DESIGN

A systematic review of the relevant literature using the PubMed NLM database.

RESULT(S)

There are no randomized controlled trials evaluating the impact of HT on sperm retrieval or reproductive outcomes in men with KS. On average, surgical sperm retrieval rates in men with KS are around 51%, with a range of 28%-69%. Young patient age is the most consistent positive predictor of sperm retrieval. Lower retrieval rates have been reported in a small subset of KS adults who previously received exogenous T, although the nature, duration, and reason for such therapy in these patient subsets are unknown.

CONCLUSION(S)

Early HT is recommended in patients with KS, but its effect on fertility potential has not been definitively studied. Larger studies are needed to better answer this question. Cryopreservation of sperm-containing semen or testicular tissue from a significant proportion of affected adolescents is possible, even when containing very low numbers of spermatozoa, and should be considered to maximize future fertility potential.

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.

Bone mass in subjects with Klinefelter syndrome: role of testosterone levels and androgen receptor gene CAG polymorphism

CONTEXT

Klinefelter syndrome (KS) is a chromosomal alteration characterized by supernumerary X-chromosome(s), primary hypogonadism, decreased pubertal peak bone mineral density (BMD), and accelerated bone loss during adulthood. Decreased bone mass has been traditionally related to low testosterone levels. However, testosterone replacement therapy does not necessarily increase bone mass in these patients, and low BMD can be observed also in patients with normal testosterone levels. The androgen receptor (AR) gene CAG polymorphism seems to modulate the sensitivity to testosterone and previous studies have related it to some clinical aspects of KS, to include BMD, gynecomastia, testes and prostate volume, and hemoglobin concentration.

OBJECTIVE

To analyze the relation between bone mass, testosterone, and AR CAG polymorphism in men with KS.

DESIGN

Cross-sectional cohort study.

SETTING

University department.

PATIENTS

One hundred twelve consecutive treatment-naïve 47,XXY Klinefelter patients (mean age 33.5 ± 4.7 yr) and 51 age-matched normal male controls.

MAIN OUTCOME MEASURES

Dual-energy x-ray absorptiometry, CAG repeat length polymorphism, X-chromosome inactivation, and testosterone levels.

RESULTS

Forty-nine of 112 KS subjects (42.5%) had low bone mass (osteopenia or osteoporosis). Lumbar and/or femoral T-scores were lower in KS patients compared with controls. No significant relationship was observed between testosterone levels and bone parameters, and the prevalence of osteopenia/osteoporosis was similar in subjects with normal and low testosterone levels (43.7% and 40.5%, respectively). The mean CAG repeat length calculated after X-chromosome inactivation analysis showed no differences between patients with normal and low bone mass.

CONCLUSIONS

Testosterone levels and AR CAG polymorphism are not associated with bone mass phenotype in KS.

Genetic and epigenetic factors: Role in male infertility

Genetic factors contribute upto 15%-30% cases of male infertility. Formation of spermatozoa occurs in a sequential manner with mitotic, meiotic, and postmeiotic differentiation phases each of which is controlled by an intricate genetic program. Genes control a variety of physiologic processes, such as hypothalamus-pituitary-gonadal axis, germ cell development, and differentiation. In the era of assisted reproduction technology, it is important to understand the genetic basis of infertility to provide maximum adapted therapeutics and counseling to the couple.

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).