The Klinefelter syndrome: current management and research challenges

Klinefelter Syndrome: A Genetic Disorder Leading to Neuroendocrine Modifications and Psychopathological Vulnerabilities in Children-A Literature Review and Case Report

Klinefelter syndrome (KS), characterized by an additional X-chromosome in males, manifests in a wide range of neuroendocrine and psychiatric symptoms. Individuals with KS often face increased risks of hormonal dysfunction, leading to depression and anxiety, although extended research during pediatric and adolescent age is still limited. This critical phase, decisive for KS children, is influenced by a combination of genetic, environmental and familial factors, which impact brain plasticity. In this report, we reviewed, in a narrative form, the crucial KS psychopathological hallmarks in children. To better describe neuroendocrine and neuropsychiatric outcomes in children with KS, we presented the case of an 11-year-old prepubertal child with mosaic KS who was referred to our Center of Developmental Psychopathology due to a decline in his academic performance, excessive daytime fatigue and increased distractibility over the past few months. Family history revealed psychiatric conditions among first- and second-degree relatives, including recently divorced parents and a 15-year-old sister. Early-onset persistent depressive disorder and anxious traits were diagnosed. Timely identification of susceptible children, with thorough examination of familial psychiatric history, environmental influences and neurocognitive profile, alongside targeted interventions, could potentially mitigate lifelong psychopathology-related disabilities in pediatric and adolescent KS cases, including those with mosaic KS.

Klinefelter syndrome presenting as metastatic bilateral breast cancer: missed diagnostic opportunities

Klinefelter syndrome (KS) is the most common cause of primary hypogonadism in male patients; however, the diagnosis of KS is frequently delayed or missed. This delay can lead to undesirable outcomes for patients, especially considering that individuals with KS have a higher risk of developing specific malignancies, including breast cancer, non-Hodgkin's lymphoma and mediastinal germ cell tumours. We present a case of a male patient in his 60s, where the established diagnosis of metastatic bilateral breast cancer prompted us to investigate and subsequently confirm a diagnosis of KS. This case highlights the diagnostic challenges of KS and emphasises the unfavourable consequences of a delayed diagnosis. We aim to raise awareness and enhance physicians' understanding of KS and its non-reproductive manifestations, with a view to promote early recognition and improve patient outcomes.

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.

First baseline data of the Klinefelter ItaliaN Group (KING) cohort: clinical features of adult with Klinefelter syndrome in Italy

BACKGROUND

Klinefelter syndrome (KS) is frustratingly under-diagnosed. KS have a broad spectrum of clinical features, making it difficult to identify.  OBJECTIVE: We describe KS clinical presentation in a large Italian cohort.

DESIGN

This is the first observational cohort study within a national network, the Klinefelter ItaliaN Group (KING). Primary outcomes were to describe the basic clinical features and the actual phenotype of KS in Italy. Secondary outcomes were to determine age at diagnosis and geographical distribution.

METHODS

We performed a basic phenotyping and evaluation of the hormonal values of 609 adult KS patients.

RESULTS

Mean age at diagnosis was 37.4 ± 13.4 years. The overall mean testicular size was 3 ml, and 2.5 ml in both testes in untreated KS group. BMI was 26.6 ± 5.8 kg/m², and 25.5% of KS had metabolic syndrome (MetS). LH and FSH were increased, and mean total testosterone were 350 ± 9.1 ng/dl. A descriptive analysis showed that 329 KS patients were evaluated in Northern Italy, 76 in Central and 204 in Southern Italy. Analysis of variance demonstrated significant statistical differences (p < 0001) between the age at diagnosis of the three geographical groups. Compared with the expected number among male patients matched for age in Italy, only 16% of KS patients received a diagnosis.

CONCLUSIONS

These data are the results of the only national database available that collects the clinical and hormonal data of the KS patients, currently referred at the KING centers. In Italy the typical KS patient is overweight, with small testes, and elevated LH and FSH. Only 25.5% of them are diagnosed with MetS. Early detection and timely treatment are mandatory.

Population-based Assessment of Cardiometabolic-related Diagnoses in Youth With Klinefelter Syndrome: A PEDSnet Study

CONTEXT

Diabetes and cardiovascular diseases are common among men with Klinefelter syndrome (KS) and contribute to high morbidity and mortality.

OBJECTIVE

To determine if cardiometabolic-related diagnoses are more prevalent among youth with KS than matched controls in a large population-based cohort.

METHODS

Secondary data analysis of electronic health records from 6 pediatric institutions in the United States (PEDSnet). Patients included all youth with KS in the database (n = 1080) and 4497 youth without KS matched for sex, age (mean 13 years at last encounter), year of birth, race, ethnicity, insurance, site, and duration of care (mean 7 years). The main outcome measures were prevalence of 5 cardiometabolic-related outcomes: overweight/obesity, dyslipidemia, dysglycemia, hypertension, and liver dysfunction.

RESULTS

The odds of overweight/obesity (OR 1.6; 95% CI 1.4-1.8), dyslipidemia (3.0; 2.2-3.9), and liver dysfunction (2.0; 1.6-2.5) were all higher in KS than in controls. Adjusting for covariates (obesity, testosterone treatment, and antipsychotic use) attenuated the effect of KS on these outcomes; however, boys with KS still had 45% greater odds of overweight/obesity (95% CI 1.2-1.7) and 70% greater odds of liver dysfunction (95% CI 1.3-2.2) than controls, and both dyslipidemia (1.6; 1.1-2.4) and dysglycemia (1.8; 1.1-3.2) were higher in KS but of borderline statistical significance when accounting for multiple comparisons. The odds of hypertension were not different between groups.

CONCLUSION

This large, population-based cohort of youth with KS had a higher odds of most cardiometabolic-related diagnoses than matched controls.

Genetic Factors of Non-Obstructive Azoospermia: Consequences on Patients' and Offspring Health

Non-Obstructive Azoospermia (NOA) affects about 1% of men in the general population and is characterized by clinical heterogeneity implying the involvement of several different acquired and genetic factors. NOA men are at higher risk to be carriers of known genetic anomalies such as karyotype abnormalities and Y-chromosome microdeletions in respect to oligo-normozoospermic men. In recent years, a growing number of novel monogenic causes have been identified through Whole Exome Sequencing (WES). Genetic testing is useful for diagnostic and pre-TESE prognostic purposes as well as for its potential relevance for general health. Several epidemiological observations show a link between azoospermia and higher morbidity and mortality rate, suggesting a common etiology for NOA and some chronic diseases, including cancer. Since on average 50% of NOA patients has a positive TESE outcome, the identification of genetic factors in NOA patients has relevance also to the offspring's health. Although still debated, the observed increased risk of certain neurodevelopmental disorders, as well as impaired cardiometabolic and reproductive health profile in children conceived with ICSI from NOA fathers may indicate the involvement of transmissible genetic factors. This review provides an update on the reproductive and general health consequences of known genetic factors causing NOA, including offspring's health.

The Evidence for Fertility Preservation in Pediatric Klinefelter Syndrome

Klinefelter syndrome (KS) is a common cause of non-obstructive azoospermia (NOA). Advances in fertility preservation (FP) techniques, such as the use of microdissection testicular sperm extraction (micro-TESE), have improved sperm retrieval rates (SRR) up to 40–50% in this population. Age has been suggested to have an impact on FP, postulating that sperm production may deteriorate over time due to germ cell loss. As such, sperm retrieval for patients with KS at a younger age has been proposed to further improve SRR; however, whether such practice pragmatically improves SRR is yet to be determined, and controversy remains with concerns over trauma caused by FP procedures on further impairment of testicular function. There has also been a debate on the ethics of performing FP procedures in the pediatric population. Optimizing FP for patients with KS invariably requires a holistic multidisciplinary approach. This review aimed to evaluate the latest evidence in performing FP in pediatric patients with KS, and discuss the controversy surrounding such practice. Hormonal changes in patients with KS during childhood and the use of hormonal manipulation to optimize SSR in this population have also been reviewed.

Laparoscopic sleeve gastrectomy for morbid obesity and Klinefelter syndrome: clinical report on two patients, with long-term follow-up

INTRODUCTION

Klinefelter syndrome (KS) can appear as a wide spectrum of clinical manifestations, with no guidelines for appropriate treatment. We present the first study of bariatric surgery (BS) with a 48-month follow-up, for the management of two patients affected by obesity and KS.

CASES PRESENTATION

The first patient was a 32-year-old man with diagnosis of Klinefelter mosaicism (46 XY/47, XXY), Body Mass Index (BMI) of 50 kg/m², metabolic syndrome and Binge Eating Disorder (BED). He underwent a Laparoscopic Sleeve Gastrectomy (LSG) with weight loss (BMI = 38 kg/m²) and improvements to his metabolic profile at 48 months. The second patient was a 44-year-old man with KS (47, XXY), BMI of 49 kg/m², Obstructive Sleep Apnea Syndrome and BED. He underwent a banded LSG. After 48 months, he showed a satisfactory weight loss (BMI = 32 kg/m²) and amelioration of comorbidities.

CONCLUSION

In patients with KS, LSG demonstrated long-term beneficial effects for weight loss and amelioration of comorbidities. An interdisciplinary approach is mandatory, since it leads to adherence to follow-up programs and mental health well-being.

Estradiol-Testosterone Imbalance Is Associated with Erectile Dysfunction in Patients with Klinefelter Syndrome

Erectile dysfunction (ED) is a frequent sexual disorder in adult men. Klinefelter syndrome (KS) is the most common sex chromosomal disorder and a frequent cause of male hypogonadism. Psychological and cognitive aspects are quite typical in KS and have been linked to ED, while the role of testosterone (T) levels in sexual function of KS subjects has not been fully elucidated. The purpose of the present study is to investigate the role of hormonal disturbances in erectile function of subjects with KS. We conducted a retrospective study involving 52 Klinefelter patients newly diagnosed who never received androgen replacing therapy. All the subjects underwent medical history, accurate physical examination, and blood tests. The International Index of Erectile Function questionnaire (IIEF-EF) score correlated negatively with estradiol/testosterone ratio (E2/T); this correlation remained statistically significant after correction for age (ρ −0.320 p = 0.018). A multiple linear regression analysis identified age and E2/T as the main predictors of IIEF-EF score (R2 0.169 F = 3.848 p = 0.008). Our findings corroborate previous KS data obtained in the general population showing an association between higher E2/T ratio and impaired erectile function. Larger studies are required to better elucidate the pathophysiology of ED in patients with KS.

Evaluation of the Efficacy of Transdermal and Injection Testosterone Therapy in Klinefelter Syndrome: A Real-Life Study

Context

Klinefelter Syndrome (KS) is the most frequent sex chromosome disorder in males. Due to hypergonadotropic hypogonadism, treatment with testosterone replacement therapy (TRT) is commonly indicated. There are no international guidelines for the most appropriate TRT in KS.

Objective

We aimed to evaluate how different routes of testosterone administration impact testosterone-responsive variables, as well as the development of later metabolic diseases and other complications.

Methods

We conducted a retrospective study covering 5 years from 2015 to 2020. Data on TRT, biochemical parameters, bone mineral density (BMD), medications, comorbidity, and karyotyping were derived from electronic patient records and The Danish Cytogenetic Register.

Results

A total of 147 KS males were included: 81 received injection TRT, 61 received transdermal TRT, and 5 did not receive TRT. Testosterone levels were similar in the 2 TRT groups (P = 0.9), while luteinizing hormone and follicle-stimulating hormone levels were higher in the group receiving transdermal TRT (P = 0.002). Levels of cholesterol, blood glucose, hemoglobin A1c, hemoglobin, hematocrit, liver parameters, prostate-specific antigen, and spine and hip BMD were similar in the 2 treatment groups (Ps > 0.05).

Conclusion

TRT, irrespective of route of administration, affects androgen-responsive variables similarly in males with KS. Neither long-acting injection nor transdermal gel seem to reduce the risk of metabolic diseases significantly. These results should encourage clinicians in seeking the route of administration resulting in the highest degree of adhesion to treatment based on individual patient preferences. Implementation of shared decision-making with patients may be important when choosing TRT.

European academy of andrology guidelines on Klinefelter Syndrome Endorsing Organization: European Society of Endocrinology

BACKGROUND

Knowledge about Klinefelter syndrome (KS) has increased substantially since its first description almost 80 years ago. A variety of treatment options concerning the spectrum of symptoms associated with KS exists, also regarding aspects beyond testicular dysfunction. Nevertheless, the diagnostic rate is still low in relation to prevalence and no international guidelines are available for KS.

OBJECTIVE

To create the first European Academy of Andrology (EAA) guidelines on KS.

METHODS

An expert group of academicians appointed by the EAA generated a consensus guideline according to the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) system.

RESULTS

Clinical features are highly variable among patients with KS, although common characteristics are severely attenuated spermatogenesis and Leydig cell impairment, resulting in azoospermia and hypergonadotropic hypogonadism. In addition, various manifestations of neurocognitive and psychosocial phenotypes have been described as well as an increased prevalence of adverse cardiovascular, metabolic and bone-related conditions which might explain the increased morbidity/mortality in KS. Moreover, compared to the general male population, a higher prevalence of dental, coagulation and autoimmune disorders is likely to exist in patients with KS. Both genetic and epigenetic effects due to the supernumerary X chromosome as well as testosterone deficiency contribute to this pathological pattern. The majority of patients with KS is diagnosed during adulthood, but symptoms can already become obvious during infancy, childhood or adolescence. The paediatric and juvenile patients with KS require specific attention regarding their development and fertility.

CONCLUSION

These guidelines provide recommendations and suggestions to care for patients with KS in various developmental stages ranging from childhood and adolescence to adulthood. This advice is based on recent research data and respective evaluations as well as validations performed by a group of experts.

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.

Early neurodevelopmental and medical profile in children with sex chromosome trisomies: Background for the prospective eXtraordinarY babies study to identify early risk factors and targets for intervention

Sex chromosome trisomies (SCT), including Klinefelter syndrome/XXY, Trisomy X, and XYY syndrome, occur in 1 of every 500 births. The past decades of research have resulted in a broadening of known associated medical comorbidities as well as advances in psychological research. This review summarizes what is known about early neurodevelopmental, behavioral, and medical manifestations in young children with SCT. We focus on recent research and unanswered questions related to the risk for neurodevelopmental disorders that commonly present in the first years of life and discuss the medical and endocrine manifestations of SCT at this young age. The increasing rate of prenatal SCT diagnoses provides the opportunity to address gaps in the existing literature in a new birth cohort, leading to development of the eXtraordinarY Babies Study. This study aims to better describe and compare the natural history of SCT conditions, identify predictors of positive and negative outcomes in SCT, evaluate developmental and autism screening measures commonly used in primary care practices for the SCT population, and build a rich data set linked to a bank of biological samples for future study. Results from this study and ongoing international research efforts will inform evidence-based care and improve health and neurodevelopmental outcomes.

Integration and reanalysis of transcriptomics and methylomics data derived from blood and testis tissue of men with 47,XXY Klinefelter syndrome indicates the primary involvement of Sertoli cells in the testicular pathogenesis

Klinefelter syndrome (KS; 47,XXY) is the most common sex chromosomal anomaly and causes a multitude of symptoms. Often the most noticeable symptom is infertility caused by azoospermia with testicular histology showing hyalinization of tubules, germ cells loss, and Leydig cell hyperplasia. The germ cell loss begins early in life leading to partial hyalinization of the testis at puberty, but the mechanistic drivers behind this remain poorly understood. In this systematic review, we summarize the current knowledge on developmental changes in the cellularity of KS gonads supplemented by a comparative analysis of the fetal and adult gonadal transcriptome, and blood transcriptome and methylome of men with KS. We identified a high fraction of upregulated genes that escape X-chromosome inactivation, thus supporting previous hypotheses that these are the main drivers of the testicular phenotype in KS. Enrichment analysis showed overrepresentation of genes from the X- and Y-chromosome and testicular transcription factors. Furthermore, by re-evaluation of recent single cell RNA-sequencing data originating from adult KS testis, we found novel evidence that the Sertoli cell is the most affected cell type. Our results are consistent with disturbed cross-talk between somatic and germ cells in the KS testis, and with X-escapee genes acting as mediators.

41,XXY * male mice: An animal model for Klinefelter syndrome

Klinefelter syndrome (KS, 47,XXY) is the most frequent male chromosomal aneuploidy resulting in a highly heterogeneous clinical phenotype associated with hormonal dysbalance, increased rate of co-morbidities, and reduced lifespan. Two hallmarks of KS-affecting testicular functions are consistently observed: Hypergonadotropic hypogonadism and germ cell (GC) loss resulting in infertility. Although KS is being studied for decades, the underlying mechanisms for the observed pathophysiology are still unclear. Due to ethical restrictions, studies in humans are limited, and consequently, suitable animal models are needed to address the consequences of a supernumerary X chromosome. Mouse strains with comparable aneuploidies have been generated and yielded highly relevant insights into KS. We briefly describe the establishment of the KS mouse models, summarize the knowledge gained by their use, compare findings from the mouse models to those obtained in clinical studies, and also reflect on limitations of the currently used models derived from the B6Ei.Lt-Y* mouse strain, in which the Y chromosome is altered and its centromere position changed into a more distal location provoking meiotic non-disjunction. Breeding such as XY* males to XX females, the target 41,XX^Y *, and 41,XXY males are generated. Here, we summarize features of both models but report in particular findings from our 41,XX^Y * mice including some novel data on Sertoli cell characteristics.

Germ cell loss in Klinefelter syndrome: When and why?

Klinefelter syndrome (KS) is a quite common disorder with an incidence of 1-2 in 1,000 new-born males. Most patients are diagnosed in the light of a clinical checkup when consulting a fertility clinic with an unfulfilled child wish. Infertility in KS patients is caused by a massive germ cell loss, leading to azoospermia in more than 90% of the adult patients. Most seminiferous tubules in the adult KS testis are degenerated or hyalinized and testicular fibrosis can be observed, starting from puberty. However, focal spermatogenesis can be found in the testis of some patients. This offers the opportunity to extract spermatozoa from the testis by testicular sperm extraction (TESE). Nevertheless, TESE is only successful in about half of the KS adults seeking to father children. The reason for the germ cell loss remains unclear. To date, it is still debated whether the testicular tissue changes and the germ cell loss seen in KS is directly caused by an altered X-linked gene expression, the altered somatic environment, or a deficiency in the germ cells. In this review, we provide an overview of the current knowledge about the germ cell loss in KS patients.

High-resolution analysis of germ cells from men with sex chromosomal aneuploidies reveals normal transcriptome but impaired imprinting

Background

The most common sex chromosomal aneuploidy in males is Klinefelter syndrome, which is characterized by at least one supernumerary X chromosome. While these men have long been considered infertile, focal spermatogenesis can be observed in some patients, and sperm can be surgically retrieved and used for artificial reproductive techniques. Although these gametes can be used for fertility treatments, little is known about the molecular biology of the germline in Klinefelter men. Specifically, it is unclear if germ cells in Klinefelter syndrome correctly establish the androgenetic DNA methylation profile and transcriptome. This is due to the low number of germ cells in the Klinefelter testes available for analysis.

Results

Here, we overcame these difficulties and successfully investigated the epigenetic and transcriptional profiles of germ cells in Klinefelter patients employing deep bisulfite sequencing and single-cell RNA sequencing. On the transcriptional level, the germ cells from Klinefelter men clustered together with the differentiation stages of normal spermatogenesis. Klinefelter germ cells showed a normal DNA methylation profile of selected germ cell-specific markers compared with spermatogonia and sperm from men with normal spermatogenesis. However, germ cells from Klinefelter patients showed variations in the DNA methylation of imprinted regions.

Conclusions

These data indicate that Klinefelter germ cells have a normal transcriptome but might present aberrant imprinting, showing impairment in germ cell development that goes beyond mere germ cell loss.

Electronic supplementary material

The online version of this article (10.1186/s13148-019-0720-3) contains supplementary material, which is available to authorized users.

TESTICULAR REGRESSION SYNDROME: PRACTICE VARIATION IN DIAGNOSIS AND MANAGEMENT

Objective: The purpose of this study was to assess clinical practice patterns with regard to diagnosis and management of testicular regression syndrome (TRS), a condition in 46,XY males with male phenotypic genitalia and bilateral absence of testes. Methods: A retrospective review was conducted at two large pediatric academic centers to examine diagnostic and management approaches for TRS. Results: Records of 57 patients were reviewed. Diagnostic methods varied widely between patients and included hormonal testing, karyotype, imaging, and surgical exploration, with multiple diagnostic methods frequently used in each patient. Of the 30 subjects that had reached adolescence at the time of the study, 17 (57%) had gaps in care of more than 5 years during childhood. Thirty subjects had received testosterone replacement therapy at a mean age of 12.1 ± 1.0 years. Forty-seven percent had a documented discussion of infertility. Eighty-two percent discussed prosthesis placement, with 35% having prostheses placed. Twenty-three percent were seen by a psychosocial provider. The between-site differences were age at fertility discussion, age at and number of prostheses placed, and type/age of testosterone initiation. Conclusion: Our findings highlight the wide variation in diagnostic approaches, follow-up frequency, testosterone initiation, fertility counseling, and psychosocial support for patients with TRS. Developing evidence-based guidelines for the evaluation and management of TRS would help reduce inconsistencies in care and unnecessary testing. Ongoing follow-up and coordination of care, even during the years when no hormonal treatment is being administered, could lead to opportunities for psychosocial support and improved interdisciplinary approach to care. Abbreviations: AMH = antimüllerian hormone; CAH = congenital adrenal hyperplasia; DSD = differences/disorders of sex development; hCG = human chorionic gonadotropin; TRS = testicular regression syndrome.

Step-by-step loupes-mTESE in non-obstructive azoospermic men, a retrospective study

Background

Men with non-obstructive azoospermia (NOA) may have sperm in their testes and a procedure of sperm retrieval and assisted reproduction is required in them to allow fertility. Standard procedures such as fine needle aspiration (FNA) and conventional testicular sperm extraction (cTESE) harvest random samples with a sperm retrieval rate (SRR) of 45%. Microdissection testicular sperm extraction (mTESE) is nowadays considered to be the most accurate technique to retrieve sperm in men with NOA. This procedure can identify dilated tubules that are more likely to contain viable sperm with a SRR of 60%.

Results

In our center, testicular biopsy was conducted in a standard fashion in 321 patients with NOA until March 2003. From then to December 2017, due to the lack of an operating microscope, we used 6 fold magnifying loupes to perform a step-by-step macro- mTESE in 1050 patients. Sperm was found in the first testis in 61% of the cases, leading to stop the procedure with less testicular damage. We increased our SRR from 43 to 51.8% in an acceptable operating time of 75mn for both sides.

Conclusions

In institutions where surgeons cannot afford an operating microscope, this modified mTESE technique using × 6 magnifying loupes is reliable, especially in patients with low testicular volumes and high FSH, in whom dilated tubules can be easily identified from the surrounding tissue.

Development of a Pediatric Fertility Preservation Program: A Report From the Pediatric Initiative Network of the Oncofertility Consortium

Infertility is known to decrease quality of life among adults. In some cases, infertility is caused by medical conditions and/or treatments prescribed in childhood, and using methods to protect or preserve fertility may expand future reproductive possibilities. Structured programs to offer counseling about infertility risk and fertility preservation options are essential in the care of pediatric patients facing fertility-threatening conditions or treatments, yet multiple barriers to program development exist. This report was developed from the institutional experiences of members of the Pediatric Initiative Network of the Oncofertility Consortium, with the intent of providing guidance for health care providers aiming to establish programs at institutions lacking pediatric fertility preservation services. The mechanics of building a fertility preservation program are discussed, including essential team members, target populations, fertility preservation options (both established and experimental), survivorship issues, research opportunities, and ethical considerations. Common barriers to program development and utilization, including low referral rates and financial concerns, are also discussed, and recommendations made for overcoming such barriers.

Klinefelter syndrome: From pediatrics to geriatrics

BACKGROUND

Klinefelter syndrome (KS) is one of the major causes of nonobstructive azoospermia (NOA). Microdissection testicular sperm extraction (micro-TESE) is often performed to retrieve sperm. Infertility specialists have to care for KS patients on a lifelong basis.

METHODS

Based on a literature review and our own experience, male infertility treatment and KS pathophysiology were considered on a lifelong basis.

MAIN FINDINGS

Patients diagnosed early often have an increased number of aberrant X chromosomes. Cryptorchidism and hypospadias are often found, and surgical correction is required. Cryopreservation of testicular sperm during adolescence is an issue of debate because the sperm retrieval rate (SRR) in KS patients decreases with age. The SRR in adult KS patients is higher than that in other patients with NOA; however, low testosterone levels after micro-TESE will lower the general health and quality of life. KS men face a number of comorbidities, such as malignancies, metabolic syndrome, diabetes, cardiovascular disease, bone disease, and immune diseases, which ultimately results in increased mortality rates.

CONCLUSION

A deeper understanding of the pathophysiology of KS and the histories of KS patients before they seek infertility treatment, during which discussions with multidisciplinary teams are sometimes needed, will help to properly treat these patients.

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.

Endocrine aspects of Klinefelter syndrome

PURPOSE OF REVIEW

Klinefelter syndrome is the most common sex chromosome abnormality in men. Hypogonadism and testicular degeneration are almost universal. Truncal adiposity, metabolic syndrome and low bone mass occur frequently. This review summarizes the most recent advances in the pathogenesis and management of the endocrine abnormalities in Klinefelter syndrome. It is expected that optimal endocrine management will improve outcomes and quality of life in Klinefelter syndrome.

RECENT FINDINGS

In Klinefelter syndrome, testosterone replacement is routinely prescribed despite lack of evidence on the optimal dose and time for initiation of therapy. Cross-sectional studies have linked hypogonadism to the development of metabolic abnormalities and low bone mass. Testosterone therapy, however, is not consistently associated with improved metabolic and bone outcomes. Increased truncal adiposity and high rates of metabolic syndrome are present in prepubertal children. A randomized trial of oxandrolone in prepubertal boys showed improvement in visual-motor function, socialization and cardiometabolic health. Testicular sperm extraction (TESE) has success rates similar to other causes of nonobstructive azoospermia when performed between 16 and 35 years of age.

SUMMARY

Endocrine care in Klinefelter syndrome should start in childhood and include evaluation of metabolic risk factors and bone health. Further research to guide evidence-based endocrine care is very much needed.

Recent advances in managing and understanding Klinefelter syndrome

Klinefelter syndrome can present as a wide spectrum of clinical manifestations at various stages in life, making it a chromosomal disorder with no standardized set of guidelines for appropriate management. Understanding the genetic and hormonal causes of this syndrome can allow physicians to treat each patient on a more individualized basis. The timing of diagnosis and degree of symptoms can guide management. This report will provide an updated review of the clinical presentation at various stages in life and the implications for management.

Transcriptome profiling of fetal Klinefelter testis tissue reveals a possible involvement of long non-coding RNAs in gonocyte maturation

In humans, the most common sex chromosomal disorder is Klinefelter syndrome (KS), caused by the presence of one or more extra X-chromosomes. KS patients display a varying adult phenotype but usually present with azoospermia due to testicular degeneration, which accelerates at puberty. The timing of the germ cell loss and whether it is caused by dysgenetic fetal development of the testes is not known. We investigated eight fetal KS testes and found a marked reduction in MAGE-A4-positive pre-spermatogonia compared with testes from 15 age-matched controls, indicating a failure of the gonocytes to differentiate into pre-spermatogonia. Transcriptome analysis by RNA-sequencing of formalin-fixed, paraffin-embedded testes originating from four fetal KS and five age-matched controls revealed 211 differentially expressed transcripts in the fetal KS testis. We found a significant enrichment of upregulated X-chromosomal transcripts and validated the expression of the pseudoautosomal region 1 (PAR1) gene, AKAP17A. Moreover, we found enrichment of long non-coding RNAs in the KS testes (e.g. LINC01569 and RP11-485F13.1). In conclusion, our data indicate that the testicular phenotype observed among adult men with KS is initiated already in fetal life by failure of the gonocyte differentiation into pre-spermatogonia, which could be due to aberrant expression of long non-coding RNAs.

Klinefelter syndrome: more than hypogonadism

Klinefelter syndrome (KS) is the most frequent chromosome disorder in males (1:650 newborn males), defined by 47,XXY karyotype. The classical phenotype is that of a tall male with relatively long legs, small, firm testes and gynecomastia. Azoospermia and infertility are almost inevitably present, but may be overcome by TESE and ICSI. Nevertheless, a broad spectrum of phenotypes has been described and more than 70% of the actually existing KS men may remain undiagnosed throughout their lifespan. Accordingly, hypogonadism is usually not evident until early adulthood and progresses with ageing. KS patients present a series of comorbidities that increase morbidity and mortality by 40%. Such disturbances are the impaired metabolic profile (obesity, dyslipidemia, insulin resistance) and a tendency to thrombosis, which all favor cardiovascular disease. They also present susceptibility for specific neoplasias (breast cancer, extragonadal germ cell tumors), autoimmune diseases as well as osteoporosis and bone fractures. Moreover, KS has been associated with verbal processing and attention deficits as well as social skill impairments, leading KS individuals to academic and professional achievements inferior to those of their peers of comparable socio-economic status. Nevertheless, the majority fall within the average range regarding their intellectual abilities and adaptive functioning. Testosterone replacement therapy (TRT) is the mainstay of treatment in hypogonadal KS patients; however, randomized trials are needed to determine optimal therapeutic regimens and follow-up schedules.

Oxandrolone Treatment Results in an Increased Risk of Gonadarche in Prepubertal Boys With Klinefelter Syndrome

CONTEXT

Klinefelter syndrome (KS) is a common genetic condition in which males have an extra X chromosome. KS is associated with testosterone deficiency, neurodevelopmental delays, and cardiometabolic disorders. There has been recent interest in prepubertal androgen treatment; however, the effects on puberty and gonadal function are unknown.

OBJECTIVE

To compare onset of puberty and testicular function in prepubertal boys treated with 2 years of oxandrolone (Ox) vs placebo (Pl).

DESIGN

Double-blind, randomized, controlled trial.

SETTING

Single tertiary care referral center.

PARTICIPANTS

Eighty prepubertal boys with KS; mean age: 8.0 ± 2.2 years (range: 4 to 12).

INTERVENTIONS

Ox 0.05 mg/kg vs identical-appearing Pl capsule given for 2 years.

OUTCOME MEASURES

Onset of gonadarche (testicular volume ≥4 mL) and onset of pubarche (Tanner 2 pubic hair); change in testicular hormone concentrations.

RESULTS

Ox-treated group had 20.5 times higher odds of reaching gonadarche (OR 95% CI: 6.5, 77.8) and 28.1 times higher odds of reaching pubarche (OR 95% CI: 8.8, 110.4) during the 2-year study period after adjusting for baseline age. Gonadarche and pubarche both occurred at a younger age in the Ox group (gonadarche: 9.8 ± 1.5 vs 12.1 ± 1.0 years, P < 0.001; pubarche: 10.2 ± 1.1 vs 11.6 ± 1.3 years, P = 0.02). Serum concentrations of testicular hormones and gonadotropins were not different between groups.

CONCLUSIONS

Two years of Ox treatment in prepubertal boys with KS results in an increased risk of early gonadarche, on average 2 years earlier than in Pl-treated boys. Ox did not affect serum concentrations of testicular hormones.

Klinefelter Syndrome: Integrating Genetics, Neuropsychology, and Endocrinology

Although first identified over 70 years ago, Klinefelter syndrome (KS) continues to pose substantial diagnostic challenges, as many patients are still misdiagnosed, or remain undiagnosed. In fact, as few as 25% of patients with KS are accurately diagnosed and most of these diagnoses are not made until adulthood. Classic characteristics of KS include small testes, infertility, hypergonadothropic hypogonadism, and cognitive impairment. However, the pathophysiology behind KS is not well understood, although genetic effects are also thought to play a role. For example, recent developments in genetics and genomics point to a fundamental change in our understanding of KS, with global epigenetic and RNA expression changes playing a central role for the phenotype. KS is also associated with more general health markers, including higher morbidity and mortality rates and lower socioeconomic status (which likely affect both morbidity and mortality). In addition, hypogonadism is associated with greater risk of metabolic syndrome, type 2 diabetes, cardiovascular disease, breast cancer, and extragonadal germ cell tumors. Medical treatment typically focuses on testosterone replacement therapy (TRT), although the effects of this therapy have not been studied rigorously, and future studies need to evaluate the effects of TRT on metabolic risk and neurocognitive outcomes. This review presents a comprehensive interdisciplinary examination of recent developments in genetic, endocrine, and neurocognitive science, including the study of animal models. It provides a number of recommendations for improving the effectiveness of research and clinical practice, including neonatal KS screening programs, and a multidisciplinary approach to KS treatment from childhood until senescence.

Transcriptome analysis of the adult human Klinefelter testis and cellularity-matched controls reveals disturbed differentiation of Sertoli- and Leydig cells

The most common human sex chromosomal disorder is Klinefelter syndrome (KS; 47,XXY). Adult patients with KS display a diverse phenotype but are nearly always infertile, due to testicular degeneration at puberty. To identify mechanisms causing the selective destruction of the seminiferous epithelium, we performed RNA-sequencing of 24 fixed paraffin-embedded testicular tissue samples. Analysis of informative transcriptomes revealed 235 differentially expressed transcripts (DETs) in the adult KS testis showing enrichment of long non-coding RNAs, but surprisingly not of X-chromosomal transcripts. Comparison to 46,XY samples with complete spermatogenesis and Sertoli cell-only-syndrome allowed prediction of the cellular origin of 71 of the DETs. DACH2 and FAM9A were validated by immunohistochemistry and found to mark apparently undifferentiated somatic cell populations in the KS testes. Moreover, transcriptomes from fetal, pre-pubertal, and adult KS testes showed a limited overlap, indicating that different mechanisms are likely to operate at each developmental stage. Based on our data, we propose that testicular degeneration in men with KS is a consequence of germ cells loss initiated during early development in combination with disturbed maturation of Sertoli- and Leydig cells.

Epigenetics in Turner syndrome

Background

Monosomy of the X chromosome is the most frequent genetic abnormality in human as it is present in approximately 2% of all conceptions, although 99% of these embryos are spontaneously miscarried. In postnatal life, clinical features of Turner syndrome may include typical dysmorphic stigmata, short stature, sexual infantilism, and renal, cardiac, skeletal, endocrine and metabolic abnormalities.

Main text

Turner syndrome is due to a partial or total loss of the second sexual chromosome, resulting in the development of highly variable clinical features. This phenotype may not merely be due to genomic imbalance from deleted genes but may also result from additive influences on associated genes within a given gene network, with an altered regulation of gene expression triggered by the absence of the second sex chromosome. Current studies in human and mouse models have demonstrated that this chromosomal abnormality leads to epigenetic changes, including differential DNA methylation in specific groups of downstream target genes in pathways associated with several clinical and metabolic features, mostly on autosomal chromosomes. In this article, we begin exploring the potential involvement of both genetic and epigenetic factors in the origin of X chromosome monosomy. We review the dispute between the meiotic and post-zygotic origins of 45,X monosomy, by mainly analyzing the findings from several studies that compare gene expression of the 45,X monosomy to their euploid and/or 47,XXX trisomic cell counterparts on peripheral blood mononuclear cells, amniotic fluid, human fibroblast cells, and induced pluripotent human cell lines. From these studies, a profile of epigenetic changes seems to emerge in response to chromosomal imbalance. An interesting finding of all these studies is that methylation-based and expression-based pathway analyses are complementary, rather than overlapping, and are correlated with the clinical picture displayed by TS subjects.

Conclusions

The clarification of these possible causal pathways may have future implications in increasing the life expectancy of these patients and may provide informative targets for early pharmaceutical intervention.

Aberrant ocular architecture and function in patients with Klinefelter syndrome

Klinefelter Syndrome (KS), the most common chromosomal disorder in men (47,XXY), is associated with numerous comorbidities. Based on a number of isolated case reports, we performed the first systematic and comprehensive evaluation of eye health in KS patients with a focus on ocular structure and vascularization. Twenty-one KS patients and 26 male and 38 female controls underwent a variety of non-invasive examinations investigating ocular morphology (examination of retinal thickness, optic nerve head, and cornea) and function (visual field testing and quantification of ocular vessel density by optical coherence tomography angiography). In comparison to healthy controls, KS patients exhibited a smaller foveal avascular zone and a decreased retinal thickness due to a drastically thinner outer nuclear layer. The cornea of KS patients showed a decreased peripheral thickness and volume. In perimetry evaluation, KS patients required brighter stimuli and gave more irregular values. KS patients show an ocular phenotype including morphological and functional features, which is very likely caused by the supernumerary X chromosome. Thus, KS should not be limited to infertility, endocrine dysfunction, neurocognitive and psychosocial comorbidities. Defining an aberrant ocular morphology and function, awareness for possible eye problems should be raised.

Fertility counseling and preservation: considerations for the pediatric endocrinologist

Infertility is a distressing consequence of numerous pediatric medical conditions and treatments. The field of pediatric fertility preservation has expanded rapidly over the past decade, and clinical guidelines emphasize the importance of discussing infertility risk and fertility preservation options with patients and families in a timely manner. Understanding the various mechanisms and presentations of fertility issues across diagnoses is imperative to provide counseling to patients and families, and identify individuals who may benefit from fertility preservation. The goals of this manuscript are to outline current fertility preservation options in pediatrics, review populations at-risk for infertility that are seen in pediatric endocrinology, and discuss other important issues related to fertility preservation including ethical considerations.

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.