Age, Sperm Retrieval, and Testicular Histology in Klinefelter Syndrome.

PURPOSE: We sought to examine sperm retrieval and testicular histology in males of different ages with Klinefelter syndrome. MATERIALS AND METHODS: We identified all males with Klinefelter syndrome who underwent microdissection testicular sperm extraction at our institution from 1995 to 2020. Patients were divided into adolescent (<20 years) and adult (≥20 years) cohorts. Histology and sperm retrieval were compared using chi-square statistics. Multivariable logistic regression models were used to examine factors associated with successful sperm retrieval. RESULTS: We identified 217 males with Klinefelter syndrome, of whom 59 were adolescents and 158 were adults. Adults were stratified into 10-year groupings (20-29 years, n = 62; 30-39 years, n = 88; ≥40 years, n = 8). Approximately 17% of adolescents had testis histology containing germ cells compared with 15% of the 20 to 29-year cohort, 14% of the 30 to 39-year cohort, and 0% over 40 years. In comparison to adolescents (53%), the sperm retrieval rate was significantly higher in the 20 to 29-year cohort (71%, P = .04) and lower in the ≥40-year cohort (13%, P = .03). In multivariable analysis, the presence of hypospermatogenesis on testis biopsy (OR 5.8, P = .03) was associated with higher odds of successful sperm retrieval. CONCLUSIONS: Younger males more frequently had germ cell-containing testis histology, however this finding was not associated with a higher odds of sperm retrieval. Reproductive urologists should counsel azoospermic males with Klinefelter syndrome that sperm retrieval during adolescence for fertility preservation is not required and can be performed in young adulthood.

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.

[Clinicopathological characteristics of Klinefelter syndrome: a testicular biopsy analysis of 87 cases].

Objective: To investigate the clinicopathological characteristics of testicular biopsies from Klinefelter syndrome (KS) patients. Methods: The testicular biopsy specimens of 87 patients with KS (a total of 107 biopsy specimens) were collected from the Department of Pathology, Peking University Third Hospital, Beijing, China from January 2017 to July 2022. All patients were diagnosed as KS by peripheral blood karyotyping analysis. The testicular histopathologic features, testicular volume and hormone levels were evaluated retrospectively. The histopathologic analysis was used to assess the quantity and morphology of Leydig cells, the spermatogenic state of seminiferous tubules, the thickening of the basement membrane of seminiferous tubules and the changes of stroma. Results: Leydig cell proliferative nodules were seen in 95.3% (102/107) of KS testicular biopsy tissues. The eosinophilic inclusion bodies and lipofuscin in Leydig cells were found in 52.3% (56/107) and 57.9% (62/107) of specimens, respectively. The Sertoli cell only seminiferous tubules and the hyalinized tubules were found in 66.4% (71/107) and 76.6% (82/107) of the examined tissues, respectively. The tubules with complete spermatogenic arrest were found in 15.9% (17/107) of specimens, and 5.6% (6/107) of the specimens showed low spermatogenesis or incomplete spermatogenic arrest. In 85.0% (91/107) of the specimens, increased thick-walled small vessels with hyaline degeneration were identified. Conclusions: The most common features of KS testicular specimens are Leydig cell proliferative nodules, hyaline degeneration of seminiferous tubules and proliferation of thick-walled blood vessels. Testicular biopsy specimens of KS are rare. The pathologists can make a tentative diagnosis of KS based on the histological findings, combined with the ultrasound and laboratory results, which is helpful for further diagnosis and treatment of KS.

Testicular Architecture of Men with 46,XX Testicular Disorders of Sex Development.

BACKGROUND: A subtype of disorders of sex development (DSD) in individuals with a 46,XX karyotype who are phenotypically male is classified as testicular DSD (46,XX TDSD). These individuals develop testes but are infertile due to germ cell loss. However, little is known about their testicular architecture. METHODS: We analyzed biopsies of four SRY positive 46,XX TDSD men for testicular architecture, Sertoli (SCs) and Leydig cells (LCs). These were compared with biopsies of men with normal spermatogenesis (NS, n = 4), men with Klinefelter syndrome, 47 XXY (KS, n = 4), and men with AZF deletions (AZF, n = 5). Testicular architecture was evaluated and SCs and LCs were analyzed for specific markers (SC: SOX9, DMRT1; LC: INSL3). RESULTS: A smaller number of tubules, more SOX9-negative but similar proportions of DMRT1-negative SCs were found in 46,XX TDSD compared to NS. The lower number of tubules and severe LC hyperplasia observed in 46,XX TDSD were similar to KS. CONCLUSION: Testicular architecture and marker expression of SCs and LCs in 46,XX TDSD men display unique patterns, which are discernable from chromosomal aneuploidies. Given the reduced Y-chromosomal gene content in 46,XX TDSD, the supernumerary X chromosome effects may be decisive regarding the damage on testicular composition and endocrine function.

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.

Clinicopathological characteristics of Klinefelter syndrome: a testicular biopsy analysis of 87 cases / 中华病理学杂志

Objective: To investigate the clinicopathological characteristics of testicular biopsies from Klinefelter syndrome (KS) patients. Methods: The testicular biopsy specimens of 87 patients with KS (a total of 107 biopsy specimens) were collected from the Department of Pathology, Peking University Third Hospital, Beijing, China from January 2017 to July 2022. All patients were diagnosed as KS by peripheral blood karyotyping analysis. The testicular histopathologic features, testicular volume and hormone levels were evaluated retrospectively. The histopathologic analysis was used to assess the quantity and morphology of Leydig cells, the spermatogenic state of seminiferous tubules, the thickening of the basement membrane of seminiferous tubules and the changes of stroma. Results: Leydig cell proliferative nodules were seen in 95.3% (102/107) of KS testicular biopsy tissues. The eosinophilic inclusion bodies and lipofuscin in Leydig cells were found in 52.3% (56/107) and 57.9% (62/107) of specimens, respectively. The Sertoli cell only seminiferous tubules and the hyalinized tubules were found in 66.4% (71/107) and 76.6% (82/107) of the examined tissues, respectively. The tubules with complete spermatogenic arrest were found in 15.9% (17/107) of specimens, and 5.6% (6/107) of the specimens showed low spermatogenesis or incomplete spermatogenic arrest. In 85.0% (91/107) of the specimens, increased thick-walled small vessels with hyaline degeneration were identified. Conclusions: The most common features of KS testicular specimens are Leydig cell proliferative nodules, hyaline degeneration of seminiferous tubules and proliferation of thick-walled blood vessels. Testicular biopsy specimens of KS are rare. The pathologists can make a tentative diagnosis of KS based on the histological findings, combined with the ultrasound and laboratory results, which is helpful for further diagnosis and treatment of KS.

Transcriptomic differences between fibrotic and non-fibrotic testicular tissue reveal possible key players in Klinefelter syndrome-related testicular fibrosis.

Klinefelter syndrome (KS; 47,XXY) affects 1-2 in 1000 males. Most men with KS suffer from an early germ cell loss and testicular fibrosis from puberty onwards. Mechanisms responsible for these processes remain unknown. Previous genomics studies on testis tissue from men with KS focused on germ cell loss, while a transcriptomic analysis focused on testicular fibrosis has not yet been performed. This study aimed to identify factors involved in the fibrotic remodelling of KS testes by analysing the transcriptome of fibrotic and non-fibrotic testicular tissue. RNA sequencing was performed to compare the genes expressed in testicular samples with (KS and testis atrophy) and without (Sertoli cell-only syndrome and fertile controls) fibrosis (n = 5, each). Additionally, differentially expressed genes (DEGs) between KS and testis atrophy samples were studied to reveal KS-specific fibrotic genes. DEGs were considered significant when p < 0.01 and log2FC > 2. Next, downstream analyses (GO and KEGG) were performed. Lastly, RNA in situ hybridization was performed to validate the results. The first analysis (fibrotic vs non-fibrotic) resulted in 734 significant DEGs (167 up- and 567 down-regulated). Genes involved in the extracellular structure organization (e.g. VCAM1) were found up-regulated. KEGG analysis showed an up-regulation of genes involved in the TGF-ß pathway. The KS vs testis atrophy analysis resulted in 539 significant DEGs (59 up- and 480 down-regulated). Chronic inflammatory response genes were found up-regulated. The overlap of X-linked DEGs from the two analyses revealed three genes: matrix-remodelling associated 5 (MXRA5), doublecortin (DCX) and variable charge X-Linked 3B (VCX3B). RNA in situ hybridization showed an overexpression of VCAM1, MXRA5 and DCX within the fibrotic group compared with the non-fibrotic group. To summarize, this study revealed DEGs between fibrotic and non-fibrotic testis tissue, including VCAM1. In addition, X-linked fibrotic genes were revealed, e.g. MXRA5, DCX and VCX3B. Their potential role in KS-related testicular fibrosis needs further study.

Testicular biopsy for fertility preservation in early-diagnosed Klinefelter patients: patient characteristics and long-term follow-up.

RESEARCH QUESTION: Which early-diagnosed Klinefelter syndrome patients have been offered cryopreservation of testicular tissue as part of fertility preservation before spermatogonial stem cell (SSC) loss? Do these Klinefelter syndrome patients present with behavioural, cognitive and/or psychological problems? Does a testicular biopsy procedure have long-term effects on the gonadal development of Klinefelter syndrome patients? DESIGN: Early-diagnosed Klinefelter syndrome patients followed between 2009 and 2020 and offered testicular tissue banking in an experimental context at the Universitair Ziekenhuis Brussel were included. The prevalence of behavioural, cognitive and/or psychological problems was determined. Changes in testicular volume and in gonadal function (LH, FSH, testosterone and inhibin B [INHB]) were studied. RESULTS: Of the 48 Klinefelter syndrome patients included, 22 had testicular tissue removed (biopsy group) and 26 had no surgical intervention (control group). The need for specialized education was significantly higher in prenatally (P = 0.0159) and prepubertally (P = 0.0002) diagnosed Klinefelter syndrome patients. Psychological problems were significantly more prevalent in Klinefelter syndrome patients who did not opt for fertility preservation (P = 0.0447). In the first 4.2 (1.9-9.1) years after testicular biopsy, no difference in testicular volume was observed between the biopsied and the contralateral non-biopsied testes (P > 0.9999). After pubertal onset, no differences in LH, FSH, testosterone and INHB were found between the biopsy and the control groups (P = 0.1324 for LH, P > 0.9999 for FSH, P = 0.5433 for testosterone, P > 0.9999 for INHB). CONCLUSION: Early-diagnosed Klinefelter syndrome patients presented with behavioural, cognitive and/or psychological problems. Only psychological problems seemed to influence the decision towards fertility preservation. Follow-up data confirm that harvesting testicular tissue does not have a long-term impact on the gonadal development of Klinefelter syndrome patients.

Intratesticular xenografting of Klinefelter pre-pubertal testis tissue as potential model to study testicular fibrosis.

RESEARCH QUESTION: Is intratesticular xenotransplantation a potential ex-vivo model for studying testicular fibrosis related to Klinefelter syndrome? STUDY DESIGN: First, a feasibility study of an ex-vivo model to study testicular fibrosis in patients with Klinefelter syndrome was performed. Testis tissue from boys with pre-pubertal Klinefelter syndrome (n = 3) and controls (n = 2) (<18 years) was grafted to the mouse testis (n = 12) and recovered after 2, 4, 6 and 8 weeks. Part two of this study consisted of a validation of this model, evaluating the effects of the mast cell blocker ketotifen on the histology of the grafts of Klinefelter syndrome (n = 5) and controls (n = 3), transplanted to mice (n = 10), after 4 weeks of ketotifen or saline treatment. Immunohistochemistry determined the histology of the grafts and the presence of mast cells and spermatogonia. RESULTS: The feasibility study showed that 4 weeks after transplantation, all Klinefelter syndrome grafts could be recovered. Later, degeneration was observed. Most recovered grafts showed an intact histology, with 67 ± 12% intact tubules for the Klinefelter syndrome grafts and 65 ± 15% of intact tubules for the control grafts. In the few remaining Klinefelter syndrome grafts, treatment with ketotifen improved testicular histology compared with non-treated grafts. Graft survival was patient dependent. No germ cell loss was observed after transplantation. CONCLUSION: Xenografting could become a model for the longitudinal study of the fibrotic process related to Klinefelter syndrome; however, the current model has a limited survival period and patient-specific differences in histology.

Z-scores for comparative analyses of spermatogonial numbers throughout human development.

OBJECTIVE: To normalize age-dependent effects on standardized measures of spermatogonial quantity such as the number of spermatogonia per tubular cross-section (S/T) or fertility index. DESIGN: Published quantitative histologic data on human spermatogonial numbers were used to create Z-scores for reference means and tested on archived testicular tissue samples. SETTING: Retrospective cohort study. PATIENT(S): The sample cohort comprised testicular samples from 24 boys with cancer diagnosis and 10 with Klinefelter syndrome, as part of the fertility preservation programs NORDFERTIL and Androprotect, as well as archived histologic samples from 35 prepubertal boys with acute lymphoblastic leukemia and 20 testicular biobank samples. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Z-score values for S/T and fertility index on the basis of morphology and germ cell-specific markers (MAGEA4 and/or DDX4) were calculated, and the impact of cancer therapy exposure and genetic disorders on Z-score values was evaluated. RESULT(S): The Z-scores for S/T values in the nontreated samples (-2.08 ± 2.20, n = 28) and samples treated with nonalkylating agents (-1.90 ± 2.60, n = 25) were comparable within ±3 standard deviations of the reference mean value but differed significantly from samples exposed to alkylating agents (-12.14 ± 9.20, n = 22) and from patients with Klinefelter syndrome (-11.56 ± 4.89, n = 8). The Z-scores for S/T were correlated with increasing cumulative exposure to alkylating agents (r = -0.7020). CONCLUSION(S): The Z-score values for S/T allow for the quantification of genetic and cancer treatment-related effects on testicular tissue stored for fertility preservation, facilitating their use for patient counseling.

Relationship between testicular histopathology and the success of testicular sperm extraction in patients with non-mosaic Klinefelter syndrome / Relación entre la histopatología testicular y el éxito de la extracción de espermatozoides testiculares de pacientes con síndrome de Klinefelter sin mosaicismo

OBJECTIVE: To investigate the effect of testicular histopathology on the success of microscopic testicular sperm extraction (mTESE) and the factors that could predict the success of mTESE in patients with non-mosaic Klinefelter syndrome (KS). MATERIAL AND METHODS: Forty-one KS patients diagnosed with non-obstructive azoospermia (NOA) who had undergone mTESE at our clinic were included in the study. The patients were divided into 5 groups according to the histopathology results: hyalinisation of tubules (HT), sertoli cell only (SCO), early maturation arrest (EMA), late maturation arrest (LMA), and hypospermatogenesis (HS). The groups were compared with regard to age, duration of infertility, hormone profile, testicular volume, and sperm retriveal rate. The clinical features of the patients with mTESE from whom sperm could or could not be obtained were also compared with the aim of investigating the predictive value of testicular histopathology and the other variables for prediction of the success of mTESE. RESULTS: Sperm could be obtained through mTESE in 13 out of 41 patients (31.7%). A statistically significant difference was determined between the groups with regard to the rate of sperm collection. No significant difference was determined between the histopathology groups with regard to the other variables. A statistically significant difference was determined between the groups from whic sperm could be collected or not with regard to age, Johnsen criteria, SCO, EMA and LMA variables. Multi-variate analysis revealed that age and Johnsen score were the independent variables predictive for success of mTESE. CONCLUSION: The present study has revealed that impairment in testicular histopathology negatively affects the success of mTESE and that it is a predictive factor for the success of mTESE in patients with KS. Increased patient age was also determined to negatively affect the success of mTESE and the operation was demonstrated to be more successful before 34 years of age

OBJETIVO: Estudiar el efecto de la histopatología testicular en el éxito de la extracción microscópica de espermatozoides testiculares (EETm) y los factores que podrían pronosticar el éxito de la EETm en pacientes con síndrome de Klinefelter (SK) sin mosaicismo. MATERIAL Y MÉTODOS: En el estudio se incluyó a 41 pacientes con SK diagnosticados de azoospermia no obstructiva (ANO) a quienes se les había realizado la EETm en nuestra clínica. Se dividió a los pacientes en 5 grupos, de acuerdo con los resultados de la histopatología: hialinización de túbulos (HT), células de Sertoli solamente (SCS), detención de la maduración temprana (DMT), detención de la maduración tardía (DMTa) e hipoespermatogénesis (HS). En los grupos se compararon la edad, la duración de la infertilidad, el perfil hormonal, el volumen testicular y la tasa de recuperación de esperma. También se compararon las características clínicas de los pacientes con EETm de los que se pudo obtener esperma o no con el objetivo de estudiar el valor pronóstico de la histopatología testicular y otras variables para pronosticar el éxito de la EETm. RESULTADOS: Se pudo obtener esperma a través de la EETm de 13 de 41 pacientes (31,7%). Se estableció una diferencia estadísticamente importante entre los grupos respecto a la tasa de recolección de esperma. No se estableció ninguna diferencia importante entre los grupos de histopatología respecto a las otras variables. Se estableció una diferencia estadísticamente importante entre los grupos de los cuales se pudo recolectar esperma o no respecto a la edad, a los criterios de Johnsen, SCS, DMT y DMTa. El análisis multivariante reveló que la edad y la puntuación de Johnsen fueron las variables independientes pronósticas del éxito de la EETm. CONCLUSIÓN: El presente estudio ha revelado que el deterioro de la histopatología testicular afecta negativamente al éxito de la EETm, y que es un factor pronóstico para el éxito de la EETm en pacientes con SK. También se estableció que el aumento de la edad del paciente afectaba negativamente al éxito de la EETm, y se demostró que la operación tenía más éxito cuando se realizaba antes de los 34 años

The contribution of Xp22.31 gene dosage to Turner and Klinefelter syndromes and sex-biased phenotypes.

Turner syndrome (TS) is a rare developmental condition in females caused by complete, or partial, loss of the second sex chromosome; it is associated with a number of phenotypes including short stature, ovarian failure and infertility, as well as neurobehavioural and cognitive manifestations. In contrast, Klinefelter syndrome (KS) arises from an excess of X chromosome material in males (typical karyotype is 47,XXY); like TS, KS is associated with infertility and hormonal imbalance, and behavioural/neurocognitive differences from gonadal sex-matched counterparts. Lower dosage of genes that escape X-inactivation may partially explain TS phenotypes, whilst overdosage of these genes may contribute towards KS-related symptoms. Here, I discuss new findings from individuals with deletions or duplications limited to Xp22.31 (a region escaping X-inactivation), and consider the extent to which altered gene dosage within this small interval (and of the steroid sulfatase (STS) gene in particular) may influence the phenotypic profiles of TS and KS. The expression of X-escapees can be higher in female than male tissues; I conclude by considering how lower Xp22.31 gene dosage in males may increase their likelihood of exhibiting particular phenotypes relative to females. Understanding the genetic contribution to specific phenotypes in rare disorders such as TS and KS, and to more common sex-biased phenotypes, will be important for developing more effective, and more personalised, therapeutic approaches.

Central hypogonadism in Klinefelter syndrome: report of two cases and review of the literature.

PURPOSE: Klinefelter syndrome (KS) is characterized by late adolescence/young adulthood onset of primary hypogonadism. Hypogonadotropic hypogonadism (HH), when congenital, is usually associated with absent/incomplete puberty and low/normal gonadotropins. We report the clinical and genetic features of two subjects with KS and an unexpected HH hormone profile. METHODS: Magnetic resonance imaging (MRI) of hypothalamus-pituitary region and next generation sequencing (NGS) of congenital HH-associated genes were obtained. A narrative review of the literature was conducted. RESULTS: Patients were diagnosed with Klinefelter syndrome following karyotype analysis. Nevertheless, they showed unusual features: both had incomplete puberty, low gonadotropins and testosterone levels, and the first one was anosmic. Sellar lesions were excluded by MRI, and NGS was negative in both subjects. Our data add to those of the only 14 similar cases reported so far. Unexplained HH rarely occurs in KS and is variably associated with anosmia, other pituitary hormones deficiencies and heterogeneous karyotypes. However, most cases show an early, pre-pubertal onset of hypogonadism. If the causes behind this gonadotropins defect are largely unknown, hereby we provide the first review of the literature on this topic and propose some pathogenetic hypotheses, including the coexistence of KS and congenital HH as suggested by overlapping clinical features in some of these patients. CONCLUSION: HH is an exceptional occurrence in Klinefelter syndrome and is associated with heterogeneous phenotypes and, probably, aetiologies. Moreover, KS could underlie HH nonresponsive to gonadotropins. An exhaustive diagnostic workup and a tailored clinical management are advisable in these rare forms.

Genital malformation: Trigger of the diagnosis of severe variants of Klinefelter syndrome. / Malformación genital: Disparador del diagnóstico de variantes severas de síndrome de Klinefelter.

INTRODUCTION: Among the disorders of sexual development, Klinefelter syndrome and its variants are classified as an alteration in the number of sex chromosomes. These patients show signs of hypergonadotropic hypogonadism at puberty, however cases of severe variants also present neurocognitive and language problems from an early age. OBJECTIVE: To describe two patients with genital malformation with genetic diagnosis of severe variants of Klinefelter syndrome, and to review clinical and therapeutic aspects. CLINICAL CASES: Case 1: Diagnosis of atypical genitalia at birth: Small and curved phallus with the urethral meatus at scrotal level, and bifid scrotum. No other somatic abnormality was observed, except for subtle clinodactyly of the fifth finger. Karyotype: 49, XXXXY. At one year of life, genitalia were reconstructed. The patient presented a global developmental delay, mainly in language, which was managed with early stimulation and speech and language therapy since he was two months old. Finally, he was able to attend kindergarten. Case 2: At one month of life, a small and severe curved phallus (more than 70°) was observed, and testicles were in the scrotum. Karyotype: 48, XXYY. At one year of life, the penile malformation was corrected. The patient presented global developmental delay, mainly in expressive language which was managed with early stimulation since the age of four months, achieving kindergarten attendance. CONCLUSION: Genital malformations led to the diagno sis of severe variants of Klinefelter syndrome, and were corrected around the year of life. The early identification of these variants allowed the intervention of the neurostimulation team, favoring the neurocognitive development and social integration of these children.

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.

High prevalence of cardiometabolic risk features in adolescents with 47,XXY/Klinefelter syndrome.

Klinefelter syndrome (KS) occurs in 1:600 males and is associated with high morbidity and mortality due to diabetes and cardiovascular disease. Up to 50% of men with KS have metabolic syndrome, a cluster of features conferring increased risk for diabetes and cardiovascular disease. These cardiometabolic (CM) risk features have not been studied in adolescents with KS. The objective of this cohort study was to compare CM risk features in adolescents with KS to controls matched for sex, age, and BMI z score. Fifty males with KS (age 10-17 years) were well-matched to male controls (n = 50) for age (14.0 ± 1.7 vs. 14.0 ± 1.5 years) and BMI z score (0.3 ± 1.3 vs. 0.4 ± 1.2). Three CM risk features were present in 30% of adolescents with KS compared to 12% of controls (RR 2.5, 95% CI 1.1-5.9, p = .048). The KS group had significantly lower HDL cholesterol (p = .006), higher triglycerides (p < .001), and greater waist circumference percentile (p < .001). Despite a normal BMI, the prevalence of CM risk features was very high in adolescents with KS, particularly for central adiposity and dyslipidemia. The pathophysiology of this metabolic profile independent of obesity needs further investigation to facilitate prevention of the high morbidity of cardiovascular disease and diabetes in this population. ClinicalTrials.gov identifiers: NCT01585831 and NCT02723305.

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.

Epigenetics and genomics in Klinefelter syndrome.

Since the first description of Klinefelter syndrome (KS) was published in 1942 in The Journal of Clinical Endocrinology, large inter-individual variability in the phenotypic presentation has been demonstrated. However, our understanding of the global impact of the additional X chromosome on the genome remains an enigma. Evidence from the existing literature of KS indicates that not just one single genetic mechanism can explain the phenotype and the variable expressivity, but several mechanisms may be at play concurrently. In this review, we describe different genetic mechanisms and recent advances in the understanding of the genome, epigenome, and transcriptome of KS and the link to the phenotype and clinical heterogeneity. Future studies are needed to unite clinical data, genomic data, and basic research attempting to understand the genetics behind KS. Unraveling the genetics of KS will be of clinical relevance as it may enable the use of polygenic risk scores to predict future disease susceptibility and enable clinical risk stratification of KS patients in the future.