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Introduction: There is increasing evidence that gender dysphoria (GD) is more prevalent in the Klinefelter Syndrome (KS) population than in males in the general population; however, the exact incidence is uncertain. The aim of this study was to further explore the prevalence of gender-related issues, the role that physical characteristics play in gender identity, and the issues surrounding Hormone Replacement Therapy (HRT) in KS., Methods: As part of a registered Quality Improvement Project (QIP), one online 23-point questionnaire on KS patient attitudes toward gender identity was shared with members of the Klinefelter Syndrome Association (KSA). In total, 139 anonymous responses were collected between December 2021 and January 2023. The questionnaire was developed with the guidance of multiple clinicians (including gender psychiatrists, urologists, psychosexual medicine specialists, and endocrinologists) and patient Delphi rounds. Data was reviewed and analyzed by 4 independent researchers within the QIP team., Results: Only 53% of KS patients responding to this survey fully identified as male and 19% stated that they did not enjoy living as the sex on their birth certificate, with 43% considering changing aspects of their physical appearance to better match their gender. Regarding HRT, 67% of respondents were receiving Testosterone Replacement Therapy (TRT). 63% wanted TRT and 17% wanted estrogen, including 6% of TRT users who would prefer estrogen instead. 36% that were currently receiving TRT did not identify as male, and 3 participants stated that they have GD., Conclusion: These results indicate that a significant proportion of KS patients do not fully identify with the male gender and are unhappy living as the sex on their birth certificate. Although TRT worked for most, its use should be discussed carefully with those with gender identity concerns.

Context: Klinefelter syndrome (KS) is associated with hypergonadotropic hypogonadism, which contributes to characteristic phenotypical manifestations including metabolic alterations. Extensive research has demonstrated important associations between androgens and liver function., Objectives: Investigation of the association between metabolic parameters, sex hormones and liver function in males with KS, both treated (T-KS) and untreated (U-KS) and healthy control males., Methods: A total of 65 KS males were recruited, of which 32 received testosterone replacement therapy (TRT). Also, 69 healthy controls were recruited. We used alanine aminotransferase (ALAT), alkaline phosphatase and PP (prothrombin-proconvertin time ratio) as the main liver markers. Multivariable regression was performed within the three groups. All statistics were calculated using STATA. Principal component analysis was utilized to demonstrate the interconnected patterns among all measured biomarkers, and to elucidate how the different groups were linked to these patterns., Results: Higher levels of main liver markers were observed in U-KS compared to controls, with no significant differences between U-KS and T-KS. T-KS had lower abdominal fat, total cholesterol, and LDL cholesterol than U-KS. Using multivariable models, variation in ALAT in U-KS was explained by HOMA2%S; in T-KS by BMI and SHBG; and in controls by hip circumference and estradiol. We found no multivariable models explaining variation in PP in U-KS; in T-KS, PP was explained by BMI and LDL cholesterol, and in controls by total cholesterol. Using principal component analysis U-KS was positively associated to D1 (an obese profile, which also included ALAT) and controls negatively associated with D1 (non-obese profile)., Conclusion: KS males have mild liver dysfunction reflected by a significant increase in the main liver markers and decrease in albumin. The presented data underscore a primary role of metabolic conditions including obesity, insulin resistance and unfavourable lipid profile, in the elevated liver function markers seen in males with KS. Whether TRT can improve liver function in KS warrants further studies. Our findings, highlight that an evaluation of the liver function should be part of the clinical care in males with KS., (© 2024. The Author(s).)

Purpose: The role of osteocalcin (OCN) in pubertal development, male hypogonadism, and the effect of testosterone (Te) replacement therapy (TRT) remains unclear. We aimed to investigate the total OCN (tOCN) concentrations in male patients with Klinefelter syndrome (KS), a model of adult hypergonadotropic hypogonadism., Methods: This retrospective longitudinal study investigated 254 male patients with KS (47,XXY) between 2007 and 2021 at an academic referral center, categorized as (1) prepubertal, (2) pubertal, and (3) adults. All prepubertal patients were Te-naïve. Adult patients were subcategorized as (1) eugonadal, (2) hypogonadal, and (3) receiving TRT. We also analyzed 18 adult patients with available tOCN levels before and 3 months after TRT commencement., Results: The tOCN levels varied throughout the lifespan according to pubertal status, were highest in eugonadal and significantly lower in TRT subjects, correlated with both LH (p = 0.017) and FSH levels (p = 0.004) in adults, and significantly declined after 3 months of TRT (p = 0.006) in the adult KS cohort. HPG-axis hormones levels demonstrated no correlation in prepubertal boys. Adjustment for age and body mass index confirmed previous results and revealed significant inverse correlations with total Te (p = 0.004), calculated free Te (p = 0.016), the Te/LH (p = 0.010), and calculated free Te/LH ratios (p = 0.031)., Conclusion: In KS, a model of male hypergonadotropic hypogonadism, tOCN levels were not associated with gonadal function during normal prepuberty and pubertal development but were associated with worse testicular function and a higher degree of HPG stimulation in adults. TRT acutely reduced tOCN levels in adults., (© 2024. The Author(s).)

Managing patients unable to produce sex steroids using gonadotropins to mimic minipuberty in hypogonadotropic hypogonadism, or sex steroids in patients with Klinefelter or Turner syndrome, is promising. There is a need to pursue research in this area, with large prospective cohorts and long-term data before these treatments can be routinely considered., Competing Interests: Disclosure The authors declare no conflict of interest regarding the content of this article., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Men with Klinefelter syndrome (KS) develop hypergonadotropic hypogonadism, are in need of testosterone replacement therapy (TRT), and present with a more than 4-fold increased risk of thrombosis. TRT in KS has the potential to modify thrombotic risk, but data are scarce., Aim: To assess effects of 18 months of TRT on hemostasis in KS and identify genes associated with the prothrombotic phenotype., Methods: Untreated and TRT-treated men with KS were included at baseline and matched to healthy controls. TRT was initiated in untreated KS and all groups were reassessed after 18 months of follow-up. Thrombin generation was evaluated with or without thrombomodulin, and fibrin clot lysis was evaluated by turbidity measurements. RNA expression was assessed in blood, fat, and muscle tissue of patients with TRT-treated KS and controls., Results: Thrombin generation with thrombomodulin was slightly increased in untreated KS, but overall KS was not associated with a hypercoagulable state. KS presented with fibrinolytic impairment associated with higher body fat and higher levels of fibrinogen. Eighteen months of TRT in KS was associated with a reduction in body fat and fibrinogen, attenuating the prothrombotic profile. The expression of ENPP4 was higher in men with KS and served as a key player among a group of genes associated with impaired fibrinolysis., Conclusion: KS is associated with a specific expression profile contributing to fibrinolytic impairment and increased thrombotic risk in the patients. TRT in patients with KS has the potential for alleviating the prothrombotic phenotype, in particular by reducing body fat and fibrinogen., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Klinefelter's syndrome (KS) was once considered infertile due to congenital chromosomal abnormalities, but the presence of focal spermatozoa changed this. The key to predict and promote spermatogenesis is to find targets that regulate focal spermatogenesis., Objective: To explore the trend of fertility changes in KS patients at different ages and identify potential therapeutic targets., Methods: Bibliometric analysis was used to collect clinical research data on KS from the Web of Science Core Collection (WoSCC) from 1992 to 2022. A cross-sectional study was conducted on 75 KS patients who underwent microscopic testicular sperm extraction (mTESE) from 2017 to 2022 in the real world. The reproductive hormones, testicular histopathology, androgen receptors, insulin-like factor 3 (INSL3) receptors and sperm recovery rate (SRR) were analyzed., Results: Male infertility, dysplasia, Sertoli cells, Leydig cells, testosterone and spermatogenesis were the research focuses related to KS. Luteinizing hormone (LH), testosterone, and INSL3 were evaluation indicators of Leydig cell function that fluctuate with age. Testosterone and LH peaked at ages 13-19 and 30-45, while INSL3 only peaked at ages 13-19. 27 patients (27/75) recovered sperm through mTESE and experienced SRR peaks at the ages of 20, 28, 34, and 37. The SRR of fibrosis patients was 46.15%, fatty degeneration was 7.14%, and melanosis was 40.00%. The INSL3 and androgen receptors were highly expressed and roughly balanced in focal spermatogenesis., Conclusion: Abnormal metabolism of Leydig cells led to imbalanced expression of INSL3 and androgen receptors, which might be a potential target for spermatogenesis in KS., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Liu, Zhang, Gao, Lin, Zhu, Zheng, Ye, Luo, Qing, Xiao, Hu, Zhou and Zhang.)

Background: Although Klinefelter syndrome (KS) is the most frequent sex-hormone disorder, there is ongoing uncertainty about the often associated sex-hormone deficiency, its impact on common comorbidities, and therefore about prevention and treatment. In this study, we focus on bone loss, reported to occur in over 40% of KS patients, and the impact of testosterone replacement therapy (TRT) on this comorbidity., Objectives: This single-center retrospective cohort study in a tertiary hospital compared the effect of treatment with TRT to no TRT on evolution of bone mineral density (BMD) in KS patients., Methods: After a medical chart review, a total of 52 KS subjects were included in this study. BMD was measured by dual-energy X-ray absorptiometry (DXA) and expressed as T-scores., Results: The subjects were divided into three groups, according to TRT. In the subgroup that only started TRT after baseline measurements (mean age 31 years), we observed significant gain in BMD T-score at the lumbar spine (0.58 ± 0.60, p = 0.003; mean gain of 0.62% areal BMD per year) and total femur T-score (0.24 ± 0.39, p = 0.041; mean gain of 0.25% areal BMD per year) after a mean follow-up period of 7.5 years. Compared to untreated subjects, a significant difference in evolution was demonstrated at the lumbar level (+0.58 ± 0.60 vs. -0.14 ± 0.42, p = 0.007). In untreated subjects with normal testosterone levels, a loss of BMD (-0.27 ± 0.37, p = 0.029; mean loss of 0.49% areal BMD per year) at the femoral neck was measured. This decline was equal to the predicted loss seen in the general male population., Conclusion: TRT results in BMD gain in patients with KS with testosterone deficiency, mainly at the lumbar spine. However, this effect is limited (0.62% per year). Patients who were not treated with TRT because of sufficient endogenous testosterone levels, showed only the predicted age-related bone loss during follow-up. The need for TRT in maintaining bone health in KS should be evaluated on an individual basis according to the degree of sex steroid deficiency., (© 2023 American Society of Andrology and European Academy of Andrology.)

Objective: Klinefelter syndrome is the most common chromosomal disorder in males and the most common cause of hypergonadotropic hypogonadism. We describe the natural history of testicular dysfunction in patients with Klinefelter syndrome through the integration of clinical, hormonal, and quantitative ultrasound data in a life-course perspective., Design: Prospective semilongitudinal study., Methods: We included 155 subjects with 47,XXY karyotype (age range: 7 months-55 years) naïve to testosterone replacement therapy. Subjects were divided according to pubertal stage and age group (transition age and adults). Serial clinical, hormonal, and testicular ultrasound (US) assessments were performed., Results: Testicular development progresses until Tanner stage 4, with subsequent regression, whereas Sertoli and germ cell impairment is not hormonally detected before Tanner stages 3-4, as reflected by normal inhibin B values until stage 4 and the fall in the inhibin B/follicle-stimulating hormone ratio thereafter. The testosterone/luteinizing hormone ratio peaks during Tanner stages 2-3 and declines from Tanner stage 4 onward, preceding the development of overt hypogonadism. US echotexture progressively worsens until transition age, reflecting ongoing gonadal compromise, whereas quantitative US echotexture measures and the presence of both hypoechoic lesions and microlithiasis independently and significantly predict a lower circulating testosterone level., Conclusions: The findings from this large prospective study contribute to our understanding of the natural history of testicular dysfunction in Klinefelter syndrome, underlining the importance of quantitative testicular US in infancy and childhood, as well as during pubertal development and transition age, for the optimal care of Klinefelter syndrome patients., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society.)

47,XXY, also known as Klinefelter syndrome, is the most commonly occurring sex chromosomal aneuploidy (SCA). Hormonal replacement therapy (HRT) has been associated with improved neurodevelopmental capabilities in boys with 47,XXY, although studies investigating HRT's possible positive effect on behavioral outcomes are scarce. This study explores the association between behavioral outcomes and HRT in boys ages 7-12. Patients were divided into 4 groups based on HRT status: untreated, early hormonal treatment (EHT), hormonal booster therapy (HBT), and both EHT and HBT. Analysis of Variance (ANOVA) and Kruskal-Wallis tests were conducted to determine group differences on the Child Behavior Checklist (CBCL) and the Behavior Rating Inventory of Executive Function (BRIEF). The treated groups were found to have better scores in emotional control, initiative, organization of materials, behavioral rating index, metacognition index, and global executive composite than the untreated group on the BRIEF. On the CBCL, the treated groups presented better scores for somatic complaints, social problems, thought problems, attention problems, aggressive behavior, internalizing problems, total problems, affective problems, somatic problems, ADHD problems, oppositional defiant problems, and sluggish problems in comparison to the untreated group. These results offer evidence that HRT, specifically the combination of both EHT and HBT, may be successful in mitigating some undesirable behavioral outcomes. Further research is necessary to determine the efficacy of the combination of EHT and HBT regarding dosage, specific ages, and long-term benefits.

Background: Men with Klinefelter syndrome (KS) are routinely offered testosterone replacement therapy (TRT) suggested to potentially promote platelet aggregation and increase cardiovascular risk., Objective: We investigated platelet aggregation in men with KS before and during TRT., Materials and Methods: Forty-one adult men with KS participated, of which 20 had no history of TRT at baseline, with 15 completing follow-up after 18 months TRT. Further, we included 21 adult men with KS on long-term TRT (>10 years) and a male reference population. We assessed platelet impedance aggregometry using adenosine diphosphate (6.5 μM), thrombin-receptor-activating-peptide-6 (TRAP 32 μM), and arachidonic acid (ASPI 0.5 mM) as agonists in KS compared to a male reference population and stratified by route of TRT administration., Results: Platelet aggregation among men with KS at baseline or during TRT was not increased compared with the male reference population. For all three agonist, no change was seen in platelet aggregation in KS at follow-up compared with baseline (p ≥ 0.2). Platelet aggregation was not associated with total testosterone and furthermore, platelet count was not affected by treatment with testosterone. Men with KS treated with testosterone gel showed slightly increased TRAP- and ASPI-induced platelet aggregation compared with those treated with testosterone injection (p = 0.02 and p = 0.04, respectively)., Discussion and Conclusions: We observed normal platelet aggregation in men with KS before TRT and following both short and long term treatment. Our findings do not support an independent role of platelets in driving the cardiovascular risk in KS., (© 2022 The Authors. Andrology published by Wiley Periodicals LLC on behalf of American Society of Andrology and European Academy of Andrology.)

Although Klinefelter syndrome (KS) is common, it is rarely recognised in childhood, sometimes being identified with speech or developmental delay or incidental antenatal diagnosis. The only regular feature is testicular dysfunction. Postnatal gonadotropin surge (mini-puberty) may be lower, but treatment with testosterone needs prospective studies. The onset of puberty is at the normal age and biochemical hypogonadism does not typically occur until late puberty. Testosterone supplementation can be considered then or earlier for clinical hypogonadism. The size at birth is normal, but growth acceleration is more rapid in early and mid-childhood, with adult height greater than mid-parental height. Extreme tall stature is unusual. The incidence of adolescent gynaecomastia (35.6%) is not increased compared with typically developing boys and can be reduced or resolved by testosterone supplementation, potentially preventing the need for surgery. Around two-thirds require speech and language therapy or developmental support and early institution of therapy is important. Provision of psychological support may be helpful in ameliorating these experiences and provide opportunities to develop strategies to recognise, process and express feelings and thoughts. Boys with KS are at increased risk of impairment in social cognition and less accurate perceptions of social emotional cues. The concept of likely fertility problems needs introduction alongside regular reviews of puberty and sexual function in adolescents. Although there is now greater success in harvesting sperm through techniques such as testicular sperm extraction, it is more successful in later than in early adolescence. In vitro maturation of germ cells is still experimental., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

While approximately half of adult Klinefelter syndrome (KS) patients have retrievable sperm on micro testicular sperm extraction, success is limited by testicular hyalinization beginning at puberty. Recent surgical and laboratory advances lend themselves to experimental fertility preservation in appropriately selected adolescent KS patients., (Copyright © 2022 European Association of Urology. Published by Elsevier B.V. All rights reserved.)

Purpose: The purpose of this study was to delineate the effects of variable hormone replacement therapies on neuromotor function in a large cohort of males with 47,XXY from birth to adulthood., Methods: A total of 270 participants aged 16 days to 17 years 11 months prenatally diagnosed with 47,XXY were assessed by their pediatric endocrinologist and were administered hormone replacement therapies accordingly. Infants and school-aged children with 47,XXY were administered neuromotor assessments during routine neurodevelopmental evaluations. For statistical analysis, participants were segregated on the basis of treatment status. Two-tailed t tests, 1-way analysis of variance, and post hoc analysis determined significant group differences on each assessment., Results: In infants, the early hormonal treatment (EHT) group performed significantly better than the untreated group on fine motor and motor composite domains. In school-aged children, we observed significantly improved scores on fine motor control, coordination, agility, and strength domains among males treated with EHT (or any combination thereof) compared with those who did not receive early treatment., Conclusion: The highest treated combination group was associated with the highest neuromotor function, although the EHT group also often performed better than the other groups. This suggests EHT may be essential in promoting long-term optimal neuromotor outcome in males with an additional X., Competing Interests: Conflict of Interest The authors declare no conflicts of interest., (Copyright © 2022 American College of Medical Genetics and Genomics. Published by Elsevier Inc. All rights reserved.)

Objective: Klinefelter syndrome (KS) (47,XXY and variants, KS) is the most common sex chromosome disorder in humans. However, little is known about the onset and progression of puberty in patients with KS. In this study, we describe the onset and progression of puberty in a large series of boys with KS in a single tertiary centre., Design and Patients: Retrospective data (Tanner stages, testicular length, testosterone supplementation, levels of luteinizing hormone [LH] and testosterone) before possible testosterone treatment on 72 KS patients with 47,XXY karyotype were reviewed, and G (n = 59 patients) and P (n = 56 patients) stages were plotted on puberty nomograms., Measurements and Results: One boy had a delayed onset of puberty, as he was at the G1 stage at the age of 13.8 years (-2.2 SDs). No observations of delay were made of boys at Stage G2. The progression of G stages was within normal limits in the majority of patients; only few boys were late at G3 (4.1%; 1 out of 24) and G4 (7.4%; 2 out of 27). Testosterone supplementation was started at the average age of 15.5 years to 35 boys (47%), 2 of whom were over 18 years old. LH level was on average 18.2 IU/L (SD: 6.3 IU/L) and testosterone 9.1 nmol/L (SD: 3.1 nmol/L) when testosterone supplementation was started., Conclusions: Our results suggest that puberty starts within the normal age limits in boys with KS, and testosterone supplementation is not needed for the initial pubertal progression in the majority of patients., (© 2021 The Authors. Clinical Endocrinology published by John Wiley & Sons Ltd.)

A 54-year-old man with Klinefelter's syndrome presented to the neuro-ophthalmology clinic with progressive painless visual blurring in the right eye over 2 years. He was receiving intramuscular testosterone therapy for hypogonadism and hypromellose for dry eye. Acuity was reduced bilaterally, and the right optic nerve head appeared pale and asymmetrically cupped. Optical coherence tomography revealed loss of retinal nerve fibre layer thickness in the right eye and visual field testing showed a developing right-ring scotoma. Blood tests showed vitamin B 12 and folate deficiencies and polycythaemia. The patient was managed with intramuscular hydroxocobalamin, oral folate administration and re-initiation of his glaucoma medication. In Klinefelter's syndrome, signs of comorbid deficiency can be masked by the polycythaemic effect of testosterone therapy. For patients on long-term testosterone therapy, such as those with Klinefelter's syndrome, we recommend baseline ophthalmic examination and assessment, including intraocular pressure measurement, pachymetry, gonioscopy and screening 24-2 visual field testing., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

49,XXXXY was previously associated with profound to severe intellectual deficits. However, prior research papers on the cognitive profiles of this population were confounded by small samples sizes, wide age spreads, and incomplete histories of testosterone replacement therapy. This study is the first comprehensive, international investigation of the neurocognitive aspects of 49,XXXXY, and the potential effects of biological treatment on this profile. Sixty-seven boys from infancy to 11 years of age were enrolled in this longitudinal study, with the majority of boys postnatally diagnosed though chromosomal analysis. These boys received a comprehensive neurocognitive evaluation tailored to specific language-based deficits and cognitive challenges. Results revealed higher neurocognitive capacities, both verbally and nonverbally, than previously reported in this disorder. Infant boys with 49,XXXXY who received early hormonal therapy (EHT) had significantly higher scores on the cognitive domain of the Bayley Scales of Infant Development than untreated infants (p = .013). In addition, treated school-aged participants had significantly better scaled scores than untreated boys in form completion (p = .042), a task that requires deductive reasoning, on nonverbal testing on the Leiter International Performance Scales. This study indicates greater cognitive capacities with a wide range of abilities in the child with 49,XXXXY, thus warranting further investigation to identify and understand the critical influences on the etiology and the variability of those capacities., (© 2020 Wiley Periodicals LLC.)

The aim was to define the true incidence of gynaecomastia in adolescent boys with Klinefelter syndrome (KS) and to observe testosterone treatment effects on its duration by examination of the prospectively collected data from a specialist referral clinic for boys with KS, with comparison being made with KS boys identified by a historical newborn chromosome screening programme, together with chromosomally normal controls. Fifty-nine boys over age 13 years were referred to a specialist KS clinic; 21 developed gynaecomastia. The comparator was 14 KS boys identified at birth and 94 chromosomally normal control boys. Testosterone was routinely started at the onset of puberty if gynaecomastia, a manifestation of clinical hypogonadism, was present. Oral or transdermal testosterone was administered in the morning, in a reverse physiological rhythm, and doses were increased according to standard pubertal regimens. The incidence of gynaecomastia was not increased in both the KS cohorts compared with controls. The incidence and age of onset of gynaecomastia was 35.6%, at 12.3 (1.8) years in the KS clinic group; 36.0%, at 13.7 (0.6) years in the newborn survey group; and 34.0%, at 13.6 (0.8) years in the controls. Full resolution of the gynaecomastia occurred in the 12/14 KS clinic boys on testosterone treatment who had completed puberty and as long as adherence was maintained.Conclusion: The incidence of gynaecomastia in KS boys (overall 35.6%) is not increased over typically developing boys. Commencing testosterone when gynaecomastia develops with physiological dose escalation and full adherence can result in the resolution of the gynaecomastia. What is Known: • Gynaecomastia is a common feature in Klinefelter syndrome men. • Hypogonadism occurs from mid-puberty onwards with the absence of the usual rise in testosterone levels. What is New: • The incidence of pubertal gynaecomastia in Klinefelter syndrome is not different from typically developing boys. • Early and prompt starting of testosterone gel treatment and increasing the dose physiologically may help to resolve the gynaecomastia without the need for surgery., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: 47,XXY is associated with variable neurodevelopmental outcomes including deficits in expressive and receptive language development. Early hormonal treatment (EHT) has been associated with mitigating some deficiencies in boys with 47,XXY. This study investigates these language capabilities of 47,XXY boys in the first five years of life and the associated effects of EHT on these capabilities., Methods: One hundred and seventy-five boys with 47,XXY between the ages of 0 and 5 years, 11 months completed neurodevelopmental assessments specific to age examining their expressive and receptive language capabilities. Subjects were grouped by treatment (EHT and No-T) and differences were analyzed., Results: In the age groups of under 12 months, 24-35 months, 36-47 months, and 60-71 months, the EHT group scored significantly higher on expressive language assessments than the No-T group (p = 0.09, p = 0.0002, p = 0.009, and p = 0.02, respectively). In the age groups of under 12 months and 24-35 months, the EHT group scored significantly better on the auditory comprehension domain of the PLS-4/5 (p = 0.02 and p = 0.05, respectively) than the No-T group., Conclusion: Study data suggest EHT may be essential in optimizing receptive and expressive language development in 47,XXY boys during early childhood, which is critical in fostering reading skills and later academic success.

Purpose: Insulin-like factor 3 (INSL3) is an emerging testicular marker, yet larger studies elucidating the clinical role of INSL3 in patients with hypogonadism are lacking. The aim was to describe serum INSL3 concentrations analyzed by LC-MS/MS methodology in males with hypogonadotropic hypogonadism (HH) and Klinefelter syndrome (KS)., Methods: This was a combined study from two tertiary centers in Denmark and France analyzing INSL3 concentrations by LC-MS/MS. In total, 103 patients with HH and 82 patients with KS were grouped into treated (HH: n = 96; KS: n = 71) or untreated (HH: n = 7; KS: n = 11). Treatment modalities included testosterone and hCG. Serum concentrations and standard deviation (SD) scores of INSL3, total testosterone, and LH according to age and treatment were evaluated., Results: In both HH and KS, INSL3 concentrations were low. In HH, INSL3 was low regardless of treatment, except for some hCG-treated patients with normal concentrations. In untreated HH, testosterone was low, while normal to high in most testosterone- and hCG-treated patients. In untreated KS, INSL3 and testosterone concentrations were low to normal, while in testosterone-treated KS, serum INSL3 was low in most patients. INSL3 SD scores were significantly lower in untreated HH than in untreated KS (p = 0.01)., Conclusions: The dichotomy between lower INSL3 and higher testosterone concentrations, particularly observed in hCG-treated patients with HH, confirms that INSL3 is a different marker of Leydig cell function than testosterone. However, the clinical application of INSL3 in males with hypogonadism remains unclear.

Klinefelter syndrome (KS) affects males born with an additional X chromosome giving the genotype 47XXY classically. This syndrome has primary features of infertility and hypogonadism along with other features including a genetically hypercoagulable state. When associated with other risk factors, KS further increases the risk of venous thromboembolism and could result in life-threatening pulmonary embolism (PE). There should be a lower threshold in suspecting PE as a cause of acute respiratory failure in this patient group and thrombolysis should be considered early in normotensive PE with severe hypoxia for best patient outcomes. Furthermore, clinicians should be cautious in managing testosterone therapy in patients with KS and additional thromboembolic risk factors., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: Low testosterone (T) in Klinefelter's syndrome (KS) can contribute to typical features of the syndrome such as reduced bone mineral density, obesity, metabolic disturbances and increased cardiovascular risk. The aim of the present study is to review and meta-analyze all available information regarding possible differences in metabolic and bone homeostasis profile between T treated (TRT) or untreated KS and age-matched controls., Methods: We conducted a random effect meta-analysis considering all the available data from observational or randomized controlled studies comparing TRT-treated and untreated KS and age-matched controls. Data were derived from an extensive MEDLINE, Embase, and Cochrane search., Results: Out of 799 retrieved articles, 21 observational and 22 interventional studies were included in the study. Retrieved trials included 1144 KS subjects and 1284 healthy controls. Not-treated KS patients showed worse metabolic profiles (including higher fasting glycemia and HOMA index as well as reduced HDL-cholesterol and higher LDL-cholesterol) and body composition (higher body mass index and waist circumference) and reduced bone mineral density (BMD) when compared to age-matched controls. TRT in hypogonadal KS subjects was able to improve body composition and BMD at spinal levels but it was ineffective in ameliorating lipid and glycemic profile. Accordingly, TRT-treated KS subjects still present worse metabolic parameters when compared to age-matched controls., Conclusion: TRT outcomes observed in KS regarding BMD, body composition and glyco-metabolic control, are similar to those observed in male with hypogonadism not related to KS. Moreover, body composition and BMD are better in treated than untreated hypogonadal KS. Larger and longer randomized placebo-controlled trials are advisable to better confirm the present data, mainly derived from observational studies.

This cross-sectional study examined the neurodevelopment of a large, prenatally diagnosed population of boys with 47,XXY; investigated the potentially positive effects of early hormonal therapy (EHT) on language, cognition, and motor in this population; and identified novel at risk biomarkers associated with 47,XXY. Two-hundred and seventy two evaluations were collected from 148 prenatally diagnosed boys with 47,XXY between 0 and 36 months and separated into one of three groups, depending on visit age: Y1 (0-12 months; n = 100), Y2 (13-24 months; n = 90), and Y3 (25-36 months; n = 82). Those who received EHT (administered by 12 months) were further separated (Y1, n = 37; Y2, n = 34; Y3, n = 30). Neurodevelopmental evaluations consisted of Preschool Language Scales, Early Language Milestone Scale, and Bayley Scales of Infant and Toddler Development and evaluated the effect of EHT on auditory comprehension, expressive communication, receptive language, cognition, and motor. EHT was found to be associated with a positive effect within the first year of life in these domains, as well as in the second and third year of life. Additionally, three novel at-risk biomarkers were identified in this cohort: feeding difficulties in infancy, positional torticollis, and the need for orthotics. The positive effects of EHT observed in language, cognition, and motor at variable stages within the first 3 years of life provide additional evidence into the possible efficacy of early biological treatment for boys with 47,XXY to address the neurodevelopmental dysfunction., (© 2020 Wiley Periodicals, Inc.)

Klinefelter syndrome (KS; 47,XXY) is the most common sex chromosome abnormality in males (150 per 100,000 males). The condition leads to hypergonadotropic hypogonadism and ever since the condition was described approximately 80 years ago, testosterone treatment has been the cornerstone in care for individuals with KS. However, KS is associated with an array of health-related and socioeconomic challenges and it is becoming progressively clear that proper care for boys and men with KS reaches far beyond simply supplementing with testosterone. There are no widely implemented guidelines for KS care, and studies investigating crucial aspects of testosterone treatment in individuals with KS, including both beneficial and potentially adverse effects, have only begun to emerge during the last decades. For this descriptive review, we present an overview of literature describing health-related outcomes of testosterone treatment in KS and outline the clinical applications of testosterone treatment in KS. Collectively, beneficial effects of testosterone treatment on overall health in KS are described with few apparent adverse effects. However, larger randomized studies in adult and pediatric patients are warranted to elucidate key aspects of treatment. We stress the implementation of centralized multidisciplinary clinics and the need for a dedicated international guideline to ensure optimal care of boys and men with KS., (© 2020 Wiley Periodicals, Inc.)

We provide an in-depth review of the role of androgens in male maturation and development, from the fetal stage through adolescence into emerging adulthood, and discuss the treatment of disorders of androgen production throughout these time periods. Testosterone, the primary androgen produced by males, has both anabolic and androgenic effects. Androgen exposure induces virilization and anabolic body composition changes during fetal development, influences growth and virilization during infancy, and stimulates development of secondary sexual characteristics, growth acceleration, bone mass accrual, and alterations of body composition during puberty. Disorders of androgen production may be subdivided into hypo- or hypergonadotropic hypogonadism. Hypogonadotropic hypogonadism may be either congenital or acquired (resulting from cranial radiation, trauma, or less common causes). Hypergonadotropic hypogonadism occurs in males with Klinefelter syndrome and may occur in response to pelvic radiation, certain chemotherapeutic agents, and less common causes. These disorders all require testosterone replacement therapy during pubertal maturation and many require lifelong replacement. Androgen (or gonadotropin) therapy is clearly beneficial in those with persistent hypogonadism and self-limited delayed puberty and is now widely used in transgender male adolescents. With more widespread use and newer formulations approved for adults, data from long-term randomized placebo-controlled trials are needed to enable pediatricians to identify the optimal age of initiation, route of administration, and dosing frequency to address the unique needs of their patients., (© Endocrine Society 2020. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

During adolescence, androgens are responsible for the development of secondary sexual characteristics, pubertal growth, and the anabolic effects on bone and muscle mass. Testosterone is the most abundant testicular androgen, but some effects are mediated by its conversion to the more potent androgen dihydrotestosterone (DHT) or to estradiol. Androgen deficiency, requiring replacement therapy, may occur due to a primary testicular failure or secondary to a hypothalamic-pituitary disorder. A very frequent condition characterized by a late activation of the gonadal axis that may also need androgen treatment is constitutional delay of puberty. Of the several testosterone or DHT formulations commercially available, very few are employed, and none is marketed for its use in adolescents. The most frequently used androgen therapy is based on the intramuscular administration of testosterone enanthate or cypionate every 3 to 4 weeks, with initially low doses. These are progressively increased during several months or years, in order to mimic the physiology of puberty, until adult doses are attained. Scarce experience exists with oral or transdermal formulations. Preparations containing DHT, which are not widely available, are preferred in specific conditions. Oxandrolone, a non-aromatizable drug with higher anabolic than androgenic effects, has been used in adolescents with preserved testosterone production, like Klinefelter syndrome, with positive effects on cardiometabolic health and visual, motor, and psychosocial functions. The usual protocols applied for androgen therapy in boys and adolescents are discussed.

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., (© Endocrine Society 2019. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

This cross-sectional, retrospective analysis investigated the possible effect of hormonal replacement therapy (HRT) on working memory (WM) and competency/adaptive functioning (CAF) in boys with 47,XXY; the effect of timing of 47,XXY diagnosis on these variables; and the relationship between WM and CAF, if any. A total of 111 boys with 47,XXY, ranging from 6 to 16 years of age (M = 9 years 4 months; SD = 2 years 1 month), were evaluated using the Wechsler Intelligence Scale for Children, and Child Behavior Checklist. Participants were grouped by HRT status and timing of diagnosis. Analysis of variance testing performed on the prenatally diagnosed boys revealed a statistically significant difference in WM for the HRT groups (F[3,84] = 7.467, p = .000174), where WM of the no-HRT group (M = 92.37, SD = 17.83) was lower than that of the early hormonal therapy group (M = 106.39, SD = 12.01; p = .0092). Additionally, there was a positive correlation between low WM capabilities and poor school performance (r = .5106, p = .0027) in the prenatally diagnosed, untreated boys. Our results highlight the potentially positive effects of HRT on WM and CAF in boys with 47,XXY. Further research is required to better determine the underlying relationship among the biological mechanisms of HRT, WM, and CAF outcomes, and timing of diagnosis in boys with 47,XXY., (© 2019 Wiley Periodicals, Inc.)

Rationale: Recurrence of Klinefelter syndrome (KS) in non-twin brothers is very rare. This study examined the inheritance pattern of supernumerary X chromosomes in non-twin brothers., Patient Concerns: A 16-year-old man presented with small-sized testicles. During his diagnostic work-up, his brother, in his late 20's, also complained of small testes and erectile dysfunction., Diagnosis: Chromosome analysis in peripheral blood revealed non-mosaic 47,XXY karyotype in both brothers. Their mother showed a normal 46,XX karyotype., Interventions: To examine the inheritance pattern of supernumerary X chromosomes, quantitative-fluorescence PCR was performed with small tandem repeat markers. It revealed that their supernumerary X chromosomes were inherited from different parents., Outcomes: After the diagnosis of KS, 2 brothers started to receive testosterone treatment., Conclusion: This case report is the first to report differences in the origins of supernumerary X chromosomes in brothers with KS and furthers the current understanding of the cytogenetic mechanisms in KS.

Introduction : Klinefelter syndrome (KS) represents the most common chromosomal abnormality in the general population, and one of the most common genetic etiologies of nonobstructive azoospermia (NOA) and in severe oligospermia. Once considered untreatable, men with KS and NOA now have a variety of treatment options to obtain paternity. Areas covered : The cornerstone of treatment for both KS and NOA patients remains the surgical retrieval of viable sperm, which can be used for intracytoplasmic sperm injection to obtain pregnancy. Although the field has advanced significantly since the early 1990s, approximately half of men with KS will ultimately fail fertility treatments. Presented is a critical review of the available evidence that has attempted to identify predictive factors for successful sperm recovery. To optimize surgical success, a variety of treatment modalities have also been suggested and evaluated, including hormonal manipulation and timing of retrieval. Expert opinion : Individuals with KS have a relatively good prognosis for sperm recovery compared to other men with idiopathic NOA. Surgical success is heavily dependent upon surgical technique and the experience of the andrology/embryology team tasked with the identification and use of testicular sperm.

Context: Variation in pubertal timing is associated with a wide range of adult risks and outcomes, but it is unclear whether these associations are causal, and it is largely unknown whether these associations can be modified by treatment., Evidence Acquisition: We conducted PubMed searches to identify Mendelian randomization (MR) studies on the influence of pubertal timing on adult health and studies on sex-steroid treatment of the following conditions associated with reduced reproductive endocrine function in adolescence: constitutional delay, Turner syndrome, and Klinefelter syndrome., Evidence Synthesis: Results of MR studies suggest that earlier pubertal timing increases body mass index; increases risk for breast, ovarian, endometrial, and prostate cancers; elevates fasting glucose levels and blood pressure; impairs lung capacity and increases risk for asthma; leads to earlier sexual intercourse and first birth; decreases time spent in education; and increases depressive symptoms in adolescence. Later pubertal timing appears to lower bone mineral density (BMD). Although studies of constitutional delay have not shown that sex-steroid treatment alters adult height or BMD, studies of girls with Turner syndrome and boys with Klinefelter syndrome suggest that earlier initiation of sex-steroid treatment improves physical and neurocognitive outcomes., Conclusions: Despite having some limitations, MR studies suggest that pubertal timing causally influences many adult conditions and disease risks. Studies of Turner syndrome and Klinefelter syndrome suggest that earlier sex-steroid exposure may have short- and long-term benefits. The mechanisms underlying these findings and the effects of trends and treatments affecting pubertal timing remain to be determined., (Copyright © 2019 Endocrine Society.)

Background: The background for the increased occurrence of thrombosis seen in Klinefelter syndrome (KS) is unknown. The aim was to compare thrombin generation and coagulation inhibition between men with KS and controls, and to investigate whether coagulation in KS was associated with testosterone treatment (TT), and as such, measures of androgen action., Methods: Untreated men with KS (U-KS) or testosterone treated men with KS (T-KS) were included. KS groups were matched by age and education to groups of control males with no history of TT. Blood samples were collected after overnight fasting. Low tissue factor (1pM) thrombin generation was expressed as lag time (min), time to peak (min), peak (nmol/L), and endogenous thrombin potential (nmol/L × min, ETP). Coagulation inhibitors, sex hormones, and haematocrit were measured. Matched groups were compared by Student's t-test or Wilcoxon rank sum test. Among KS, TT status as an outcome predictor was evaluated by linear regression., Results: 18 U-KS and 27 T-KS with corresponding controls participated. Thrombin generation was not different comparing U-KS and T-KS with respective control groups. Among KS, ETP was lower in T-KS compared with U-KS and inversely associated with testosterone, LH-testosterone ratio and haematocrit., Conclusion: Neither U-KS nor T-KS expressed a pro-coagulant state compared with controls. Thrombin generation among KS was inversely associated with androgen action and lower in T-KS compared with U-KS. Whether TT is capable of lowering thrombotic risk among men with KS needs to be assessed prospectively., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Several studies have reported over-representation of psychiatric disorders among patients with Klinefelter' Syndrome (KS), with forensic complications., Objective: Consider determinants of sexual assault in patient with KS., Review: In this work, we present the case of Jules, 23 years old, with KS, benefiting from steroid replacement therapy, convicted of rape of a minor and evaluated in this context. We question here the role of his genetic pathology and of his hormonal treatment in this sexual assault., Findings: According to evidence from the literature, it is not possible to determine with certainty the fair value of each factor and their impact on the occurrence of the sexual criminal act. Indeed, although the crime rate among KS subjects is higher than in the general population, the majority of them have never been in trouble with the law; moreover, these subjects were no more likely to commit violent sexual acts than were criminals without KS. As for hormonal treatment, it seems that testosterone is better viewed as a facilitator of initiating an aggressive response than as a primary inductor., Conclusion: In conclusion, the onset of sexual violence that accompanied the introduction of hormonal treatment into a patient with KS suggests an effective involvement of steroid replacement therapy, even small, in the criminal act. This must incite clinicians to extreme prudence and to take account of multidisciplinary expertise (psychiatrist, endocrinologist) in order to reconsider the continuation of the treatment in this particular forensic context. Finally, we discuss other factors that can precipitate such a violent act., (Copyright © 2018 L’Encéphale, Paris. Published by Elsevier Masson SAS. All rights reserved.)

Klinefelter syndrome (KS, 47,XXY) is the most common sex chromosome aneuploidy in males. A variety of complex clinical needs is associated with KS, including physical, cognitive and psychosocial impairments. Standard treatment for KS consists of androgen replacement therapy in adolescence to offset testosterone deficiency. Such treatment has a beneficial effect on the physical and behavioral manifestations of this syndrome. Whether androgen supplementation has a significant influence on the brain, however, is unknown. In the current study, we examined regional gray matter volume in boys with KS to assess whether treatment with oxandrolone, a synthetic hormone analog of testosterone, was associated with structural changes in the brain. Specifically, we focused our investigation on the hippocampus, given (1) its involvement in KS, and (2) the high concentration of androgen receptors found in this region. Structural magnetic resonance imaging data was acquired from a subsample of boys who completed a 2-year double-blind clinical trial in which patients were randomized to treatment with oxandrolone or to placebo, as well as from a sample of typically developing (TD) boys. Group differences in hippocampal volume were examined. A significant main effect of group was observed. Pairwise comparisons indicated smaller hippocampal volume in the placebo group relative to the oxandrolone group, as well as smaller volume in the placebo group relative to the TD control group. No difference in volume was observed between the treatment and TD groups. Moreover, across KS subgroups, a significant positive association was observed between hippocampus volume and performance on a spatial memory task, indicating treatment-based changes in brain structure may underlie cognitive change. These findings confirm prior reports implicating a role of the hippocampus in KS and are important in extending previous research by demonstrating a significant effect of androgens on brain structure., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Introduction: Klinefelter syndrome (KS) is the result of sex chromosome aneuploidy most often characterized as 47,XXY. The typical features of KS include tall stature, gynecomastia, small firm testicles, hypergonadotropic hypogonadism, and infertility. However, abnormalities in neurodevelopment, cognition, and social and behavioral functioning also can be present. The abnormalities in neurodevelopment are believed to be due in part to androgen deficiency during early development and puberty., Aim: To discuss the role of androgens in normal adolescent development; discuss the cognitive, behavioral, and social functioning of children with KS; evaluate the evidence for early androgen therapy in men with KS; and discuss management strategies in the development of boys with KS., Methods: A systematic review of early androgen therapy and KS was performed using PubMed-Medline and Scopus databases. Relevant articles commenting on social, behavioral, cognitive, and physical outcomes among infants, children, and adolescents were included for reporting and discussion., Main Outcome Measures: Social and behavior functioning; cognitive outcomes; adverse effects associated with androgen therapy., Results: 3 retrospective articles and 2 randomized controlled trials addressing early androgen therapy in boys with KS were reviewed. These studies showed an improvement in several aspects of social and cognitive functioning based on validated questionnaires. Treatment strategies, potential negative effects, and limitations of the literature on early androgen therapy in boys with KS are discussed., Conclusion: Our findings indicate that early androgen supplementation in children with KS combined with specific educational, family, and social support improves behavioral functioning. The optimal timing of hormonal therapy might require prospective studies, but based on our data and review of the literature, the benefit of early hormonal and therapeutic intervention in KS is very encouraging. Flannigan R, Patel P, Paduch DA. Klinefelter Syndrome. The Effects of Early Androgen Therapy on Competence and Behavioral Phenotype. Sex Med Rev 2018;6:595-606., (Copyright © 2018 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.)

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.

Purpose: To assess different aspects of bone damage in untreated adult patients with Klinefelter Syndrome (KS) before and during testosterone replacement therapy (TRT)., Methods: Fifteen untreated hypogonadal men with KS and 26 control subjects (C) matched for age and BMI were recruited. Sex hormone levels were measured in all subjects. Lumbar spine (LS) and femoral (neck: FN and total hip: TH) bone mineral density (BMD), trabecular bone score (TBS), hip structure analysis (HSA) and fat measures (percentage of fat mass, android/gynoid ratio and visceral adipose tissue) were evaluated by DEXA. In KS patients, blood analysis and DEXA measurements were assessed at baseline and repeated yearly for three years during TRT., Results: Fat measures were significantly higher in KS than C (p < 0.01). In contrast, mean LS, FN and TH BMD were significantly reduced in KS compared to C (p < 0.01), while there was no difference in TBS. HSA revealed a significantly lower cortical thickness and significantly higher buckling ratio in KS compared to C at all femoral sites (p < 0.01). In KS patients, TRT significantly increased BMD at LS only, but did not improve TBS and HSA parameters. Fat measures were inversely associated with TBS values, and TRT did not influence this relationship., Conclusions: In untreated hypogonadal men with KS, lumbar and femoral BMD was reduced, and femoral bone quality was impaired. Adiposity seemed to have a detrimental effect on lumbar bone microarchitecture, as indirectly evaluated by TBS. However, TRT failed to remedy these negative effects on bone.

Klinefelter syndrome is a frequent cause of hypogonadism, but despite hundreds of publications on different aspects of Klinefelter syndrome, only a few studies dealt with sexual dysfunction. In particular, testosterone is critical for various aspects of sexual response, but its role on sexuality in Klinefelter syndrome patients is debatable and no studies have evaluated the efficacy of testosterone treatment on sexual dysfunction in these subjects. Furthermore, the impact of psychological and relational aspects on sexual function of Klinefelter syndrome subjects is poorly defined. In this study, we aimed to determine the presence and type of sexual dysfunctions in Klinefelter syndrome subjects; to correlate them with testosterone levels and psychosexological and relational domains; and to evaluate the effects of testosterone therapy. We studied 62 non-mosaic naïve Klinefelter syndrome patients and 60 age-matched controls by means of medical history, psychosexological history, 15-item International Index of Erectile Function questionnaire, endocrine assessment, and dynamic penile color Doppler ultrasound. Twenty-five hypogonadal Klinefelter syndrome patients were studied after 6 months of testosterone replacement therapy. Klinefelter syndrome subjects have reduced 15-item International Index of Erectile Function scores regarding sexual desire, intercourse satisfaction, and overall satisfaction with respect to controls, and these aspects were significantly associated with testosterone levels. Klinefelter syndrome subjects had also higher prevalence of erectile dysfunction, but no relation with testosterone levels was evident. A high prevalence of a range of psychological disturbances was present in Klinefelter syndrome subjects with erectile dysfunction with respect to those without erectile dysfunction. No statistical difference in the prevalence of premature and delayed ejaculation was observed between Klinefelter syndrome and control subjects. Testosterone replacement therapy improved sexual desire, intercourse satisfaction, and overall satisfaction scores, but had no effect on erectile function. Penile color Doppler ultrasound was normal in all subjects. This study shows that sexual dysfunction in Klinefelter syndrome is multifactorial and related only in part to hypogonadism and largely to psychological disturbances. Evaluation and therapy of sexual dysfunction should include a combined andrological and psychosexological approach., (© 2018 American Society of Andrology and European Academy of Andrology.)

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., (© 2018 John Wiley & Sons Ltd.)

47,XXY (KS) occurs in 1:650 male births, though less than 25% are ever identified. We assessed stability of neurocognitive features across diverse populations and quantified factors mediating outcome. Forty-four boys from the Netherlands (NL) and 54 boys from the United States (US) participated. The Wechsler Intelligence Scales assessed intellectual functioning; the ANT program evaluated cognitive function; and the CBCL assessed behavioral functioning. ANOVA was used for group comparisons. Hierarchical regressions assessed variance explained by each independent variable: parental education, timing of diagnosis, testosterone, age, and nationality. Parental education, timing of diagnosis, and hormonal treatment all played an important role in neurocognitive performance. The observed higher IQ and better attention regulation in the US group as compared to the NL group was observed with decreased levels of behavioral problems in the US group. Cognitive measures that were different between the NL and US groups, i.e., attention regulation and IQ scores, were also significantly influenced by external factors including timing of diagnosis, testosterone treatment, and parental education. On the ANT, a cognitive phenotype of 47,XXY was observed, with similar scores on 9 out of the 10 ANT subtests for the NL and US groups. This study lays additional features to the foundation for an algorithm linking external variables to outcome on various neurodevelopmental measures., (© 2018 Wiley Periodicals, Inc.)

We compared thrombophilia and hypofibrinolysis in 6 men with Klinefelter syndrome (KS), without previously known familial thrombophilia, who had sustained deep venous thrombosis (DVT)-pulmonary emboli (PE) or mesenteric artery thrombosis on testosterone replacement therapy (TRT). After the diagnosis of KS, TRT had been started in the 6 men at ages 11, 12, 13, 13, 19, and 48 years. After starting TRT, DVT-PE or mesenteric artery thrombosis was developed in 6 months, 1, 11, 11, 12, and 49 years. Of the 6 men, 4 had high (>150%) factor VIII (177%, 192%, 263%, and 293%), 3 had high (>150%) factor XI (165%, 181%, and 193%), 1 was heterozygous for the factor V Leiden mutation, and 1 was heterozygous for the G20210A prothrombin gene mutation. None of the 6 men had a precipitating event before their DVT-PE. We speculate that the previously known increased rate of DVT-PE and other thrombi in KS reflects an interaction between prothrombotic, long-term TRT with previously undiagnosed familial thrombophilia. Thrombophilia screening in men with KS before starting TRT would identify a cohort at increased risk for subsequent DVT-PE, providing an optimally informed estimate of the risk/benefit ratio of TRT.

Purpose: Liquid-chromatography tandem mass-spectrometry (LC-MS/MS) was developed in parallel to Immunoassays (IAs) and today is proposed as the "gold standard" for steroid assays. Leydig cells of men with Klinefelter syndrome (KS) are able to respond to human chorionic gonadotropin (hCG) stimulation, even if testosterone (T) production was impaired. The aim was to evaluate how results obtained by IAs and LC-MS/MS can differently impact on the outcome of a clinical research on gonadal steroidogenesis after hCG stimulation., Methods: A longitudinal, prospective, case-control clinical trial. (clinicaltrial.gov NCT02788136) was carried out, enrolling KS men and healthy age-matched controls, stimulated by hCG administration. Serum steroids were evaluated at baseline and for 5 days after intramuscular injection of 5000 IU hCG using both IAs and LC-MS/MS., Results: 13 KS patients (36 ± 9 years) not receiving T replacement therapy and 14 controls (32 ± 8 years) were enrolled. T, progesterone, cortisol, 17-hydroxy-progesterone (17OHP) and androstenedione, were significantly higher using IAs than LC-MS/MS. IAs and LC-MS/MS showed direct correlation for all five steroids, although the constant overestimation detected by IAs. Either methodology found the same 17OHP and T increasing profile after hCG stimulation, with equal areas under the curves (AUCs)., Conclusions: Although a linearity between IA and LC-MS/MS is demonstrated, LC-MS/MS is more sensitive and accurate, whereas IA shows a constant overestimation of sex steroid levels. This result suggests the need of reference intervals built on the specific assay. This fundamental difference between these two methodologies opens a deep reconsideration of what is needed to improve the accuracy of steroid hormone assays.

Objectives: To examine the effects of early low-dose androgen on motor, cognitive, and behavioral function in prepubertal boys with Klinefelter syndrome (47,XXY)., Study Design: Double-blind trial of 84 boys, ages 4-12 years, randomized to oxandrolone (Ox; 0.06?mg/kg daily; n?=?43) or placebo (Pl; n?=?41) for 24 months. Standardized assessments were performed at baseline and every 12 months for 24 months evaluating motor, cognitive, and behavioral function., Results: The 24-month outcomes were better in the Ox vs. Pl group on 1 of 5 primary endpoints (motor function/strength): Bruininks Visual-Motor scale (P?=?.005), without significant differences between the 2 groups for the other 4 components. Secondary analyses suggested improvement in the Ox vs. Pl group in the anxiety/depression (P?=?.03) and social problems (P?=?.01) scales on the Child Behavior Checklist, anxiety (P?=?.04) on the Piers Harris Self Concept Scale, and interpersonal problems (P?=?.02) on the Children's Depression Inventory, without significant differences in hyperactive or aggressive behaviors., Conclusions: This double-blind, randomized trial demonstrates that 24 months of childhood low-dose androgen treatment in boys with Klinefelter syndrome benefited 1 of 5 primary endpoints (visual-motor function). Secondary analyses demonstrated positive effects of androgen on aspects of psychosocial function (anxiety, depression, social problems), without significant effects on cognitive function, or hyperactive or aggressive behaviors., Trial Registration: ClinicalTrials.gov: NCT00348946., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Klinefelter's syndrome is the most common chromosomal disorder associated with testicular dysfunction and male infertility. Those affected by Klinefelter's syndrome are at increased risk of systemic lupus erythematosus, breast cancer, non-Hodgkin's lymphoma, and lung cancer. Nephrotic syndrome in association with Klinefelter's syndrome has never been reported in the literature.

Context: Klinefelter syndrome (KS) is a common condition in males, resulting in androgen deficiency and cardiometabolic diseases. These interrelated conditions may be present in prepubertal boys with KS., Objective: To determine whether supplemental low-dose androgen has a beneficial effect on body composition in prepubertal boys with KS., Design, Setting, and Participants: We conducted a secondary analysis of a randomized, double-blind, placebo-controlled clinical trial in 93 boys with KS aged 4 to 12 years., Interventions: Oral oxandrolone (Ox) 0.06 mg/kg/d or placebo for 2 years., Outcome Measures: The primary outcome was percent body fat standard deviation score (%BF SDS) at 2 years. Secondary outcomes included additional measures of cardiometabolic health and safety., Results: The %BF SDS at 2 years was significantly lower in the treatment (0.29 ± 0.76 SDS) compared with placebo group (0.81 ± 0.72 SDS) after adjusting for age and baseline %BF SDS (95% confidence interval for the difference between means -0.86 to -0.19 SDS, P = 0.009). Ox resulted in lower triglycerides (P = 0.043), but also lower high-density lipoprotein (HDL) cholesterol (P < 0.001) and a more rapid advancement in bone age (P = 0.011)., Conclusions: Ox has positive effects on measures of cardiometabolic health in prepubertal boys with KS; however, it does lower HDL cholesterol and advance bone age., (Copyright © 2017 by the Endocrine Society)

Klinefelter syndrome (KS) is the most common sex chromosomal disorder with an estimated prevalence of 1 in 500-1000. Increased incidences of anxiety, depression, substance abuse, psychotic and behavioral disorders, and sexual disorders have been reported in patients with KS. The aim of this case study was to report a case of a man with untreated KS who was also diagnosed with type II bipolar disorder. This case report raises awareness regarding psychiatric diagnoses that may be associated with such a highly prevalent condition. A 46-year-old man who had previously been diagnosed with an untreated KS was examined in our Psychiatric Department with an acute hypomanic episode. Clinical improvement was observed within 4 days and psychiatric symptoms were resolved in 7 days without use of medication. A psychiatric history of a depressive episode and at least two hypomanic episodes, as well as a family history of two relatives diagnosed with bipolar disorder, strongly suggest that our patient has type II bipolar disorder. Bipolar disorder may be a comorbid disorder in patients with KS. Routine screening for mood disorders and appropriate referral and evaluation should be performed. Future genetic research is warranted to explore why some chromosomal abnormalities (e.g., duplications), especially those located on the X chromosome, such as Klinefelter syndrome, may be associated with a bipolar or psychotic disorder in some individuals but not in others.

Aim: Genetic inborn along with acquired diseases arise due to the lesions in genome of multipotent hematopoietic stem cells. The aim was to study an influence of constitutional anomaly, Klinefelter syndrome, and additional structural rearrangements on the BCR-ABL tyrosine kinase inhibitor targeted therapy efficacy., Material and Methods: We describe a 32-year-old male patient with chronic myeloid leukemia (CML) who was detected to have sex chromosomal abnormality during evaluation for Philadelphia chromosome., Results: At diagnosis of CML, two clones were detected by standard cytogenetic investigation of bone marrow cells: 1) clone with translocation t(9;22)(q34;q11), with two sex X chromosomes and absence sex chromosome Y; 2) clone with t(9;22) and unbalanced t(Y;20)(q11;q13). Analysis of blast transformed lymphocytes from peripheral blood showed karyotype 47,XXY. Monitoring of targeted therapy with second generation inhibitor of BCR-ABL tyrosine kinase indicated a cytogenetic remission and absence of BCR-ABL1 fusion signals after 11 months., Conclusions: Absence of translocation t(9;22)(q34;q11) in blast transformed T-lymphocytes at diagnosis of CML evidences that this translocation may appear not only at the level of multipotent haemopoietic cell progenitors but also may have oligo lineage myeloid origin. Presence of additional structural chromosomal abnormality in the clone with t(9;22)(q34;q11) does not affect the efficacy of therapy with the use of second generation BCR-ABL tyrosine kinase inhibitor.

Background: Men with Klinefelter syndrome (KS) show hypergonadotropic hypogonadism, but the pathogenesis of hypotestosteronemia remains unclear. Testicular steroidogenesis in KS men was evaluated over three decades ago after human chorionic gonadotropin (hCG) stimulation, but inconclusive results were obtained. Intriguingly, some recent studies show increased intratesticular testosterone concentrations in men with KS., Objective: To analyze serum steroid profile, as a proxy of testicular steroidogenesis, after hCG stimulation in KS compared with control men., Design: A prospective, longitudinal, case-control, clinical trial., Methods: Thirteen KS patients (36±9 years) not receiving testosterone (TS) replacement therapy and 12 eugonadic controls (32±8 years) were enrolled. Serum steroids were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) at baseline and for five consecutive days after intramuscular injection of 5000IU hCG., Results: Progesterone (P), 17-hydroxyprogesterone (17OHP), TS, and estradiol (E2) showed a significant increase (P<0.001) after hCG stimulation in both groups. On the contrary, androstenedione (AS) and dehydroepiandrosterone did not increase after hCG stimulation. The 17OHP/P ratio increased in both groups (P<0.001), the TS/AS ratio (17β-hydroxysteroid dehydrogenase type 3 (17βHSD3) activity) did not increase after hCG in any group, and the E2/TS ratio (aromatase activity) increased significantly in both groups (P=0.009 in KS and P<0.001 in controls). Luteinizing hormone decreased after hCG in both groups (P=0.014 in KS and P<0.001 in controls), whereas follicle-stimulating hormone decreased only in control men (P<0.001)., Conclusion: This study demonstrates for the first time using LC-MS/MS that Leydig cells of KS men are able to respond to hCG stimulation and that the first steps of steroidogenesis are fully functional. However, the TS production in KS men is impaired, possibly related to reduced hydroxysteroid deydrogenase activity due to an unfavorable intratesticular metabolic state., (© 2016 European Society of Endocrinology.)

Klinefelter syndrome is usually characterised by the presence of a eunuchoid body habitus and testes that are usually small and firm, with low testosterone, and elevated luteinising hormone and follicle-stimulating hormone levels, consistent with hypergonadotropic hypogonadism. Low levels of gonadotropins in karyotypically proven cases are not expected, they are extremely rare occurrences. We report a case of a patient who was diagnosed to have Klinefelter syndrome (47 XXY) with low gonadotropin levels. The rest of his anterior pituitary hormonal profile was normal with no lesions in the pituitary gland on imaging. He was continued on androgen replacement therapy., (2015 BMJ Publishing Group Ltd.)