Clinical Guidelines and Standards · Guidelines by Clinical Area
Zitzmann M, Sansone A, Jannini EA, Jones H, Ferlin A, Lunenfeld B
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This is the inaugural recommendation for the management of the Aging Male with Klinefelter Syndrome (KS), a demographic characterized by primary hypogonadism in the presence of one or more supernumerary X-chromosomes with irregular gene-inactivation, and metabolic dysregulation, contributing a component of functional hypogonadism as aging in these men progresses. The unique constellation of symptoms spanning multiple organ systems and health domains necessitates specialized diagnostic and therapeutic strategies. Neglecting the specific needs of this population can precipitate a considerable decline in quality of life and overall health outcomes. Our recommendations advocate for a multidisciplinary approach involving endocrinologists, urologists, geneticists, mental health professionals, and other specialists, to address the complex interplay of hormonal imbalances, metabolic disorders, cardiovascular risk factors including arrhythmia, bone health concerns, psychological and sexual challenges, ophthalmological problems, and dental issues. By providing a structured framework for comprehensive and individualized care, these recommendations aim to bridge existing healthcare gaps, optimize well-being, and enhance the overall quality of life for aging men with KS.
Grande G et al., 2026 · The Journal of clinical endocrinology and metabolism · Free to read
Male factor infertility (MFI) is frequently labelled idiopathic when evaluation relies primarily on semen analysis, potentially overlooking endocrine and pathophysiological mechanisms relevant for targeted management. To phenotypically define MFI and develop a pathophysiology-based classification aimed at reducing idiopathic infertility following comprehensive evaluation. Prospective monocentric cohort study conducted at a tertiary referral academic centre. Eight hundred male partners of infertile couples evaluated between October 2024 and January 2026 after exclusion of isolated female factor infertility. Prevalence of MFI categories, hormonal patterns across phenotypes, and proportion of idiopathic infertility after comprehensive work-up. All patients underwent standardized clinical evaluation, hormonal assessment (total testosterone, FSH, LH), testicular ultrasound, and complete semen analysis. Microbiological testing, transrectal ultrasound, and genetic analyses were performed according to guidelines. Primary spermatogenic failure was the most prevalent category (56.0%), followed by infection/inflammation (22.4%) and hypogonadotropic hypogonadism (8.5%). Idiopathic infertility was identified in only 5.3% of cases. Distinct endocrine profiles were observed, with high-FSH spermatogenic failure representing the dominant phenotype. Comprehensive phenotyping markedly reduces the proportion of patients classified as having idiopathic infertility and identifies clinically relevant subgroups. This prospective study provides validation of a pathophysiology-based classification and supports a shift toward endocrine-integrated diagnostic strategies in male infertility, with potential implications for targeted management.
Rocca MS et al., 2026 · Journal of translational medicine · Free to read
Standard semen analysis has little prognostic value in distinguishing fertile from infertile men. Furthermore, in men with semen parameters within the reference ranges, it cannot distinguish fertile men from infertile men, i.e. partners of couples with idiopathic infertility. Oxidative stress, mitochondrial dysfunction, sperm telomere shortening, and DNA fragmentation have been proposed as contributors to impaired male fertility. However, these biomarkers have not been evaluated as a whole in subjects with normal semen parameters, partners of fertile and infertile couples. To characterise a multidimensional panel of sperm biomarkers-including sperm telomere length (STL), mitochondrial DNA copy number (mtDNAcn), reactive oxygen species (ROS), lipid peroxidation (LP), sperm chromatin dispersion (SCD), and respiratory control ratio (RCR)-and to identify whether these parameters might discriminate, in men with normal semen parameters, infertile men from fertile controls. A total of 150 men with semen parameters within the normal ranges were enrolled: 47 male partners of couples with idiopathic infertility and 103 fertile controls. STL and mtDNAcn were quantified by qPCR; ROS were assessed using OxiSperm®II with semiquantitative imaging; LP was measured spectrophotometrically in seminal plasma; SCD was used to determine DNA fragmentation; and mitochondrial function was evaluated by oxygen consumption and RCR. Correlations between biomarkers and semen parameters were analysed using Pearson or Spearman coefficients, and intergroup comparisons were adjusted for age. Semen parameters did not differ significantly between male partners of fertile and infertile couples. compared to men of fertile couples, men of infertile couples exhibited significantly shorter STL (0.57 ± 0.59 vs 1.21 ± 1.13, p_adj = 0.001) and higher oxidative stress, with both ROS (8300.9 ± 4214.8 vs 6555.3 ± 3394.3, p_adj = 0.027) and LP (88.33 ± 55.50 vs 40.29 ± 46.98, p_adj < 0.001) markedly elevated. mtDNAcn, SCD, and RCR showed no difference between the groups. Across the entire cohort, STL correlated negatively with ROS and LP and positively with RCR. ROS correlated negatively with total sperm count, motility and RCR, and positively with LP. LP displayed the strongest pattern of associations, correlating negatively with concentration, total count, motility, STL and RCR, and positively with age and volume. Among men with normal semen analysis, partners of couples with idiopathic infertility exhibit a distinct sperm molecular profile characterised by telomere shortening and oxidative imbalance. STL, ROS and LP emerged as age-independent biomarkers associated with infertility status and showed promising discriminatory ability in this cohort, supporting their integration as second-level tests to complement routine semen analysis in cases of normozoospermia.
Ponce MR et al., 2026 · Andrology · Free full text on PubMed Central
Transgender individuals assigned male at birth (AMAB) may choose to preserve their fertility prior to starting gender-affirming hormone therapy (GAHT). However, limited data exist regarding the baseline reproductive and hormonal characteristics of this population before and after GAHT. To characterize semen quality and hormonal profiles in transgender AMAB individuals prior to GAHT and compare findings with cisgender men and with transgender individuals who discontinued GAHT for at least 3 months. This retrospective study included transgender AMAB individuals from two tertiary andrology centers who underwent sperm cryopreservation before GAHT initiation (treatment-naïve group). Clinical evaluation included anthropometric measures, testicular volume assessment, varicocele detection, and sex hormone measures. Semen parameters were analyzed according to WHO criteria and compared with those of cisgender men and previously treated transgender individuals. Thirty-two treatment-naïve transgender AMAB individuals were included. Hormonal parameters were generally within reference ranges. Only 46.9% of treatment-naïve individuals met WHO criteria for normozoospermia, compared with 75.5% of cisgender controls. Compared with nine previously treated individuals, estradiol levels were higher and seminal volume lower. A higher frequency of seminal abnormalities was observed, although not statistically significant. A substantial proportion of treatment-naïve transgender AMAB individuals exhibited impaired semen parameters prior to GAHT initiation. Prior GAHT exposure showed a trend toward poorer semen quality. These findings support early fertility counseling and preservation in transgender individuals prior to GAHT initiation.
Delbarba A et al., 2026 · Reviews in endocrine & metabolic disorders · Free full text on PubMed Central
Male hypogonadism is associated with significant alterations in body composition, including reduced lean body mass (LBM), increased fat body mass (FBM), particularly visceral adiposity, and impaired muscle function, contributing to frailty and cardiometabolic risk. These changes reflect the disruption of a complex endocrine crosstalk among bone, muscle, and adipose tissue, mediated by cytokines such as osteokines, myokines, and adipokines. This dysregulation promotes the development of osteosarcopenic obesity, a condition characterized by the coexistence of low bone mass, sarcopenia, and excess adiposity. Testosterone (T) plays a central role in maintaining body composition by stimulating muscle protein synthesis, inhibiting adipogenesis, and preserving bone health. Its deficiency, irrespective of etiology, leads to rapid impairment of anabolic pathways, resulting in decreased lean mass and increased fat accumulation. Evidence from clinical and experimental models demonstrates that these alterations are partially reversible with T replacement therapy (TRT), although variability exists depending on the underlying cause of hypogonadism. Dual-energy X-ray absorptiometry (DXA) represents the gold standard for assessing bone mineral density (BMD) and a key tool for evaluating body composition through a three-compartment model. It allows precise quantification of fat and lean mass, as well as their regional distribution, with minimal radiation exposure. In this review, we provide a comprehensive and clinically oriented overview of body composition alterations in male hypogonadism, focusing on underlying pathophysiological mechanisms and the practical application of DXA across different clinical scenarios. We discuss evidence from conditions such as Klinefelter syndrome, Kallmann syndrome, androgen deprivation therapy, HIV infection, and transgender care, aiming to offer a pragmatic framework for integrating body composition assessment into routine practice and improving patient management.
Zitzmann M et al., 2021 · Andrology · Free to read
Knowledge about Klinefelter syndrome (KS) has increased substantially since its first description almost 80 years ago. A variety of treatment options concerning the spectrum of symptoms associated with KS exists, also regarding aspects beyond testicular dysfunction. Nevertheless, the diagnostic rate is still low in relation to prevalence and no international guidelines are available for KS. To create the first European Academy of Andrology (EAA) guidelines on KS. An expert group of academicians appointed by the EAA generated a consensus guideline according to the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) system. Clinical features are highly variable among patients with KS, although common characteristics are severely attenuated spermatogenesis and Leydig cell impairment, resulting in azoospermia and hypergonadotropic hypogonadism. In addition, various manifestations of neurocognitive and psychosocial phenotypes have been described as well as an increased prevalence of adverse cardiovascular, metabolic and bone-related conditions which might explain the increased morbidity/mortality in KS. Moreover, compared to the general male population, a higher prevalence of dental, coagulation and autoimmune disorders is likely to exist in patients with KS. Both genetic and epigenetic effects due to the supernumerary X chromosome as well as testosterone deficiency contribute to this pathological pattern. The majority of patients with KS is diagnosed during adulthood, but symptoms can already become obvious during infancy, childhood or adolescence. The paediatric and juvenile patients with KS require specific attention regarding their development and fertility. These guidelines provide recommendations and suggestions to care for patients with KS in various developmental stages ranging from childhood and adolescence to adulthood. This advice is based on recent research data and respective evaluations as well as validations performed by a group of experts.
Milardi D et al., 2020 · Klinefelter's Syndrome
Klinefelter syndrome (KS) is a common genetic disorder characterized by an additional X chromosome in males. A deficient androgen production and a varied observed response of end-organs to testosterone can lead to delayed progression of puberty with reduction in muscle development and facial/body hair, osteoporosis, and gynecomastia. Medical management during puberty focuses on the preservation of fertility and testosterone replacement treatment (TRT) to reduce the current or future consequences of testicular fibrosis. However, more research is needed to establish the need and conditions for TRT in adolescence, as well as the opportunity and timing for sperm recovery in adolescents and young boys with KS. Furthermore, screening for associated diseases such as metabolic syndrome, osteoporosis, and malignancies should be guaranteed during this lifetime. Preventive care should be provided by diagnosis, ideally through a multidisciplinary approach.
Pizzocaro A et al., 2020 · Journal of endocrinological investigation
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. 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. 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. 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.
Nieschlag E et al., 2016 · Andrology
Following the 1st International Workshop on the Klinefelter Syndrome in 2010 (Juul et al., 2011), the 2nd IWKS took place in Münster, Germany from March 10 to 12, 2016 and was organized by the Centre of Reproductive Medicine and Andrology of the University of Münster. During the program, talks were presented by leading researchers in the field followed by lively discussions among the 120 participants. The talks comprehensively covered basic and clinical aspects of the syndrome. The basic aspects included the mechanisms of X chromosome inactivation (Joost Gribnau, Christine Disteche), sex chromosome evolution in the primate lineage (Gabriel Marais), epigenetics (Joana Viana), gene expression studies (Liborio Stuppia), and animal models (Art Arnold, Armin Raznahan, Joachim Wistuba). Among the clinical aspects, current views on early/prenatal diagnosis (Frank Tüttelmann) and transitional care (Niels E. Skakkebæk, Alan Rogol) were reviewed. A large part of the workshop was devoted to comorbidities – with focus on cardiovascular and metabolic problems (Michael Zitzmann, Anders Bojesen) as well as osteoporosis (Alberto Ferlin). Neuropsychological, behavioral, and socioeconomic aspects were discussed (Hanna Swaab, Anne Skakkebæk, Nicole Tartaglia). Divergent experiences and opinions on fertility preservation and optimal time for TESE were presented (Sabine Kliesch, Hervé Lejeune). Following new findings on testicular steroidogenesis (Manuela Simoni), testosterone replacement in infants and young children (Carole Samango-Sprouse) and age-specific recommendations for management of patients with Klinefelter Syndrome (KS) met with great interest (Anders Juul). Differences and similarities between KS and Turner syndrome provided further insights into disorders of sex chromosome aneuploidies (Claus H. Gravholt). Finally, results of the 'dsd-LIFE study' on quality of life, satisfaction with care and needs of adolescents and men with KS (Birgit Köhler) and the European COST Initiative on DSD including KS (Olaf Hiort) were presented (for details of the program see www.klinefelter2016.de). The purpose of the concluding round table was to discuss – based on the presentations and interactions of this workshop – the shortcomings of current care of patients with KS and to indicate future directions for patient management and research. As an introduction, tribute was paid to Harry F. Klinefelter (1912–1990), who first described this syndrome in 1942 (Klinefelter et al., 1942). Of the 120 workshop participants, only Alan Rogol and Eberhard Nieschlag had met Harry Klinefelter in person, the former as one of his medical teachers at John Hopkins in Baltimore and the latter at an International Klinefelter Symposium in Murnau in the Bavarian Alps in 1983 (Bandmann et al., 1984). The discussion was opened by arguments for and against neonatal screening for KS as this question had come up repeatedly during the workshop. Alan Rogol gave the reasons for screening all male newborns for 47,XXY (and perhaps all children for sex chromosome aneuploidy): primarily in anticipation of services required in childhood, such as early treatment of deficits encountered in speech, behavior/regulation of emotion, physical findings, delayed childhood milestones. Furthermore, for information of parents, doctors, and health care practitioners as well as school and pre-school personnel (as much as parents wish, for there is a risk of stigmatization). An overarching service/education that pediatricians have to offer is anticipatory guidance, and newborn screening would allow pediatricians to provide this guidance to families concerned with KS. However, based on his experience in Denmark, Claus H. Gravholt felt that it was premature to screen large populations for KS, as we do not yet have evidence that the different treatment options that we can provide are efficient and reduce morbidity, mortality, and improve outcome. There is no proof yet that early diagnosis and treatment [truncated]