It's not all about the testes: medical issues in Klinefelter patients

The Klinefelter Syndrome and Testicular Sperm Retrieval Outcomes

Klinefelter syndrome (KS), caused by the presence of an extra X chromosome, is the most prevalent chromosomal sexual anomaly, with an estimated incidence of 1:500/1000 per male live birth (karyotype 47,XXY). High stature, tiny testicles, small penis, gynecomastia, feminine body proportions and hair, visceral obesity, and testicular failure are all symptoms of KS. Endocrine (osteoporosis, obesity, diabetes), musculoskeletal, cardiovascular, autoimmune disorders, cancer, neurocognitive disabilities, and infertility are also outcomes of KS. Causal theories are discussed in addition to hormonal characteristics and testicular histology. The retrieval of spermatozoa from the testicles for subsequent use in assisted reproduction treatments is discussed in the final sections. Despite testicular atrophy, reproductive treatments allow excellent results, with rates of 40–60% of spermatozoa recovery, 60% of clinical pregnancy, and 50% of newborns. This is followed by a review on the predictive factors for successful sperm retrieval. The risks of passing on the genetic defect to children are also discussed. Although the risk is low (0.63%) when compared to the general population (0.5–1%), patients should be informed about embryo selection through pre-implantation genetic testing (avoids clinical termination of pregnancy). Finally, readers are directed to a number of reviews where they can enhance their understanding of comprehensive diagnosis, clinical care, and fertility preservation.

Oncologic manifestations of Klinefelter syndrome

Klinefelter syndrome (47,XXY) has a prevalence of approximately 1 in 500 males. It is a condition characterized by an extra X chromosome and is an underdiagnosed clinical entity. Inactivation of genes enables their escape from regulatory mechanisms, which can result in such classic physical manifestations as hypogonadism, gynecomastia, infertility, and various hormonal and physical abnormalities. While the endocrine manifestations of 47,XXY are well-known, the oncologic manifestations have received less attention. An association between cancer and 47,XXY has not as yet been clearly defined, with variability noted in the prevalence of different malignancies in 47,XXY patients. The mechanisms underlying these altered oncologic risks are still under debate. Some of the proposed explanations include hormone imbalance, developmental malfunctions, and failed DNA repair mechanisms. However, the recognition of the oncological associations linked to 47,XXY could be helpful. Screening measures in certain malignancies may enable an earlier diagnosis of 47,XXY and the implementation of more customized care in 47,XXY and the mosaic variants.. The data for this review was compiled from relevant PubMed articles published within the last three decades and organized based on cancer type.

Genetic risk factors for venous thromboembolism among infertile men with Klinefelter syndrome

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Infertile males with KS have sex-chromosome abnormalities, endocrinal disturbances and other health problems.

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Hereditary thrombophilia may exacerbate tendency to thrombosis in KS patients.

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Genotype and allele frequency of thrombophilic gene variants were remarkably high in men with KS.

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The coexistence of different mutant alleles was evident in infertile KS males.

Background

Klinefelter syndrome (KS) is one of the commonest sex chromosome disorders. Affected males become infertile and highly susceptible to several health problems, including vascular thromboembolism (VTE). The risk of VTE may be exacerbated by an underlying genetically inherited thrombophilia. In this study, we aimed to investigate the genotype and allele frequencies of common gene polymorphisms related to hereditary thrombophilia in infertile males with KS compared to normal, fertile men.

Methods

Eighty-five infertile males with KS and 75 healthy control males were included in this case-control study. Genetic testing was done using an extended thrombophilia gene panel by Multiplex PCR reverse hybridization method.

Results

There was an increased frequency of mutant alleles and heterozygous genotypes of FV Leiden, FV H 1299R, Pro G20210A, MTHFR C677T and PAI-1 4G/5G thrombophilic gene polymorphisms in KS patients compared to the control group. It was shown that 10.7% of KS patients had the A3 haplotype of the EPCR gene in comparison to 5.3% of control patients. The A3/A3 genotype was found only in KS patients (7.1%). Carriers of more than one mutant allele in KS patients exceeded the control (p < 0.001).

Conclusion

A high prevalence of thrombophilic gene polymorphisms and the coexistence of different mutant alleles were evident in infertile KS males. These data highlight the importance of conducting further studies to understand the role of hereditary thrombophilia in predicting venous thrombosis in patients with Klinefelter syndrome.

Delayed Puberty by Ziram Is Associated with Down Regulation of Testicular Phosphorylated AKT1 and SIRT1/PGC-1α Signaling

Ziram is a dimethyldithiocarbamate fungicide, which may influence the male reproductive system as a potential endocrine disruptor. We interrogated the disruption of ziram on rat progenitor Leydig cell development. Prepubertal male Sprague-Dawley rats were orally treated with 0, 2, 4, or 8 mg/kg ziram for 2 weeks. We investigated the effects of ziram on serum testosterone levels, Leydig cell number, and Leydig and Sertoli cell gene and protein expression, SIRT1/PGC-1α levels, and phosphorylation of AKT1, ERK1/2, and AMPK in vivo. We also interrogated the effects of ziram on reactive oxidative species (ROS) level, apoptosis rate, and mitochondrial membrane potential of progenitor Leydig cells in vitro. Ziram decreased serum testosterone and follicle-stimulating hormone levels, the down-regulated Leydig cell-specific gene ( Lhcgr, Scarb1, Star, Cyp17a1, and Hsd17b3), and their protein expression. However, ziram stimulated anti-Müllerian hormone production. Ziram lowered SIRT1/PGC-1α and phosphorylated protein levels of AKT1. Ziram induced ROS and apoptosis and lowered the mitochondrial membrane potential of progenitor Leydig cells in vitro. In conclusion, ziram disrupts Leydig cell development during the prepubertal period potentially through the SIRT1/PGC-1α and phosphorylated AKT1 signaling.

Gut Endotoxin Leading to a Decline IN Gonadal function (GELDING) - a novel theory for the development of late onset hypogonadism in obese men

Obesity is an increasing public health problem, with two-thirds of the adult population in many Western countries now being either overweight or obese. Male obesity is associated with late onset hypogonadism, a condition characterised by decreased serum testosterone, sperm quality plus diminished fertility and quality of life. In this paper we propose a novel theory underlying the development of obesity related hypogonadism- the GELDING theory (Gut Endotoxin Leading to a Decline IN Gonadal function). Several observational studies have previously reported an association between obesity related hypogonadism (low testosterone) and systemic inflammation. However, for the first time we postulate that the trans-mucosal passage of bacterial lipopolysaccharide (LPS) from the gut lumen into the circulation is a key inflammatory trigger underlying male hypogonadism. Obesity and a high fat/high calorie diet are both reported to result in changes to gut bacteria and intestinal wall permeability, leading to the passage of bacterial endotoxin (lipopolysaccharide- LPS) from within the gut lumen into the circulation (metabolic endotoxaemia), where it initiates systemic inflammation. Endotoxin is known to reduce testosterone production by the testis, both by direct inhibition of Leydig cell steroidogenic pathways and indirectly by reducing pituitary LH drive, thereby also leading to a decline in sperm production. In this paper we also highlight the novel evolutionary benefits of the GELDING theory. Testosterone is known to be a powerful immune-suppressive, decreasing a man's ability to fight infection. Therefore we postulate that the male reproductive axis has evolved the capacity to lower testosterone production during times of infection and resulting endotoxin exposure, decreasing the immunosuppressive influence of testosterone, in turn enhancing the ability to fight infection. While this response is adaptive in times of sepsis, it becomes maladaptive in the setting of "non-infectious" obesity related metabolic endotoxaemia.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Early onset of puberty in an obese boy with Klinefelter syndrome

Klinefelter syndrome (KS) is one of the most common disease entities characterized by X-chromosomal aberration causing the primary hypogonadism in adult men. Patients with KS seem to be typically characterized by tall, slender bodies with delayed puberty and hypergonadotropic hypogonadism. However, it has been known that they have a broad spectrum of phenotype ranging from almost normal external appearances to typical phenotype. Only 25% KS Patients are ever diagnosed because KS remains unrecognized. Also, boys with KS have an onset of pubertal development within the normal range, not delayed onset of puberty. Adolescents with KS are generally diagnosed as having the lack of pubertal progress. Early detection of KS can be difficult without awareness. We report an unusual case of early onset of puberty in obese boy with KS who presented with a unilateral non-hormone secreting testicular teratoma.

Bone Mineral Status in Children and Adolescents with Klinefelter Syndrome

Objective. Klinefelter syndrome (KS) has long-term consequences on bone health. However, studies regarding bone status and metabolism during childhood and adolescence are very rare. Patients. This cross-sectional study involved 40 (mean age: 13.7 ± 3.8 years) KS children and adolescents and 80 age-matched healthy subjects. For both patient and control groups, we evaluated serum levels of ionised and total calcium, phosphate, total testosterone, luteinising hormone, follicle stimulating hormone, parathyroid hormone (PTH), 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D, osteocalcin, bone alkaline phosphatase, and urinary deoxypyridinoline concentrations. We also calculated the z-scores of the phalangeal amplitude-dependent speed of sound (AD-SoS) and the bone transmission time (BTT). Results. KS children and adolescents showed significantly reduced AD-SoS (p < 0.005) and BTT (p < 0.0005) z-scores compared to the controls. However, KS patients presented significantly higher PTH (p < 0.0001) and significantly lower 25(OH)D (p < 0.0001), osteocalcin (p < 0.05), and bone alkaline phosphatase levels (p < 0.005). Interestingly, these metabolic bone disorders were already present in the prepubertal subjects. Conclusions. KS children and adolescents exhibited impaired bone mineral status and metabolism with higher PTH levels and a significant reduction of 25-OH-D and bone formation markers. Interestingly, this impairment was already evident in prepubertal KS patients. Follow-ups should be scheduled with KS patients to investigate and ameliorate bone mineral status and metabolism until the prepubertal ages.

Sinus node dysfunction requiring permanent pacemaker implantation in a young adult with Klinefelter syndrome

Patient: Male, 22

Final Diagnosis: Sinus node dysfunction

Symptoms: Bradycardia • lassitude

Medication: —

Clinical Procedure: Pacemaker implantation

Specialty: Cardiology

Clinical genetic testing for male factor infertility: current applications and future directions

Spermatogenesis involves the aggregated action of up to 2300 genes, any of which, could, potentially, provide targets for diagnostic tests of male factor infertility. Contrary to the previously proposed common variant hypothesis for common diseases such as male infertility, genome-wide association studies and targeted gene sequencing in cohorts of infertile men have identified only a few gene polymorphisms that are associated with male infertility. Unfortunately, the search for genetic variants associated with male infertility is further hampered by the lack of viable animal models of human spermatogenesis, difficulty in robustly phenotyping infertile men and the complexity of pedigree studies in male factor infertility. In this review, we describe basic genetic principles involved in understanding the genetic basis of male infertility and examine the utility and proper clinical use of the proven genetic assays of male factor infertility, specifically Y chromosome microdeletions, chromosomal translocations, karyotype, cystic fibrosis transmembrane conductance regulator mutation analysis and sperm genetic tests. Unfortunately, these tests are only able to diagnose the cause of about 20% of male factor infertility. The remainder of the review will be devoted to examining novel tests and diagnostic tools that have the potential to explain the other 80% of male factor infertility that is currently classified as idiopathic. Those tests include epigenetic analysis of the spermatozoa and the evaluation of rare genetic variants and copy number variations in patients. Success in advancing to the implementation of such areas is not only dependent on technological advances in the laboratory, but also improved phenotyping in the clinic.

Klinefelter syndrome: are we missing opportunities for early detection?

Klinefelter syndrome is a common condition that remains underdiagnosed, particularly prior to adulthood. Early detection could prevent morbidity and mortality, but the classic phenotype of small testes and tall stature may not be apparent until adolescence, and there is minimal guidance regarding whom to screen. We performed a retrospective study at Boston Children's Hospital in patients with the ICD-9 code for "Klinefelter syndrome" diagnosed prior to age 20 years, and determined age and reason for diagnosis, karyotype, heights, and comorbid conditions. Eighty percent had a 47,XXY karyotype, of whom half were diagnosed at age 11 to 19 years. The most common comorbidities were neurocognitive, including learning disabilities (67%), psychosocial problems (33%), and attention deficit disorder (27%). Subjects were only slightly taller than average in childhood (height standard deviation score = 0.64). These data show that Klinefelter syndrome is associated with long-standing comorbidities that frequently remain under-recognized; a karyotype should be considered in boys with neurocognitive problems.