Endocrine, cardiac and neuropsychological aspects of adult congenital adrenal hyperplasia

OBJECTIVE

To investigate the metabolic, cardiovascular, and neuropsychological phenotype, quality of life (QoL), and hormonal regulation in individuals with congenital adrenal hyperplasia (CAH), a group of autosomal recessive disorders characterized by impaired synthesis of cortisol in the adrenal cortex and, if untreated compensatory hyperandrogenism. CAH is associated with an increased cardiovascular and metabolic morbidity, possibly due to overtreatment with glucocorticoids, leading to weight gain, insulin resistance, and metabolic syndrome.

DESIGN, PARTICIPANTS, MEASUREMENTS

Thirty-seven individuals with CAH and 33 age- and sex-matched controls were evaluated at a single centre at Aarhus University Hospital with echocardiography, electrocardiogram, 24-h blood pressure, biochemistry, anthropometrics, and autism spectrum, anxiety, depression, personality, cognitive failures, and QoL were assessed using questionnaires.

RESULTS

CAH individuals had lower height than controls (170.5 vs. 182.9 cm in males and 160.2 vs. 170.1 cm in females, p < 0.01). Compared with female controls, females with CAH had higher haemoglobin (8.8 vs. 8.2 mmol/L, p = 0.003) and BMI (29.7 vs. 25.5 kg/m2, p = 0.006), reduced insulin sensitivity (HOMA-IR): 2.7 vs. 1.9, p = 0.018), prolonged E-wave deceleration time (193 vs. 174 cm, p = 0.015), and E/é ratios (5.4 vs. 4.5, p = 0.017), and lower self-reported QoL. Males with CAH had more cognitive complaints (p = 0.034) and higher autistic scores (19.9 vs. 14.9; p = 0.068) compared with male controls. More individuals with CAH than controls reported writing problems.

CONCLUSION

A sex-specific comorbidity profile is evident in CAH, with females presenting with decreased metabolic and overall self-reported health, whereas males with CAH presented with increased cognitive complaints and autistic traits.

Testosterone Replacement Therapy in Klinefelter Syndrome-Follow-up Study Associating Hemostasis and RNA Expression

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.

Complete or partial loss of the Y chromosome in an unselected cohort of 865 non-vasectomized, azoospermic men

BACKGROUND

Structural abnormalities as well as minor variations of the Y chromosome may cause disorders of sex differentiation or, more frequently, azoospermia. This study aimed to determine the prevalence of loss of Y chromosome material within the spectrum ranging from small microdeletions in the azoospermia factor region (AZF) to complete loss of the Y chromosome in azoospermic men.

RESULTS

Eleven of 865 azoospermic men (1.3%) collected from 1997 to 2022 were found to have a karyotype including a 45,X cell line. Two had a pure 45,X karyotype and nine had a 45,X/46,XY mosaic karyotype. The AZF region, or part of it, was deleted in eight of the nine men with a structural abnormal Y-chromosome. Seven men had a karyotype with a structural abnormal Y chromosome in a non-mosaic form. In addition, Y chromosome microdeletions were found in 34 men with a structural normal Y chromosome. No congenital malformations were detected by echocardiography and ultrasonography of the kidneys of the 11 men with a 45,X mosaic or non-mosaic cell line.

CONCLUSIONS

In men with azoospermia, Y chromosome loss ranging from small microdeletions to complete loss of the Y chromosome was found in 6.1% (53/865). Partial AZFb microdeletions may give a milder testicular phenotype compared to complete AZFb microdeletions.

The testicular microvasculature in Klinefelter syndrome is immature with compromised integrity and characterized by excessive inflammatory cross-talk

STUDY QUESTION

Does Klinefelter syndrome (KS) lead to a distinct gene expression pattern at single-cell level in the testes that could provide insight into the reported microvascular dysfunction in the testes?

SUMMARY ANSWER

A distinct gene expression pattern within microvascular-associated cells of males with KS suggests excessive endothelial cell (EC) activation, disorganized vessel formation, and the presence of immature vessels with compromised integrity.

WHAT IS KNOWN ALREADY

Recent studies show that males with KS exhibit microvascular dysfunction in their testes, which affects blood flow and is associated with lower circulating levels of testosterone.

STUDY DESIGN, SIZE, DURATION

A comparative cross-sectional study of males with KS (n = 6), non-obstructive azoospermia (NOA) (n = 5), cryptozoospermia (n = 3), and controls (n = 15) was carried out.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We analyzed publicly available single-cell RNA sequencing data of testicular cells from males with KS, males with NOA, males with cryptozoospermia, and controls. The integration of these datasets allowed us to analyze gene expression profiles and communication patterns among the cell types within the testis and to identify capillary ECs to investigate changes at the microvascular level.

MAIN RESULTS AND THE ROLE OF CHANCE

Rooted in changes at the single-cell level, our study demonstrates a shift in gene expression forming the foundation for altered cellular communication, microvascular remodeling, and pro-inflammatory responses within the testes of males with KS. We identified genes that were dysregulated in capillary ECs from males with KS (Padj < 0.05). Specifically, the unique microvascular gene expression in males with KS indicated enhanced capillary EC activation and increased inflammatory cross-talk, leading to impaired vessel maturation and increased EC barrier permeability.

LIMITATIONS, REASONS FOR CAUTION

Our study is constrained by an unbalanced design, with varying sample sizes and number of cells within each group. We acknowledge the restricted access to clinical information. In addition, our findings were deduced from changes in gene expression, which limits us to infer potential biological consequences arising from these alterations. Furthermore, the absence of a pre-pubertal age group limits the generalizability of our findings and warrants further investigation.

WIDER IMPLICATIONS OF THE FINDINGS

This study offers novel insights into the testicular pathophysiology in KS and underscores the potential contribution of microvascular dysfunction to the hypogonadism and infertility observed in males with KS. While this study aims to better understand the microvascular dysfunction in KS, the precise connections to testosterone deficiency and testicular atrophy remain to be fully elucidated.

STUDY FUNDING/COMPETING INTEREST(S)

A.S. was supported by the Independent Research Fund Denmark (0134-00130B). C.H.G. was supported by Novo Nordisk Foundation (NNF15OC0016474, NNF20OC0060610), 'Fonden til lægevidenskabens fremme', the Familien Hede Nielsen foundation and the Independent Research Fund Denmark (0134-00406A). E.B.J. was supported by Aarhus University and E.B.J. and C.H.G by the Independent Research Fund Denmark (2096-00165A). J.M.K. was supported by Lundbeckfonden (R307-2018-3667), Carlsberg Fonden (CF19-0687), Novo Nordisk Fonden (0073440) and Steno Diabetes Center Aarhus (SDCA). The authors declare no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

The multi-omic landscape of sex chromosome abnormalities: current status and future directions

Sex chromosome abnormalities (SCAs) are chromosomal disorders with either a complete or partial loss or gain of sex chromosomes. The most frequent SCAs include Turner syndrome (45,X), Klinefelter syndrome (47,XXY), Trisomy X syndrome (47,XXX), and Double Y syndrome (47,XYY). The phenotype seen in SCAs is highly variable and may not merely be due to the direct genomic imbalance from altered sex chromosome gene dosage but also due to additive alterations in gene networks and regulatory pathways across the genome as well as individual genetic modifiers. This review summarizes the current insight into the genomics of SCAs. In addition, future directions of research that can contribute to decipher the genomics of SCA are discussed such as single-cell omics, spatial transcriptomics, system biology thinking, human-induced pluripotent stem cells, and animal models, and how these data may be combined to bridge the gap between genomics and the clinical phenotype.

Dosage of the pseudoautosomal gene SLC25A6 is implicated in QTc interval duration

The genetic architecture of the QT interval, defined as the period from onset of depolarisation to completion of repolarisation of the ventricular myocardium, is incompletely understood. Only a minor part of the QT interval variation in the general population has been linked to autosomal variant loci. Altered X chromosome dosage in humans, as seen in sex chromosome aneuploidies such as Turner syndrome (TS) and Klinefelter syndrome (KS), is associated with altered QTc interval (heart rate corrected QT), indicating that genes, located in the pseudoautosomal region 1 of the X and Y chromosomes may contribute to QT interval variation. We investigate the dosage effect of the pseudoautosomal gene SLC25A6, encoding the membrane ADP/ATP translocase 3 in the inner mitochondrial membrane, on QTc interval duration. To this end we used human participants and in vivo zebrafish models. Analyses in humans, based on 44 patients with KS, 44 patients with TS, 59 male and 22 females, revealed a significant negative correlation between SLC25A6 expression level and QTc interval duration. Similarly, downregulation of slc25a6 in zebrafish increased QTc interval duration with pharmacological inhibition of K_ATP channels restoring the systolic duration, whereas overexpression of SLC25A6 shortened QTc, which was normalized by pharmacological activation of K_ATP channels. Our study demonstrate an inverse relationship between SLC25A6 dosage and QTc interval indicating that SLC25A6 contributes to QT interval variation.

X chromosome dosage and the genetic impact across human tissues

BACKGROUND

Sex chromosome aneuploidies (SCAs) give rise to a broad range of phenotypic traits and diseases. Previous studies based on peripheral blood samples have suggested the presence of ripple effects, caused by altered X chromosome number, affecting the methylome and transcriptome. Whether these alterations can be connected to disease-specific tissues, and thereby having clinical implication for the phenotype, remains to be elucidated.

METHODS

We performed a comprehensive analysis of X chromosome number on the transcriptome and methylome in blood, fat, and muscle tissue from individuals with 45,X, 46,XX, 46,XY, and 47,XXY.

RESULTS

X chromosome number affected the transcriptome and methylome globally across all chromosomes in a tissue-specific manner. Furthermore, 45,X and 47,XXY demonstrated a divergent pattern of gene expression and methylation, with overall gene downregulation and hypomethylation in 45,X and gene upregulation and hypermethylation in 47,XXY. In fat and muscle, a pronounced effect of sex was observed. We identified X chromosomal genes with an expression pattern different from what would be expected based on the number of X and Y chromosomes. Our data also indicate a regulatory function of Y chromosomal genes on X chromosomal genes. Fourteen X chromosomal genes were downregulated in 45,X and upregulated in 47,XXY, respectively, in all three tissues (AKAP17A, CD99, DHRSX, EIF2S3, GTPBP6, JPX, KDM6A, PP2R3B, PUDP, SLC25A6, TSIX, XIST, ZBED1, ZFX). These genes may be central in the epigenetic and genomic regulation of sex chromosome aneuploidies.

CONCLUSION

We highlight a tissue-specific and complex effect of X chromosome number on the transcriptome and methylome, elucidating both shared and non-shared gene-regulatory mechanism between SCAs.

New developments and future trajectories in supernumerary sex chromosome abnormalities: a summary of the 2022 3rd International Workshop on Klinefelter Syndrome, Trisomy X, and XYY

The 3rd International Workshop on Klinefelter Syndrome, Trisomy X, and 47,XYY syndrome was held in Leiden, the Netherlands, on September 12-14, 2022. Here, we review new data presented at the workshop and discuss scientific and clinical trajectories. We focus on shortcomings in knowledge and therefore point out future areas for research. We focus on the genetics and genomics of supernumerary sex chromosome syndromes with new data being presented. Most knowledge centre specifically on Klinefelter syndrome, where aspects on testosterone deficiency and the relation to bone, muscle and fat were discussed, as was infertility and the treatment thereof. Both trisomy X and 47,XYY syndrome are frequently affected by infertility. Transitioning of males with Klinefelter syndrome was addressed, as this seemingly simple process in practise is often difficult. It is now realized that neurocognitive changes are pervasive in all supernumerary sex chromosome syndromes, which were extensively discussed. New intervention projects were also described, and exciting new data concerning these were presented. Advocacy organizations were present, describing the enormous burden carried by parents when having to explain their child's specific syndrome to most professionals whenever in contact with health care and education systems. It was also pointed out that most countries do not have health care systems that diagnose patients with supernumerary sex chromosome syndromes, thus pinpointing a clear deficiency in the current genetic testing and care models. At the end of the workshop, a roadmap towards the development of new international clinical care guidelines for Klinefelter syndrome was decided.

Epigenetic and transcriptomic alterations in offspring born to women with type 1 diabetes (the EPICOM study)

BACKGROUND

Offspring born to women with pregestational type 1 diabetes (T1DM) are exposed to an intrauterine hyperglycemic milieu and has an increased risk of metabolic disease later in life. In this present study, we hypothesize that in utero exposure to T1DM alters offspring DNA methylation and gene expression, thereby altering their risk of future disease.

METHODS

Follow-up study using data from the Epigenetic, Genetic and Environmental Effects on Growth, Metabolism and Cognitive Functions in Offspring of Women with Type 1 Diabetes (EPICOM) collected between 2012 and 2013.

SETTING

Exploratory sub-study using data from the nationwide EPICOM study.

PARTICIPANTS

Adolescent offspring born to women with T1DM (n=20) and controls (n=20) matched on age, sex, and postal code.

MAIN OUTCOME MEASURES

This study investigates DNA methylation using the 450K-Illumina Infinium assay and RNA expression (RNA sequencing) of leucocytes from peripheral blood samples.

RESULTS

We identified 9 hypomethylated and 5 hypermethylated positions (p < 0.005, |ΔM-value| > 1) and 38 up- and 1 downregulated genes (p < 0.005, log2FC ≥ 0.3) in adolescent offspring born to women with T1DM compared to controls. None of these findings remained significant after correction for multiple testing. However, we identified differences in gene co-expression networks, which could be of biological significance, using weighted gene correlation network analysis. Interestingly, one of these modules was significantly associated with offspring born to women with T1DM. Functional enrichment analysis, using the identified changes in methylation and gene expression as input, revealed enrichment in disease ontologies related to diabetes, carbohydrate and glucose metabolism, pathways including MAPK1/MAPK3 and MAPK family signaling, and genes related to T1DM, obesity, atherosclerosis, and vascular pathologies. Lastly, by integrating the DNA methylation and RNA expression data, we identified six genes where relevant methylation changes corresponded with RNA expression (CIITA, TPM1, PXN, ST8SIA1, LIPA, DAXX).

CONCLUSIONS

These findings suggest the possibility for intrauterine exposure to maternal T1DM to impact later in life methylation and gene expression in the offspring, a profile that may be linked to the increased risk of vascular and metabolic disease later in life.

Sex chromosome aneuploidies give rise to changes in the circular RNA profile: A circular transcriptome-wide study of Turner and Klinefelter syndrome across different tissues

Purpose: The landscape of circular RNAs (circRNAs), an important class of non-coding RNAs that regulate gene expression, has never been described in human disorders of sex chromosome aneuploidies. We profiled circRNAs in Turner syndrome females (45,X; TS) and Klinefelter syndrome males (47,XXY; KS) to investigate how circRNAs respond to a missing or an extra X chromosome.

Methods: Samples of blood, muscle and fat were collected from individuals with TS (n = 33) and KS (n = 22) and from male (n = 16) and female (n = 44) controls. CircRNAs were identified using a combination of circRNA identification pipelines (CIRI2, CIRCexplorer2 and circRNA_finder).

Results: Differential expression of circRNAs was observed throughout the genome in TS and KS, in all tissues. The host-genes from which several of these circRNAs were derived, were associated with known phenotypic traits. Furthermore, several differentially expressed circRNAs had the potential to capture micro RNAs that targeted protein-coding genes with altered expression in TS and KS.

Conclusion: Sex chromosome aneuploidies introduce changes in the circRNA transcriptome, demonstrating that the genomic changes in these syndromes are more complex than hitherto thought. CircRNAs may help explain some of the genomic and phenotypic traits observed in these syndromes.

Reduced fibrin clot lysis in Klinefelter syndrome associated with hypogonadism

Objective

Klinefelter syndrome (KS) is associated with increased risk of thrombosis. Hypogonadism and accumulating body fat in KS have a potential impact on fibrinolysis. In this study, we assessed the fibrinolytic system and the association with testosterone levels in KS.

Design

This study is a cross-sectional comparison of men with KS and age-matched male controls.

Methods

Fibrin clot lysis was evaluated by turbidity measurements and by measuring levels of individual fibrinolytic proteins in plasma samples. Fibrin clot structure was evaluated by scanning electron microscopy. Total testosterone was measured by liquid chromatography-tandem mass spectrometry. Body fat was evaluated by dual-energy X-ray absorptiometry.

Results

In this study, 45 men with KS and 45 age- and education-matched controls were included. Men with KS had a 24% reduction in fibrin clot lysis compared with controls (46.2 ± 17.1 vs 60.6 ± 18.8 %/h, P = 0.0003) and higher levels of fibrinogen, factor XIII (P ≤ 0.01), and plasminogen activator inhibitor type 1 (P = 0.04). Men with KS had lower total testosterone (P = 0.008) and higher body fat (P = 0.001). In KS, reduced fibrin clot lysability was associated with higher fibrinogen and body fat related to decreasing total testosterone and hypogonadism among men with KS. Fibrin clot structure was not different compared to KS and controls.

Conclusions

Fibrin clot lysis in KS was markedly reduced, potentially contributing to a prothrombotic state and increasing thrombotic risk. Hypogonadism in KS was associated with increased fibrinogen and total body fat, predicting reduced fibrin clot lysis.

Familial colorectal cancer and tooth agenesis caused by an AXIN2 variant: how do we detect families with rare cancer predisposition syndromes?

We present a three-generation family with an AXIN2 variant and a family history of colorectal cancer (CRC), colon polyps and tooth agenesis. A likely pathogenic variant was detected in the AXIN2 gene (c.1994dup; p.(Asn666Glnfs*41)). This variant has previously been associated with tooth agenesis and polyposis, only. In this case report we describe eight carriers with tooth agenesis and variable clinical findings, including polyps and CRC. Our case provides additional knowledge to the sparse data on genotype-phenotype association related to AXIN2 associated cancer syndrome. Further, our case highlights the importance of analysing an extended CRC and oligodontia/ectodermal dysplasia gene panel including AXIN2 but also raises awareness and discussion about appropriate surveillance program.

[Beckwith-Wiedemann over-growth syndrom]

We report a boy with congenital hemihyperplasia, umbilical hernia and temporary neonatal hypoglycemia, who was confirmed to have BWS caused by paternal uniparental disomy of chromosome 11p15.5. Additional phenotypic features comprising scoliosis, nephromegaly, focal partial epilepsy and delayed psychomotor development were coherent with the underlying genotype. This case emphasizes the importance of identifying the underlying genetic variant in order to acknowledge and manage the associated clinical complications and specific risk profile.

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

Context

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

Objective

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

Methods

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

Results

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

Conclusion

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

Klinefelter syndrome or testicular dysgenesis: Genetics, endocrinology, and neuropsychology

Klinefelter syndrome (47,XXY) is a frequent chromosomal disorder among males, often presenting with hypergonadotropic hypogonadism, small firm testicles, metabolic disorders, neurocognitive challenges, and increased height. Neurologic disorders such as epilepsy, seizures, and tremor as well as psychiatric disorders are also seen more frequently. The neurocognitive deficits seen are present in many areas of cognition, typically affecting general cognitive abilities, language, and executive functioning. Also, social dysfunction is frequent. Dyslexia is present in more than half of all males. Brain imaging studies generally show a typical pattern, with many nuclei and brain areas being smaller than among controls. However, it has not been possible to link the brain alterations found in imaging studies with the neurocognitive profile. The genetics underlying the phenotypic traits found among males with Klinefelter syndrome still remains to be elucidated; however, recent studies have described pervasive changes in the methylome and transcriptome and new and interesting candidate genes have been pinpointed, but their involvement in the phenotype of Klinefelter syndrome has not been proven.

Morbidity in Klinefelter syndrome and the effect of testosterone treatment

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.

Changes in the cohort composition of turner syndrome and severe non-diagnosis of Klinefelter, 47,XXX and 47,XYY syndrome: a nationwide cohort study

Background

Knowledge on the prevalence of sex chromosome abnormalities (SCAs) is limited, and delayed diagnosis or non-diagnosis of SCAs are a continuous concern. We aimed to investigate change over time in incidence, prevalence and age at diagnosis among Turner syndrome (TS), Klinefelter syndrome (KS), Triple X syndrome (Triple X) and Double Y syndrome (Double Y).

Methods

This study is a nationwide cohort study in a public health care system. The Danish Cytogenetic Central Registry (DCCR) holds information on all karyotypes performed in Denmark since 1961. We identified all individuals in the DCCR with a relevant SCA during 1961–2014; TS: n = 1156; KS: n = 1235; Triple X: n = 197; and Double Y: n = 287. From Statistics Denmark, which holds an extensive collection of data on the Danish population, complete data concerning dates of death and migrations in and out of Denmark were retrieved for all individuals.

Results

The prevalence among newborns was as follows: TS: 59 per 100,000 females; KS: 57 per 100,000 males; Triple X: 11 per 100,000 females; and Double Y: 18 per 100,000 males. Compared with the expected number among newborns, all TS, 38% of KS, 13% of Triple X, and 18% of Double Y did eventually receive a diagnosis. The incidence of TS with other karyotypes than 45,X (P < 0.0001), KS (P = 0.02), and Double Y (P = 0.03) increased during the study period whereas the incidence of 45,X TS decreased (P = 0.0006). The incidence of Triple X was stable (P = 0.22).

Conclusions

The prevalence of TS is higher than previously identified, and the karyotypic composition of the TS population is changing. Non-diagnosis is extensive among KS, Triple X and Double Y, whereas all TS seem to become diagnosed. The diagnostic activity has increased among TS with other karyotypes than 45,X as well as among KS and Double Y.

Anxiety and depression in Klinefelter syndrome: The impact of personality and social engagement

Klinefelter syndrome (KS) (47, XXY) is the most common sex chromosome disorder, with a prevalence of 1 in every 660 newborn males. Despite the profound adverse effects of anxiety and depression, and their greater prevalence in KS populations, no research has been conducted to date to identify the determinants of anxiety and depression among patients with KS. We examined the relationships between personality traits, social engagement, and anxiety and depression symptoms among KS patients (n = 69) and a group of male controls (n = 69) matched for age and years of education. KS patients experienced more anxiety and depression symptoms than control participants. Neuroticism was the strongest and most consistent mediator between KS and both anxiety and depression symptoms. This research suggests that neuroticism may play a central role in attention switching, anxiety and depression among patients with Klinefelter syndrome. The central role of neuroticism suggests that it may be used to help identify and treat KS patients at particularly high-risk for attention-switching deficits, anxiety and depression.

DNA hypermethylation and differential gene expression associated with Klinefelter syndrome

Klinefelter syndrome (KS) has a prevalence ranging from 85 to 250 per 100.000 newborn boys making it the most frequent sex chromosome aneuploidy in the general population. The molecular basis for the phenotypic traits and morbidity in KS are not clarified. We performed genome-wide DNA methylation profiling of leucocytes from peripheral blood samples from 67 KS patients, 67 male controls and 33 female controls, in addition to genome-wide RNA-sequencing profiling in a subset of 9 KS patients, 9 control males and 13 female controls. Characterization of the methylome as well as the transcriptome of both coding and non-coding genes identified a unique epigenetic and genetic landscape of both autosomal chromosomes as well as the X chromosome in KS. A subset of genes show significant correlation between methylation values and expression values. Gene set enrichment analysis of differentially methylated positions yielded terms associated with well-known comorbidities seen in KS. In addition, differentially expressed genes revealed enrichment for genes involved in the immune system, wnt-signaling pathway and neuron development. Based on our data we point towards new candidate genes, which may be implicated in the phenotype and further point towards non-coding genes, which may be involved in X chromosome inactivation in KS.

Klinefelter Syndrome: Integrating Genetics, Neuropsychology, and Endocrinology

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

The role of genes, intelligence, personality, and social engagement in cognitive performance in Klinefelter syndrome

INTRODUCTION

The determinants of cognitive deficits among individuals with Klinefelter syndrome (KS) are not well understood. This study was conducted to assess the impact of general intelligence, personality, and social engagement on cognitive performance among patients with KS and a group of controls matched for age and years of education.

METHODS

Sixty-nine patients with KS and 69 controls were assessed in terms of IQ, NEO personality inventory, the Autism Spectrum Quotient (AQ) scale, and measures of cognitive performance reflecting working memory and executive function.

RESULTS

Patients with KS performed more poorly on memory and executive-function tasks. Patients with KS also exhibited greater neuroticism and less extraversion, openness, and conscientiousness than controls. Memory deficits among patients with KS were associated with lower intelligence, while diminished executive functioning was mediated by both lower intelligence and less social engagement.

CONCLUSION

Our results suggest that among patients with KS, memory deficits are principally a function of lower general intelligence, while executive-function deficits are associated with both lower intelligence and poorer social skills. This suggests a potential influence of social engagement on executive cognitive functioning (and/or vice-versa) among individuals with KS, and perhaps those with other genetic disorders. Future longitudinal research would be important to further clarify this and other issues discussed in this research.

Klinefelter syndrome has increased brain responses to auditory stimuli and motor output, but not to visual stimuli or Stroop adaptation

Klinefelter syndrome (47, XXY) (KS) is a genetic syndrome characterized by the presence of an extra X chromosome and low level of testosterone, resulting in a number of neurocognitive abnormalities, yet little is known about brain function. This study investigated the fMRI-BOLD response from KS relative to a group of Controls to basic motor, perceptual, executive and adaptation tasks. Participants (N: KS = 49; Controls = 49) responded to whether the words "GREEN" or "RED" were displayed in green or red (incongruent versus congruent colors). One of the colors was presented three times as often as the other, making it possible to study both congruency and adaptation effects independently. Auditory stimuli saying "GREEN" or "RED" had the same distribution, making it possible to study effects of perceptual modality as well as Frequency effects across modalities. We found that KS had an increased response to motor output in primary motor cortex and an increased response to auditory stimuli in auditory cortices, but no difference in primary visual cortices. KS displayed a diminished response to written visual stimuli in secondary visual regions near the Visual Word Form Area, consistent with the widespread dyslexia in the group. No neural differences were found in inhibitory control (Stroop) or in adaptation to differences in stimulus frequencies. Across groups we found a strong positive correlation between age and BOLD response in the brain's motor network with no difference between groups. No effects of testosterone level or brain volume were found. In sum, the present findings suggest that auditory and motor systems in KS are selectively affected, perhaps as a compensatory strategy, and that this is not a systemic effect as it is not seen in the visual system.

Klinefelter Syndrome and medical treatment: hypogonadism and beyond

Klinefelter syndrome (KS), though described more than 70 years ago, still imposes significant diagnostic challenges. Based on data from epidemiological studies, KS is associated with increased morbidity and mortality. Although the pathophysiology and etiology behind these observations are as yet not well understood, a significant contribution of hypogonadism, central to the syndrome, is traditionally suspected. However, other unknown effects inherent to the syndrome also seem to modify the disease pattern. Herein we show that KS is under-diagnosed since only roughly 25% of patients are diagnosed and the mean age of diagnosis is during adult life. KS is associated with increased morbidity resulting in loss of 2-5 years in lifespan with increased mortality from different diseases and a poor socioeconomic profile. Small testes, hypergonadothrophic hypogonadism and cognitive impairment are usually found. The accompanying hypogonadism can lead to altered body composition and a risk of developing metabolic syndrome, type 2 diabetes and cardiovascular disease. Cancer risk is generally not different from that observed in the background population, although specific cancers like breast cancer and extragonadal germ cell tumors are seen more frequently in KS. The mainstay of medical treatment is testosterone replacement therapy to both attenuate acute and long-term consequences of hypogonadism and possibly prevent the frequent comorbidity. We believe that the diagnostic challenges should be tackled more efficiently, while there is also a pressing need to generate better evidence for timing and the proper dose of testosterone replacement. We advocate for a multidisciplinary setup with the inclusion of pediatricians, speech therapists, general practitioners, psychologists, infertility specialists, urologists and endocrinologists.

Neuropsychology and socioeconomic aspects of Klinefelter syndrome: new developments

PURPOSE OF REVIEW

To summarize recent important studies on neuropsychology and epidemiology of Klinefelter syndrome. PubMed was searched for 'Klinefelter', 'Klinefelter's' and 'XXY' in titles and abstracts. Relevant studies were obtained and reviewed, as well as other articles selected by the authors.

RECENT FINDINGS

Klinefelter syndrome is the most common sex-chromosome disorder in humans, affecting one in 660 men. The key findings in Klinefelter syndrome are small testes, hypergonadotropic hypogonadism and cognitive impairment. Klinefelter syndrome scores significantly below education matched controls on a range of cognitive tests with verbal skills displaying the largest effects. Boys with Klinefelter syndrome are often in the need of speech therapy and many suffer from learning disability and may benefit from special education. New studies are elucidating aspects of cognitive functioning and suggesting that neuropsychological treatment may be of value. The socioeconomic status and educational level of Klinefelter syndrome is severely affected with many struggling to achieve any or only shorter education, resulting in low-income levels and early retirement. In addition, few become fathers and fewer live with a partner compared with controls. Medical treatment is mainly testosterone replacement therapy in order to alleviate acute and long-term consequences of hypogonadism, as well as, treating or preventing the frequent comorbidity.

SUMMARY

The neurocognitive phenotype of Klinefelter syndrome is being unraveled and the need for psychological and cognitive treatment in many cases is evident. The neurocognitive deficits no doubt influence the socioeconomic status of many Klinefelter syndrome patients, which is clearly inferior to age-matched controls.

The role of hypogonadism in Klinefelter syndrome

Klinefelter syndrome (KS) (47, XXY) is the most abundant sex-chromosome disorder, and is a common cause of infertility and hypogonadism in men. Most men with KS go through life without knowing the diagnosis, as only 25% are diagnosed and only a few of these before puberty. Apart from hypogonadism and azoospermia, most men with KS suffer from some degree of learning disability and may have various kinds of psychiatric problems. The effects of long-term hypogonadism may be diffi cult to discern from the gene dose effect of the extra X-chromosome. Whatever the cause, alterations in body composition, with more fat and less muscle mass and diminished bone mineral mass, as well as increased risk of metabolic consequences, such as type 2 diabetes and the metabolic syndrome are all common in KS. These findings should be a concern as they are not simply laboratory findings; epidemiological studies in KS populations show an increased risk of both hospitalization and death from various diseases. Testosterone treatment should be offered to KS patients from early puberty, to secure a proper masculine development, nonetheless the evidence is weak or nonexisting, since no randomized controlled trials have ever been published. Here, we will review the current knowledge of hypogonadism in KS and the rationale for testosterone treatment and try to give our best recommendations for surveillance of this rather common, but often ignored, syndrome.

Neuroanatomical correlates of Klinefelter syndrome studied in relation to the neuropsychological profile

Brain imaging in Klinefelter syndrome (47, XXY) (KS), a genetic disorder characterized by the presence of an extra X chromosome, may contribute to understanding the relationship between gene expression, brain structure, and subsequent cognitive disabilities and psychiatric disorders. We conducted the largest to date voxel-based morphometry study of 65 KS subjects and 65 controls matched for age and education and correlated these data to neuropsychological test scores. The KS patients had significantly smaller total brain volume (TBV), total gray matter volume (GMV) and total white matter volume (WMV) compared to controls, whereas no volumetric difference in cerebral spinal fluid (CSF) was found. There were no differences in TBV, GMV, WMV or CSF between testosterone treated KS (T-KS) and untreated KS (U-KS) patients. Compared to controls, KS patients had significantly decreased GMV bilaterally in insula, putamen, caudate, hippocampus, amygdala, temporal pole and frontal inferior orbita. Additionally, the right parahippocampal region and cerebellar volumes were reduced in KS patients. KS patients had significantly larger volumes in right postcentral gyrus, precuneus and parietal regions. Multivariate classification analysis discriminated KS patients from controls with 96.9% (p < 0.001) accuracy. Regression analyses, however, revealed no significant association between GMV differences and cognitive and psychological factors within the KS patients and controls or the groups combined. These results show that although gene dosage effect of having and extra X-chromosome may lead to large scale alterations of brain morphometry and extended cognitive disabilities no simple correspondence links these measures.

Clinical review: Klinefelter syndrome--a clinical update

CONTEXT

Recently, new clinically important information regarding Klinefelter syndrome (KS) has been published. We review aspects of epidemiology, endocrinology, metabolism, body composition, and neuropsychology with reference to recent genetic discoveries.

EVIDENCE ACQUISITION

PubMed was searched for "Klinefelter," "Klinefelter's," and "XXY" in titles and abstracts. Relevant papers were obtained and reviewed, as well as other articles selected by the authors.

EVIDENCE SYNTHESIS

KS is the most common sex chromosome disorder in males, affecting one in 660 men. The genetic background is the extra X-chromosome, which may be inherited from either parent. Most genes from the extra X undergo inactivation, but some escape and serve as the putative genetic cause of the syndrome. KS is severely underdiagnosed or is diagnosed late in life, roughly 25% are diagnosed, and the mean age of diagnosis is in the mid-30s. KS is associated with an increased morbidity resulting in loss of approximately 2 yr in life span with an increased mortality from many different diseases. The key findings in KS are small testes, hypergonadotropic hypogonadism, and cognitive impairment. The hypogonadism may lead to changes in body composition and a risk of developing metabolic syndrome and type 2 diabetes. The cognitive impairment is mainly in the area of language processing. Boys with KS are often in need of speech therapy, and many suffer from learning disability and may benefit from special education. Medical treatment is mainly testosterone replacement therapy to alleviate acute and long-term consequences of hypogonadism as well as treating or preventing the frequent comorbidity.

CONCLUSIONS

More emphasis should be placed on increasing the rate of diagnosis and generating evidence for timing and dose of testosterone replacement. Treatment of KS should be a multidisciplinary task including pediatricians, speech therapists, general practitioners, psychologists, infertility specialists, urologists, and endocrinologists.

The macrophage low-grade inflammation marker sCD163 is modulated by exogenous sex steroids

Soluble CD163 (sCD163) is a novel marker linked to states of low-grade inflammation such as diabetes, obesity, liver disease, and atherosclerosis, all prevalent in subjects with Turner syndrome (TS) and Klinefelter syndrome (KS). We aimed to assess the levels of sCD163 and the regulation of sCD163 in regards to treatment with sex hormone therapy in males with and without KS and females with and without TS. Males with KS (n=70) and age-matched controls (n=71) participating in a cross-sectional study and 12 healthy males from an experimental hypogonadism study. Females with TS (n=8) and healthy age-matched controls (n=8) participating in a randomized crossover trial. The intervention comprised of treatment with sex steroids. Males with KS had higher levels of sCD163 compared with controls (1.75 (0.47-6.90) and 1.36 (0.77-3.11) respectively, P<0.001) and the levels correlated to plasma testosterone (r=-0.31, P<0.01), BMI (r=0.42, P<0.001), and homeostasis model of assessment insulin resistance (r=0.46, P<0.001). Treatment with testosterone did not significantly lower sCD163. Females with TS not receiving hormone replacement therapy (HRT) had higher levels of sCD163 than those of their age-matched healthy controls (1.38±0.44 vs 0.91±0.40, P=0.04). HRT and oral contraceptive therapy decreased sCD163 in TS by 22% (1.07±0.30) and in controls by 39% (0.55±0.36), with significance in both groups (P=0.01 and P=0.04). We conclude that levels of sCD163 correlate with endogenous testosterone in KS and are higher in KS subjects compared with controls, but treatment did not significantly lower levels. Both endogenous and exogenous estradiol in TS was associated with lower levels of sCD163.