Postnatal screening for Klinefelter syndrome: is there a rationale?

Early neurodevelopmental and medical profile in children with sex chromosome trisomies: Background for the prospective eXtraordinarY babies study to identify early risk factors and targets for intervention

Sex chromosome trisomies (SCT), including Klinefelter syndrome/XXY, Trisomy X, and XYY syndrome, occur in 1 of every 500 births. The past decades of research have resulted in a broadening of known associated medical comorbidities as well as advances in psychological research. This review summarizes what is known about early neurodevelopmental, behavioral, and medical manifestations in young children with SCT. We focus on recent research and unanswered questions related to the risk for neurodevelopmental disorders that commonly present in the first years of life and discuss the medical and endocrine manifestations of SCT at this young age. The increasing rate of prenatal SCT diagnoses provides the opportunity to address gaps in the existing literature in a new birth cohort, leading to development of the eXtraordinarY Babies Study. This study aims to better describe and compare the natural history of SCT conditions, identify predictors of positive and negative outcomes in SCT, evaluate developmental and autism screening measures commonly used in primary care practices for the SCT population, and build a rich data set linked to a bank of biological samples for future study. Results from this study and ongoing international research efforts will inform evidence-based care and improve health and neurodevelopmental outcomes.

Gene Copy Number Quantification of SHOX, VAMP7, and SRY for the Detection of Sex Chromosome Aneuploidies in Neonates

Aims: To explore the feasibility of detecting sex chromosome aneuploidies (SCAs) by means of gene copy number quantification of short stature homeobox (SHOX), vesicle-associated membrane protein 7 (VAMP7), and SRY in newborns. Materials and Methods: Gene doses of SHOX, VAMP7, and SRY were determined by quantitative polymerase chain reaction (qPCR) using DNA obtained from dried blood samples from newborns. Relative quantification values were obtained. An aneuploidy profile was established according to cutoff values. Samples with ≥2 gene doses (out of range) were reanalyzed, and those with aneuploidy profiles were confirmed by karyotyping. Sensitivity, specificity, and positive and negative predictive values were obtained. Results: A total of 10,033 samples were collected (4945 females and 5088 males). Of 244 (2.43%) samples with ≥2 gene doses that were retested, 20 cases were confirmed. The overall incidence of SCAs was 1 in 500 live newborns. There were six cases of Turner syndrome (1/824), 3 cases of XXX (1/1648), 7 cases of Klinefelter syndrome (1/726), and 4 cases of of XYY (1/1272). The sensitivity was 0.952 (95.42%); the specificity was 0.975 (97.56%); the positive predictive value was 0.909 (90.91%) and the negative predictive value was 0.987 (98.77%). Conclusions: Gene copy number analyses of the VAMP7, SHOX, and SRY genes by qPCR from blood samples spotted onto filter paper is a highly reliable method for the early detection of male and female SCAs.

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.

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.

Rapid screening for Klinefelter syndrome with a simple high-resolution melting assay: a multicenter study

Klinefelter syndrome (KS) is the set of symptoms that result from the presence of an extra X chromosome in males. Postnatal population-based KS screening will enable timely diagnosis of this common chromosomal disease, providing the opportunity for early intervention and therapy at the time point when they are most effective and may prevent later symptoms or complications. Therefore, through this study, we introduced a simple high-resolution melting (HRM) assay for KS screening and evaluated its clinical sensitivity and specificity in three medical centers using 1373 clinical blood samples. The HRM assay utilized a single primer pair to simultaneously amplify specific regions in zinc finger protein, X-linked (ZFX) and zinc finger protein, Y-linked (ZFY). In cases of KS, the ratios of ZFX/ZFY are altered compared to those in normal males. As a result, the specific melting profiles differ and can be differentiated during data analysis. This HRM assay displayed high analytical specificity over a wide range of template DNA amounts (5 ng–50 ng) and reproducibility, high resolution for detecting KS mosaicism, and high clinical sensitivity (100%) and specificity (98.1%). Moreover, the HRM assay was rapid (2 h per run), inexpensive (0.2 USD per sample), easy to perform and automatic, and compatible with both whole blood samples and dried blood spots. Therefore, this HRM assay is an ideal postnatal population-based KS screening tool that can be used for different age groups.

The benefits and limitations of cell-free DNA screening for 47, XXY (Klinefelter syndrome)

OBJECTIVE

The purpose of this paper is to provide an overview of the 47, XXY syndrome, which is the most commonly occurring X and Y chromosomal variation. This paper seeks to review what is currently known of noninvasive prenatal testing (NIPT) and 47, XXY and investigate potential risks and benefits of prenatal identification.

METHOD

A literature review of NIPT and 47, XXY was performed to identify limitations of current NIPT techniques.

RESULTS

As NIPT becomes an increasingly more routine procedure, prenatal findings of 47, XXY may increase. Awareness of this disorder and appropriate genetic counseling is necessary.

CONCLUSION

X and Y chromosomal variations will be identified through this screening, and the benefits and limitations to this finding need to be thoughtfully considered. © 2017 John Wiley & Sons, Ltd.

Novel methylation specific real-time PCR test for the diagnosis of Klinefelter syndrome

The aim of this study was to design a molecular assay for the diagnosis of Klinefelter syndrome (KS), based on the detection of supernumerary X-chromosomes (X-chs). DNA was extracted from peripheral blood samples of twenty-six 47,XXY males; two 46,XY/47,XXY males; twenty-two 46,XY males; and 15 females; and deaminated. Methylation-specific quantitative polymerase chain reaction (MS-qPCR) was performed using primers for unmethylated and methylated copies of the X-ch inactive-specific transcript (XIST-U and XIST-M) gene. X-ch disomy was determined on the basis of XIST methylation status. Degree of mosaicism in the 46,XY/47,XXY males was compared with karyotype and fluorescent in situ hybridization (FISH) results. Data analysis was performed using the Roche® LightCycler software V. 3.5.3., including determination of crossing points (CPs) by fit-point analysis and melting curve analysis. X-ch disomy was detected in all female controls and KS patients; male controls expressed XIST-M only. CPs ranged from 29.5 to 32.5 (standard deviation (s.d.) 0.8) for XIST-U and from 29 to 31 (s.d. 0.6) for XIST-M. Limit of detection of mosaicism was 1%. Based on XIST-U/XIST-M ratios for the two 47,XXY/46,XY patients, the calculated degree of mosaicism (1.8% and 17.8%) was comparable to FISH results (2.3% and 15%, respectively). Turnaround time from DNA deamination to final data analysis was under 9 h. We conclude that MS-qPCR is a sensitive, specific and rapid test for the detection of X-ch disomy, with applicability for the screening and diagnosis of KS, even in the setting of low grade 47,XXY/46,XY mosaicism.

Preserving children's fertility: two tales about children's right to an open future and the margins of parental obligations

The sources, extent and margins of parental obligations in taking decisions regarding their children's medical care are subjects of ongoing debates. Balancing children's immediate welfare with keeping their future open is a delicate task. In this paper, we briefly present two examples of situations in which parents may be confronted with the choice of whether to authorise or demand non-therapeutic interventions on their children for the purpose of fertility preservation. The first example is that of children facing cancer treatment, and the second of children with Klinefelter syndrome. We argue that, whereas decisions of whether to preserve fertility may be prima facie within the limits of parental discretion, the right to an open future does not straightforwardly put parents under an obligation to take actions that would detect or relieve future infertility in their children-and indeed in some cases taking such actions is problematic.

Preserving children's fertility: two tales about children's right to an open future and the margins of parental obligations

The sources, extent and margins of parental obligations in taking decisions regarding their children's medical care are subjects of ongoing debates. Balancing children's immediate welfare with keeping their future open is a delicate task. In this paper, we briefly present two examples of situations in which parents may be confronted with the choice of whether to authorise or demand non-therapeutic interventions on their children for the purpose of fertility preservation. The first example is that of children facing cancer treatment, and the second of children with Klinefelter syndrome. We argue that, whereas decisions of whether to preserve fertility may be prima facie within the limits of parental discretion, the right to an open future does not straightforwardly put parents under an obligation to take actions that would detect or relieve future infertility in their children-and indeed in some cases taking such actions is problematic.

Homicide and Klinefelter syndrome: a complex interaction

INTRODUCTION

Several studies have shown an association between homicide and sexual chromosomal abnormalities, but data are still lacking regarding Klinefelter syndrome.

METHODS

We retrospectively reviewed two cases of homicide perpetrators who were both diagnosed with Klinefelter syndrome on the basis of a karyotype analysis. A neurocognitive assessment was also performed (MMSE, Frontal Assessment Battery, brain CT, and electroencephalogram).

RESULTS

Numerous intermediate risk factors of homicide were shared by our two cases, including dispositional (male gender, young age, low socioeconomic status), historical (prior arrest record and past conviction for any offense), contextual (unemployment), and clinical (alcohol abuse).

CONCLUSION

It is important that clinicians go beyond obvious risk factors, such as chromosomal abnormalities, to pinpoint other meaningful risk factors and potentially facilitate preventive approaches.

A qualitative exploration of mothers' and fathers' experiences of having a child with Klinefelter syndrome and the process of reaching this diagnosis

Klinefelter syndrome (KS) is a common genetic condition that is currently under-diagnosed. The phenotype is broad, with physical, medical and psychosocial features ranging from mild to severe. When a child is diagnosed with KS, the parents may spend months to years searching for a diagnosis. This study used a qualitative methods approach to explore parents' experiences of having a child with KS and receiving a diagnosis. Fifteen semistructured one-to-one in-depth interviews were conducted to explore their experiences and views. The interviews were then transcribed, coded and thematically analysed. The interviews revealed that parents had diverse experiences related to: the timing of the diagnosis of their child and reasons why their child was investigated for KS; the information that was provided at the time of diagnosis; the supports that were available and the concerns that parents held for the future of their child. The conclusions from this study were that parents' experiences of having a child with KS and receiving a diagnosis were complex and multifaceted. This experience was shaped by the timing of when the diagnosis was received, who provided the diagnosis, what information was provided from health-care professionals and that which parents may have encountered on the internet. The long-term experiences for parents were also impacted by the level of support they received. These findings have implications for the process by which KS is recognised by the health-care community and supports available for families.

47,XXY Klinefelter syndrome: clinical characteristics and age-specific recommendations for medical management

47,XXY (Klinefelter syndrome) is the most frequent sex chromosomal disorder and affects approximately one in 660 newborn boys. The syndrome is characterized by varying degrees of cognitive, social, behavioral, and learning difficulties and in adulthood additionally primary testicular failure with small testes, hypergonadotropic hypogonadism, tall stature, and eunuchoid body proportions. The phenotype is variable ranging from "near-normal" to a significantly affected individual. In addition, newborns with Klinefelter syndrome generally present with a normal male phenotype and the only consistent clinical finding in KS is small testes, that are most often not identified until after puberty. Decreased awareness of this syndrome among health professionals and a general perception that all patients with 47,XXY exhibit the classic textbook phenotype results in a highly under-diagnosed condition with up to 75% of the patients left undetected. Typically, diagnosis is delayed with the majority of patients identified during fertility workup in adulthood, and only 10% of patients diagnosed prior to puberty. Early detection of this syndrome is recommended in order to offer treatment and intervention at the appropriate ages and stages of development for the purpose of preventing osteopenia/osteoporosis, metabolic syndrome, and other medical conditions related to hypogonadism and to the XXY as well as minimizing potential learning and psychosocial problems. The aim of this review is to present the clinical aspects of XXY and the age-specific recommendations for medical management. © 2013 Wiley Periodicals, Inc.

Timing of diagnosis of 47,XXY and 48,XXYY: a survey of parent experiences

47,XXY/Klinefelter syndrome is the most common sex chromosomal aneuploidy, yet 64% of males with this condition go undiagnosed. 48,XXYY is less common and there is less known about the diagnosis. The objective of this study is to describe the diagnosis experiences of parents of males with 47,XXY and 48,XXYY. Parents of 89 males with 47,XXY and 76 males with 48,XXYY completed a survey that gathered data about their experiences leading to a diagnosis, including the current age of the child, age at diagnosis, reasons for initial concern, and the specialists providing the diagnosis. In the 47,XXY cohort diagnosed postnatally, 59% presented with developmental delay, with a mean age at first parental concern of 5.2 years and mean age of diagnosis at 10.0 years. The remaining 41% presented with endocrinologic issues with a mean age at first concern of 19.1 years and mean age of diagnosis at 21.1 years. In the 48,XXYY group, 93% presented with developmental delay, with mean age at first parental concern of 2.4 years and mean age of diagnosis at 7.6 years. Hence, the average time from initial parental concern to diagnosis of 47,XXY or 48,XXYY ranges from 2 to 5 years, with those presenting with developmental issues having a longer lag to diagnosis compared to those presenting with endocrinologic issues. Increased awareness of the developmental, psychological, and medical features of 47,XXY and 48,XXYY is important to facilitate timely diagnosis and initiation of appropriate screenings and treatments that are important for optimal outcomes.

Rapid Diagnosis of Aneuploidy by High-Resolution Melting Analysis of Segmental Duplications

BACKGROUND

Several molecular methods, such as quantitative fluorescence PCR and multiplex ligation-dependent probe amplification, currently serve as important adjuncts to traditional karyotyping for the diagnosis of aneuploidy; however, the performance or throughput limitations of these methods hinder their use for routine prenatal diagnosis and population-based postnatal screening. We developed a novel approach, called “high-resolution melting analysis of segmental duplications,” to detect common aneuploidies.

METHODS

In this method, similar sequences located on different chromosomes are amplified simultaneously with a single primer set; the PCR products are then analyzed by high-resolution melting. Aneuploidy-associated dosage abnormalities produce different ratios of similar amplicons, which produce melting curves that are detectably different from those of samples from unaffected individuals. We applied this method to DNA samples isolated from individuals with trisomy 21 (n = 48), trisomy 18 (n = 10), trisomy 13 (n = 3), 45,X (n = 8), and 47,XXY (n = 14), and from unaffected controls (n = 48).

RESULTS

As judged by the karyotyping results, our method attained 100% diagnostic sensitivity and 99.6% diagnostic specificity. Moreover, our method was able to detect a change in chromosome dosage as low as 1.05-fold.

CONCLUSIONS

This novel method clearly differentiates samples of patients with common aneuploidies from those of unaffected controls, while markedly simplifying the assays and reducing time and costs. The assay has sufficient throughput to meet the demands of large-scale testing, such as population-based postnatal screening, and is thus suitable for routine use.