Testicular function in boys with 47,XYY and relationship to phenotype

Prenatal diagnosis of chromosomal aberrations by chromosomal microarray analysis and pregnancy outcomes of fetuses with polyhydramnios

OBJECTIVES

To explore the prenatal clinical utility of chromosome microarray analysis (CMA) for polyhydramnios and evaluate the short and long-term prognosis of fetuses with polyhydramnios.

METHODS

A total of 600 singleton pregnancies with persistent polyhydramnios from 2014 to 2020 were retrospectively enrolled in this study. All cases received amniocentesis and were subjected to CMA results. All cases were categorized into two groups: isolated polyhydramnios and non-isolated polyhydramnios [with soft marker(s) or with sonographic structural anomalies]. All fetuses were followed up from 6 months to five years after amniocentesis to acquire short and long-term prognosis.

RESULTS

The detection rates of either aneuploidy or pathogenic copy number variants in fetuses with non-isolated polyhydramnios were significantly higher than those with isolated polyhydramnios (5.0 vs. 1.5%, p = 0.0243; 3.6 vs. 0.8%, p = 0.0288). The detection rate of total chromosomal abnormalities in the structural abnormality group was significantly higher than that in the isolated group (10.0 vs. 2.3%, p = 0.0003). In the CMA-negative cases, the incidence of termination of pregnancy, neonatal and childhood death, and non-neurodevelopmental disorders in fetuses combined with structural anomalies was significantly higher than that in fetuses with isolated polyhydramnios (p < 0.05). We did not observe any difference in the prognosis between the isolated group and the combined group of ultrasound soft markers. In addition, the risk of postnatal neurodevelopmental disorders was also consistent among the three groups (1.6 vs. 1.3 vs. 1.8%).

CONCLUSION

For low-risk pregnancies, invasive prenatal diagnosis of isolated polyhydramnios might be unnecessary. CMA should be considered for fetuses with structural anomalies. In CMA-negative cases, the prognosis of fetuses with isolated polyhydramnios was good, and polyhydramnios itself did not increase the risk of postnatal neurological development disorders. The worse prognosis mainly depends on the combination of polyhydramnios with structural abnormalities.

Giftedness and atypical sexual differentiation: enhanced perceptual functioning through estrogen deficiency instead of androgen excess

Syndromic autism spectrum conditions (ASC), such as Klinefelter syndrome, also manifest hypogonadism. Compared to the popular Extreme Male Brain theory, the Enhanced Perceptual Functioning model explains the connection between ASC, savant traits, and giftedness more seamlessly, and their co-emergence with atypical sexual differentiation. Overexcitability of primary sensory inputs generates a relative enhancement of local to global processing of stimuli, hindering the abstraction of communication signals, in contrast to the extraordinary local information processing skills in some individuals. Weaker inhibitory function through gamma-aminobutyric acid type A (GABAA) receptors and the atypicality of synapse formation lead to this difference, and the formation of unique neural circuits that process external information. Additionally, deficiency in monitoring inner sensory information leads to alexithymia (inability to distinguish one's own emotions), which can be caused by hypoactivity of estrogen and oxytocin in the interoceptive neural circuits, comprising the anterior insular and cingulate gyri. These areas are also part of the Salience Network, which switches between the Central Executive Network for external tasks and the Default Mode Network for self-referential mind wandering. Exploring the possibility that estrogen deficiency since early development interrupts GABA shift, causing sensory processing atypicality, it helps to evaluate the co-occurrence of ASC with attention deficit hyperactivity disorder, dyslexia, and schizophrenia based on phenotypic and physiological bases. It also provides clues for understanding the common underpinnings of these neurodevelopmental disorders and gifted populations.

Evidence-based recommendations for delivering the diagnosis of X & Y chromosome multisomies in children, adolescents, and young adults: an integrative review

BACKGROUND

The diagnosis of supernumerary X & Y chromosome variations has increased following the implementation of genetic testing in pediatric practice. Empirical evidence suggests that the delivery of the diagnosis has a lasting impact on how affected individuals and their parents perceive and adapt to the diagnosis. The purpose of this review is to synthesize the literature to obtain useful recommendations for delivering a pediatric diagnosis of a sex chromosome multisomy (SCM) based upon a growing body of quantitative and qualitative literature on patient experiences.

METHODS

We conducted an integrative literature review using PubMed, Web of Science and CINAHL employing keywords "genetic diagnosis delivery," "genetic diagnosis disclosure," "sex chromosome aneuploidy," "Klinefelter syndrome" or ""47, XXY," "Jacob syndrome" or "47, XYY," "Trisomy X," "Triple X" or "47, XXX," and "48 XXYY from January 1, 2000, to October 31, 2023.

RESULTS

Literature supports that patients and parents value the provision of up-to-date information and connection with supportive resources. Discussion of next steps of care, including relevant referrals, prevents perceptions of provider abandonment and commitment to ongoing support. Proactively addressing special concerns such as disclosing the diagnosis to their child, family, and community is also beneficial. Tables are provided for useful information resources, medical specialties that may be required to support patients, and common misconceptions that interfere with accurate information about the diagnosis.

CONCLUSION

Patient experiences suggest there should be heightened attention to diagnosis delivery, in reference to the broader ethical and social impacts of a SCM diagnosis. We present recommendations for optimal disclosure of a SCM diagnosis in early and late childhood, adolescence, and young adulthood.

Sex chromosome aneuploidies and fertility: 47,XXY, 47,XYY, 47,XXX and 45,X/47,XXX

The overall incidence of sex chromosome aneuploidies is approximately 1 per 500 live-born infants, but far more common at conception. I shall review the fertility aspects of the sex chromosome trisomies, XXY, XYY, and XXX, with special reference to the karyotype 45,X/47,XXX. Each has a 'specific' (but variable) phenotype but may be modified by mosaicism. Although the alterations in the hypothalamic-pituitary-gonadal axis are important (and discussed), the emphasis here is on potential fertility and if one might predict that at various epochs within an individual's life span: fetal, 'mini'-puberty, childhood, puberty, and adulthood. The reproductive axis is often affected in females with the 47,XXX karyotype with diminished ovarian reserve and accelerated loss of ovarian function. Fewer than 5% of females with Turner syndrome have the 45,X/47,XXX karyotype. They have taller stature and less severe fertility issues compared to females with the 45,X or other forms of Turner syndrome mosaicism. For the 47,XXY karyotype, non-obstructive azoospermia is almost universal with sperm retrieval by micro-testicular sperm extraction possible in slightly fewer than half of the men. Men with the 47,XYY karyotype have normal to large testes and much less testicular dysfunction than those with the 47,XXY karyotype. They do have a slight increase in infertility compared to the reference population but not nearly as severe as those with the 47,XXY karyotype. Assisted reproductive technology, especially micro-testicular sperm extraction, has an important role, especially for those with 47,XXY; however, more recent data show promising techniques for the in vitro maturation of spermatogonial stem cells and 3D organoids in culture. Assisted reproductive technology is more complex for the female, but vitrification of oocytes has shown promising advances.

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.

Understanding the phenotypic spectrum and family experiences of XYY syndrome: Important considerations for genetic counseling

XYY syndrome is characterized by a variable neurodevelopmental phenotype, with features including developmental delays, cognitive impairments, and an increased risk for mental health conditions. There are two recent developments that have primarily motivated this review. The first is the increased use of non-invasive prenatal screening (NIPS), which will likely result in more individuals being diagnosed with XYY prenatally. As such, health care providers (HCPs) both within genetics and outside of the specialty are more likely to encounter this diagnosis in the future. The second is advances in the understanding of the phenotypic variability of XYY through biobank and deep phenotyping efforts. As the phenotypic spectrum of XYY syndrome continues to expand, families will face greater uncertainty when receiving this diagnosis. Given both of these developments, HCPs will need to have up-to-date and accurate information about XYY to better counsel families. Furthermore, the ability to employ effective counseling techniques, such as anticipatory guidance, will aid in supporting and guiding families through the diagnostic journey. This review aims to provide insight on the neurodevelopmental and psychosocial aspects of XYY syndrome by discussing current research and borrowing from the relevant psychosocial literature of other genetic conditions. In this way, we hope to equip HCPs with the ultimate goal of improving the care and support provided to individuals with XYY and their families.

Decreased levels of γ-aminobutyric acid in temporal lobe of children with 47,XYY syndrome

BACKGROUND

47,XYY syndrome (XYY) is a male sex chromosome disorder where subjects have one X chromosome and two copies of the Y chromosome. XYY is associated with a physical phenotype and carries increased risk of neurodevelopmental disorders such as autism spectrum disorder (ASD). Imbalance of excitation and inhibition has been proposed as a putative biological basis of disorders such as ASD [1-3] and several studies have reported atypical brain γ-aminobutyric acid (GABA) levels in this population. Given the male preponderance in the prevalence of ASD, the unique presence of the Y chromosome in males leads to the intriguing possibility of investigating boys with XYY syndrome as a model of excess Y-chromosome genes.

METHOD

In this study, we investigated the associations of genotype and clinical phenotype with levels of GABA, estimated by regionally localized edited magnetic resonance spectroscopy in boys with 47, XYY syndrome compared to age-matched typically developing (XY) peers.

RESULTS

Overall, we observed a decrease in GABA levels in XYY vs. XY, which appeared more significant in the left compared to the right hemisphere. There was no additional significant modulation of GABA levels in XYY according to presence/absence of ASD diagnosis. Interestingly, a positive correlation between bilateral GABA levels and testosterone levels was observed in pubescent XY boys that was not observed in XYY.

CONCLUSION

The inhibitory neurotransmitter GABA appears to be reduced in boys with 47,XYY, especially in the left hemisphere. Further, the typical association between GABA and testosterone levels, observed in older typically developing control boys was not evident in boys with 47,XYY.

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.