Early developmental impact of sex chromosome trisomies on attention deficit-hyperactivity disorder symptomology in young children

Neurodevelopment in Young Children With Sex Chromosome Trisomies Diagnosed Before Birth: A Cluster Analysis Study

Many studies have investigated the neuropsychological profile of individuals with sex chromosome trisomies (SCTs) and have identified some fragilities in language development within a wide individual variability. However, only a few studies have focused on children in the second year of life (12-24 months), a crucial stage for neurodevelopment. The present study aimed to identify and describe neurodevelopmental patterns in young children with SCTs. Seventy children with SCTs, ranging in age from 14 to 29 months, were administered the Griffiths Mental Development Scales, and their different neurodevelopmental profiles were identified using cluster analysis. Two-step cluster analysis highlighted two profiles of children equally distributed between groups. The two clusters showed a similar pattern but different levels of functioning, with children in Cluster 1 showing a lower performance in all the areas considered than children in Cluster 2. However, in both clusters, all the mean scores were in the normative range, with a significant gap in the linguistic area. Identifying the subgroups of young children with SCTs at higher risk can contribute to developing early monitoring protocols and targeted therapy approaches.

Incidence of sex chromosome aneuploidy in a prenatal population: 27-year longitudinal study in Northern Italy

OBJECTIVES

The availability of cell-free (cf) DNA as a prenatal screening tool affords an opportunity for non-invasive identification of sex chromosome aneuploidy (SCA). The aims of this longitudinal study were to investigate the evolution and frequency of both invasive prenatal diagnostic testing, using amniocentesis and chorionic villus sampling (CVS), and the detection of SCA in cfDNA samples from a large unselected cohort in Northern Italy.

METHODS

The results of genetic testing from CVS and amniotic fluid samples received from public and private centers in Italy from 1995 to 2021 were collected. Chromosomal analysis was performed by routine Q-banding karyotype. Regression analyses and descriptive statistics were used to determine population data trends regarding the frequency of prenatal diagnostic testing and the identification of SCA, and these were compared with the changes in indication for prenatal diagnostic tests and available screening options.

RESULTS

Over a period of 27 years, there were 13 939 526 recorded births and 231 227 invasive procedures were performed, resulting in the prenatal diagnosis of 933 SCAs. After the commercial introduction of cfDNA use in 2015, the frequency of invasive procedures decreased significantly (P = 0.03), while the frequency of prenatal SCA detection increased significantly (P = 0.007). Between 2016 and 2021, a high-risk cfDNA result was the indication for 31.4% of detected sex chromosome trisomies, second only to advanced maternal age.

CONCLUSIONS

Our findings suggest that the inclusion of SCA in prenatal cfDNA screening tests can increase the prenatal diagnosis of affected individuals. As the benefits of early ascertainment are increasingly recognized, it is essential that healthcare providers are equipped with comprehensive and evidence-based information regarding the associated phenotypic differences and the availability of targeted effective interventions to improve neurodevelopmental and health outcomes for affected individuals. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

[Formula: see text] Emotional reactivity and expressivity in young children with sex chromosome trisomies: evidence from psychophysiological and observational data

Although sex chromosomal trisomies (SCT) in children are highly prevalent and associated with an increased risk for neurodevelopmental difficulties including socio-emotional problems, little is known about underlying mechanisms that could drive this risk. Studying emotional reactivity and expressivity of young children with SCT in early childhood could identify deviations in early emotional development and potentially serve as risk markers to guide clinical care in developing interventions. Participants in the current study were 90 SCT children and 97 population-based controls, aged 1 to 7 years, who experienced a stress-inducing event in which physiological (heart rate) and observational data (expression of negative emotions) were collected. Results showed early disturbances in the emotion system of young children with SCT, in terms of blunted but prolonged emotional reactivity and a reduced emotional expressivity in response to stress. Further, the concordance between emotional reactivity (arousal response) and expressivity was significantly lower in SCT, compared to controls. Given the significant impact of emotions on adaptive day-to-day functioning, deviations in processing emotions could be an important underlying mechanism in explaining the heterogeneity and variability in developmental outcomes often described in individuals with SCT.

Neurocognitive and behavioral development in young children (1-7 years) with sex chromosome trisomy

Investigating sex chromosome trisomies (SCTs) may help in understanding neurodevelopmental pathways underlying the risk for neurobehavioral problems and psychopathology. Knowledge about the neurobehavioral phenotype is needed to improve clinical care and early intervention for children with SCT. This is especially relevant considering the increasing number of early diagnosed children with the recent introduction of noninvasive prenatal screening. The TRIXY Early Childhood Study is a longitudinal study designed to identify early neurodevelopmental risks in children with SCT, aged 1-7 years. This review summarizes the results from the TRIXY Early Childhood Study, focusing on early behavioral symptoms in areas of autism spectrum disorder, attention-deficit hyperactivity disorder, and communication disorders, and underlying neurocognitive mechanisms in domains of language, emotion regulation, executive functioning, and social cognition. Behavioral symptoms were assessed through structured behavior observation and parental questionnaires. Neurocognition was measured using performance tests, eyetracking, and psychophysiological measures of arousal. In total, 209 children aged 1-7 years were included: 107 children with SCT (33 XXX, 50 XXY, and 24 XYY) and 102 age-matched population controls. Study outcomes showed early behavioral symptoms in young children with SCT, and neurocognitive vulnerabilities, already from an early age onward. Neurobehavioral and neurocognitive difficulties tended to become more pronounced with increasing age and were rather robust, independent of specific karyotype, pre/postnatal diagnosis, or ascertainment strategy. A more longitudinal perspective on neurodevelopmental 'at-risk' pathways is warranted, also including studies assessing the effectiveness of targeted early interventions. Neurocognitive markers that signal differences in neurodevelopment may prove to be helpful in this. Focusing on early development of language, social cognition, emotion regulation, and executive functioning may help in uncovering early essential mechanisms of (later) neurobehavioral outcome, allowing for more targeted support and early intervention.

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.

Associations of psychiatric disorders with sex chromosome aneuploidies in the Danish iPSYCH2015 dataset: a case-cohort study

BACKGROUND

Increased prevalence of mental illness has been reported in clinical studies of sex chromosome aneuploidies, but accurate population-based estimates of the prevalence and clinical detection rate of sex chromosome aneuploidies and the associated risks of psychiatric disorders are needed. In this study, we provide such estimates, valid for children and young adults of the contemporary Danish population.

METHODS

We used the iPSYCH2015 case-cohort dataset, which is based on a source population of single-born individuals born in Denmark between May 1, 1981, and Dec 31, 2008. The case sample comprises all individuals from the source population with a diagnosis of any index psychiatric disorder (schizophrenia spectrum disorder, bipolar disorder, major depressive disorder, autism spectrum disorder, or ADHD) by the end of follow-up (Dec 31, 2015), registered in the hospital-based Danish Psychiatric Central Research Register. The cohort consists of individuals randomly selected from the source population, and overlaps with the case sample. Biobanked blood samples for individuals in the case and cohort samples underwent genotyping and quality-control filtering, after which we analysed microarray data to detect sex chromosome aneuploidy karyotypes (45,X, 47,XXX, 47,XXY, and 47,XYY). We estimated the population-valid prevalence of these karyotypes from the cohort sample. Weighted Cox proportional hazards models were used to estimate the risks of each index psychiatric disorder associated with each sex chromosome aneuploidy karyotype, by use of date of first hospitalisation with the index disorder in the respective case group and the cohort as outcome. The clinical detection rate was determined by comparing records of clinical diagnoses of genetic conditions from the Danish National Patient Register with sex chromosome aneuploidy karyotype determined by our study.

FINDINGS

The assessed sample comprised 119 481 individuals (78 726 in the case sample and 43 326 in the cohort) who had genotyped and quality-control-filtered blood samples, including 64 533 (54%) people of gonadal male sex and 54 948 (46%) of gonadal female sex. Age during follow-up ranged from 0 to 34·7 years (mean 10·9 years [SD 3·5 years]). Information on ethnicity was not available. We identified 387 (0·3%) individuals as carriers of sex chromosome aneuploidies. The overall prevalence of sex chromosome aneuploidies was 1·5 per 1000 individuals. Each sex chromosome aneuploidy karyotype was associated with an increased risk of at least one index psychiatric disorder, with hazard ratios (HRs) of 2·20 (95% CI 1·42-3·39) for 47,XXY; 2·73 (1·25-6·00) for 47,XXX; 3·56 (1·01-12·53) for 45,X; and 4·30 (2·48-7·55) for 47,XYY. All karyotypes were associated with an increased risk of ADHD (HRs ranging from 1·99 [1·24-3·19] to 6·15 [1·63-23·19]), autism spectrum disorder (2·72 [1·72-4·32] to 8·45 [2·49-28·61]), and schizophrenia spectrum disorder (1·80 [1·15-2·80] to 4·60 [1·57-13·51]). Increased risk of major depressive disorder was found for individuals with 47,XXY (1·88 [1·07-3·33]) and 47,XYY (2·65 [1·12-5·90]), and of bipolar disorder for those with 47,XXX (4·32 [1·12-16·62]). The proportion of sex chromosome aneuploidy carriers who had been clinically diagnosed was 93% for 45,X, but lower for 47,XXY (22%), 47,XXX (15%), and 47,XYY (15%). Among carriers, the risk of diagnosis of at least one index psychiatric disorder did not significantly differ between those who had and had not been clinically diagnosed with sex chromosome aneuploidies (p=0·65).

INTERPRETATION

Increased risks of psychiatric disorders associated with sex chromosome aneuploidies, combined with low rates of clinical diagnosis of sex chromosome aneuploidies, compromise the adequate provision of necessary health care and counselling to affected individuals and their families, which might be helped by increased application of genetic testing in clinical settings.

FUNDING

Lundbeck Foundation and National Institutes of Health.

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.

Speech Sound Development in 18-Month-Old Children With Sex Chromosome Trisomies

PURPOSE

This study aimed to describe speech sound development in a group of 18-month-old children with sex chromosome trisomies (SCTs), compared with a group of typically developing (TD) peers. Concurrent and longitudinal relationships between speech sound abilities and lexical development were examined.

METHOD

A group of 76 children aged 18 months, 38 children prenatally diagnosed with SCTs (12 with XXY, 12 with XYY, and 14 with XXX) and 38 TD children, participated in the study. From video recordings of semistructured naturalistic parent-child play sessions, quantitative and qualitative measures of speech sound development were collected (e.g., the number of consonants, type and place of articulation, and syllable structures used), and group differences were observed. The relationships between the number of consonants produced and vocabulary size at 18 and 24 months were assessed.

RESULTS

At 18 months, children with SCTs used a significantly lower number of consonants than TD children. Qualitatively, children with SCTs used significantly fewer articulatory complex consonants (fricative/affricates) and a more restricted inventory of syllable structures. The number of consonants used was significantly correlated with lexical development at 18 months. Moreover, in the SCTs group (but not in the TD group), the children with lower speech sound development at 18 months showed a significantly smaller vocabulary growth between 18 and 24 months than those with higher speech-sound development.

CONCLUSIONS

Toddlers with SCTs showed a significantly delayed speech sound development pattern rather than an atypical one. Children with SCTs with low speech sound development also showed lower vocabulary growth between 18 and 24 months of age. These results can be clinically relevant for follow-up and treatment planning for children with SCTs.

The developmental impact of sex chromosome trisomies on emerging executive functions in young children: Evidence from neurocognitive tests and daily life skills

Sex chromosomal trisomies (SCT) are associated with impairments in executive functions in school-aged children, adolescents, and adults. However, knowledge on preschool development of executive functions is limited but greatly needed to guide early intervention. The current study examined emerging executive functions in young children with SCT. Participants were 72 SCT children and 70 population-based controls, aged 3-7 years, who completed a neurocognitive assessment of both global executive function (MEFS) and verbal executive function skills (NEPSY Word Generation). Caregivers completed the Behavior Rating Inventory of Executive Function (BRIEF) questionnaire to capture real-world behavioral manifestations of impairments in executive functions. Results showed that impairments were significantly more prevalent in SCT than in controls and already present from 3 years, specifically verbal executive functions and working memory. Broader more pronounced impairments were found in older children with SCT. Age was significantly related to executive functions, but specific domains showed different relations with age. For example, deficits in planning and organizing remained evident with older age in SCT whereas it declined with age in controls. Impairments in executive functions were present across different levels of intelligence. Already at an early age, impairments across executive functions should be considered part of the neurodevelopmental profile of SCT, which appear more prominent at later age. Future studies should investigate developmental pathways of executive functions in SCT, given its relevance in cognitive, social, and emotional development. Executive functions should be screened and monitored in children with SCT and could be an important target of preventive intervention.