A review of neurocognitive functioning of children with sex chromosome trisomies: Identifying targets for early intervention

Social Communication in Young Children With Sex Chromosome Trisomy (XXY, XXX, XYY): A Study With Eye Tracking and Heart Rate Measures

OBJECTIVE

Children with sex chromosome trisomy (SCT) have an increased risk for suboptimal development. Difficulties with language are frequently reported, start from a very young age, and encompass various domains. This cross-sectional study examined social orientation with eye tracking and physiological arousal responses to gain more knowledge on how children perceive and respond to communicative bids and evaluated the associations between social orientation and language outcomes, concurrently and 1 year later.

METHOD

In total, 107 children with SCT (33 XXX, 50 XXY, and 24 XYY) and 102 controls (58 girls and 44 boys) aged between 1 and 7 years were included. Assessments took place in the USA and Western Europe. A communicative bids eye tracking paradigm, physiological arousal measures, and receptive and expressive language outcomes were used.

RESULTS

Compared to controls, children with SCT showed reduced attention to the face and eyes of the on-screen interaction partner and reduced physiological arousal sensitivity in response to direct versus averted gaze. In addition, social orientation to the mouth was related to concurrent receptive and expressive language abilities in 1-year-old children with SCT.

CONCLUSIONS

Children with SCT may experience difficulties with social communication that extend past the well-recognized risk for early language delays. These difficulties may underlie social-behavioral problems that have been described in the SCT population and are an important target for early monitoring and support.

Prenatal diagnosis, pregnancy determination and follow up of sex chromosome aneuploidy screened by non-invasive prenatal testing from 122 453 unselected singleton pregnancies: A retrospective analysis of 7-year experience

The phenotype of SCA patients are diversities, make prenatal counseling and parental decision-making following the prenatal diagnosis of SCA more complicated and challenging. NIPT has higher sensitivity and specificity in screening trisomy 21 syndrome, but the effectiveness of NIPT in detecting SCA is still controversial. This study is a large-scale retrospective cohort of positive SCA screened from unselected singleton pregnancies by non-invasive prenatal testing (NIPT) from a single prenatal center of a tertiary hospital. Clinical information, indications, diagnostic results, ultrasound findings, pregnancy determinations, and follow-up were reviewed and analyzed. 596 cases of SCA positive were screened out of 122 453, giving a positive detection rate of 0.49%. 510 cases (85.6%) conducted with amniocentesis to detect fetal chromosome, of which 236 were confirmed as true positive of SCA with PPV of 46.3% (236/510). Of the 236 cases confirmed as true positive SCA, 114 cases (48.3%)chose to terminate the pregnancy (93.0%, 65.3%, 15.4% and 10.9% for 45,X, 47,XXY, 47,XXX and 47,XYY, respectively), 122 cases (51.7%) elected to continue the pregnancy. In conclusions, NIPT as a first-tier routine method for screening autosomal aneuploidies, also could play an important role in screening SCA. Low-risk pregnant women are the main indication for the detection of SCA as NIPT test provides to non-selective population. For 47,XXX and 47,XYY with mild phenotype, couples would like to continue the pregnancy. But for 45,X and 47,XXY, parents apt to terminate pregnancy no matter ultrasound abnormalities were found or not.

Performance of noninvasive prenatal screening for fetal sex chromosome aneuploidies in a cohort of 116,862 pregnancies

BACKGROUND

Noninvasive prenatal screening (NIPS) has shown good performance in screening common aneuploidies. However, its performance in detecting fetal sex chromosome aneuploidies (SCAs) needs to be evaluated in a large cohort.

RESEARCH DESIGN AND METHODS

In this retrospective observation, a total of 116,862 women underwent NIPS based on DNA nanoball sequencing from 2015 to 2022. SCAs were diagnosed based on karyotyping or chromosomal microarray analysis (CMA). Among them, 2,084 singleton pregnancies received karyotyping and/or CMA. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of NIPS for fetal SCAs were evaluated.

RESULTS

The sensitivity was 97.7% (95%CI, 87.7-99.9), 87.3% (95% CI, 76.5-94.4), 96.1% (95%CI, 86.5-99.5), and 95.7% (95% CI, 78.1-99.9), the PPV was 25.8% (95%CI, 19.2-33.2), 80.9% (95%CI, 69.5-89.4), 79.0% (95%CI, 66.8-88.3), and 53.7% (95%CI, 37.4-69.3) for 45,X, 47,XXY, 47,XXX, and 47,XYY, respectively. The specificity was 94.1% (95%CI, 93.0-95.1) for 45,X, and more than 99.0% for sex chromosome trisomy (SCT). The NPV was over 99.0% for all.

CONCLUSIONS

NIPS screening for fetal SCAs has high sensitivity, specificity and NPV. The PPV of SCAs was moderate, but that of 45,X was lower than that of SCTs. Invasive prenatal diagnosis should be recommended for high-risk patients.

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.

Early symptoms of autism spectrum disorder (ASD) in 1-8 year old children with sex chromosome trisomies (XXX, XXY, XYY), and the predictive value of joint attention

The objective of the present study is to investigate the impact of Sex Chromosome Trisomy (SCT; XXX, XXY, XYY) on the early appearance of Autism Spectrum Disorder (ASD) symptoms, and the predictive value of Joint Attention for symptoms of ASD. SCTs are specific genetic conditions that may serve as naturalistic 'at risk' models of neurodevelopment, as they are associated with increased risk for neurobehavioral vulnerabilities. A group of 82 children with SCT (aged 1-8 years) was included at baseline of this longitudinal study. Joint Attention was measured at baseline with structured behavior observations according to the Early Social Communication Scales. ASD symptoms were assessed with the Modified Checklist for Autism in Toddlers questionnaire and Autism Diagnostic Interview-Revised in a 1-year follow-up. Recruitment and assessment took place in the Netherlands and in the United States. The results demonstrate that ASD symptoms were substantially higher in children with SCT compared to the general population, with 22% of our cohort at clinical risk for ASD, especially in the domain of social interaction and communication. Second, a predictive value of Joint Attention was found for ASD symptoms at 1-year follow-up. In this cohort, no differences were found between karyotype-subtypes. In conclusion, from a very early age, SCT can be associated with an increased risk for vulnerabilities in adaptive social functioning. These findings show a neurodevelopmental impact of the extra X or Y chromosome on social adaptive development associated with risk for ASD already from early childhood onward. These findings advocate for close monitoring and early (preventive) support, aimed to optimize social development of young children with SCT.

Early Social Behavior in Young Children with Sex Chromosome Trisomies (XXX, XXY, XYY): Profiles of Observed Social Interactions and Social Impairments Associated with Autism Spectrum Disorder (ASD)

Individuals with Sex Chromosome Trisomies (SCT; XXX, XXY, XYY) have an increased vulnerability for developing challenges in social adaptive functioning. The present study investigates social interaction behavior in the context of varying social load, and Autism Spectrum Disorder (ASD) symptomatology in young children aged 1-7.5 years old, with SCT (N = 105) and control children (N = 101). Children with SCT show less interaction behaviors and more social withdrawal, as compared to their control peers, which were most evident in the high social load condition. Second, social impairments related to ASD are more prevalent, as compared to controls (27.1% at clinical level). These findings stress the importance of early monitoring and (preventive) support of early social development in young children with SCT.

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.

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.

Structural and pragmatic language in young children with sex chromosome trisomy (XXX, XXY, XYY): Predictive value for neurobehavioral problems one year later

Objective: To investigate pragmatic language abilities in young children with an increased risk for adverse neurobehavioral and neurocognitive outcomes due to an extra X or Y chromosome (sex chromosome trisomy; SCT) and to investigate to what degree early structural and pragmatic language abilities are predictive of neurobehavioral problems one year later. Method: In total, 72 children with SCT and 71 controls aged 3-7 years were included. Language assessments included parent-reported pragmatic language skills and direct assessment of structural language abilities. Parent-reported behavioral outcomes were measured one year after the initial language assessment. Results: Children with SCT demonstrated weaker pragmatic language skills compared to controls. These differences were not driven by karyotype, time of diagnosis, or ascertainment bias and irrespective of the presence of structural language impairment. Odds of having pragmatic difficulties was 23 times higher in the SCT group, with 25% of the children not meeting age-expectations. In addition, language, in particular pragmatic language, was an important predictor for later affective, oppositional defiant, pervasive developmental, attention deficit, and social-emotional problems in young children with SCT. Conclusions: This study is one of the first studies that directly illustrates the relationship between language and behavioral outcomes in children with SCT. Our results stress the importance to closely monitor pragmatic language in addition to structural language in clinical care of children with SCT, as pragmatic language abilities could serve as an early marker for children at risk for developing behavioral problems.

"Knowledge is Power": Parent Views on the Benefits of Early Diagnosis and Awareness of Sex Chromosome Multisomy Among Pediatric Professionals

OBJECTIVE

Pediatric diagnoses of sex chromosome multisomies (SCMs) have increased as genetic testing has expanded. However, depending on SCM presentation, there may be significant delays between symptom recognition and diagnosis. We conducted a survey of parents of children diagnosed with SCMs to understand their experiences receiving an SCM diagnosis and their support needs.

METHODS

We conducted an inductive qualitative analysis of open-ended survey responses for iterative themes related to presenting symptoms, diagnostic odyssey, immediate and long-term support needs, and awareness of SCMs.

RESULTS

Of the 323 parents who completed the survey, 185 parents received a pediatric diagnosis (0-21 years) in a child. Many parents expressed feelings of relief when receiving the diagnosis, especially if it occurred after a lengthy diagnostic odyssey. Parents reported frustration that their child's nonmedical symptoms, including learning disabilities, speech delays, attention deficits, and behavioral issues, were not flagged as potential indications for SCMs and suggested that greater awareness of SCMs by pediatricians, educators, and other professionals involved in their child's care may lead to earlier diagnosis and intervention.

CONCLUSION

This is the largest qualitative study to date examining parent and caregiver experiences with a pediatric diagnosis of SCMs. Increased knowledge and awareness of nonmedical SCM symptoms are needed among medical, education, occupational, and psychology professionals for early testing referral and improved support of children with SCMs.

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.

How do genetic tests answer questions about neurodevelopmental differences? A sociological take

When it comes to neurodevelopmental differences, a genetic test result can provide compelling answers. However, it is not always clear what the relevant question is. If we want to understand the impact of a genetic diagnosis such as NGLY1 deficiency or the fragile X, trisomy X, or 22q11.2 deletion syndromes on people with neurodevelopmental differences, we must be mindful about what exactly a genetic test is supposed to tell us, where and for whom it matters, and which avenues for action it opens or forecloses. These are all moving targets. Specifically, I discuss the shifting ways a genetic test result can answer the following questions. What is this person's diagnosis? What symptoms and developmental differences are they likely to experience? What is the best way to approach their development, treatment, and care? Will they have a life worth living? When you unpack the sociological nuances of each question, the history behind them, and the uneven ways they are asked, the meanings of the answers change quite radically. I discuss the implications for social inequalities and urge experts and stakeholders to exercise agency when they interpret a genetic diagnosis. WHAT THIS PAPER ADDS: The questions a genetic test can answer depend on a range of social factors. Whether and how a genetic test result affects diagnosis, identity, prognosis, and treatment is a moving target. Genetics creates questions about a life worth living that it cannot answer alone. Stakeholders must choose the questions about neurodevelopmental differences that genetics should answer.

The impact of sex chromosome trisomies (XXX, XXY, XYY) on gaze towards faces and affect recognition: a cross-sectional eye tracking study

BACKGROUND

About 1:650-1000 children are born with an extra X or Y chromosome (47,XXX; 47,XXY; 47,XYY), which results in a sex chromosome trisomy (SCT). This international cross-sectional study was designed to investigate gaze towards faces and affect recognition during early life of children with SCT, with the aim to find indicators for support and treatment.

METHODS

A group of 101 children with SCT (aged 1-7 years old; Mage= 3.7 years) was included in this study, as well as a population-based sample of 98 children without SCT (Mage= 3.7). Eye gaze patterns to faces were measured using an eye tracking method that quantifies first fixations and fixation durations on eyes of static faces and fixation durations on eyes and faces in a dynamic paradigm (with two conditions: single face and multiple faces). Affect recognition was measured using the subtest Affect Recognition of the NEPSY-II neuropsychological test battery. Recruitment and assessment took place in the Netherlands and the USA.

RESULTS

Eye tracking results reveal that children with SCT show lower proportion fixation duration on faces already from the age of 3 years, compared to children without SCT. Also, impairments in the clinical range for affect recognition were found (32.2% of the SCT group scored in the well below average range).

CONCLUSIONS

These results highlight the importance to further explore the development of social cognitive skills of children with SCT in a longitudinal design, the monitoring of affect recognition skills, and the implementation of (preventive) interventions aiming to support the development of attention to social important information and affect recognition.

Supporting students with sex chromosome aneuploidies in educational settings: Results of a nationwide survey

Children with sex chromosome aneuploidies (SCAs) are at an increased risk for neurocognitive and behavioral disorders that may interfere with academic success, including early developmental delays, learning disabilities, executive function problems, and social communication deficits. The present national survey aimed to update and extend our understanding of school supports and educational outcomes for students with these increasingly common genetic diagnoses. Parents of children with a diagnosed SCA, birth to 21 years, living in the United States (N = 248), responded to an electronic survey with questions focused on school support plans, academic accommodations, educational therapies, school completion, and perceptions of educator awareness of SCAs. Results revealed high rates of delayed kindergarten, grade retention in primary years, and educational support plans (IEPs = 71%; Section 504 Plans = 26%). A majority (73%) of respondents with children over age 18 years (N = 41) reported their children successfully completed high school, and nearly half (46%) pursued post-secondary education opportunities. Many parents reported their children's educators had little to no knowledge of SCA conditions, justifying a need to train teachers and policy makers in the unique educational needs of children and adolescents with SCAs. School psychologists should be aware of the frequent need for accommodations and individualized support plans in this population so they can support children and families by advocating for early and comprehensive evaluations and intervention plans.

Language Development in Sex Chromosome Trisomies: Developmental Profiles at 2 and 4 Years of Age, and Predictive Measures

PURPOSE

Describing language development in children with sex chromosome trisomies (SCT) and testing the predictive value of early language measures on later outcomes.

METHOD

Thirteen children with SCT were followed longitudinally. Their developmental profile was assessed, with particular attention to language, at 2 and 4 years. The predictive value of direct (spontaneous speech analysis) and indirect (communicative development inventory) language measures at 2 on performances at 4 was tested.

RESULTS

Language performances at both ages were lower than non-verbal development. At 2, more than 50% of the group produced less than 50 words. At 4, impaired performances were observed in speech sound development and expressive morpho-syntax. Direct measures of Pre-syntactic development predicted later global language outcomes and Sentence Repetition. The number of consonants used at 2 was significantly related to Nonword Repetition at 4.

CONCLUSIONS

The study highlights the importance of early detection and careful follow-up for children with SCT.

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.

'I Wish the School Had a Better Understanding of the Diagnosis': parent perspectives on educational needs of students with sex chromosome aneuploidies

Students with sex chromosome aneuploidies (SCAs) are at increased risk for learning disabilities and often require individualized supports in the school setting. Parents of students with rare disorders such as SCAs possess a unique understanding of their child's educational experiences and play a crucial role in the development of successful school support plans. This international survey study aimed to inductively capture parent perspectives on educational needs and supports for students with SCAs. Parents of youth with SCAs ages 5-21 years (n = 305) provided free-text responses to open-ended questions about their child's education. Qualitative content analysis using a bioecological systems framework resulted in three overarching themes. Overall, parents identified multiple factors related to the SCA diagnosis that act as barriers to learning, a strong need for school-based social and emotional supports, and elusive or incomplete educational support plans. Based on these findings, we recommend developing robust family-school partnerships, increased collaboration between the school and the child's medical team, and acknowledgement of the significant role the genetic condition plays in the educational experiences of students with SCAs. Specific suggestions for school support plans for students with SCAs are explored, such as providing school-based behavioral health supports and explicit teaching of executive function strategies.

Early impact of X- and Y-chromosome variations (XXX, XXY, XYY) on social communication and social emotional development in 1-2-year-old children

Sex chromosome trisomies (SCTs) are characterized by an extra X‐ or Y‐chromosome (XXX, XXY, XYY). The present study aims to investigate early signs of social communication and social emotional development in very young children with SCT. Thirty‐four children with SCT (aged 12–24 months) were included in this study, as well as 31 age‐matched controls. Social communication was measured with structured behavior observations according to the Early Social Communication Scales, and social emotional developmental level with the Bayley Social Emotional parental questionnaire. Recruitment and assessment took place in the Netherlands and in the United States. On average, 12–24‐month old children with SCT showed difficulties with early social communication, more so in responding to others as compared to initiating social communications. During social interactions, children with SCT made less frequent eye contact, compared to controls. Also, difficulties in acquiring social emotional milestones were found in 1‐year old children with SCT, with 44% of the children having social emotional vulnerabilities in the borderline or extremely low range, compared to typically developing children. In this cohort, no significant predictive effects of karyotype‐subtype (XXX, XXY, XYY) were found. Already from a very early age, SCT can be associated with increased risk for vulnerabilities in adaptive social functioning. These findings suggest that SCT impact the maturation of the social brain already from an early age, and stress the importance of early monitoring and (preventive) support early social development in young children with SCT.

[Formula: see text]A cross-sectional study of early language abilities in children with sex chromosome trisomy (XXY, XXX, XYY) aged 1-6 years

Children with sex chromosome trisomy (SCT) are at increased risk for developing language difficulties. Earlier studies have reported that as many as 70-80% of individuals with SCT show some form of language difficulties. Language develops rapidly in the first years of life; knowledge about language development at an early age is needed. The present study aims to identify the language abilities of young children with SCT across multiple language domains and to identify the percentage of children that, according to clinical guidelines, have language difficulties. Children between the ages of 1-6-years (NSCT = 103, Ncontrols = 102) were included. Nonverbal communication, early vocabulary, semantic, syntax, and phonological skills were assessed. Language difficulties were already present in 1-year-old children with SCT and across the age range in various language domains. Clinical classification showed that, depending on the assessed domain, 14.8-50.0% of the children scored below the 16th percentile. There was no effect of time of diagnosis, ascertainment bias, research site, nor SCT specific karyotype (XXX, XXY, XYY) on language outcomes. Overall, language difficulties can already be present in very young children with SCT within various language domains. These findings appear to be robust within the SCT group. These results highlight the importance of monitoring both receptive and expressive language development already at the earliest stages of nonverbal communication. Finally, as early language skills are the building blocks for later social communication, literacy, and self-expression, studies that investigate the effect of early interventions on later language outcomes are warranted.

The Impact of Sex Chromosome Trisomies (XXX, XXY, XYY) on Early Social Cognition: Social Orienting, Joint Attention, and Theory of Mind

OBJECTIVE

About 1:650-1,000 children are born with an extra X or Y chromosome (XXX; XXY; XYY), which results in a sex chromosome trisomy (SCT). This study aims to cross-sectionally investigate the impact of SCT on early social cognitive skills. Basic orienting toward social cues, joint attention, and theory of mind (ToM) in young children with SCT were evaluated.

METHOD

About 105 children with SCT (range: 1-7 years old) were included in this study, as well as 96 age-matched nonclinical controls. Eyetracking paradigms were used to investigate the eye gaze patterns indicative of joint attention skills and orienting to social interactions. The ToM abilities were measured using the subtest ToM of the Developmental NEuroPSYchological Assessment, second edition, neuropsychological test battery. Recruitment and assessment took place in the Netherlands and in the United States.

RESULTS

Eyetracking results revealed difficulties in children with SCT in social orienting. These difficulties were more pronounced in children aged 3 years and older, and in boys with 47,XYY. Difficulties in joint attention were found over all age groups and karyotypes. Children with SCT showed impairments in ToM (26.3% in the [well] below expected level), increasing with age. These impairments did not differ between karyotypes.

CONCLUSIONS

An impact of SCT on social cognitive abilities was found already at an early age, indicating the need for early monitoring and support of early social cognition. Future research should explore the longitudinal trajectories of social development in order to evaluate the predictive relationships between social cognition and outcome later in life in terms of social functioning and the risk for psychopathology.

Early Preventive Intervention for Young Children With Sex Chromosome Trisomies (XXX, XXY, XYY): Supporting Social Cognitive Development Using a Neurocognitive Training Program Targeting Facial Emotion Understanding

BACKGROUND

Sex Chromosome Trisomies (SCTs; XXX, XXY, XYY) are genetic conditions that are associated with increased risk for neurodevelopmental problems and psychopathology. There is a great need for early preventive intervention programs to optimize outcome, especially considering the increase in prenatal diagnoses due to recent advances in non-invasive prenatal screening. This study is the first to evaluate efficacy of a neurocognitive training in children with SCT. As social behavioral problems have been identified as among the key areas of vulnerability, it was targeted at improving a core aspect of social cognition, the understanding of social cues from facial expressions.

METHODS

Participants were 24 children with SCT and 18 typically developing children, aged 4-8 years old. Children with SCT were assigned to a training (n = 13) or waiting list (no-training) group (n = 11). Children in the training group completed a neurocognitive training program (The Transporters), aimed to increase understanding of facial emotions. Participants were tested before and after the training on facial emotion recognition and Theory of Mind abilities (NEPSY-II), and on social orienting (eyetracking paradigm). The SCT no-training group and typically developing control group were also assessed twice with the same time interval without any training. Feasibility of the training was evaluated with the Social Validity Questionnaire filled out by the parents and by children's ratings on a Visual Analog Scale.

RESULTS

The SCT training group improved significantly more than the SCT no-training and TD no-training group on facial emotion recognition (large effect size; η p 2 = 0.28), performing comparable to typical controls after completing the training program. There were no training effects on ToM abilities and social orienting. Both children and parents expressed satisfaction with the feasibility of the training.

CONCLUSIONS

The significant improvement in facial emotion recognition, with large effect sizes, suggests that there are opportunities for positively supporting the development of social cognition in children with an extra X- or Y-chromosome, already at a very young age. This evidence based support is of great importance given the need for preventive and early training programs in children with SCT, aimed to minimize neurodevelopmental impact.

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

Individuals with sex chromosome trisomies ([SCT], XXX, XXY, and XYY)) are at increased risk for neurodevelopmental problems, given that a significant portion of the sex chromosome genes impact brain functioning. An elevated risk for psychopathology has also been described, including attention deficit-hyperactivity disorder (ADHD). The present study aimed at identifying early markers of ADHD, providing the first investigation of ADHD symptomology in very young children with SCT. The variety, type, and severity of ADHD symptomology in 1-6-year-old children with SCT (n = 104) were compared with population-based controls (n = 101) using the strengths and weaknesses of ADHD symptoms and normal-behavior (SWAN) parent-report questionnaire. ADHD symptomology was significantly more prevalent in SCT and already present from toddlerhood on, compared to controls. ADHD inattention symptoms were significantly increased in all karyotypes (XXX, XXY, and XYY), boys with XYY also showed significantly more hyperactivity/impulsivity symptoms than controls. Inattentiveness was more pronounced with increasing age for SCT, in contrast to controls. Within the SCT group, 24% of the children had significantly elevated ADHD symptoms at a clinical level. Already from an early age on, SCT is associated with a risk for ADHD, suggesting that its neurodevelopmental risk lies anchored in early brain maturation. Studying this genetically vulnerable population allows for the prospective study of risk markers to facilitate early and preventive interventions.

The comorbidity landscape of 47,XXX syndrome: A nationwide epidemiologic study

PURPOSE

This study aimed to describe the comorbidity pattern in 47,XXX syndrome.

METHODS

This was a registry-based study of hospital diagnoses and prescribed medication in a nationwide cohort of females with 47,XXX (n = 103) and 46,XX/47,XXX (n = 57) in which they were compared with 16,000 age-matched general population female controls.

RESULTS

The overall occurrence of hospital diagnoses was significantly increased in females with 47,XXX when compared with controls (incidence rate ratio = 2.1, CI = 1.7-2.5), and when divided into 19 organ-specific groups, there was a significantly increased risk in the following 14 groups: infection, blood, endocrine and metabolism, mental, nervous system, eye, ear, respiratory, oral cavity and gastrointestinal, musculoskeletal, perinatal, congenital malformations, external factors, and "other." The risk of being prescribed any medication was not significantly increased in females with 47,XXX when compared with controls (hazard ratio = 1.2, CI = 0.9-1.4). However, when stratified according to medication groups, a significantly increased risk was detected in 4 of 13 groups. The overall occurrence of hospital diagnoses was also significantly increased when females with 46,XX/47,XXX were compared with controls (incidence risk ratio = 1.3, CI = 1.01-1.8), but generally, in comparison with controls, females with 46,XX/47,XXX were less severely affected than females with 47,XXX.

CONCLUSION

The 47,XXX syndrome is associated with an increased occurrence of a wide variety of diseases. Increased awareness of this may contribute to improve counseling and clinical assessment of these patients.

Social functioning and emotion recognition in adults with triple X syndrome

BACKGROUND

Triple X syndrome (TXS) is caused by aneuploidy of the X chromosome and is associated with impaired social functioning in children; however, its effect on social functioning and emotion recognition in adults is poorly understood.

AIMS

The aim of this study was to investigate social functioning and emotion recognition in adults with TXS.

METHOD

This cross-sectional cohort study was designed to compare social functioning and emotion recognition between adults with TXS (n = 34) and an age-matched control group (n = 31). Social functioning was assessed with the Adult Behavior Checklist and Social Responsiveness Scale for Adults. Emotion recognition was assessed with the Emotion Recognition Task in the Cambridge Neuropsychological Test Automated Battery. Differences were analysed by Mann-Whitney U-test.

RESULTS

Compared with controls, women with TXS scored higher on the Adult Behavior Checklist, including the Withdrawn scale (P < 0.001, effect size 0.4) and Thought Problems scale (P < 0.001, effect size 0.4); and higher on the Social Responsiveness Scale for Adults, indicating impaired social functioning (P < 0.001, effect size 0.5). In addition, women with TXS performed worse on the Emotion Recognition Task, particularly with respect to recognising sadness (P < 0.005, effect size 0.4), fear (P < 0.01, effect size 0.4) and disgust (P < 0.02, effect size 0.3).

CONCLUSIONS

Our findings indicate that adults with TXS have a higher prevalence of impaired social functioning and emotion recognition. These results highlight the relevance of sex chromosome aneuploidy as a potential model for studying disorders characterised by social impairments such as autism spectrum disorder, particularly among women.

Meta-analysis of metabolites involved in bioenergetic pathways reveals a pseudohypoxic state in Down syndrome

Clinical observations and preclinical studies both suggest that Down syndrome (DS) may be associated with significant metabolic and bioenergetic alterations. However, the relevant scientific literature has not yet been systematically reviewed. The aim of the current study was to conduct a meta-analysis of metabolites involved in bioenergetics pathways in DS to conclusively determine the difference between DS and control subjects. We discuss these findings and their potential relevance in the context of pathogenesis and experimental therapy of DS. Articles published before July 1, 2020, were identified by using the search terms “Down syndrome” and “metabolite name” or “trisomy 21” and “metabolite name”. Moreover, DS-related metabolomics studies and bioenergetics literature were also reviewed. 41 published reports and associated databases were identified, from which the descriptive information and the relevant metabolomic parameters were extracted and analyzed. Mixed effect model revealed the following changes in DS: significantly decreased ATP, CoQ10, homocysteine, serine, arginine and tyrosine; slightly decreased ADP; significantly increased uric acid, succinate, lactate and cysteine; slightly increased phosphate, pyruvate and citrate. However, the concentrations of AMP, 2,3-diphosphoglycerate, glucose, and glutamine were comparable in the DS vs. control populations. We conclude that cells of subjects with DS are in a pseudo-hypoxic state: the cellular metabolic and bio-energetic mechanisms exhibit pathophysiological alterations that resemble the cellular responses associated with hypoxia, even though the supply of the cells with oxygen is not disrupted. This fundamental alteration may be, at least in part, responsible for a variety of functional deficits associated with DS, including reduced exercise difference, impaired neurocognitive status and neurodegeneration.

Evaluating the Scope of Language Impairments in a Patient with Triple X Syndrome: A Brief Report

The phenotype of triple X syndrome comprises a variety of physical, psychiatric, and cognitive features. Recent evidence suggests that patients are prone to severe language impairments. However, it remains unclear whether verbal impairments are pervasive at all levels of language, or whether one domain is relatively more spared than others. Here we document the language profile of one patient with triple X, using standardized language tests and reports. Results concur in showing that impairments are noticeable both in expressive and receptive language skills, and in vocabulary as well as in structural components of language. Although receptive ability in some tests appears relatively spared, even here A's performance is clearly below average. This single case study further underscores that language and communication at all levels can be severely compromised in patients with triple X. Practitioners should be aware of the limited language abilities that possibly exist in patients with triple X.

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.

The behavioral profile of children aged 1-5 years with sex chromosome trisomy (47,XXX, 47,XXY, 47,XYY)

Children with SCT have an increased risk of suboptimal neurodevelopment. Previous studies have shown an elevated risk for neurobehavioral problems in individuals with SCT. However, not much is known about neurobehavioral problems in very young children; knowledge that could help with early identification of children at risk for suboptimal development, and that could help establish targets for early intervention. This study addressed the question of what the behavioral profile of children with SCT aged 1–5 years looks like. In total, 182 children aged 1–5 years participated in this study (N_SCT=87, N_{nonclinical controls} = 95). Recruitment and assessment took place in the Netherlands and the United States. The SCT group was recruited through prospective follow‐up (50%), information seeking parents (31%), and clinical referral (18%). Behavioral profiles were assessed with the child behavior checklist and the ages‐and‐stages social–emotional questionnaire.

Levels of parent‐rated problem behavior were higher in children with SCT. Difficulties with overall social–emotional functioning were already present in 1‐year‐olds, and elevated scores were persistent across the full age range. Affective and pervasive developmental behaviors were seen in late toddlerhood and prominent at preschool age. Anxiety, attention deficit, and oppositional defiant behaviors were seen in preschool‐aged children. Within this cross‐sectional study, the developmental trajectory of affective, pervasive developmental, and oppositional defiant behaviors seemed to be different for SCT children than nonclinical controls.

Collectively, these results demonstrate the importance of behavioral screening for behavioral problems in routine clinical care for children with SCT from a young age. Social–emotional problems may require special attention, as these problems seem most prominent, showing increased risk across the full age range, and with these problems occurring regardless of the timing of diagnosis, and across all three SCT karyotypes.

A review of neurocognitive functioning of children with sex chromosome trisomies: Identifying targets for early intervention

Sex chromosome trisomies (SCT) are among the most common chromosomal duplications in humans. Due to recent technological advances in non‐invasive screening, SCT can already be detected during pregnancy. This calls for more knowledge about the development of (young) children with SCT. This review focused on neurocognitive functioning of children with SCT between 0 and 18 years, on domains of global intellectual functioning, language, executive functioning, and social cognition, in order to identify targets that could benefit from early treatment.

Online databases were used to identify peer‐reviewed scientific articles using specific search terms. In total 18 studies were included. When applicable, effect sizes were calculated to indicate clinical significance.

Results of the reviewed studies show that although traditionally, the focus has been on language and intelligence (IQ) in this population, recent studies suggest that executive functioning and social cognition may also be significantly affected already in childhood.

These findings suggest that neuropsychological screening of children diagnosed with SCT should be extended, to also include executive functioning and social cognition. Knowledge about these neurocognitive risks is important to improve clinical care and help identify targets for early support and intervention programs to accommodate for the needs of individuals with SCT.