A review of neurocognitive functioning and risk for psychopathology in sex chromosome trisomy (47,XXY, 47,XXX, 47, XYY)

Beyond the Extra X and Y Chromosome: The Contribution of Familial Risk for Psychopathology to the Neurodevelopmental Phenotype of Children With Sex Chromosome Trisomy

Individuals with an extra X or Y chromosome (sex chromosome trisomy or SCT) have an increased risk for symptoms of psychopathology and neurocognitive dysfunction. In this study, we evaluated the contribution of family history (FH) of neuropsychiatric or neurocognitive disorders to the phenotype of SCT. One hundred and six children with SCT and 102 nonclinical controls, all aged 1-7 years, and their primary caregiver (parent) participated. Rates of neuropsychiatric and neurocognitive disorders were collected for all first-degree family members of the children. Neurocognitive tests and parental questionnaires were used to evaluate children's neurobehavioral and neurocognitive phenotypes. Results showed no systematic differences in FH of neuropsychiatric and neurocognitive disorders between the SCT and control groups. No significant effect of a FH of psychiatric disorders was found on any of the child outcomes. FH of neurocognitive disorders had a single significant effect on child outcomes. Inattention problems in SCT were higher with a positive FH of neurocognitive disorders, showing dosage response effects. Familial factors may only minimally contribute to the overall phenotype of SCT on group level, although a positive FH of neurocognitive disorders may contribute to ADHD inattention symptoms in children with SCT, beyond the risk associated with the extra X or Y chromosome.

Social communication skills profile in infants with sex chromosome trisomy at 12 months of age

Sex Chromosome Trisomy (SCT) conditions are genetic disorders that affect approximately 1:500 children. Although there is considerable variability in phenotype, individuals with SCT have an elevated likelihood, compared to the general population, of developing social deficits and autism spectrum disorder (ASD). Studies report that 10-35 % of individuals with SCT meet criteria for ASD, depending on differences in ascertainment methods and diagnostic criteria. More specifically, ASD prevalence has been estimated at approximately 18 % (range 10-27 %) for XXY, 15 % (10.8-20 %) for XXX, and 30 % (19-43 %) for XYY.. Understanding social development in young children with SCT is important for identifying potential early predictors of later ASD diagnoses and informing early intervention efforts and specific targets for intervention. We describe the social communication profiles of 69 participants with a prenatal diagnosis of SCT (XXY/Klinefelter syndrome=45, XYY=12, and XXX=12) participating in a prospective natural history study at 12 months of age. All participants completed the Autism Diagnostic Observation Schedule- 2nd edition (ADOS-2) Toddler Module (TM) and the Bayley Scales of Infant and Toddler Development- 3rd edition (Bayley-III) associated with their 12-month visit. Supplementary analyses of the impact of wearing masks during COVID19 are included. Participants showed elevated scores on ADOS-2 TM language/ social communication and reciprocal social interaction items including use of gestures, directed babbling/vocalizations towards others and in skills related to initiating social interactions and directing facial expressions toward others. Participants showed few difficulties on items that measured restricted and repetitive behaviors (RRBs). There were no significant differences between SCT subtypes. Lower receptive and expressive language scores on the Bayley-III correlated with more challenges (higher scores) as measured by ADOS-2 TM clinical severity scores. Results show that children with SCT conditions as young as 12 months of age are at increased likelihood for social communication deficits. They also show few RRBs, differentiating them from young children diagnosed with idiopathic ASD. While 45 % had scores in the mild concern range or above, no participants received a clinical diagnosis of ASD. Prospective follow-up of this cohort will detail the developmental profile of social communication skills beyond 12 months of age and identify the proportion and early predictors of those who emerge to meet criteria for a clinical diagnosis of ASD. Results support close monitoring of early social development and provide specific early social development skills to target in future early intervention trials in infants with SCT.

The epidemiology of disorders of sex development

During recent years the epidemiology of disorders of sex development (DSD) has been more clearly delineated. Here, we provide a detailed and up-to-date synopsis of the epidemiology of DSD, incorporating the latest body of knowledge in the field for sex chromosome DSD (Turner, Klinefelter, 47,XXX, and 47,XXY syndrome, and 45,X/46,XY mosaicism) as well as for 46,XX DSD and 46,XY DSD focusing on females with congenital adrenal hyperplasia (CAH), males with 46,XX DSD, females with Mayer-Rokitansky-Küster-Hauser syndrome and females with 46,XY DSD. Despite not fitting directly within the Chicago Consensus classification for DSD, we also include the few epidemiological studies addressing ambiguous genitalia. We show that epidemiological studies have improved our understanding of DSD and led to sound estimates of prevalence, have detailed morbidity and mortality patterns and have for some conditions also shed light on the impact on socioeconomic achievements.

Sex differences in the comorbidity between attention deficit-hyperactivity disorder and posttraumatic stress disorder: A systematic literature review and meta-analysis

OBJECTIVE

Attention Deficit-Hyperactivity Disorder (ADHD) and Posttraumatic Stress Disorder (PTSD) are often comorbid and share a common core of symptoms. However, sex and gender-related factors significantly influence their prevalence, clinical presentation, and diagnosis. Here, we conducted a systematic literature review and meta-analysis to examine sex differences in ADHD/PTSD comorbidity during childhood and adulthood.

METHODS

A scoping review of PsycINFO and PubMed yielded 13 eligible studies with complete outcome data. We conducted fixed-effects meta-analyses of the sex-stratified prevalence of ADHD/PTSD using pooled odds ratios (OR) with a 95 % confidence interval (CI). Fixed-effects subgroup analyses were performed using age as a subgroup. Effect size heterogeneity was assessed using the I2 index and Cochran's Q test.

RESULTS

In the whole sample (N = 13,585; F = 7005, M = 6580), the diagnosis of ADHD/PTSD was significantly higher in females than in males (OR = 1.32, p = 0.02). Between-study heterogeneity was low-to-moderate and not significant (I2 = 41 %; p = 0.06), validating the fixed-effects model. Age-stratified subgroup analyses revealed higher ADHD/PTSD odds in females compared to males only in adult populations (OR = 1.41; p = 0.01). Additionally, females were more likely to be diagnosed with both disorders in studies where ADHD was the primary diagnosis (OR = 1.60; p = 0.002), and in studies employing structured clinical interviews as diagnostic tools (OR = 1.46; p = 0.009).

CONCLUSIONS

Our study is the first to show that the association between ADHD and PTSD is stronger in females, suggesting that ADHD may increase risk for PTSD in a sex-specific manner.

Brain structure in triple X syndrome: regional gray matter volume and cortical thickness in adult women with 47,XXX karyotype

BACKGROUND

Changes in the brain structure of women with Triple X syndrome (karyotype 47,XXX) have been described in a few studies to date, including reduced total brain volume and regional reductions in gray substance in cortical and subcortical areas. However, the empirical evidence from adults is very limited and group comparison on a voxel-wise basis for gray matter volume and cortical thickness is still missing.

METHODS

Using voxel-based morphometry (VBM) and surface-based morphometry (SBM), we investigated regional gray matter changes in a sample of n = 20 adult women (aged 18-49 years) with 47,XXX karyotype using T1-weighted 3T MRI scans.

RESULTS

Compared to an age- and education-matched control group (and controlled for differences in total intracranial volume), the VBM revealed decreased regional gray matter volumes in the hippocampus, amygdala, parts of the basal ganglia, insula, prefrontal areas and cerebellum. To a lesser extent, we also noted specific reductions in cortical thickness in a smaller part of those regions.

CONCLUSION

The observed network is significantly involved in the processing of cognitive, affective, and social stimuli and might be a potential neuronal correlate of the autism-like social-cognitive problems described in 47,XXX in the literature.

Effect of testosterone treatment during puberty in boys with Klinefelter syndrome (The TIPY Study): protocol for a nationwide randomised, double-blinded, placebo-controlled study

INTRODUCTION

Klinefelter syndrome (KS) is a genetic condition characterised by the presence of an extra X chromosome in males (47,XXY). KS is associated with various phenotypic characteristics in adult life, including infertility, hypogonadism and increased risk of type II diabetes, cardiovascular disease and osteoporosis. Additionally, individuals with KS often experience mental health challenges and functional impairments that significantly impact their quality of life. Currently, testosterone replacement therapy (TRT) in adolescence is considered the first-line treatment by some physicians for patients with KS and biochemical signs of hypogonadism. However, comprehensive evidence on its effectiveness in preventing typical phenotypic traits associated with KS remains limited, and, currently, no evidence-based recommendations for TRT in this population exist. We therefore aim to evaluate the effects of two years of TRT during puberty in boys with KS. The primary endpoint is to monitor changes in body fat percentage. Secondary endpoints include changes in pubertal development and virilisation, growth and body proportions, bone mineralisation, muscle strength, lipid and glucose metabolism, systemic inflammation, methylation, fertility and effects on the cognitive and psychopathological features of KS.

METHODS AND ANALYSIS

The TIPY study is a multicentre, national, randomised, double-blind, placebo-controlled intervention study. Participants will be recruited from four tertiary paediatric endocrine units in Denmark that manage boys with KS. Participants will be randomised to treatment with transdermal placebo or transdermal testosterone (Androgel; Besins Healthcare, Paris, France) with dose titration every 3 months based on individual measurements of serum concentrations of testosterone. Dose titration will be conducted by a single physician to ensure free testosterone remains between +1 and +3 SD for age.Thorough clinical and biochemical evaluation will be performed at baseline, after 12 months and 24 months. Additional visits for minor evaluations will occur every 3 months. Neuropsychological assessment will be conducted at baseline and after 24 months of treatment.

ETHICS AND DISSEMINATION

The study will be conducted in accordance with the Helsinki Declaration. The study has been approved by the Danish National Medical Research Ethics Committee and the Danish Medicines Agency (Clinical trials information system number 2023-505854-16-00). Results will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT06294990.

Neurodevelopmental and Mental Health Outcomes in a National Clinical Sample of Youth With Sex Chromosome Trisomies Compared With Matched Controls

OBJECTIVE

To compare the prevalence of neurodevelopmental and mental health diagnoses in a national sample of youth with sex chromosome trisomies (SCTs) with matched controls.

METHODS

Patients in PEDSnet and a diagnosis code mapping to 47,XXY/Klinefelter syndrome (n = 1171), 47,XYY/Double Y syndrome (n = 243), or 47,XXX/Trisomy X syndrome (n = 262) were matched with controls using propensity scores. Generalized estimating equations computed odds ratios (OR) with 95% confidence intervals (CI) for the prevalence of diagnoses within the neurodevelopmental and mental health composites, psychotropic medication prescriptions, and encounters with behavioral health and therapy providers. Alpha was set at 0.0025 to account for multiple comparisons.

RESULTS

Patients with SCTs had higher odds of diagnoses within the neurodevelopmental (OR 6.3, 95% CI, 5.7-7.2) and mental health composites (OR 2.7, 95% CI, 2.3-3.2) compared with matched controls. All neurodevelopmental diagnoses were more prevalent among all SCT groups compared with controls. Within the mental health composite, only the prevalence of anxiety and mood disorder was higher in all SCT groups. A higher proportion of patients with SCTs had psychotropic prescriptions compared with controls (stimulants 13.1% vs 5.2%, selective serotonin reuptake inhibitors 8.7% vs 2.8%, antipsychotics 6.5% vs 2.4%, p < 0.0001 for all). Overall, 48% of patients with SCTs had a clinical encounter with a behavioral health provider vs 16.6% of controls (OR 5.6, 95% CI, 4.1-5.1).

CONCLUSION

Compared with matched controls, youth with SCTs receiving care at US tertiary care pediatric centers have disproportionately high rates of neurodevelopmental and mental health conditions, emphasizing the need for appropriate screening and intervention in these populations.

Associations between brain network, puberty, and behaviors in boys with Klinefelter syndrome

BACKGROUND

Klinefelter syndrome (KS), also referred to as XXY syndrome, is a significant but inadequately studied risk factor for neuropsychiatric disability. Whether alterations in functional brain connectivity or pubertal delays are associated with aberrant cognitive-behavioral outcomes in individuals with KS is largely unknown. In this observational study, we investigated KS-related alterations in the resting-state brain network, testosterone level, and cognitive-behavioral impairment in adolescents with Klinefelter syndrome.

METHODS

We recruited 46 boys with KS, ages 8 to 17 years, and 51 age-matched typically developing (TD) boys. All participants underwent resting-state functional magnetic resonance imaging scans, pubertal, and cognitive-behavioral assessments. Resting-state functional connectivity and regional brain activity of the participants were assessed.

RESULTS

We found widespread alterations in global functional connectivity among the inferior frontal gyrus, temporal-parietal area, and hippocampus in boys with KS. Aberrant regional activities, including enhanced fALFF in the motor area and reduced ReHo in the caudate, were also found in the KS group compared to the TD children. Further, using machine learning methods, brain network alterations in these regions accurately differentiated boys with KS from TD controls. Finally, we showed that the alterations of brain network properties not only effectively predict cognitive-behavioral impairment in boys with KS, but also appear to mediate the association between total testosterone level and language ability, a cognitive domain at particular risk for dysfunction in this condition.

CONCLUSION

Our results offer an informatic neurobiological foundation for understanding cognitive-behavioral impairments in individuals with KS and contribute to our understanding of the interplay between pubertal status, brain function, and cognitive-behavioral outcome in this population.

Sex Differences in the Comorbidity between Attention Deficit-Hyperactivity Disorder and Posttraumatic Stress Disorder: A Systematic Literature Review and Meta-Analysis

Objective

Attention Deficit-Hyperactivity Disorder (ADHD) and Posttraumatic Stress Disorder (PTSD) are often comorbid and share a common core of symptoms. However, sex and gender-related factors significantly influence their prevalence, clinical presentation, and diagnosis. Here, we conducted a systematic literature review and meta-analysis to examine sex differences in ADHD/PTSD comorbidity during childhood and adulthood.

Methods

A scoping review of PsycINFO and PubMed yielded 13 eligible studies with complete outcome data. We conducted fixed-effects meta-analyses of the sex-stratified prevalence of ADHD/PTSD using pooled odds ratios (OR) with a 95% confidence interval (CI). Fixed-effects subgroup analyses were performed using age as a subgroup. Effect size heterogeneity was assessed using the I2 index and Cochran's Q test.

Results

In the whole sample (N= 13,585; F= 7005, M= 6580), the diagnosis of ADHD/PTSD was significantly higher in females than in males (OR = 1.32, p = 0.02). Between-study heterogeneity was low-to-moderate and not significant (I2 = 41%; p = 0.06), validating the fixed-effects model. Age-stratified subgroup analyses revealed higher ADHD/PTSD odds in females compared to males only in adult populations (OR=1.41; p = 0.01). Additionally, females were more likely to be diagnosed with both disorders in studies where ADHD was the primary diagnosis (OR = 1.60; p = 0.002), and in studies employing structured clinical interviews as diagnostic tools (OR = 1.46; p = 0.009).

Conclusions

Our study is the first to show that the association between ADHD and PTSD is stronger in females, suggesting that ADHD may increase risk for PTSD in a sex-specific manner.

A new case with coexistence of mosaic 48,XYYY/47,XYY, and CACNA1E variant in autism spectrum disorder

Autism spectrum disorder (ASD) is a genetically heterogeneous neurobehavioral disorder. The etiology and the inheritance pattern are usually multifactorial. The index case is a 3-year-old male, whose family applied to the child psychiatry outpatient clinic due to failure to speak at 30 months. He had mild dysmorphic features. He is diagnosed with ASD according to DSM-V criteria. Chromosomal analysis revealed mos 48,XYYY[28]/47,XYY[72] karyotype. In FISH analysis, nuc ish (DXZ1x1, DYZ1x3)[44]/(DXZ1x1, DYZ1x2)[156] was detected. WES results displayed a heterozygous missense variant of uncertain significance c.3545G>A in the CACNA1E gene. XYY syndrome is one of the most common sex chromosome aneuploidies, and ASD is detected 20 times more likely than males in general population. To the best of our knowledge, the first case with the coexistence of mosaic 48,XYYY/47,XYY karyotype and CACNA1E variant together may contribute to phenotypic heterogeneity. Further investigation into the functionality of the variant in CACNA1E is needed.

Age-related differences in psychopathology within sex chromosome trisomies

Sex chromosome trisomies (SCTs) are a group of genetic disorders characterized by presence of a supernumerary sex chromosome, resulting in karyotypes other than XX or XY. These include XXX (Trisomy X), XXY (Klinefelter syndrome), and XYY (Jacobs syndrome). Sex chromosome trisomies have been linked to increased risk for psychopathology; however, this relationship warrants additional research. Specifically, little is known regarding potential age-related variation in risk for psychopathology and how this may differ across karyotypes and subdomains of psychopathology, which has relevance for psychoeducation, personalized care, and mechanistic research. Thus, we used the Child Behavior Checklist (CBCL) to estimate age-related variation in psychopathology in a large cross-sectional sample of individuals with SCTs (n = 201) and euploidic controls (n = 304) spanning the age range of 5-18 years. We found that elevations of psychopathology in SCT were significantly associated with age in a manner that varied as a combined function of the karyotype and CBCL scale being considered. Post hoc tests revealed there is a uniquely pronounced age-associated increase in severity of social problems in XYY, alongside a lack of statistical evidence for age-related variation in the severity of psychopathology for other CBCL domains and SCT karyotypes. Our findings are relevant for advancing the personalization of clinical assessment and monitoring in SCTs. They also highlight potential windows of dynamic risk emergence for closer clinical and biological study, as well as opportunities to provide intervention to mitigate future risk.

White matter organization abnormalities in adults with 47,XXX: A 7 Tesla MRI study

47,XXX (Triple X syndrome) is a sex chromosome aneuploidy characterized by the presence of a supernumerary X chromosome in affected females, and has been associated with a variable cognitive, behavioral, and psychiatric phenotype. Alterations in brain gray matter structure and function have been reported, but less is known about white matter (WM) organization in 47,XXX. Therefore, we conducted 7 T diffusion tensor imaging and characterized fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity of 22 adult women with 47,XXX and 22 age-matched typically developing females using tract-based spatial statistics. Relationships between phenotypic traits and WM organization characteristics in 47,XXX were also investigated. Adults with 47,XXX showed lower axial diffusivity in the body of the corpus callosum and the right superior longitudinal fasciculus. WM organization variability was not associated with IQ and social cognition and social functioning deficits in 47,XXX. Our findings indicate an effect of a supernumerary X chromosome in adult women on axonal integrity of the body of the corpus callosum and the right superior longitudinal fasciculus. These findings provide additional insight into the role of the X chromosome on WM organization. Future research is warranted to explore the clinical significant impact of altered WM organization in 47,XXX.

Intracortical myelin across laminae in adult individuals with 47,XXX: a 7 Tesla MRI study

47,XXX (Triple X syndrome) is a sex chromosome aneuploidy characterized by the presence of a supernumerary X chromosome in affected females and is associated with a variable cognitive, behavioral, and psychiatric phenotype. The effect of a supernumerary X chromosome in affected females on intracortical microstructure is currently unknown. Therefore, we conducted 7 Tesla structural MRI and compared T1 (ms), as a proxy for intracortical myelin (ICM), across laminae of 21 adult women with 47,XXX and 22 age-matched typically developing females using laminar analyses. Relationships between phenotypic traits and T1 values in 47,XXX were also investigated. Adults with 47,XXX showed higher bilateral T1 across supragranular laminae in the banks of the superior temporal sulcus, and in the right inferior temporal gyrus, suggesting decreases of ICM primarily within the temporal cortex in 47,XXX. Higher social functioning in 47,XXX was related to larger inferior temporal gyrus ICM content. Our findings indicate an effect of a supernumerary X chromosome in adult-aged women on ICM across supragranular laminae within the temporal cortex. These findings provide insight into the role of X chromosome dosage on ICM across laminae. Future research is warranted to further explore the functional significance of altered ICM across laminae in 47,XXX.

The emotional journey of adapting to prenatally identified trisomy X

There is a paucity of research on the experiences of parents of children with trisomy X (47,XXX). Increased prenatal diagnoses associated with advances in noninvasive prenatal screening necessitate a better understanding of how trisomy X impacts family systems. This qualitative investigation aimed to describe the lived experience of parents of young daughters with prenatally identified trisomy X to guide genetic counseling. Semi-structured qualitative interviews were conducted via teleconferencing with parents (n = 11) of girls with trisomy X, ages 6-44 months. A descriptive phenomenological approach was used to code transcripts for significant statements and reduce data into themes describing the experience of receiving a diagnosis of trisomy X and the experience of early parenting in this population. Participants described an emotional journey of adapting to prenatally identified trisomy X. Four descriptive themes included two related, yet distinct, life stages: Negative Diagnostic Experience and a Hopeful Early Childhood, as well as two ongoing experiences: Persistent Ambiguity and Coping with and Adapting to Uncertainty. Results suggest providers should carefully consider word choice and timing in delivery of diagnosis, and genetic counseling should provide expectant parents with current research specific to trisomy X, facilitate connections with other parents of young girls with trisomy X, introduce developmental monitoring approaches, and be prepared to support families with a range of emotional responses to the diagnosis and decisions regarding disclosure.

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.

Prevalence of high-penetrant copy number variants in 7734 low-risk pregnancies

BACKGROUND

The rate of clinically significant copy number variants in chromosomal microarray analysis in low-risk pregnancies is approximately 1%. However, these results include copy number variants with low and variable penetrance, although some patients might be interested only in the detection of high-penetrant variants.

OBJECTIVE

This study aimed to calculate the prevalence of high-penetrant copy number variants in a large cohort of low-risk pregnancies.

STUDY DESIGN

This retrospective study was performed using microarray results of pregnancies with normal ultrasound and maternal serum screening. All clinically significant (pathogenic and likely pathogenic) copy number variants were recorded. Of these, only high-penetrant findings were selected. Findings with low and medium penetrance and copy number variants with unknown clinical penetrance, including uniparental disomy of segments not related to known imprinted syndromes, mosaic aneuploidy of <50%, and segmental mosaicism, were excluded. The calculation was performed for the overall cohort, for women aged >35 years and women aged <35 years, and after omission of noninvasive prenatal screening theoretically detectable findings (trisomies 13, 18, and 21).

RESULTS

Clinically significant copy number variants were detected in 118 of 7734 cases (1.50% or 1:65), and high-penetrant copy number variants were detected in 33 of 7734 cases (0.43% or 1:234). In women aged ≥35 years, the rates of high-penetrant copy number variants were 29 of 5734 cases (0.51% or 1:198) and 4 of 2000 cases (0.20% or 1:500) in women aged <35 years (P=.0747). Following the omission of 12 theoretically noninvasive prenatal screening-detectable findings, the rates of high-penetrant copy number variants declined to 21 of 7722 cases (0.27% or 1:368) in the whole cohort-18 of 5723 cases (0.31% or 1:318) in woman aged ≥35 years and 3 of 1999 cases (0.15% or 1:666) in younger women (P=.319).

CONCLUSION

The risk of high-penetrant copy number variants in low-risk pregnancies exceeds the risk of miscarriage after invasive testing, even after normal noninvasive prenatal screening results. These results are of importance to genetic counselors and obstetricians, to facilitate maternal informed decision-making when considering invasive prenatal testing in low-risk pregnancies.

Diversity and Classification of Genetic Variations in Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a neurodevelopmental condition with symptoms that affect the whole personality and all aspects of life. Although there is a high degree of heterogeneity in both its etiology and its characteristic behavioral patterns, the disorder is well-captured along the autistic triad. Currently, ASD status can be confirmed following an assessment of behavioral features, but there is a growing emphasis on conceptualizing autism as a spectrum, which allows for establishing a diagnosis based on the level of support need, free of discrete categories. Since ASD has a high genetic predominance, the number of genetic variations identified in the background of the condition is increasing exponentially as genetic testing methods are rapidly evolving. However, due to the huge amount of data to be analyzed, grouping the different DNA variations is still challenging. Therefore, in the present review, a multidimensional classification scheme was developed to accommodate most of the currently known genetic variants associated with autism. Genetic variations have been grouped according to six criteria (extent, time of onset, information content, frequency, number of genes involved, inheritance pattern), which are themselves not discrete categories, but form a coherent continuum in line with the autism spectrum approach.

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.

(Not) getting what you want: frustration and emotion regulation in children with sex chromosome trisomies

The presence of an additional X or Y chromosome (sex chromosome trisomies, SCT) is associated with an increased risk for neurodevelopmental difficulties, including socio-emotional problems, across the life span. Studying emotion regulation in young children with SCT could signal deviations in emotional development that serve as risk markers to guide clinical care. This study explored the presence and variety of emotion regulation strategies in 75 SCT children and 81 population-based controls, aged 1-7 years, during a frustration-inducing event in which physiological (heart rate) and observational data (behavioral responses) were collected. Children with SCT were equally physiologically aroused by the event as compared to controls. However, they showed more emotion regulation difficulties in terms of behavior compared to controls that were not explicable in terms of differences in general intellectual functioning. Specifically, they had a more limited range of behavioral alternatives and tended to rely longer on inefficient strategies with increasing age. The field of practice should be made aware of these early risk findings regarding emotion regulation in SCT, which may potentially lay the foundation for later socio-emotional problems, given the significant impact of emotion regulation on child and adult mental health outcomes. The current results may help to design tailored interventions to reduce the impact of the additional sex chromosome on adaptive functioning, psychopathology, and quality of life.

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.

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.

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.

Sex and gender in neurodevelopmental conditions

Health-related conditions often differ qualitatively or quantitatively between individuals of different birth-assigned sexes and gender identities, and/or with different gendered experiences, requiring tailored care. Studying the moderating and mediating effects of sex-related and gender-related factors on impairment, disability, wellbeing and health is of paramount importance especially for neurodivergent individuals, who are diagnosed with neurodevelopmental conditions with uneven sex/gender distributions. Researchers have become aware of the myriad influences that sex-related and gender-related variables have on the manifestations of neurodevelopmental conditions, and contemporary work has begun to investigate the mechanisms through which these effects are mediated. Here we describe topical concepts of sex and gender science, summarize current knowledge, and discuss research and clinical challenges related to autism, attention-deficit/hyperactivity disorder and other neurodevelopmental conditions. We consider sex and gender in the context of epidemiology, behavioural phenotypes, neurobiology, genetics, endocrinology and neighbouring disciplines. The available evidence supports the view that sex and gender are important contributors to the biological and behavioural variability in neurodevelopmental conditions. Methodological caveats such as frequent conflation of sex and gender constructs, inappropriate measurement of these constructs and under-representation of specific demographic groups (for example, female and gender minority individuals and people with intellectual disabilities) limit the translational potential of research so far. Future research and clinical implementation should integrate sex and gender into next-generation diagnostics, mechanistic investigations and support practices.

A Cross-Species Neuroimaging Study of Sex Chromosome Dosage Effects on Human and Mouse Brain Anatomy

All eutherian mammals show chromosomal sex determination with contrasting sex chromosome dosages (SCDs) between males (XY) and females (XX). Studies in transgenic mice and humans with sex chromosome trisomy (SCT) have revealed direct SCD effects on regional mammalian brain anatomy, but we lack a formal test for cross-species conservation of these effects. Here, we develop a harmonized framework for comparative structural neuroimaging and apply this to systematically profile SCD effects on regional brain anatomy in both humans and mice by contrasting groups with SCT (XXY and XYY) versus XY controls. Total brain size was substantially altered by SCT in humans (significantly decreased by XXY and increased by XYY), but not in mice. Robust and spatially convergent effects of XXY and XYY on regional brain volume were observed in humans, but not mice, when controlling for global volume differences. However, mice do show subtle effects of XXY and XYY on regional volume, although there is not a general spatial convergence in these effects within mice or between species. Notwithstanding this general lack of conservation in SCT effects, we detect several brain regions that show overlapping effects of XXY and XYY both within and between species (cerebellar, parietal, and orbitofrontal cortex), thereby nominating high priority targets for future translational dissection of SCD effects on the mammalian brain. Our study introduces a generalizable framework for comparative neuroimaging in humans and mice and applies this to achieve a cross-species comparison of SCD effects on the mammalian brain through the lens of SCT.SIGNIFICANCE STATEMENT Sex chromosome dosage (SCD) affects neuroanatomy and risk for psychopathology in humans. Performing mechanistic studies in the human brain is challenging but possible in mouse models. Here, we develop a framework for cross-species neuroimaging analysis and use this to show that an added X- or Y-chromosome significantly alters human brain anatomy but has muted effects in the mouse brain. However, we do find evidence for conserved cross-species impact of an added chromosome in the fronto-parietal cortices and cerebellum, which point to regions for future mechanistic dissection of sex chromosome dosage effects on brain development.

Deep phenotypic analysis of psychiatric features in genetically defined cohorts: application to XYY syndrome

BACKGROUND

Recurrent gene dosage disorders impart substantial risk for psychopathology. Yet, understanding that risk is hampered by complex presentations that challenge classical diagnostic systems. Here, we present a suite of generalizable analytic approaches for parsing this clinical complexity, which we illustrate through application to XYY syndrome.

METHOD

We gathered high-dimensional measures of psychopathology in 64 XYY individuals and 60 XY controls, plus additional interviewer-based diagnostic data in the XYY group. We provide the first comprehensive diagnostic description of psychiatric morbidity in XYY syndrome and show how diagnostic morbidity relates to functioning, subthreshold symptoms, and ascertainment bias. We then map behavioral vulnerabilities and resilience across 67 behavioral dimensions before borrowing techniques from network science to resolve the mesoscale architecture of these dimensions and links to observable functional outcomes.

RESULTS

Carriage of an extra Y-chromosome increases risk for diverse psychiatric diagnoses, with clinically impactful subthreshold symptomatology. Highest rates are seen for neurodevelopmental and affective disorders. A lower bound of < 25% of carriers are free of any diagnosis. Dimensional analysis of 67 scales details the profile of psychopathology in XYY, which survives control for ascertainment bias, specifies attentional and social domains as the most impacted, and refutes stigmatizing historical associations between XYY and violence. Network modeling compresses all measured symptom scales into 8 modules with dissociable links to cognitive ability, adaptive function, and caregiver strain. Hub modules offer efficient proxies for the full symptom network.

CONCLUSIONS

This study parses the complex behavioral phenotype of XYY syndrome by applying new and generalizable analytic approaches for analysis of deep-phenotypic psychiatric data in neurogenetic disorders.

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.

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.

Autism under the umbrella of ESSENCE

This brief article gives a short overview of "comorbidity" in autism. The most common co-occurring disorders will be presented and discussed within the context of ESSENCE (Early Symptomatic Syndromes Eliciting Neurodevelopmental Clinical Examinations), a concept that provides a holistic perspective for neurodevelopmental disorders. The ESSENCE concept also considers the heterogeneous and changing clinical panorama of developmental disorders over time, and also the multifactorial etiologies, including so called behavioral phenotype syndromes. Aspects on behavioral interventions in autism are presented-interventions that need to be adapted and take into account all non-autism associated ESSENCE, including intellectual disability and Attention-Deficit/Hyperactivity Disorder (ADHD). The article also focuses on current research on pharmacological intervention based on the hypothesis of imbalance in excitatory/inhibitory transmitter systems in autism and some other ESSENCE.

Triple X syndrome: Psychiatric disorders and impaired social functioning as a risk factor

BACKGROUND

Women with triple X syndrome (TXS) have an extra X chromosome. TXS appeared to be associated with psychiatric disorders in biased or underpowered studies.

AIM

This study aims to describe the prevalence of psychiatric disorders in adults with TXS in a relatively large and less biased group of participants.

METHOD

In this cross-sectional study, data were collected from 34 women with TXS (mean age = 32.9; s.d. = 13.1) and 31 controls (mean age = 34.9; s.d. = 13.7). Psychiatric disorders were assessed using the MINI International Neuropsychiatric Interview (MINI) and the adult behavior checklist (ABCL). Trait and state anxiety were assessed using the State-Trait Anxiety Inventory.

RESULTS

In the TXS group, MINI results showed a higher prevalence of major depressive episodes (43.3%), psychotic disorders (29.4%), and suicidality (23.5%). Only 50% of the TXS group earned a normal score for the total syndrome score using the ABCL. In addition, levels of trait anxiety were higher in the TXS group. Only three women in each group received psychotropic medication. Impaired social functioning appeared to represent a major risk factor in TXS as regards psychotic, affective disorders, trait anxiety, and low self-esteem.

CONCLUSIONS

Women with TXS are vulnerable to developing psychiatric disorders, and women with both TXS and impaired social functioning are even more vulnerable.

X chromosome aneuploidies and schizophrenia: association analysis and phenotypic characterization

AIM

The aims of the present study were: (i) to examine the association between schizophrenia (SCZ) and 47, XXY or 47, XXX in a large case-control sample; and (ii) to characterize the clinical features of patients with SCZ with these X chromosome aneuploidies.

METHODS

To identify 47, XXY and 47, XXX, array comparative genomic hybridization (aCGH) was performed in 3188 patients with SCZ and 3586 controls. We examined the association between 47, XXY and 47, XXX and SCZ in males and females separately using exact conditional tests to control for platform effects. Clinical data were retrospectively examined for patients with SCZ with X chromosome aneuploidies.

RESULTS

Of the analyzed samples, 3117 patients (97.8%) and 3519 controls (98.1%) passed our quality control. X chromosome aneuploidies were exclusively identified in patients: 47, XXY in seven patients (0.56%), 47, XXX in six patients (0.42%). Statistical analysis revealed a significant association between SCZ and 47, XXY (P = 0.028) and 47, XXX (P = 0.011). Phenotypic data were available from 12 patients. Treatment-resistance to antipsychotics and manic symptoms were observed in six patients each (four with 47, XXY and two with 47, XXX for both), respectively. Statistical analysis revealed that treatment-resistance to antipsychotics, mood stabilizer use, and manic symptoms were significantly more common in patients with 47, XXY than in male patients without pathogenic copy number variations.

CONCLUSION

These findings indicate that both 47, XXY and 47, XXX are significantly associated with risk for SCZ. Patients with SCZ with 47, XXY may be characterized by treatment-resistance and manic symptoms.

Resting-state functional connectivity in adults with 47,XXX: a 7 Tesla MRI study

Triple X syndrome is a sex chromosomal aneuploidy characterized by the presence of a supernumerary X chromosome, resulting in a karyotype of 47,XXX in affected females. It has been associated with a variable cognitive, behavioral, and psychiatric phenotype, but little is known about its effects on brain function. We therefore conducted 7 T resting-state functional magnetic resonance imaging and compared data of 19 adult individuals with 47,XXX and 21 age-matched healthy control women using independent component analysis and dual regression. Additionally, we examined potential relationships between social cognition and social functioning scores, and IQ, and mean functional connectivity values. The 47,XXX group showed significantly increased functional connectivity of the fronto-parietal resting-state network with the right postcentral gyrus. Resting-state functional connectivity (rsFC) variability was not associated with IQ and social cognition and social functioning deficits in the participants with 47,XXX. We thus observed an effect of a supernumerary X chromosome in adult women on fronto-parietal rsFC. These findings provide additional insight into the role of the X chromosome on functional connectivity of the brain. Further research is needed to understand the clinical implications of altered rsFC in 47,XXX.

Cross-Disorder Analysis of Genic and Regulatory Copy Number Variations in Bipolar Disorder, Schizophrenia, and Autism Spectrum Disorder

BACKGROUND

We aimed to determine the similarities and differences in the roles of genic and regulatory copy number variations (CNVs) in bipolar disorder (BD), schizophrenia (SCZ), and autism spectrum disorder (ASD).

METHODS

Based on high-resolution CNV data from 8708 Japanese samples, we performed to our knowledge the largest cross-disorder analysis of genic and regulatory CNVs in BD, SCZ, and ASD.

RESULTS

In genic CNVs, we found an increased burden of smaller (<100 kb) exonic deletions in BD, which contrasted with the highest burden of larger (>500 kb) exonic CNVs in SCZ/ASD. Pathogenic CNVs linked to neurodevelopmental disorders were significantly associated with the risk for each disorder, but BD and SCZ/ASD differed in terms of the effect size (smaller in BD) and subtype distribution of CNVs linked to neurodevelopmental disorders. We identified 3 synaptic genes (DLG2, PCDH15, and ASTN2) as risk factors for BD. Whereas gene set analysis showed that BD-associated pathways were restricted to chromatin biology, SCZ and ASD involved more extensive and similar pathways. Nevertheless, a correlation analysis of gene set results indicated weak but significant pathway similarities between BD and SCZ or ASD (r = 0.25-0.31). In SCZ and ASD, but not BD, CNVs were significantly enriched in enhancers and promoters in brain tissue.

CONCLUSIONS

BD and SCZ/ASD differ in terms of CNV burden, characteristics of CNVs linked to neurodevelopmental disorders, and regulatory CNVs. On the other hand, they have shared molecular mechanisms, including chromatin biology. The BD risk genes identified here could provide insight into the pathogenesis of BD.

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.

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.

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.

Does the autism phenotype differ when selecting groups by neurodevelopmental versus genetic diagnosis? An observational study comparing autism and sex chromosome trisomy

Background: Autism is diagnosed on the basis of social and non-social behavioural features that are assumed to cluster together, and assumed to be distinct from other aspects of development, such as language ability. It is unclear, however, if these assumptions are valid. This study presents a novel approach to answering this question by investigating whether correlations between autism features are similar for groups selected on behavioural versus genetic diagnosis. Methods: The autism phenotype was assessed by diagnostic interview in young people aged 7 to 14 diagnosed with autism ( N=61) or sex chromosome trisomy (SCT; N=49). Data were analysed by confirmatory factor analysis and MANOVA. Results: Autism features showed a similar factor structure and were distinct from language ability in both groups. However, the SCT group was more likely to show clinically-significant difficulties in just some aspects of autism and a lower level of non-social autism features for their social-communication disabilities. Conclusions: We suggest the group differences emerged because autism diagnostic criteria do not map exactly on the autism phenotype as it manifests "naturally". Conventional diagnostic criteria for autism miss those with uneven profiles of difficulty and those with relatively low levels of restricted and repetitive behaviours and interests.

'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.

Children's Behavior and Maternal Parenting Stress in Young Children With Sex Chromosome Trisomies

OBJECTIVE

Children and adolescents with sex chromosome trisomies (SCTs) usually show a higher frequency of behavioral problems than typically developing (TD) children. However, little is known about the presence of behavioral issues in toddlers with SCT. This study aimed at investigating their behavioral profile in the second year of life and its impact on maternal stress.

METHOD

Participants were 87 children ranging in age from 18 to 26 months: 63 children with SCTs (all diagnosed prenatally) and 24 TD children. Their psychomotor and language development and their behavioral profile were assessed. In addition, the level of maternal parenting stress was evaluated.

RESULTS

Both psychomotor and language development were significantly lower in children with SCTs than in TD children. Conversely, no significantly greater behavioral problems emerged in children with SCTs. However, a significantly higher level of parenting stress related to a dysfunctional interaction with the child emerged in the mothers of children with SCTs. In this population, maternal stress seemed positively related to their children's emotional problems and pervasive disorders and negatively related to their children's psychomotor and linguistic competence.

CONCLUSION

Although no significant behavioral issues emerged in the second year of life, the relationships found between children's behavioral profiles and maternal parenting stress highlight the importance of prenatal counseling and support groups for parents of children with SCTs. This might help them recognize the first signs of behavioral problems and become aware of their influence on parenting stress.

Differences/Disorders of Sex Development: Medical Conditions at the Intersection of Sex and Gender

Defined as congenital conditions in which development of chromosomal, gonadal, or anatomic sex is atypical, differences or disorders of sex development (DSDs) comprise many discrete diagnoses ranging from those associated with few phenotypic differences between affected and unaffected individuals to those where questions arise regarding gender of rearing, gonadal tumor risk, genital surgery, and fertility. Controversies exist in numerous areas including how DSDs are conceptualized, how to refer to the set of conditions and those affected by them, and aspects of clinical management that extend from social media to legislative bodies, courts of law, medicine, clinical practice, and scholarly research in psychology and sociology. In addition to these aspects, this review covers biological and social influences on psychosocial development and adjustment, the psychosocial and psychosexual adaptation of people born with DSDs, and roles for clinical psychologists in the clinical management of DSDs. Expected final online publication date for the Annual Review of Clinical Psychology, Volume 18 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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.

Altered subcortical and cortical brain morphology in adult women with 47,XXX: a 7-Tesla magnetic resonance imaging study

Background

Triple X syndrome (47,XXX) is a relatively common sex chromosomal aneuploidy characterized by the presence of a supernumerary X chromosome in females and has been associated with a variable cognitive, behavioural and psychiatric phenotype. 47,XXX may serve as a suitable model for studying the effect of genetic architecture on brain morphology. Previous studies have shown alterations in brain structure in 47,XXX particularly in childhood and adolescence. In this study, we examined subcortical and cortical brain morphology in adult women with 47,XXX using ultra-high field 7T MRI. Given previous evidence of impaired social functioning and emotion recognition in adults with 47,XXX, we also investigated the relationship of these functions with brain morphology.

Methods

Twenty-one adult women with 47,XXX and 22 age- and sex-matched healthy controls were included. Structural T1-weighted images were acquired using a 7-Tesla magnetic resonance scanner. Measures of subcortical brain volumes, cortical surface area and thickness, and cortical folding were obtained and compared between the groups using general linear models. Additionally, we examined potential relationships between brain outcome measures and social functioning and social cognition in 47,XXX using correlation analyses.

Results

Adults with 47,XXX showed lower volumes of the thalamus, caudate, putamen, hippocampus, nucleus accumbens and pallidum, and larger lateral ventricle volumes. Lower surface area was found in the superior frontal gyrus and superior temporal gyrus in 47,XXX participants compared to healthy controls. Altered cortical thickness and cortical folding were not present in 47,XXX. Cortical thickness was associated with social cognition in 47,XXX.

Conclusions

Results suggest that a supernumerary X chromosome in females affects subcortical and lateral ventricle volumes, and cortical surface area in adulthood. 47,XXX may serve as a suitable model for studying genetic influences on structural brain morphology across developmental stages in order to understand neurobiological mechanisms underlying cognitive and behavioural impairments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11689-022-09425-1.

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.

Patterns of psychopathology and cognition in sex chromosome aneuploidy

Background

Sex chromosome aneuploidies (SCAs) are a collectively common family of genetic disorders that increase the risk for neuropsychiatric and cognitive impairment. Beyond being important medical disorders in their own right, SCAs also offer a unique naturally occurring model for studying X- and Y-chromosome influences on the human brain. However, it remains unclear if (i) different SCAs are associated with different profiles of psychopathology and (ii) the notable interindividual variation in psychopathology is related to co-occurring variation in cognitive ability.

Methods

We examined scores for 11 dimensions of psychopathology [Child/Adult Behavior Checklist (CBCL)] and general cognitive ability [full-scale IQ (FSIQ) from Wechsler tests] in 110 youth with varying SCAs (XXY = 41, XYY = 22, XXX = 27, XXYY = 20) and 131 typically developing controls (XX = 59, XY = 72).

Results

All SCAs were associated with elevated CBCL scores across several dimensions of psychopathology (two-sample t tests comparing the euploidic and aneuploidic groups [all |T| > 9, and p < 0.001]). Social and attentional functioning were particularly sensitive to the carriage of a supernumerary Y-chromosome. In particular, the XYY group evidenced significantly more social problems than both extra-X groups (Cohen’s d effect size > 0.5, Bonferroni corrected p < .05). There was marked variability in CBCL scores within each SCA group, which generally correlated negatively with IQ, but most strongly so for social and attentional difficulties (standardized β, − 0.3). These correlations showed subtle differences as a function of the SCA group and CBCL scale.

Conclusions

There is domain-specific variation in psychopathology across SCA groups and domain-specific correlation between psychopathology and IQ within SCAs. These findings (i) help to tailor clinical assessment of this common and impactful family of genetic disorders and (ii) suggest that dosage abnormalities of X- and Y-linked genes impart somewhat distinct profiles of neuropsychiatric risk.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11689-021-09407-9.