Neuropsychological and functional cognitive skills of 35 unselected adults with sex chromosome abnormalities

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.

Short report. Narrative competence in Italian preschool children with sex chromosome trisomies

BACKGROUND

The neuropsychological profile of children with sex chromosome trisomies [SCTs] is frequently characterised by delays and impairments in language development. However, no studies so far have specifically investigated their narrative competence.

AIMS

The aim of the study was to analyse the oral narrative competence of preschool children with SCTs due to the importance of this skill for language development and learning abilities.

METHODS AND PROCEDURES

Participants were 34 Italian children with SCTs one-to-one matched by age and sex to typically developing [TD] children. A storytelling task, the Narrative Competence Task, was used to assess the macrostructural and microstructural features of the children's narratives.

OUTCOMES AND RESULTS

Children with SCTs showed significantly lower scores than TD peers in all the narrative indices considered, except for mental state lexicon and story length in words.

CONCLUSIONS AND IMPLICATIONS

The problems found in narrative competence confirmed the existence of difficulties in the language development of children with SCTs. Narrative difficulties could affect these children's future learning skills and academic achievements.

'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.

Klinefelter syndrome or testicular dysgenesis: Genetics, endocrinology, and neuropsychology

Klinefelter syndrome (47,XXY) is a frequent chromosomal disorder among males, often presenting with hypergonadotropic hypogonadism, small firm testicles, metabolic disorders, neurocognitive challenges, and increased height. Neurologic disorders such as epilepsy, seizures, and tremor as well as psychiatric disorders are also seen more frequently. The neurocognitive deficits seen are present in many areas of cognition, typically affecting general cognitive abilities, language, and executive functioning. Also, social dysfunction is frequent. Dyslexia is present in more than half of all males. Brain imaging studies generally show a typical pattern, with many nuclei and brain areas being smaller than among controls. However, it has not been possible to link the brain alterations found in imaging studies with the neurocognitive profile. The genetics underlying the phenotypic traits found among males with Klinefelter syndrome still remains to be elucidated; however, recent studies have described pervasive changes in the methylome and transcriptome and new and interesting candidate genes have been pinpointed, but their involvement in the phenotype of Klinefelter syndrome has not been proven.

Executive function in XXY: Comparison of performance-based measures and rating scales

Few studies have systematically assessed executive functioning (EF) skills in boys with XXY, and these are limited by small samples and restricted EF assessment. This study used a broader battery of performance-based measures as well as parent-rating scales of EF in 77 boys and adolescents with XXY (mean age = 12.5 years), recruited from a clinical trial and an outpatient clinic. Exploratory factor analyses were used to create EF domains from performance-based measures, and similar domains were measured using the Behavior Rating Inventory of Executive Function and Conners Parent-Rating Scales. The boys with XXY showed a distinct EF profile, with the greatest deficit in attention and more moderate deficits in working memory, switching, and planning/problem solving. Parent ratings showed similar challenges, as well as impaired inhibition. Independent sample t-tests showed no difference on performance measures between boys diagnosed or not diagnosed with attention-deficit/hyperactivity disorder (ADHD), although parents of boys diagnosed with ADHD reported more difficulties. There were no differences on performance-based tests between those diagnosed pre- and postnatally, although parents of postnatally diagnosed boys reported more metacognitive problems. Language deficits, cognition, and socio-economic status did not account for EF deficits.

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.

Current survey of early childhood intervention services in infants and young children with sex chromosome aneuploidies

Sex chromosome aneuploidies (SCAs) are the most commonly occurring aneuploidies in children with a collective prevalence rate of 1 in 500 live births. Prior research has documented SCAs are associated with an increased risk for early expressive language and gross motor delays, learning disorders, ADHD, autism spectrum disorder, anxiety, and executive function problems. Although SCAs have been historically underdiagnosed in young children, recent advances in noninvasive prenatal testing have resulted in an increasing nationwide cohort of infants with confirmed diagnoses. Consequently, early childhood support systems must prepare for an influx of children with known risks for associated developmental delays and potential school problems. This national survey aimed to update our understanding of current early childhood intervention services for young children with SCA in the United States and to describe parent perspectives and priorities. Descriptive statistics, chi-square tests, and logistic regression models controlling for parent education revealed a majority of respondents reported receiving public early childhood intervention services with speech therapy as the most common service. There were significant differences in early childhood intervention services by timing of diagnosis (prenatal vs. postnatal), number of sex chromosomes (trisomy vs. tetra/pentasomy), and geographic location. Parents described interventions as desirable and effective yet also difficult to obtain due to issues with the SCA phenotype, lack of provider knowledge, and challenges navigating the intervention systems. Results support the need for enhanced provider training in SCAs, policy change for early childhood intervention qualification criteria for SCA conditions, and collaboration between medical and early childhood settings.

Language phenotypes in children with sex chromosome trisomies

Background Sex chromosome trisomies (47,XXX, 47,XXY and 47,XYY) are known to be a risk factor for language disorder, but it is hard to predict outcomes, because many cases are identified only when problems are found. Methods We recruited children aged 5-16 years with all three types of trisomy, and divided them into a High Bias group, identified in the course of investigations for neurodevelopmental problems, and a Low Bias group, identified via prenatal screening or other medical investigations. Children from a twin sample were used to compare pattern and severity of language problems: they were subdivided according to parental concerns about language/history of speech-language therapy into a No Concerns group (N = 118) and a Language Concerns group (N = 57). Children were assessed on a psychometric battery and a standardized parent checklist. After excluding children with intellectual disability, autism or hearing problems, the sample included 28 XXX, 18 XXY and 14 XYY Low Bias cases and 7 XXX, 13 XXY and 17 XYY High Bias cases. Results Variation within each trisomy group was substantial: within the Low Bias group, overall language scores were depressed relative to normative data, but around one third had no evidence of problems. There was no effect of trisomy type, and the test profile was similar to the Language Concerns comparison group. The rate of problems was much greater in the High Bias children with trisomies. Conclusions When advising parents after discovery of a trisomy, it is important to emphasise that, though there is an increased risk of language problems, there is a very wide range of outcomes. Severe language problems are more common in those identified via genetic testing for neurodevelopmental problems but these are not characteristic of children identified on prenatal screening.

Language phenotypes in children with sex chromosome trisomies

Background: Sex chromosome trisomies (47,XXX, 47,XXY and 47,XYY) are known to be a risk factor for language disorder, but typical outcomes are hard to estimate, because many cases are identified only when problems are found. Methods: We recruited children aged 5-16 years with all three types of trisomy, and divided them into a High Bias group, identified in the course of investigations for neurodevelopmental problems, and a Low Bias group, identified via prenatal screening or other medical investigations. Children from a twin sample were used to compare the pattern and severity of language problems: they were subdivided according to parental concerns about language/history of speech-language therapy into a No Concerns group (N = 132) and a Language Concerns group (N = 41). Children were individually assessed on a psychometric battery, and a standardized parent checklist. After excluding children with intellectual disability, autism or hearing problems, psychometric data were available for 31 XXX, 20 XXY and 19 XYY Low Bias cases and 13 XXX, 25 XXY and 32 XYY High Bias cases. Results: Variation within each trisomy group was substantial: within the Low Bias group, overall language scores were depressed relative to normative data, but around one-third had no evidence of problems. There was no effect of trisomy type, and the test profile was similar to the Language Concerns comparison group. The rate of problems was much greater in the High Bias children with trisomies. Conclusions: When advising parents after discovery of a trisomy, it is important to emphasise that, though there is an increased risk of language problems, there is a very wide range of outcomes. Severe language problems are more common in those identified via genetic testing for neurodevelopmental problems but these are not typical of children identified on prenatal screening.

Phonemic and Semantic Verbal Fluency in Sex Chromosome Aneuploidy: Contrasting the Effects of Supernumerary X versus Y Chromosomes on Performance

OBJECTIVES

Past research suggests that youth with sex chromosome aneuploidies (SCAs) present with verbal fluency deficits. However, most studies have focused on sex chromosome trisomies. Far less is known about sex chromosome tetrasomies and pentasomies. Thus, the current research sought to characterize verbal fluency performance among youth with sex chromosome trisomies, tetrasomies, and pentasomies by contrasting how performance varies as a function of extra X number and X versus Y status.

METHODS

Participants included 79 youth with SCAs and 42 typically developing controls matched on age, maternal education, and racial/ethnic background. Participants completed the phonemic and semantic conditions of a verbal fluency task and an abbreviated intelligence test.

RESULTS

Both supernumerary X and Y chromosomes were associated with verbal fluency deficits relative to controls. These impairments increased as a function of the number of extra X chromosomes, and the pattern of impairments on phonemic and semantic fluency differed for those with a supernumerary X versus Y chromosome. Whereas one supernumerary Y chromosome was associated with similar performance across fluency conditions, one supernumerary X chromosome was associated with relatively stronger semantic than phonemic fluency skills.

CONCLUSIONS

Verbal fluency skills in youth with supernumerary X and Y chromosomes are impaired relative to controls. However, the degree of impairment varies across groups and task condition. Further research into the cognitive underpinnings of verbal fluency in youth with SCAs may provide insights into their verbal fluency deficits and help guide future treatments. (JINS, 2018, 24, 917-927).

Klinefelter Syndrome: Integrating Genetics, Neuropsychology, and Endocrinology

Although first identified over 70 years ago, Klinefelter syndrome (KS) continues to pose substantial diagnostic challenges, as many patients are still misdiagnosed, or remain undiagnosed. In fact, as few as 25% of patients with KS are accurately diagnosed and most of these diagnoses are not made until adulthood. Classic characteristics of KS include small testes, infertility, hypergonadothropic hypogonadism, and cognitive impairment. However, the pathophysiology behind KS is not well understood, although genetic effects are also thought to play a role. For example, recent developments in genetics and genomics point to a fundamental change in our understanding of KS, with global epigenetic and RNA expression changes playing a central role for the phenotype. KS is also associated with more general health markers, including higher morbidity and mortality rates and lower socioeconomic status (which likely affect both morbidity and mortality). In addition, hypogonadism is associated with greater risk of metabolic syndrome, type 2 diabetes, cardiovascular disease, breast cancer, and extragonadal germ cell tumors. Medical treatment typically focuses on testosterone replacement therapy (TRT), although the effects of this therapy have not been studied rigorously, and future studies need to evaluate the effects of TRT on metabolic risk and neurocognitive outcomes. This review presents a comprehensive interdisciplinary examination of recent developments in genetic, endocrine, and neurocognitive science, including the study of animal models. It provides a number of recommendations for improving the effectiveness of research and clinical practice, including neonatal KS screening programs, and a multidisciplinary approach to KS treatment from childhood until senescence.

Intelligence and specific cognitive functions in intellectual disability: implications for assessment and classification

PURPOSE OF REVIEW

Current diagnostic criteria for intellectual disability categorize ability as measured by IQ tests. However, this does not suit the new conceptualization of intellectual disability, which refers to a range of neuropsychiatric syndromes that have in common early onset, cognitive impairments, and consequent deficits in learning and adaptive functioning. A literature review was undertaken on the concept of intelligence and whether it encompasses a range of specific cognitive functions to solve problems, which might be better reported as a profile, instead of an IQ, with implications for diagnosis and classification of intellectual disability.

RECENT FINDINGS

Data support a model of intelligence consisting of distinct but related processes. Persons with intellectual disability with the same IQ level have different cognitive profiles, based on varying factors involved in aetiopathogenesis. Limitations of functioning and many biopsychological factors associated with intellectual disability are more highly correlated with impairments of specific cognitive functions than with overall IQ.

SUMMARY

The current model of intelligence, based on IQ, is of limited utility for intellectual disability, given the wide range and variability of cognitive functions and adaptive capacities. Assessing level of individual impairment in executive and specific cognitive functions may be a more useful alternative. This has considerable implications for the revision of the International Classification of Diseases and for the cultural attitude towards intellectual disability in general.

The role of genes, intelligence, personality, and social engagement in cognitive performance in Klinefelter syndrome

INTRODUCTION

The determinants of cognitive deficits among individuals with Klinefelter syndrome (KS) are not well understood. This study was conducted to assess the impact of general intelligence, personality, and social engagement on cognitive performance among patients with KS and a group of controls matched for age and years of education.

METHODS

Sixty-nine patients with KS and 69 controls were assessed in terms of IQ, NEO personality inventory, the Autism Spectrum Quotient (AQ) scale, and measures of cognitive performance reflecting working memory and executive function.

RESULTS

Patients with KS performed more poorly on memory and executive-function tasks. Patients with KS also exhibited greater neuroticism and less extraversion, openness, and conscientiousness than controls. Memory deficits among patients with KS were associated with lower intelligence, while diminished executive functioning was mediated by both lower intelligence and less social engagement.

CONCLUSION

Our results suggest that among patients with KS, memory deficits are principally a function of lower general intelligence, while executive-function deficits are associated with both lower intelligence and poorer social skills. This suggests a potential influence of social engagement on executive cognitive functioning (and/or vice-versa) among individuals with KS, and perhaps those with other genetic disorders. Future longitudinal research would be important to further clarify this and other issues discussed in this research.

Everyday executive functions in Down syndrome from early childhood to young adulthood: evidence for both unique and shared characteristics compared to youth with sex chromosome trisomy (XXX and XXY)

Executive functions (EF) are thought to be impaired in Down syndrome (DS) and sex chromosome trisomy (Klinefelter and Trisomy X syndromes; +1X). However, the syndromic specificity and developmental trajectories associated with EF difficulties in these groups are poorly understood. The current investigation (a) compared everyday EF difficulties in youth with DS, +1X, and typical development (TD); and (b) examined relations between age and EF difficulties in these two groups and a TD control group cross-sectionally. Study 1 investigated the syndromic specificity of EF profiles on the Behavior Rating Inventory of Executive Function (BRIEF) in DS (n = 30), +1X (n = 30), and a TD group (n = 30), ages 5–18 years. Study 2 examined age effects on EF in the same cross-sectional sample of participants included in Study 1. Study 3 sought to replicate Study 2's findings for DS by examining age-EF relations in a large independent sample of youth with DS (n = 85) and TD (n = 43), ages 4–24 years. Study 1 found evidence for both unique and shared EF impairments for the DS and +1X groups. Most notably, youth with +1X had relatively uniform EF impairments on the BRIEF scales, while the DS group showed an uneven BRIEF profile with relative strengths and weaknesses. Studies 2 and 3 provided support for fairly similar age-EF relations in the DS and TD groups. In contrast, for the +1X group, findings were mixed; 6 BRIEF scales showed similar age-EF relations to the TD group and 2 showed greater EF difficulties at older ages for +1X. These findings will be discussed within the context of efforts to identify syndrome specific cognitive-behavioral profiles for youth with different genetic syndromes in order to inform basic science investigations into the etiology of EF difficulties in these groups and to develop treatment approaches that are tailored to the needs of these groups.

Over-expression of XIST, the Master Gene for X Chromosome Inactivation, in Females With Major Affective Disorders

Background

Psychiatric disorders are common mental disorders without a pathological biomarker. Classic genetic studies found that an extra X chromosome frequently causes psychiatric symptoms in patients with either Klinefelter syndrome (XXY) or Triple X syndrome (XXX). Over-dosage of some X-linked escapee genes was suggested to cause psychiatric disorders. However, relevance of these rare genetic diseases to the pathogenesis of psychiatric disorders in the general population of psychiatric patients is unknown.

Methods

XIST and several X-linked genes were studied in 36 lymphoblastoid cell lines from healthy females and 60 lymphoblastoid cell lines from female patients with either bipolar disorder or recurrent major depression. XIST and KDM5C expression was also quantified in 48 RNA samples from postmortem human brains of healthy female controls and female psychiatric patients.

Findings

We found that the XIST gene, a master in control of X chromosome inactivation (XCI), is significantly over-expressed (p = 1 × 10^− 7, corrected after multiple comparisons) in the lymphoblastoid cells of female patients with either bipolar disorder or major depression. The X-linked escapee gene KDM5C also displays significant up-regulation (p = 5.3 × 10^− 7, corrected after multiple comparisons) in the patients' cells. Expression of XIST and KDM5C is highly correlated (Pearson's coefficient, r = 0.78, p = 1.3 × 10^− 13). Studies on human postmortem brains supported over-expression of the XIST gene in female psychiatric patients.

Interpretations

We propose that over-expression of XIST may cause or result from subtle alteration of XCI, which up-regulates the expression of some X-linked escapee genes including KDM5C. Over-expression of X-linked genes could be a common mechanism for the development of psychiatric disorders between patients with those rare genetic diseases and the general population of female psychiatric patients with XIST over-expression. Our studies suggest that XIST and KDM5C expression could be used as a biological marker for diagnosis of psychiatric disorders in a significantly large subset of female patients.

Research in context

Due to lack of biological markers, diagnosis and treatment of psychiatric disorders are subjective. There is utmost urgency to identify biomarkers for clinics, research, and drug development. We found that XIST and KDM5C gene expression may be used as a biological marker for diagnosis of major affective disorders in a significantly large subset of female patients from the general population. Our studies show that over-expression of XIST and some X-linked escapee genes may be a common mechanism for development of psychiatric disorders between the patients with rare genetic diseases (XXY or XXX) and the general population of female psychiatric patients.

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XIST and KDM5C genes are over-expressed in a large subset of female patients with major affective disorders.

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Over-expression of XIST and KDM5C genes could be used as a biomarker for diagnosis of individual patients.

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Over-expression of XIST and X-linked escapee genes including KDM5C may cause major affective disorders.

Is it all the X: familial learning dysfunction and the impact of behavioral aspects of the phenotypic presentation of XXY?

The behavioral phenotype of children with XXY has not been extensively studied until recently and this research has been confounded by insufficient study populations and ascertainment biases. The aim of the study was to expand the behavioral aspect of the XXY phenotype as well as investigate the role of existing familial learning disabilities (FLD) on behavioral problems. Behavioral phenotype of XXY includes social anxiety, ADHD, social communication, and atypical peer interactions. The Child Behavior Checklist (CBCL), Social Responsiveness Scale (SRS), and Gilliam Autism Rating Scale (GARS) were completed by the parents of 54 boys with XXY who had not received hormonal replacement prior to participation. Our findings suggest fewer behavioral deficits and lower severity in the general 47,XXY population than previously published and found significant differences between the groups with a positive FLD on the behavioral assessments. Findings demonstrate that boys with FLD exhibit an increased incidence and severity of behavioral problems. Our study expands on the findings of Samango-Sprouse et al. [Samango-Sprouse et al. (2012b) J Intellect Disabil Res] and the significant influence that FLD has on not only neurodevelopment, but also behavioral deficits. Our study suggests that part of the XXY phenotypic profile may be modulated by FLD. Further study is underway to examine the interaction between the many salient factors effecting behavioral and neurodevelopmental progression in XXY and variant forms. © 2013 Wiley Periodicals, Inc.

Deficits in inhibitory executive functions in Klinefelter (47, XXY) syndrome

Klinefelter syndrome (47, XXY) is a sex chromosome aneuploidy associated with mild deficits in cognitive and language functions. Dysfunctions have also been reported in performance of tasks which examine executive functions. However, it is unclear whether the impaired performance is caused or accentuated by problems with semantic processing and information processing speed. In the present study we used an experimental task which is relatively insensitive to these confounding factors. We examined inhibitory executive functions in a group of XXY males compared with male (XY) and female (XX) controls, using a dichotic listening speech sound task with instructions to focus attention on either the right or the left ear stimulus. With this task, inhibitory executive functions can be assessed separately from language, processing speed, and attention orientation abilities. We found that XXY males showed a selective deficit in inhibitory executive functions compared to both control groups, whereas attentional orientation was not impaired. The present findings suggest that executive dysfunctions associated to Klinefelter syndrome can be selectively identified, and are particularly accentuated in the inhibitory sub-component. Such improved understanding of the nature of executive dysfunctions in XXY males may aid the development of specific neuropsychological rehabilitation strategies.

Detectando más-formações, detectando riscos: dilemas do diagnóstico pré-natal

Este artigo tem como objetivo analisar os fatores que moldam as culturas materiais da biomedicina contemporânea. Trata do desenvolvimento histórico das técnicas diagnósticas e de como elas definem a "norma" e influenciam a evolução dos comportamentos dos profissionais e dos familiares. Pretende-se esclarecer esses processos a partir de uma reconstrução da evolução histórica do diagnóstico pré-natal, seguida de uma análise detalhada do caso de uma anomalia particular: as ACS, ou seja, as aneuploidias dos cromossomas sexuais. Embora alguns casos de ACS impliquem graves problemas de saúde, que chegam a comprometer a própria sobrevivência do indivíduo, a grande maioria das crianças que possui um número anormal de cromossomas sexuais é afetada por uma deficiência que pode ser qualifi cada como "menor" (em numerosos casos o diagnóstico definitivo das ACS só se coloca na adolescência). Assim, especialmente nos contextos em que existe o aborto legalizado, o diagnóstico pré-natal visibiliza a construção do "feto anormal" e o "risco de ter uma criança anormal" como fenômeno técnico-social, construído ao longo do tempo, de maneira indissociável, pelas técnicas da biomedicina, pela organização do trabalho médico, pelas limitações legais e pelas considerações socioculturais

Executive function in young males with Klinefelter (XXY) syndrome with and without comorbid attention-deficit/hyperactivity disorder

Deficits in executive function (EF) are reported to occur in individuals with Klinefelter syndrome (XXY). The degree of impairment, if any, is variable and the nature of these deficits has not been clearly elucidated in young males. In this report, we (a) examine EF skills using multiple tasks in a non-clinic referred group of youth with XXY, (b) describe the extent of EF weaknesses in XXY when this group is compared with typical males of a similar SES or typical males with similar verbal abilities, and (c) evaluate the contribution of comorbid attention-deficit/hyperactivity disorder (ADHD) to EF skills. The sample included 27 males with XXY (ages 9-25), 27 typically developing age- and vocabulary-matched males, and 22 age- and socioeconomic status-matched males. EF tasks included Verbal Fluency, the Trail Making Test, and the CANTAB Spatial Working Memory and Stockings of Cambridge tasks. Mixed model analysis of variance was used to compare the groups on EF tasks and revealed a main effect of group but no group by task interaction. Overall, the XXY group performed less well than both control groups, but performance did not differ significantly as a function of task. ADHD comorbidity in males with XXY was related to poorer EF skills.

Triple X syndrome: characteristics of 42 Italian girls and parental emotional response to prenatal diagnosis

We report clinical and behavioural evaluation data in 42 Italian girls with triple X syndrome whose diagnosis was made prenatally between 1998 and 2006 in three Italian centres. At initial evaluation, reproductive and medical histories were collected. Clinical assessment of the child was performed by a clinical geneticist and included a detailed personal history, physical evaluation and auxological measurements. To analyse how parents coped with specific events in the prenatal and postnatal periods, we conducted an interview that included 35 specific questions designed to elicit retrospective judgements on prenatal communication, present and future worries, needs and expectations. In a subset of probands, we also administered the formal Italian Temperament Questionnaire assessment test that investigates adaptation, general environment and socialisation. This test also assesses the emotional component of temperament. Clinical results in the affected children are similar to those previously reported with evidence of increased growth in the pre-puberal age and an average incidence of congenital malformation and health needs. Median age for the time first words were pronounced was 12 months, showing a slight delay in language skills, which tended to improve by the time they reached school age. Parental responses to the interview demonstrated residual anxiety but with a satisfactory adaptation to and a positive recall of the prenatal counselling session. Parental adaptation of the 47,XXX girls require indeed a proper educational support. This support seems to be available in Italy. An integrated approach to prenatal counselling is the best way to manage the anxiety and falsely imagined consequences that parents feel after being told that their foetus bears such a genetic abnormality.

Autism-lessons from the X chromosome

Recognized cases of autism spectrum disorders are on the rise. It is unclear whether this increase is attributable to secular trends in biological susceptibility, or to a change in diagnostic practices and recognition. One hint concerning etiological influences is the universally reported male excess (in the range of 4:1 to 10:1). Evidence suggests that genetic influences from the X chromosome play a crucial role in engendering this male vulnerability. In this review, we discuss three categories of genetic disease that highlight the importance of X-linked genes in the manifestation of an autistic phenotype: aneuploides (Turner syndrome and Klinefelter syndrome), trinucleotide expansions (Fragile X syndrome) and nucleotide mutations (Rett Syndrome, Neuroligins 3 & 4, and SLC6A8). The lessons from these diseases include an understanding of autistic features as a broad phenotype rather than as a single clinical entity, the role of multiple genes either alone or in concert with the manifestation of autistic features, and the role of epigenetic factors such as imprinting and X-inactivation in the expression of disease severity. Better understanding of the clinical phenotypes of social cognition and the molecular neurogenetics of X-linked gene disorders will certainly provide additional tools for understanding autism in the years to come.

The cognitive phenotype in Klinefelter syndrome: a review of the literature including genetic and hormonal factors

Klinefelter syndrome (KS) or 47,XXY occurs in approximately 1 in 650 males. Individuals with KS often present with physical characteristics including tall stature, hypogonadism, and fertility problems. In addition to medical findings, the presence of the extra X chromosome can lead to characteristic cognitive and language deficits of varying severity. While a small, but significant downward shift in mean overall IQ has been reported, the general cognitive abilities of patients with KS are not typically in the intellectual disability range. Most studies support that males with KS have an increased risk of language disorders and reading disabilities. Results of other studies investigating the relationship between verbal and nonverbal/spatial cognitive abilities have been mixed, with differing results based on the age and ascertainment method of the cohort studied. Executive function deficits have been identified in children and adults with KS, however, the research in this area is limited and further investigation of the neuropsychological profile is needed. In this article, we review the strengths and weaknesses of previous cognitive and neuropsychological studies in males with KS in childhood and adulthood, provide historical perspective of these studies, and review what is known about how hormonal and genetic factors influence cognitive features in 47,XXY/KS.

Turner syndrome and schizophrenia: a further hint for the role of the X-chromosome in the pathogenesis of schizophrenic disorders

Abnormalities of sex chromosomes are associated with various forms of neuropsychiatric disorders, such as schizophrenia. Turner syndrome occurs approximately threefold more frequently in female schizophrenics compared to the general female population. A single case is reported. We report on a case of a 41-year-old woman with Turner syndrome, schizophrenia, mental retardation, and hypothyroidism. A polymorphism of the HOPA gene within Xq13 termed HOPA(12bp) is associated with schizophrenia, mental retardation, and hypothyroidism. Interestingly, Xq13 is the X-chromosome region that contains the X-inactivation center and a gene escaping X-inactivation whose gene product may be involved in the X-inactivation process as well as in the pathogenesis of sex chromosome anomalies such as Turner syndrome. These genes that escape X-inactivation may produce their gene products in excess, influencing normal brain growth and differentiation. Our case gives a further hint for an involvement of the X-chromosome in the pathogenesis of schizophrenia.

Neurocognitive outcomes of individuals with a sex chromosome trisomy: XXX, XYY, or XXY: a systematic review

AIM

To review systematically the neurodevelopmental characteristics of individuals with sex chromosome trisomies (SCTs).

METHOD

A bibliographic search identified English-language articles on SCTs. The focus was on studies unbiased by clinical referral, with power of at least 0.69 to detect an effect size of 1.0.

RESULTS

We identified 35 articles on five neonatally identified samples that had adequate power for our review. An additional 11 studies were included where cases had been identified for reasons other than neurodevelopmental concerns. Individuals with an additional X chromosome had mean IQs that were within broadly normal limits but lower than the respective comparison groups, with verbal IQ most affected. Cognitive outcomes were poorest for females with XXX. Males with XYY had normal-range IQs, but all three SCT groups (XXX, XXY, and XYY) had marked difficulties in speech and language, motor skills, and educational achievement. Nevertheless, most adults with SCTs lived independently. Less evidence was available for brain structure and for attention, social, and psychiatric outcomes. Within each group there was much variation.

INTERPRETATION

Individuals with SCTs are at risk of cognitive and behavioural difficulties. However, the evidence base is slender, and further research is needed to ascertain the nature, severity, and causes of these difficulties in unselected samples.

Triple X syndrome: a review of the literature

The developmental and clinical aspects in the literature on triple X syndrome are reviewed. Prenatal diagnosis depends on karyotyping. The incidence is 1 of 1000 females. At birth, 47,XXX girls have a lower mean birth weight and a smaller head circumference. Triple X diagnosis was not suspected at birth. The maternal age seems to be increased. Toddlers with triple X syndrome show delayed language development. The youngest girls show accelerated growth until puberty. EEG abnormalities seem to be rather common. Many girls show motor-coordination problems and auditory-processing disorders are not rare. Scoliosis is probably more common in adolescent cases. The IQ levels are 20 points below that of controls, and verbal IQ is lowest. The girls struggle with low self-esteem and they need psychological, behavioural and educational support. They perform best in stable families. After leaving school they seem to feel better. In adults, premature ovarian failure seems to be more prevalent than in controls. MRIs of the brain seem to show decreased brain volumes. The 47,XXX women most often find jobs that reflect their performance abilities. Psychotic illness seems to be more prevalent in triple X adult women than in controls. Psychotic disorders respond well to psychotropic drugs. Triple X adults suffer more frequently from cyclothymic and labile personality traits. Research on triple X syndrome may yield more insight into brain and behaviour relations, developmental psychopathology, auditory-processing disorders, EEG disorders, personality and psychotic disorders, etc.

Dysregulation of X-linked gene expression in Klinefelter's syndrome and association with verbal cognition

Klinefelter's Syndrome (KS) is a chromosomal karyotype with one or more extra X chromosomes. KS individuals often show language impairment and the phenotype might be due to overexpression of genes on the extra X chromosome(s). We profiled mRNA derived from lymphoblastoid cell lines from males with documented KS and control males using the Affymetrix U133P microarray platform. There were 129 differentially expressed genes (DEGs) in KS group compared with controls after Benjamini-Hochberg false discovery adjustment. The DEGs included 14 X chromosome genes which were significantly over-represented. The Y chromosome had zero DEGs. In exploratory analysis of gene expression-cognition relationships, 12 DEGs showed significant correlation of expression with measures of verbal cognition in KS. Overexpression of one pseudoautosomal gene, GTPBP6 (GTP binding protein 6, putative) was inversely correlated with verbal IQ (r = -0.86, P < 0.001) and four other measures of verbal ability. Overexpression of XIST was found in KS compared to XY controls suggesting that silencing of many genes on the X chromosome might occur in KS similar to XX females. The microarray findings for eight DEGs were validated by quantitative PCR. The 14 X chromosome DEGs were not differentially expressed in prior studies comparing female and male brains suggesting a dysregulation profile unique to KS. Examination of X-linked DEGs, such as GTPBP6, TAF9L, and CXORF21, that show verbal cognition-gene expression correlations may establish a causal link between these genes, neurodevelopment, and language function. A screen of candidate genes may serve as biomarkers of KS for early diagnosis.

Klinefelter syndrome in clinical practice

Klinefelter syndrome is the most common sex-chromosome disorder; it affects approximately one in every 660 men. This syndrome is characterized by the presence of one or more extra X chromosomes, and the karyotype 47,XXY is the most prevalent type. The 'prototypic' man with Klinefelter syndrome has traditionally been described as tall, with narrow shoulders, broad hips, sparse body hair, gynecomastia, small testicles, androgen deficiency, azoospermia and decreased verbal intelligence. A less distinct phenotype has, however, been described. Klinefelter syndrome is an underdiagnosed condition; only 25% of the expected number of patients are diagnosed, and of these only a minority are diagnosed before puberty. Patients with Klinefelter syndrome should be treated with lifelong testosterone supplementation that begins at puberty, to secure proper masculine development of sexual characteristics, muscle bulk and bone structure, and to prevent the long-term deleterious consequences of hypogonadism; however, the optimal testosterone regimen for patients with Klinefelter syndrome remains to be established.

Parental decisions to abort or continue a pregnancy following prenatal diagnosis of chromosomal abnormalities in a setting where termination of pregnancy is not legally available

OBJECTIVE

To learn about parental decisions to abort or continue a pregnancy after prenatal diagnosis of chromosomal abnormalities among the population in Uruguay.

METHODS

Between 1982 and 2003, 14 656 amniocentesis and 2740 chorionic villus samplings were performed in a referral Genetic Unit. Chromosomal anomalies were found in 376 cases (2.16%) and included Down syndrome, aneuploidies in which a severe prognosis was expected, sex chromosome aneuploidy and aneuploidies with a low risk of an abnormal clinical phenotype. The couples that received abnormal results were contacted by phone and asked if they had continued or interrupted the pregnancy after the diagnosis and genetic counseling.

RESULTS

We contacted 207 couples (55%). When confronted with Down syndrome or an aneuploidy in which a severe prognosis was expected, 89% and 96% of patients, respectively, decided to terminate the pregnancy. When confronted with sex chromosome aneuploidy or aneuploidies with a low risk of an abnormal clinical phenotype, 79% and 90% of patients, respectively, decided to continue the pregnancy.

CONCLUSIONS

The present study shows that when faced with an anomaly such as Down syndrome and aneuploidies in which a severe prognosis was expected, most of the couples decided to terminate the pregnancy, although TOP is not legally available in Uruguay.

Klinefelter's syndrome (XXY) as a genetic model for psychotic disorders

Males with an extra-X chromosome (Klinefelter's syndrome) frequently, although not always, have an increased prevalence of psychiatric disturbances that range from attention deficit disorder in childhood to schizophrenia or severe affective disorders during adulthood. In addition, they frequently have characteristic verbal deficits. Thus, examining brain magnetic resonance imaging (MRI) scans of these individuals may yield clues to the influence of X chromosome genes on brain structural variation corresponding to psychiatric and cognitive disorders. Eleven adult XXY and 11 age matched XY male controls were examined with a structured psychiatric interview, battery of cognitive tests, and an MRI scan. Ten of eleven of the XXY men had some form of psychiatric disturbance, four of whom had auditory hallucinations compared with none of the XY controls. Significantly smaller frontal lobe, temporal lobe, and superior temporal gyrus (STG) cortical volumes were observed bilaterally in the XXY men. In addition, diffusion tensor imaging (DTI) of white matter integrity resulted in four regions of reduced fractional anisotropy (FA) in XXY men compared with controls, three in the left hemisphere, and one on the right. These correspond to the left posterior limb of the internal capsule, bilateral anterior cingulate, and left arcuate bundle. Specific cognitive deficits in executive functioning attributable to frontal lobe integrity and verbal comprehension were noted. Thus, excess expression of one or more X chromosome genes influences both gray and white matter development in frontal and temporal lobes, as well as white matter tracts leading to them, and may in this way contribute to the executive and language deficits observed in these adults. Future prospective studies are needed to determine which gene or genes are involved and whether their expression could be modified with appropriate treatments early in life. Brain expressed genes that are known to escape inactivation on extra-X chromosomes would be prime candidates.

YqTER deletion causes arrest of spermatogenesis in early puberty

We report a 12-7/12 year-old male with obesity, eunuchoid proportions, genetic stigmata of Turner's syndrome and mild developmental delay. We investigated whether cytogenetic alterations could be responsible for his phenotype. Conventional karyotype in 70 peripheral blood cells was 45,X(15%)/46,XYqh-(85%). Dual FISH on 1,000 nuclei revealed 8% of X0 cells (DXZ1 X-centromeric probe) and 92% of XY cells (DYZ3 Y-centromeric probe). We studied Y chromosome microdeletions by PCR. The patient showed a terminal Yq deletion from the 5I interval including the AZFb and AZFc regions. FSH, LH and testosterone (468 ng/dl) were within the normal range for his age. At Tanner IV pubertal development the spermiogram showed azoospermia and the testicular aspirate spermatic arrest. The present report suggests that Y chromosome deletions including AZFb and AZFc regions may cause spermatogenic arrest in early puberty.

How common is intersex? a response to Anne Fausto-Sterling

Anne Fausto-Sterling s suggestion that the prevalence of intersex might be as high as 1.7% has attracted wide attention in both the scholarly press and the popular media. Many reviewers are not aware that this figure includes conditions which most clinicians do not recognize as intersex, such as Klinefelter syndrome, Turner syndrome, and late-onset adrenal hyperplasia. If the term intersex is to retain any meaning, the term should be restricted to those conditions in which chromosomal sex is inconsistent with phenotypic sex, or in which the phenotype is not classifiable as either male or female. Applying this more precise definition, the true prevalence of intersex is seen to be about 0.018%, almost 100 times lower than Fausto-Sterling s estimate of 1.7%.