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

Understanding the Neuropsychological Implications of Klinefelter Syndrome in Pediatric Populations: Current Perspectives

Klinefelter syndrome (KS), also known as 47,XXY, is a genetic disorder characterized by the presence of an extra X chromosome. Despite the prevalence of verbal learning disabilities, memory impairments, and executive function deficits in individuals with KS, comprehensive research on the neuropsychological profiles of affected children and adolescents remains limited. Additionally, KS has been associated with comorbid conditions such as depression, anxiety, schizophrenia, attention-deficit hyperactivity disorder (ADHD), and autism spectrum disorders (ASDs). However, systematic investigations into the neuropsychological manifestations of KS in pediatric populations are scarce. Therefore, the primary objectives of this review are to provide an overview of key studies examining the neuropsychological profiles of children and adolescents with KS and to delineate the limitations and implications of existing research findings. By synthesizing available literature, this review aims to bridge the gap in understanding the cognitive and behavioral characteristics of children and adolescents with KS, shedding light on potential avenues for future research and clinical interventions. Ultimately, this review serves as a valuable resource for clinicians, researchers, policymakers, parents, and educators involved in the assessment and management of the neuropsychological aspects of Klinefelter syndrome in pediatric populations.

Executive Dysfunction in Klinefelter Syndrome: Associations With Brain Activation and Testicular Failure

CONTEXT

Executive dysfunction is a well-recognized component of the cognitive phenotype of Klinefelter syndrome (KS), yet the neural basis of KS-associated cognitive weaknesses, and their association with testicular failure is unknown.

OBJECTIVE

We investigated executive function, brain activation, and pubertal development in adolescents with and without KS.

METHODS

Forty-three adolescents with KS (mean age 12.3 ± 2.3 years) and 41 typically developing boys (mean age 11.9 ± 1.8 years) underwent pubertal evaluation, behavioral assessment, and completed functional magnetic resonance imaging (fMRI) as they performed an executive function task, the go/no-go task. Group differences in activation were examined. Associations among activation, executive function, and pubertal development measures were tested in secondary analyses.

RESULTS

Boys with KS exhibited reduced executive function, as well as lower activation in brain regions subserving executive function, including the inferior frontal gyrus, anterior insula, dorsal anterior cingulate cortex, and caudate nucleus. Secondary analyses indicated that the magnitude of activation differences in boys with KS was associated with severity of pubertal developmental delay, as indexed by lower testosterone (t(36) = 2.285; P = .028) and lower testes volume (t(36) = 2.238; P = .031). Greater parent-reported attention difficulties were additionally associated with lower testicular volume (t(36) = -2.028; P = .050).

CONCLUSION

These findings indicate a neural basis for executive dysfunction in KS and suggest alterations in pubertal development may contribute to increased severity of this cognitive weakness. Future studies that examine whether these patterns change with testosterone replacement therapy are warranted.

Cognition, Academic Achievement, Adaptive Behavior, and Quality of Life in Child and Adolescent Boys with Klinefelter Syndrome

OBJECTIVE

Klinefelter syndrome (KS; 47, XXY), the most common sex chromosome aneuploidy in males, is characterized by testicular failure and testosterone deficiency as well as a variety of cognitive, social, and emotional challenges. In the current study, we aimed to clarify the cognitive-behavioral profile of peripubertal boys with KS using measures of cognition, academic achievement, adaptive behavior, and quality of life.

METHOD

We compared 47 boys with KS (7-16 years of age) with 55 performance IQ-matched boys without KS on measures of cognition (WISC-V), executive function (BRIEF-2), academic achievement (KTEA-3), adaptive behavior (Vineland-3), and quality of life (PROMIS). In exploratory analyses, we examined associations among these measures and potential associations with pubertal metrics.

RESULTS

Boys with KS demonstrated a significantly different profile of cognition, behavioral ratings of executive function, academic achievement, adaptive behavior, and quality of life compared with their typically developing peers, with, on average, lower functioning. The groups showed significantly different correlations between cognition and aspects of quality of life. No associations were observed between behavior and pubertal development.

CONCLUSION

Taken together, these findings indicated that boys with KS are at increased risk for cognitive difficulties, which may affect academic achievement, adaptive behavior, and quality of life. Although initial exploratory analyses indicated that the magnitude of these alterations was not correlated with severity of testicular failure, longitudinal analyses currently being conducted by our group may help clarify the trajectory of these difficulties through the pubertal transition and testosterone replacement.

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

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

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

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

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.

Prenatal Genetic Diagnosis of a Sex Chromosome Aneuploidy: Parent Experiences

Sex chromosome aneuploidies (SCAs) occur in 1 in every 400 births. SCAs are highly variable and have uncertain prognoses, complicating the delivery of prenatal cell-free DNA (cfDNA) results or diagnosis following amniocentesis or chorionic villus sampling. Using a mixed-methods approach, we explored the experiences of parents receiving a prenatal diagnosis of a fetus with SCA. Responses to open-ended questions were qualitatively analyzed. Of the 323 parents who completed the survey, 122 received a prenatal diagnosis and answered at least one open-ended question. Most parents did not recall being informed that cfDNA screening or amniocentesis could reveal the presence of a SCA prior to testing and described feeling unprepared for a positive result. Variation was found between parents who were delivered a diagnosis by a genetic professional versus other clinical specialties. Many parents expressed that the diagnosis was delivered in a way that emphasized the negative attributes of the SCA and that they were provided limited support materials. Parents who received a prenatal diagnosis of a SCA expressed a desire for more supportive delivery of prenatal diagnosis that focuses on parental education and nuanced discussion of potential phenotypes. Genetic counselors should be aware of the range of parental experiences when receiving a SCA diagnosis from non-genetic providers. Prenatal SCA diagnoses are predicted to increase as prenatal cfDNA screening becomes more widely used. Collaborations for greater provider education and comprehensive materials on SCAs are essential to facilitate the delivery of SCA diagnoses and improve parent understanding and support.