The importance of understanding cognitive trajectories: the case of 22q11.2 deletion syndrome

Endocrine manifestations in adults with 22q11.2 deletion syndrome: a retrospective single-center cohort study

INTRODUCTION AND OBJECTIVE

Patients with the 22q11.2 deletion syndrome (22q11DS) frequently display cardiological and psychiatric diseases, but are also at increased risk for endocrine manifestations. The aim of this study was to evaluate the screening, prevalence, and management of hypoparathyroidism and thyroid disease in patients with 22q11DS, to evaluate the metabolic profile, and to compare these results with current literature and guidelines.

DESIGN

We performed a retrospective study of patients with genetically confirmed 22q11DS, followed at the center for human genetics of the University Hospitals Leuven, resulting in a cohort of 75 patients. Medical history, medication, and laboratory results concerning hypoparathyroidism, thyroid dysfunction, and the metabolic profile were collected.

RESULTS

Of the total cohort, 26 patients (35%) had at least one hypocalcaemic episode. During hypocalcaemia, parathyroid hormone (PTH) was measured in only 12 patients with 11 having normal or low PTH, confirming a diagnosis of hypoparathyroidism. Recurrent episodes of hypocalcaemia occurred in seventeen patients (23%). Adherence to the guidelines was low, with 13% of patients having a yearly serum calcium evaluation, 12% receiving daily calcium supplements, and 20% receiving non-active vitamin D. Hypothyroidism was present in 31 patients (44%) and hyperthyroidism in 6 patients (8%). Information on body mass index (BMI) was available in 52 patients (69%), of which 38% were obese (BMI ≥ 30 kg/m2).

CONCLUSION

Hypoparathyroidism, hypothyroidism, and obesity are common endocrine manifestations in patients with 22q11DS but are probably underdiagnosed and undertreated, indicating the need for multidisciplinary follow-up including an endocrinologist.

Prenatal cardiac findings and 22q11.2 deletion syndrome: Fetal detection and evaluation

Clinical features of 22q11.2 microdeletion syndrome (22q11.2DS) are highly variable between affected individuals and frequently include a subset of conotruncal and aortic arch anomalies. Many are diagnosed with 22q11.2DS when they present as a fetus, newborn or infant with characteristic cardiac findings and subsequently undergo genetic testing. The presence of an aortic arch anomaly with characteristic intracardiac anomalies increases the likelihood that the patient has 22q11.2 DS, but those with an aortic arch anomaly and normal intracardiac anatomy are also at risk. It is particularly important to identify the fetus at risk for 22q11.2DS in order to prepare the expectant parents and plan postnatal care for optimal outcomes. Fetal anatomy scans now readily identify aortic arch anomalies (aberrant right subclavian artery, right sided aortic arch or double aortic arch) in the three-vessel tracheal view. Given the association of 22q11.2DS with aortic arch anomalies with and without intracardiac defects, this review highlights the importance of recognizing the fetus at risk for 22q11.2 deletion syndrome with an aortic arch anomaly and details current methods for genetic testing. To assist in the prenatal diagnosis of 22q11.2DS, this review summarizes the seminal features of 22q11.2DS, its prenatal presentation and current methods for genetic testing.

Altered developmental trajectories of verbal learning skills in 22q11.2DS: associations with hippocampal development and psychosis

BACKGROUND

The cognitive profile in 22q11.2 deletion syndrome (22q11.2DS) is often characterized by a discrepancy between nonverbal vs. verbal reasoning skills, in favor of the latter skills. This dissociation has also been observed in memory, with verbal learning skills described as a relative strength. Yet the development of these skills is still to be investigated. We thus aimed to explore verbal learning longitudinally. Furthermore, we explored verbal learning and its respective associations with hippocampal alterations and psychosis, which remain largely unknown despite their high prevalence in 22q11.2DS.

METHODS

In total, 332 individuals (173 with 22q11.2DS) aged 5-30 years completed a verbal-paired associates task. Mixed-models regression analyses were conducted to explore developmental trajectories with threefold objectives. First, verbal learning and retention trajectories were compared between 22q11.2DS vs. HC. Second, we examined hippocampal volume development in 22q11.2DS participants with lower vs. higher verbal learning performance. Third, we explored verbal learning trajectories in 22q11.2DS participants with vs. without positive psychotic symptoms and with vs. without a psychotic spectrum disorder (PSD).

RESULTS

Our findings first reveal lower verbal learning performance in 22q11.2DS, with a developmental plateau emerging from adolescence. Second, participants with lower verbal learning scores displayed a reduced left hippocampal tail volume. Third, participants with PSD showed a deterioration of verbal learning performance, independently of verbal reasoning skills.

CONCLUSION

Our study challenges the current view of preserved verbal learning skills in 22q11.2DS and highlights associations with specific hippocampal alterations. We further identify verbal learning as a novel cognitive marker for psychosis in 22q11.2DS.

Chromosome 22q11.2 Deletion Syndrome: A Comprehensive Review of Molecular Genetics in the Context of Multidisciplinary Clinical Approach

The 22q11.2 deletion syndrome is a multisystemic disorder characterized by a marked variability of phenotypic features, making the diagnosis challenging for clinicians. The wide spectrum of clinical manifestations includes congenital heart defects-most frequently conotruncal cardiac anomalies-thymic hypoplasia and predominating cellular immune deficiency, laryngeal developmental defects, midline anomalies with cleft palate and velar insufficiency, structural airway defects, facial dysmorphism, parathyroid and thyroid gland hormonal dysfunctions, speech delay, developmental delay, and neurocognitive and psychiatric disorders. Significant progress has been made in understanding the complex molecular genetic etiology of 22q11.2 deletion syndrome underpinning the heterogeneity of clinical manifestations. The deletion is caused by chromosomal rearrangements in meiosis and is mediated by non-allelic homologous recombination events between low copy repeats or segmental duplications in the 22q11.2 region. A range of genetic modifiers and environmental factors, as well as the impact of hemizygosity on the remaining allele, contribute to the intricate genotype-phenotype relationships. This comprehensive review has been aimed at highlighting the molecular genetic background of 22q11.2 deletion syndrome in correlation with a clinical multidisciplinary approach.

Prenatal Screening and Diagnostic Considerations for 22q11.2 Microdeletions

Diagnosis of a chromosome 22q11.2 microdeletion and its associated deletion syndrome (22q11.2DS) is optimally made early. We reviewed the available literature to provide contemporary guidance and recommendations related to the prenatal period. Indications for prenatal diagnostic testing include a parent or child with the 22q11.2 microdeletion or suggestive prenatal screening results. Definitive diagnosis by genetic testing of chorionic villi or amniocytes using a chromosomal microarray will detect clinically relevant microdeletions. Screening options include noninvasive prenatal screening (NIPS) and imaging. The potential benefits and limitations of each screening method should be clearly conveyed. NIPS, a genetic option available from 10 weeks gestational age, has a 70-83% detection rate and a 40-50% PPV for most associated 22q11.2 microdeletions. Prenatal imaging, usually by ultrasound, can detect several physical features associated with 22q11.2DS. Findings vary, related to detection methods, gestational age, and relative specificity. Conotruncal cardiac anomalies are more strongly associated than skeletal, urinary tract, or other congenital anomalies such as thymic hypoplasia or cavum septi pellucidi dilatation. Among others, intrauterine growth restriction and polyhydramnios are additional associated, prenatally detectable signs. Preconception genetic counselling should be offered to males and females with 22q11.2DS, as there is a 50% risk of transmission in each pregnancy. A previous history of a de novo 22q11.2 microdeletion conveys a low risk of recurrence. Prenatal genetic counselling includes an offer of screening or diagnostic testing and discussion of results. The goal is to facilitate optimal perinatal care.

Behaviors related to autism spectrum disorder in children with developmental language disorder and children with 22q11.2 deletion syndrome

Background and Aim

Children with Developmental Language Disorder (DLD) are at an increased risk to develop behaviors associated with Autism Spectrum Disorder (ASD). The relationship between early language difficulties and the occurrence of ASD-related behaviors in DLD is poorly understood. One factor that may hinder progress in understanding this relationship is the etiological heterogeneity of DLD. We therefore study this relationship in an etiologically homogeneous group of children, who share phenotypic characteristics with children with DLD: children with the 22q11.2 Deletion Syndrome (22q11DS). We compare children with 22q11DS, to children with DLD and age-matched typically developing children (TD).

Method

44 children with 22q11DS, 65 children with DLD and 81 TD children, between 3.0-6.5 years old, participated in a longitudinal cohort study that included a baseline measure and a follow-up measure with a 1-year interval. A parental questionnaire (SRS-2) was used to measure the incidence of behaviors in two key behavioral domains associated with ASD: Social Communication and Interaction and Restricted Repetitive Behaviors and Interests. At baseline, we assessed children's expressive and receptive language abilities as well as their intellectual functioning with standardized tests. We compared the distribution of ASD-related behaviors between the three groups. We used regression analyses to investigate whether language abilities at baseline predict ASD-related behavior at follow-up, accounting for ASD-related behavior at baseline, demographic variables and intellectual functioning.

Results

Both the children with 22q11DS and the children with DLD displayed significantly more ASD-related behaviors than the TD children. Over 30% of children in both clinical groups had scores exceeding the subclinical threshold for ASD in both behavioral domains. Both in 22q11DS and DLD, baseline receptive language scores were negatively correlated with ASD-related behaviors 1 year later, when controlling for baseline SRS-scores. However, this association was statistically significant only in children with 22q11DS, even when controlled for IQ-scores, and it was significantly stronger as than in the TD group. The strength of the association did not differ significantly between 22q11DS and DLD.

Conclusion

Both children with 22q11DS and children with DLD present with elevated rates of ASD-related behaviors at a preschool-age. Only in children with 22q11DS we observed that weaker receptive language skills were related to increased behavioral problems in the domain of social communication and interaction one year later.

Implications

Our findings indicate that relations between early language impairment and other behavioral phenotypes may be more feasible to detect in a subgroup of children with a homogeneous etiology, than in a group of children with a heterogeneous etiology (such as children with DLD). Our results in 22q11DS reveal that receptive language is especially important in predicting the occurrence of ASD-related behaviors. Future research is needed to determine to what extent receptive language predicts the occurrence of ASD-related behaviors in children with DLD, especially among those children with DLD with the weakest receptive language. Clinically, screening for ASD-related behaviors in children with developmental language difficulties is recommended from a young age, especially among children with receptive language difficulties.

Variability in Neuropsychological Phenotypes in Patients with 22Q11.2 Deletion Syndrome: Case Series

Children with 22q11.2 deletion syndrome (22q11.2DS) have diverse neurodevelopmental and mental health profiles involving cognitive impairments and behavioral symptomatology that evolve over the lifespan. 22q11.2DS is the second-most common cause of developmental delay in children. Frequent physical manifestations include impact to skeletal, cardiac, immunological, respiratory, renal, auditory, and gastrointestinal systems. Neuropsychological impact ranges from early developmental delay to learning disabilities to more global intellectual disability. This population is also at higher risk for psychiatric conditions including Attention Deficit Hyperactivity Disorder, Anxiety Disorder, Bipolar Disorder and early Schizophrenia. The present case series relays cross-sectional findings from a 3-year -old Black/Non-Hispanic male, a 5-year -old White/Hispanic/Latina female, and an 8-year -old White/Hispanic/Latina female, diagnosed with 22q11.2DS via whole exome sequencing. Based on the referral question, various components of intellectual, attention/executive, memory, language, visual-motor/fine-motor, academic, adaptive, and emotional/behavioral functioning were examined across cases. Results revealed cognitive scores that ranged from exceptionally low to below average, consistent with the variability in cognitive functioning documented in the literature. Their neurodevelopmental and mental health symptoms appear to be consistent with time points reported in the literature including Autism Spectrum Disorder in the youngest patient and elevated levels of anxiety and internalizing behaviors in the oldest patient, placing that patient at a greater risk for further psychiatric difficulties. Therefore, longitudinal documentation of linkages between clinical neuropsychological presentations and specific genetic characteristics in 22q11.2DS is warranted to identify consistent developmental differences across the lifespan.

Consequences of 22q11.2 Microdeletion on the Genome, Individual and Population Levels

Chromosomal 22q11.2 deletion syndrome (22q11.2DS) (ORPHA: 567) caused by microdeletion in chromosome 22 is the most common chromosomal microdeletion disorder in humans. Despite the same change on the genome level, like in the case of monozygotic twins, phenotypes are expressed differently in 22q11.2 deletion individuals. The rest of the genome, as well as epigenome and environmental factors, are not without influence on the variability of phenotypes. The penetrance seems to be more genotype specific than deleted locus specific. The transcript levels of deleted genes are not usually reduced by 50% as assumed due to haploinsufficiency. 22q11.2DS is often an undiagnosed condition, as each patient may have a different set out of 180 possible clinical manifestations. Diverse dysmorphic traits are present in patients from different ethnicities, which makes diagnosis even more difficult. 22q11.2 deletion syndrome serves as an example of a genetic syndrome that is not easy to manage at all stages: diagnosis, consulting and dealing with.

Developmental Support for Infants With Genetic Disorders

As the technical ability for genetic diagnosis continues to improve, an increasing number of diagnoses are made in infancy or as early as the neonatal period. Many of these diagnoses are known to be associated with developmental delay and intellectual disability, features that would not be clinically detectable at the time of diagnosis. Others may be associated with cognitive impairment, but the incidence and severity are yet to be fully described. These neonates and infants with genetic diagnoses therefore represent an emerging group of patients who are at high risk for neurodevelopmental disabilities. Although there are well-established developmental supports for high-risk infants, particularly preterm infants, after discharge from the NICU, programs specifically for infants with genetic diagnoses are rare. And although previous research has demonstrated the positive effect of early developmental interventions on outcomes among preterm infants, the impact of such supports for infants with genetic disorders who may be born term, remains to be understood. We therefore review the literature regarding existing developmental assessment and intervention approaches for children with genetic disorders, evaluating these in the context of current developmental supports postdischarge for preterm infants. Further research into the role of developmental support programs for early assessment and intervention in high-risk neonates diagnosed with rare genetic disorders is needed.

Cytogenetic and genetic investigation of miscarriage cases in Eastern China

Objective: Recurrent miscarriage (RM) affects about 5% of pregnancies. Etiology of 30-50% RM cases remains unknown. Advanced highly sensitive detection and analysis methods may help solve some of the cases.Methods: Products of conception from 1155 RM cases were analyzed using classic karyotyping. Some cases without abnormal findings were subjected to next generation DNA sequencing (NGS) and chromosome copy number variation (CNV) analysis.Results: Classic karyotyping identified abnormalities in 56.62% of the cases. Of the103 specimens analyzed using NGS, 39 (37.86%) were found to carry "pathogenic" CNVs. Recurrent microdeletions and microduplications were identified, and some with unique distribution patterns.Conclusion: NGS CNV analysis is a highly sensitive and flexible method for detecting genetic abnormalities in RM cases.

Psychiatric disorders and autism in young children with 22q11.2 deletion syndrome compared to children with idiopathic autism

BACKGROUND

The 22q11.2 deletion syndrome (22q11DS) is a neurogenetic condition characterized by high rates of psychiatric disorders. To our knowledge, this is the first study to assess psychiatric disorders in young children with 22q11DS using a structured psychiatric diagnostic interview, and one of few studies to use the complete gold standard diagnostic evaluation to examine the prevalence of autism spectrum disorder (ASD) in young children with 22q11DS and compare it to a matched control group with iASD.

METHODS

We identified the psychiatric disorders and autistic phenotype of young children with 22q11DS (age 3-8 years) and compared them with those of age and sex-matched children with idiopathic autism (iASD). We used the gold standard psychiatric and ASD assessments including the Autism Diagnostic Interview-Revised (ADI-R), the Autism Diagnostic Observation Schedule (ADOS) and a clinical examination by a child psychiatrist.

RESULTS

Eighty-four percent of the children with 22q11DS had at least one psychiatric disorder, including anxiety disorders and ADHD, and 16% met strict criteria for ASD. Children with 22q11DS and ASD symptoms had less severe overall ASD symptoms than those with iASD. Children with 22q11DS, regardless of ASD diagnosis, were characterized by repetitive restricted behaviors.

CONCLUSIONS

Our results highlight the need to screen for psychiatric disorders in 22q11DS and treat them already in preschool years.

Neurologic challenges in 22q11.2 deletion syndrome

Children with 22q11.2 deletion syndrome often come to medical attention due to signs and symptoms of neurologic dysfunction. It is imperative to understand the expected neurologic development of patients with this diagnosis in order to be alert for the potential neurologic complications, including cortical malformations, tethered cord, epilepsy, and movement disorders. We present an update of brain imaging findings from the CHOP 22q and You Center, a review of the current literature, and our current management practices for neurological issues.

Understanding the pediatric psychiatric phenotype of 22q11.2 deletion syndrome

The purpose of this article is to provide an overview of current insights into the neurodevelopmental and psychiatric manifestations of 22q11.2 deletion syndrome (22q11DS) in children and adolescents. The pediatric neuropsychiatric expression of 22q11DS is characterized by high variability, both interindividual and intraindividual (different expressions over the lifespan). Besides varying levels of intellectual disability, the prevalence of autism spectrum disorders, attention deficit disorders, anxiety disorders, and psychotic disorders in young individuals with 22q11DS is significantly higher than in the general population, or in individuals with idiopathic intellectual disability. Possible explanations for this observed phenotypic variability will be discussed, including genetic pleiotropy, gene-environment interactions, the age-dependency of phenotypes, but also the impact of assessment and ascertainment bias as well as the limitations of our current diagnostic classification system. The implications inferred by these observations aforementioned bear direct relevance to both scientists and clinicians. Observations regarding the neuropsychiatric manifestations in individuals with 22q11DS exemplify the need for a dimensional approach to neuropsychiatric assessment, in addition to our current categorical diagnostic classification system. The potential usefulness of 22q11DS as a genetic model to study the early phases of schizophrenia as well as the phenomenon of neuropsychiatric pleiotropy observed in many CNV's will be delineated. From a clinical perspective, the importance of regular neuropsychiatric evaluations with attention to symptoms not always captured in diagnostic categories and of maintaining equilibrium between individual difficulties and competencies and environmental demands will be discussed.

Neurodevelopmental outcome in 22q11.2 deletion syndrome and management

The 22q11.2 deletion syndrome (22q11.2 DS) places affected individuals at an increased risk for neurodevelopmental/cognitive, behavioral and social-emotional difficulties. Poor cognitive functioning and intellectual disabilities, attention and executive functioning deficits, learning disorders, emotional dysregulation and impairments in social processing are common among individuals with 22q11.2 DS. Identifying risk and protective/resilience factors that can be detected in early life and can predict neurodevelopmental outcomes for people with 22q11.2 DS is of significant clinical relevance and might allow for early detection and intervention. Given the focus of this review, we will discuss the possible contributing factors that influence the neurodevelopmental outcome in 22q1.2 DS, the cognitive phenotype in 22q11.2 DS, the different developmental trajectories across life span, and the implications for clinical practice and management.

Exploratory study on cognitive abilities and social responsiveness in children with 22q11.2 deletion syndrome (22q11DS) and children with idiopathic intellectual disability (IID)

BACKGROUND

Development of cognitive skills and social responsiveness are areas of concern in children with 22q11.2 deletion syndrome (22q11DS). It remains unclear if the cognitive and social profiles and trajectories are syndrome-specific or similar to those of children with idiopathic intellectual disabilities (IID) with or without comorbid autism spectrum disorder (ASD).

AIMS AND METHODS

In this exploratory study, we examined and compared five broad cognitive abilities (BCAs) and the social responsiveness in primary school-aged children with 22q11DS (age 6-13, n = 21) and IQ-matched peers with IID (n = 21). The relative strengths and weaknesses of both groups were re-evaluated after 19 to 30 months.

OUTCOMES AND RESULTS

Four different cognitive trajectories (i.e. absolute progress, stability, growing into deficit, and absolute decline) were demonstrated in both groups. Most children showed combined types of trajectories across BCAs resulting in a complex changing cognitive profile. In the 22q11DS group, social responsiveness problems increased, whereas no significant change was observed in the IID group.

CONCLUSIONS AND IMPLICATIONS

Results reflect similar cognitive and social responsiveness profiles and trajectories across groups with children with 22q11DS being more at risk for growing into a social deficit. We recommend repeated monitoring of social skills development to adapt the environmental demands to the child's individual social capacities.

Atypical language characteristics and trajectories in children with 22q11.2 deletion syndrome

BACKGROUND

22q11.2 deletion syndrome (22q11.2DS) is a genetic condition associated with a highly variable phenotypic expression. During childhood speech and language deficits are commonly observed. Findings of cross-sectional studies suggest syndrome-specific and changing language profiles, but a longitudinal approach to identify developmental changes is still lacking to date.

AIMS

The present study aimed to delineate language characteristics and trajectories by comparing the performance of Dutch-speaking school-aged children with 22q11.2DS (n = 18) to those of peers with idiopathic intellectual disability (IID, n  = 19) and to those of children with IID and comorbid autism spectrum disorder (IID + ASD, n = 23). The literature shows contradictory findings regarding language comprehension difficulties in children with 22q11.2DS, we focused on the receptive-expressive language discrepancy. Given their relative strength for verbal short-term memory (VSTM) tasks, a fine-grained error categorization was included to elucidate a possible influence of VSTM on the expressive language outcomes. Finally, we suggested that the inability of children with 22q11.2DS to use contextual information could interfere with morphosyntactic measures.

METHODS

All groups (22q11.2DS, IID, and IID + ASD) were matched for nonverbal fluid reasoning (Gf) using the Analogies and Categories subtests of the Snijders-Oomen Nonverbal Intelligence Test or the Matrix Reasoning and Picture Concepts subtests of the Wechsler Preschool and Primary Scale of Intelligence. Several structural language skills were measured using the Clinical Evaluation of Language Fundamentals and Peabody Picture Vocabulary Test. The same instruments were re-administered after 18 to 24 months. A fine-grained error analysis of the Formulating and Recalling Sentences subtests, both measuring expressive syntax, explored factors contributing to expressive language deficits.

RESULTS

In children with 22q11.2DS the relative advantage of receptive over expressive language had decreased compared to children with IID. For children with 22q11.2DS, complex sentence comprehension remained very challenging over time. Expressive language skills seemed less limited compared to children with IID, and were accompanied by less VSTM difficulties. In children with 22q11.2DS and children with IID + ASD, variable patterns of strengths and weaknesses were demonstrated, resulting in subtle differences between these groups. Error analyses indicated disregard of content-contextual cues and use of vague and elliptic language as being typical for children with 22q11.2DS.

CONCLUSIONS

We recommend that in children with 22q11.2DS the impact of the receptive language impairment should be comprehensively examined and followed-up since it can have a negative effect on their social communication skills, adaptive functioning and academic achievement. Error analysis underscores that multiple measures should be used to evaluate the child's expressive language ability. Further research should focus on developmental trajectories of social communication skills and on the use of intervention strategies to improve language comprehension and pragmatics in school-aged children with 22q11.2DS.

Overview of Social Cognitive Dysfunctions in Rare Developmental Syndromes With Psychiatric Phenotype

Rare neurodevelopmental syndromes often present social cognitive deficits that may underlie difficulties in social interactions and increase the risk of psychosis or autism spectrum disorders. However, little is known regarding the specificities of social cognitive impairment across syndromes while it remains a major challenge for the care. Our review provides an overview of social cognitive dysfunctions in rare diseases associated with psychiatric symptoms (with a prevalence estimated between 1 in 1,200 and 1 in 25,000 live births: 22q11.2 deletion syndrome, Angelman syndrome, Fragile X syndrome, Klinefelter syndrome, Prader-Willi syndrome, Rett syndrome, Smith-Magenis syndrome, Turner syndrome, and Williams syndrome) and shed some light on the specific mechanisms that may underlie these skills in each clinical presentation. We first detail the different processes included in the generic expression "social cognition" before summarizing the genotype, psychiatric phenotype, and non-social cognitive profile in each syndrome. Then, we offer a systematic review of the social cognitive abilities and the disturbed mechanisms they are likely associated with. We followed the PRISMA process, including the definition of the relevant search terms, the selection of studies based on clear inclusion, and exclusion criteria and the quality appraisal of papers. We finally provide insights that may have considerable influence on the development of adapted therapeutic interventions such as social cognitive training (SCT) therapies specifically designed to target the psychiatric phenotype. The results of this review suggest that social cognition impairments share some similarities across syndromes. We propose that social cognitive impairments are strongly involved in behavioral symptoms regardless of the overall cognitive level measured by intelligence quotient. Better understanding the mechanisms underlying impaired social cognition may lead to adapt therapeutic interventions. The studies targeting social cognition processes offer new thoughts about the development of specific cognitive training programs, as they highlight the importance of connecting neurocognitive and SCT techniques.