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Journal of Neurodevelopmental Disorders Jun 2024Angelman syndrome (AS) is a neurodevelopmental disorder associated with severe global developmental delay. However, the ages at which different developmental skills are...
BACKGROUND
Angelman syndrome (AS) is a neurodevelopmental disorder associated with severe global developmental delay. However, the ages at which different developmental skills are achieved in these individuals remain unclear. We seek to determine the probability and the age of acquisition of specific developmental milestones and daily living skills in individuals with AS across the different molecular subtypes, viz. class I deletion, class II deletion, uniparental disomy, imprinting defect, and UBE3A variants.
METHODS
Caregivers participating in a longitudinal multicenter Angelman Syndrome Natural History Study completed a questionnaire regarding the age at which their children achieved specific developmental milestones and daily living skills. The Cox Proportional Hazard model was applied to analyze differences in the probability of achievement of skills at various ages among five molecular subtypes of AS.
RESULTS
Almost all individuals, regardless of molecular subtype, were able to walk with support by five years of age. By age 15, those with a deletion had at least a 50% probability of acquiring 17 out of 30 skills compared to 25 out of 30 skills among those without a deletion. Overall, fine and gross motor skills such as holding and reaching for small objects, sitting, and walking with support were achieved within a fairly narrow range of ages, while toileting, feeding, and hygiene skills tend to have greater variability in the ages at which these skills were achieved. Those without a deletion had a higher probability (25-92%) of achieving daily living skills such as independently toileting and dressing compared to those with a deletion (0-13%). Across all molecular subtypes, there was a low probability of achieving independence in bathing and brushing teeth.
CONCLUSION
Individuals with AS without a deletion are more likely to achieve developmental milestones and daily living skills at an earlier age than those with a deletion. Many individuals with AS are unable to achieve daily living skills necessary for independent self-care.
Topics: Humans; Angelman Syndrome; Activities of Daily Living; Female; Child, Preschool; Male; Child; Adolescent; Infant; Child Development; Longitudinal Studies; Motor Skills; Developmental Disabilities; Adult; Young Adult
PubMed: 38879552
DOI: 10.1186/s11689-024-09548-7 -
Cortex; a Journal Devoted To the Study... May 2024Hebb repetition learning (HRL) refers to neurodevelopmental processes characterised by repeated stimulus exposure without feedback, which result in changes in behaviour...
Hebb repetition learning (HRL) refers to neurodevelopmental processes characterised by repeated stimulus exposure without feedback, which result in changes in behaviour and/or responses, e.g., long-term learning of serial order. Here, we investigate effects of HRL on serial order memory. The present research aimed to assess the reliability of new HRL measures and investigate their relationships with language and reading skills (vocabulary, grammar, word reading) in adolescents with intellectual disability (ID). A comparison group of children of similar mental age with typical development (TD) was also assessed. ID and TD groups were tested on HRL tasks, evaluating test-retest and split-half reliability. The relationship between HRL and language and reading was analysed after accounting for the influence of mental age and verbal short-term memory. The HRL tasks displayed moderate test-retest (and split-half) reliability, HRL tasks with different stimuli (verbal, visual) were related, and we identified issues with one method of HRL scoring. The planned regression analyses failed to show relationships between HRL and language/reading skills in both groups when mental age, a very strong predictor, was included. However, further exploratory regression analyses without mental age revealed HRL's predictive capabilities for vocabulary in the ID group and reading in the TD group, results which need further investigation and replication. HRL displays promise as a moderately reliable metric and exhibits varied and interpretable predictive capabilities for language and reading skills across groups.
PubMed: 38878338
DOI: 10.1016/j.cortex.2024.05.012 -
Molecular Autism Jun 2024Mutations in the X-linked gene cyclin-dependent kinase-like 5 (CDKL5) cause a severe neurological disorder characterised by early-onset epileptic seizures, autism and...
BACKGROUND
Mutations in the X-linked gene cyclin-dependent kinase-like 5 (CDKL5) cause a severe neurological disorder characterised by early-onset epileptic seizures, autism and intellectual disability (ID). Impaired hippocampal function has been implicated in other models of monogenic forms of autism spectrum disorders and ID and is often linked to epilepsy and behavioural abnormalities. Many individuals with CDKL5 deficiency disorder (CDD) have null mutations and complete loss of CDKL5 protein, therefore in the current study we used a Cdkl5 rat model to elucidate the impact of CDKL5 loss on cellular excitability and synaptic function of CA1 pyramidal cells (PCs). We hypothesised abnormal pre and/or post synaptic function and plasticity would be observed in the hippocampus of Cdkl5 rats.
METHODS
To allow cross-species comparisons of phenotypes associated with the loss of CDKL5, we generated a loss of function mutation in exon 8 of the rat Cdkl5 gene and assessed the impact of the loss of CDLK5 using a combination of extracellular and whole-cell electrophysiological recordings, biochemistry, and histology.
RESULTS
Our results indicate that CA1 hippocampal long-term potentiation (LTP) is enhanced in slices prepared from juvenile, but not adult, Cdkl5 rats. Enhanced LTP does not result from changes in NMDA receptor function or subunit expression as these remain unaltered throughout development. Furthermore, Ca permeable AMPA receptor mediated currents are unchanged in Cdkl5 rats. We observe reduced mEPSC frequency accompanied by increased spine density in basal dendrites of CA1 PCs, however we find no evidence supporting an increase in silent synapses when assessed using a minimal stimulation protocol in slices. Additionally, we found no change in paired-pulse ratio, consistent with normal release probability at Schaffer collateral to CA1 PC synapses.
CONCLUSIONS
Our data indicate a role for CDKL5 in hippocampal synaptic function and raise the possibility that altered intracellular signalling rather than synaptic deficits contribute to the altered plasticity.
LIMITATIONS
This study has focussed on the electrophysiological and anatomical properties of hippocampal CA1 PCs across early postnatal development. Studies involving other brain regions, older animals and behavioural phenotypes associated with the loss of CDKL5 are needed to understand the pathophysiology of CDD.
Topics: Animals; Long-Term Potentiation; Receptors, N-Methyl-D-Aspartate; Receptors, AMPA; Spasms, Infantile; Disease Models, Animal; Rats; Protein Serine-Threonine Kinases; Hippocampus; Pyramidal Cells; Male; CA1 Region, Hippocampal; Epileptic Syndromes; Genetic Diseases, X-Linked; Synapses; Excitatory Postsynaptic Potentials
PubMed: 38877552
DOI: 10.1186/s13229-024-00601-9 -
BMC Health Services Research Jun 2024To reduce the impact of chronic diseases (cardiovascular disease, diabetes mellitus type 2, and chronic lung disease (asthma or chronic obstructive pulmonary disease...
BACKGROUND
To reduce the impact of chronic diseases (cardiovascular disease, diabetes mellitus type 2, and chronic lung disease (asthma or chronic obstructive pulmonary disease (COPD)), it is imperative that care is of high quality and suitable to patients' needs. Patients with intellectual disabilities (ID) differ from the average patient population in general practice because of their limitations in adaptive behaviour and intellectual functioning, and concomitant difficulties recognising and reacting to disease symptoms, proactively searching health information, and independently managing diseases effectively. Because of these differences, information on their care needs is essential for suitable chronic disease management (CDM). Inadequate recognition of the care needs of this vulnerable population may hamper the harmonisation of evidence-based and person-centred care, compounded by issues such as stigma, misconceptions, and diagnostic overshadowing. This study therefore aimed to explore the needs of patients with ID from perspectives of both patients and of healthcare providers (HCPs) in the context of CDM in general practice.
METHODS
This qualitative study recruited patients with ID for face-to-face individual interviews and HCPs for focus groups. With the Chronic Care Model as the underlying framework, semi-structured interviews and focus-group guides were defined to explore patients' care needs and HCPs' perspectives. All interviews and focus groups were audio-recorded and transcribed verbatim. Using Atlas.ti software, data were analysed using reflexive thematic analysis.
RESULTS
Between June and September 2022, 14 patients with ID and cardiovascular disease, diabetes mellitus type 2, and/or asthma/COPD were interviewed; and 32 general practitioners and practice nurses participated in seven focus groups. We identified six care needs underpinning suitable CDM: trusting relationship between patient and HCP; clear expectations about the CDM process; support in disease management; directive decision-making; support in healthy lifestyle; accessible medical information.
CONCLUSIONS
This vulnerable patient population has complex care needs that must be acknowledged for suitable CDM. Although HCPs largely recognise these needs, organisational factors and lack of training or experience with patients with ID hamper HCPs' ability to fully adjust care provision to these needs. Access to, and knowledge of, easy-language information on chronic diseases and communication guidelines could aid HCPs to facilitate patients in managing their diseases more adequately.
Topics: Humans; Chronic Disease; Male; Netherlands; Female; Intellectual Disability; Middle Aged; General Practice; Qualitative Research; Focus Groups; Adult; Aged; Health Services Needs and Demand; Needs Assessment; Interviews as Topic; Pulmonary Disease, Chronic Obstructive; Diabetes Mellitus, Type 2; Asthma
PubMed: 38877510
DOI: 10.1186/s12913-024-11155-0 -
Molecular Autism Jun 2024Positive assortative mating (AM) in several neuropsychiatric traits, including autism, has been noted. However, it is unknown whether the pattern of AM is different in...
BACKGROUND
Positive assortative mating (AM) in several neuropsychiatric traits, including autism, has been noted. However, it is unknown whether the pattern of AM is different in phenotypically defined autism subgroups [e.g., autism with and without intellectually disability (ID)]. It is also unclear what proportion of the phenotypic AM can be explained by the genetic similarity between parents of children with an autism diagnosis, and the consequences of AM on the genetic structure of the population.
METHODS
To address these questions, we analyzed two family-based autism collections: the Simons Foundation Powering Autism Research for Knowledge (SPARK) (1575 families) and the Simons Simplex Collection (SSC) (2283 families).
RESULTS
We found a similar degree of phenotypic and ancestry-related AM in parents of children with an autism diagnosis regardless of the presence of ID. We did not find evidence of AM for autism based on autism polygenic scores (PGS) (at a threshold of |r|> 0.1). The adjustment of ancestry-related AM or autism PGS accounted for only 0.3-4% of the fractional change in the estimate of the phenotypic AM. The ancestry-related AM introduced higher long-range linkage disequilibrium (LD) between single nucleotide polymorphisms (SNPs) on different chromosomes that are highly ancestry-informative compared to SNPs that are less ancestry-informative (D on the order of 1 × 10).
LIMITATIONS
We only analyzed participants of European ancestry, limiting the generalizability of our results to individuals of non-European ancestry. SPARK and SSC were both multicenter studies. Therefore, there could be ancestry-related AM in SPARK and SSC due to geographic stratification. The study participants from each site were unknown, so we were unable to evaluate for geographic stratification.
CONCLUSIONS
This study showed similar patterns of AM in autism with and without ID, and demonstrated that the common genetic influences of autism are likely relevant to both autism groups. The adjustment of ancestry-related AM and autism PGS accounted for < 5% of the fractional change in the estimate of the phenotypic AM. Future studies are needed to evaluate if the small increase of long-range LD induced by ancestry-related AM has impact on the downstream analysis.
Topics: Humans; Autistic Disorder; Phenotype; Male; Female; Linkage Disequilibrium; Multifactorial Inheritance; Child; Genetic Predisposition to Disease; Polymorphism, Single Nucleotide; Adult; Intellectual Disability
PubMed: 38877467
DOI: 10.1186/s13229-024-00605-5 -
Translational Psychiatry Jun 2024Impaired behavioural flexibility is a core feature of neuropsychiatric disorders and is associated with underlying dysfunction of fronto-striatal circuitry. Reduced...
Impaired behavioural flexibility is a core feature of neuropsychiatric disorders and is associated with underlying dysfunction of fronto-striatal circuitry. Reduced dosage of Cyfip1 is a risk factor for neuropsychiatric disorder, as evidenced by its involvement in the 15q11.2 (BP1-BP2) copy number variant: deletion carriers are haploinsufficient for CYFIP1 and exhibit a two- to four-fold increased risk of schizophrenia, autism and/or intellectual disability. Here, we model the contributions of Cyfip1 to behavioural flexibility and related fronto-striatal neural network function using a recently developed haploinsufficient, heterozygous knockout rat line. Using multi-site local field potential (LFP) recordings during resting state, we show that Cyfip1 heterozygous rats (Cyfip1) harbor disrupted network activity spanning medial prefrontal cortex, hippocampal CA1 and ventral striatum. In particular, Cyfip1 rats showed reduced influence of nucleus accumbens and increased dominance of prefrontal and hippocampal inputs, compared to wildtype controls. Adult Cyfip1 rats were able to learn a single cue-response association, yet unable to learn a conditional discrimination task that engages fronto-striatal interactions during flexible pairing of different levers and cue combinations. Together, these results implicate Cyfip1 in development or maintenance of cortico-limbic-striatal network integrity, further supporting the hypothesis that alterations in this circuitry contribute to behavioural inflexibility observed in neuropsychiatric diseases including schizophrenia and autism.
Topics: Animals; Haploinsufficiency; Rats; Schizophrenia; Male; Adaptor Proteins, Signal Transducing; Prefrontal Cortex; Autistic Disorder; CA1 Region, Hippocampal; Disease Models, Animal; Nerve Net; Behavior, Animal; Corpus Striatum; Ventral Striatum
PubMed: 38876996
DOI: 10.1038/s41398-024-02969-x -
Frontiers in Neuroanatomy 2024Angelman syndrome (AS) is a neurogenetic disorder caused by mutations or deletions in the maternally-inherited allele, leading to a loss of UBE3A protein expression in...
Angelman syndrome (AS) is a neurogenetic disorder caused by mutations or deletions in the maternally-inherited allele, leading to a loss of UBE3A protein expression in neurons. The paternally-inherited allele is epigenetically silenced in neurons during development by a noncoding transcript (). The absence of neuronal UBE3A results in severe neurological symptoms, including speech and language impairments, intellectual disability, and seizures. While no cure exists, therapies aiming to restore UBE3A function-either by gene addition or by targeting -are under development. Progress in developing these treatments relies heavily on inferences drawn from mouse studies about the function of UBE3A in the human brain. To aid translational efforts and to gain an understanding of UBE3A and biology with greater relevance to human neurodevelopmental contexts, we investigated UBE3A and expression in the developing brain of the rhesus macaque, a species that exhibits complex social behaviors, resembling aspects of human behavior to a greater degree than mice. Combining immunohistochemistry and hybridization, we mapped UBE3A and regional and cellular expression in normal prenatal, neonatal, and adolescent rhesus macaque brains. We show that key hallmarks of UBE3A biology, well-known in rodents, are also present in macaques, and suggest paternal silencing in neurons-but not glial cells-in the macaque brain, with onset between gestational day 48 and 100. These findings support proposals that early-life, perhaps even prenatal, intervention is optimal for overcoming the maternal allele loss of linked to AS.
PubMed: 38873093
DOI: 10.3389/fnana.2024.1410791 -
Cureus May 2024Pituitary stalk interruption syndrome is a triad of thin (<1 mm) or complete absence of the pituitary stalk with either an aplastic or ectopic posterior lobe of the...
Pituitary stalk interruption syndrome is a triad of thin (<1 mm) or complete absence of the pituitary stalk with either an aplastic or ectopic posterior lobe of the pituitary gland and a hypoplastic or absent anterior lobe of the pituitary. Patients present with growth retardation, short height, seizures, intellectual disability, and absence of sexual maturation at the expected time. Here, we presented a case of a 12-year-old male with stunted growth. Upon examination, there was reduced height, more than 3 standard deviations below the average for his chronological age. Laboratory results showed reduced levels of growth hormone and thyrotropin. Dual-energy X-ray absorptiometry revealed osteoporosis, while an X-ray of the wrist for bone age corresponded to seven years. MRI imaging confirmed the classical triad of findings for pituitary stalk interruption syndrome. Consequently, the patient was referred back to the endocrinology clinic for further management.
PubMed: 38872685
DOI: 10.7759/cureus.60232 -
Journal of Neurodevelopmental Disorders Jun 2024Intellectual and developmental disabilities (IDDs) are associated with both cognitive challenges and difficulties in conceptual, social, and practical areas of living,...
BACKGROUND
Intellectual and developmental disabilities (IDDs) are associated with both cognitive challenges and difficulties in conceptual, social, and practical areas of living, commonly referred to as adaptive behavior (DSM-5). Although cross-sectional associations between intelligence or cognition and adaptive behavior have been reported in IDD populations, no study to date has examined whether developmental changes in cognition contribute to or track with changes in adaptive behavior. The present study sought to examine associations of longitudinal developmental change in domains of cognition (NIH Toolbox Cognition Battery, NIHTB-CB) and adaptive behavior domains (Vineland Adaptive Behavior Scales-3; VABS-3) including Socialization, Communication, and Daily Living Skills (DLS) over a two year period in a large sample of children, adolescents and young adults with IDD.
METHODS
Three groups were recruited, including those with fragile X syndrome, Down syndrome, and other/idiopathic intellectual disability. Eligible participants (n = 263) included those who were between 6 and 26 years (m = 15.52, sd = 5.17) at Visit 1, and who had a diagnosis of, or suspected intellectual disability (ID), including borderline ID, with a mental age of at least 3.0 years. Participants were given cognitive and adaptive behavior assessments at two time points over a two year period (m = 2.45 years, range = 1.27 to 5.56 years). In order to examine the association of developmental change between cognitive and adaptive behavior domains, bivariate latent change score (BLCS) models were fit to compare change in the three cognitive domains measured by the NIHTB-CB (Fluid Cognition, Crystallized Cognition, Total Cognition) and the three adaptive behavior domains measured by the VABS-3 (Communication, DLS, and Socialization).
RESULTS
Over a two year period, change in cognition (both Crystallized and Total Composites) was significantly and positively associated with change in daily living skills. Also, baseline cognition level predicted growth in adaptive behavior, however baseline adaptive behavior did not predict growth in cognition in any model.
CONCLUSIONS
The present study demonstrated that developmental changes in cognition and adaptive behavior are associated in children and young adults with IDD, indicating the potential for cross-domain effects of intervention. Notably, improvements in DLS emerged as a primary area of adaptive behavior that positively related to improvements in cognition. This work provides evidence for the clinical, "real life" meaningfulness of changes in cognition detected by the NIHTB-CB in IDD, and provides empirical support for the NIHTB-CB as a fit-for-purpose performance-based outcome measure for this population.
Topics: Humans; Male; Child; Adolescent; Female; Adaptation, Psychological; Young Adult; Adult; Intellectual Disability; Developmental Disabilities; Cognition; Longitudinal Studies; Activities of Daily Living; Socialization; Down Syndrome; Fragile X Syndrome
PubMed: 38872099
DOI: 10.1186/s11689-024-09542-z -
Journal of Neurodevelopmental Disorders Jun 2024Fragile X syndrome (FXS) is caused by epigenetic silencing of the X-linked fragile X messenger ribonucleoprotein 1 (FMR1) gene located on chromosome Xq27.3, which leads... (Review)
Review
Fragile X syndrome (FXS) is caused by epigenetic silencing of the X-linked fragile X messenger ribonucleoprotein 1 (FMR1) gene located on chromosome Xq27.3, which leads to the loss of its protein product, fragile X messenger ribonucleoprotein (FMRP). It is the most prevalent inherited form of intellectual disability and the highest single genetic cause of autism. Since the discovery of the genetic basis of FXS, extensive studies using animal models and human pluripotent stem cells have unveiled the functions of FMRP and mechanisms underlying FXS. However, clinical trials have not yielded successful treatment. Here we review what we have learned from commonly used models for FXS, potential limitations of these models, and recommendations for future steps.
Topics: Fragile X Syndrome; Humans; Animals; Fragile X Mental Retardation Protein; Disease Models, Animal; Pluripotent Stem Cells
PubMed: 38872088
DOI: 10.1186/s11689-024-09545-w