Communication of individuals with CDKL5 deficiency disorder as observed by caregivers: A descriptive qualitative study.

CDKL5 deficiency disorder (CDD) is a genetically caused developmental epileptic encephalopathy that causes severe communication impairments. Communication of individuals with CDD is not well understood in the literature and currently available measures are not well validated in this population. Accurate and sensitive measurement of the communication of individuals with CDD is important for understanding this condition, clinical practice, and upcoming interventional trials. The aim of this descriptive qualitative study was to understand how individuals with CDD communicate, as observed by caregivers. Participants were identified through the International CDKL5 Disorder Database and invited to take part if their child had a pathogenic variant of the CDKL5 gene and they had previously completed the Communication and Symbolic Behavior Checklist (CSBS-DP ITC). The sample comprised caregivers of 23 individuals with CDD, whose ages ranged from 2 to 30 years (median 13 years), 15 were female, and most did not use words. Semistructured interviews were conducted via videoconference and analyzed using a conventional content analysis. Three overarching categories were identified: mode, purpose and meaning, and reciprocal exchanges. These categories described the purposes and mechanism of how some individuals with CDD communicate, including underpinning influential factors. Novel categories included expressing a range of emotions, and reciprocal exchanges (two-way interactions that varied in complexity). Caregivers observed many communication modes for multiple purposes. Understanding how individuals with CDD communicate improves understanding of the condition and will guide research to develop accurate measurement for clinical practice and upcoming medication trials.

Rett syndrome diagnostic odyssey: Limitations of NextGen sequencing.

Typical (or classic) Rett syndrome (RTT) is an X-linked neurodevelopmental disorder characterized by a period of regression, partial or complete loss of purposeful hand movements, and acquired speech, impaired gait, and stereotyped hand movements. In over 95% of typical RTT, a pathogenic variant is found in the methyl-CPG binding protein 2 gene (MECP2). Here, we describe a young woman with clinically diagnosed typical RTT syndrome who lacked a genetic diagnosis despite 20 years of investigation and multiple rounds of sequencing the MECP2 gene. Recently, additional genetic testing using next-generation sequencing was completed, which revealed a partial insertion of the BCL11A gene within exon 4 of MECP2, resulting in a small deletion in MECP2, causing likely disruption of MeCP2 function due to a frameshift. This case demonstrates the ever-changing limitations of genetic testing, as well as the importance of continual pursuit of a diagnosis as technologies improve and are more widely utilized.

Parental age effects and Rett syndrome.

Rett syndrome (RTT) is a progressive neurodevelopmental disorder, and pathogenic Methyl-CpG-binding Protein 2 (MECP2) variants are identified in >95% of individuals with typical RTT. Most of RTT-causing variants in MECP2 are de novo and usually on the paternally inherited X chromosome. While paternal age has been reported to be associated with increased risk of genetic disorders, it is unknown whether parental age contributes to the risk of the development of RTT. Clinical data including parental age, RTT diagnostic status, and clinical severity are collected from 1226 participants with RTT and confirmed MECP2 variants. Statistical analyses are performed using Student t-test, single factor analysis of variance (ANOVA), and multi-factor regression. No significant difference is observed in parental ages of RTT probands compared to that of the general population. A small increase in parental ages is observed in participants with missense variants compared to those with nonsense variants. When we evaluate the association between clinical severity and parental ages by multiple regression analysis, there is no clear association between clinical severity and parental ages. Advanced parental ages do not appear to be a risk factor for RTT, and do not contribute to the clinical severity in individuals with RTT.

Early life seizures and olfactory communication in rats.

OBJECTIVE: Early life seizures (ELS) are commonly associated with autism spectrum disorder (ASD); however, the exact role of ELS in the pathology is unknown. Prior studies have demonstrated social deficits, a core feature of ASD, following ELS; consequently, alterations in sensory modalities may contribute to the overall social deficits. Considering the speculated contribution of sensory deficit to social communication, we examined the developmental consequences of early postnatal kainic acid (KA)-induced seizures on olfactory preference and neural markers in the olfactory bulb in both male and female Sprague Dawley rats. METHODS: KA-induced seizures or saline was administered. Rats were then exposed to a series of biologically relevant scents including male scent, female scent, nest scent, and phenylethylamine during the juvenile period and again during adulthood. Alterations in sensory modalities were expected to be expressed via abnormal preference for certain scents and/or production of abnormal ultrasonic vocalizations in response to scents. The olfactory bulbs were also assessed for the biologically relevant markers glial fibrillary acidic protein (GFAP) and calcium/calmodulin-dependent protein kinase II (CAMKII). RESULTS: Our findings resulted in no significant differences in olfactory preference following ELS for juveniles or adults compared to controls. Similarly, there were no differences in GFAP expression or the ratio of phosphorylated CAMKII to CAMKII in either olfactory bulb. Interestingly, despite a lack of treatment differences, different scents were shown to elicit different responses in juvenile rats, yet these differences subsided in adulthood. SIGNIFICANCE: Overall, the results of this study suggest that olfaction does not contribute to socialization deficit following ELS within the KA model.

Psychometric evaluation of clinician- and caregiver-reported clinical severity assessments for individuals with CDKL5 deficiency disorder.

OBJECTIVE: The CDKL5 Clinical Severity Assessment (CCSA) is a comprehensive, content-validated measurement tool capturing the diverse challenges of cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD), a genetically caused developmental epileptic encephalopathy (DEE). The CCSA is divided into clinician-reported (CCSA-Clinician) and caregiver-reported (CCSA-Caregiver) assessments. The aim of this study was to evaluate the factor structure of these measures through confirmatory factor analysis (CFA) and evaluate their validity and reliability. METHODS: Participants were recruited from the International CDKL5 Clinical Research Network to take part in an in-clinic CCSA-Clinician evaluation (n = 148) and/or complete the CCSA-Caregiver questionnaire (n = 198). CFA was used to determine domains, and factor loadings and validity were assessed. For the CCSA-Clinician, inter-rater reliability was assessed by nine CDD experienced clinicians via 14 pre-recorded evaluations. Eight clinicians re-viewed and re-scored the videos after 4 weeks to evaluate intra-rater reliability. The CCSA-Caregiver was completed on a second occasion by 34 caregivers after 2-4 weeks to assess test-retest reliability. RESULTS: CFA resulted in three domains for the CCSA-Clinician (motor and movement, communication, vision) and four domains for the CCSA-Caregiver (seizures, behavior, alertness, feeding), with good item loadings across both measures. Structural statistics, internal consistency, discriminant validity, and reliability were satisfactory for both measures, and scores were consistent between known groups. SIGNIFICANCE: This study provides strong evidence that the CCSA measures are suitable to assess the clinical severity of individuals with CDD, supporting their use in clinical trials. Further evaluation of responsiveness to change in a longitudinal assessment is planned. Use may also be appropriate in similar DEEs but would require validation in those populations.

Deep postnatal phenotyping of a new mouse model of nonketotic hyperglycinemia.

Nonketotic hyperglycinemia due to deficient glycine cleavage enzyme activity causes a severe neonatal epileptic encephalopathy. Current therapies based on mitigating glycine excess have only limited impact. An animal model with postnatal phenotyping is needed to explore new therapeutic approaches. We developed a Gldc p.Ala394Val mutant model and bred it to congenic status in two colonies on C57Bl/6J (B6) and J129X1/SvJ (J129) backgrounds. Mutant mice had reduced P-protein and enzyme activity indicating a hypomorphic mutant. Glycine levels were increased in blood and brain regions, exacerbated by dietary glycine, with higher levels in female than male J129 mice. Birth defects were more prevalent in mutant B6 than J129 mice, and hydrocephalus was more frequent in B6 (40%) compared to J129 (none). The hydrocephalus rate was increased by postnatal glycine challenge in B6 mice, more so when delivered from the first neonatal week than from the fourth. Mutant mice had reduced weight gain following weaning until the eighth postnatal week, which was exacerbated by glycine loading. The electrographic spike rate was increased in mutant mice following glycine loading, but no seizures were observed. The alpha/delta band intensity ratio was decreased in the left cortex in female J129 mice, which were less active in an open field test and explored less in a Y-maze, suggesting an encephalopathic effect. Mutant mice showed no evidence of memory dysfunction. This partial recapitulation of human symptoms and biochemistry will facilitate the evaluation of new therapeutic approaches with an early postnatal time window likely most effective.

Parent-reported outcome measures evaluating communication in individuals with rare neurodevelopmental disorders: A systematic review.

BACKGROUND: Communication impairments are a leading concern for parent caregivers of individuals with rare neurodevelopmental disorders (RNDDs). Clinical trials of disease modifying therapies require valid and responsive outcome measures that are relevant to individuals with RNDDs. Identifying and evaluating current psychometric properties for communication measures is a critical step towards the selection and use of appropriate instruments. AIMS: This systematic review offers (1) a description of parent-reported communication measures and (2) evidence for their psychometric properties, in RNDDs. METHODS: The systematic review protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD42022334649). MEDLINE (Ovid), Embase, PsychINFO, Web of Science, CINAHL Plus, Cochrane Library, ClinicalTrials.gov, the Australian New Zealand Clinical Trials Registry were searched from inception to August 2023. Methodological assessment of quality was completed using the COnsensus-based Standards for the selection of health status Measurement INstruments (COSMIN) checklist. Parent-reported measures used in observational studies and clinical trials were identified. Data on utility, reliability and validity for RNDDs were extracted. MAIN CONTRIBUTION: Sixteen parent-reported communication measures were used in RNDD research, the Vineland Adaptive Behavior Scales being most commonly used. Validation data in RNDDs were identified for six of these measures. Limitations related to sample size or the scope of psychometric testing. CONCLUSIONS: Many communication measures have been used for RNDDs but there are few data validating their use. Valid and reliable methods of measuring communication in persons with RNDDs is a priority for future high-quality clinical trials. WHAT THIS PAPER ADDS: What is already known on the subject Communication is a critical domain for families with a child with a rare neurodevelopmental disorder (RNDD). Validated outcome measures are essential for accurate evaluation and interpretation of responses to treatments in clinical trials. What this paper adds to existing knowledge We identified 16 parent-reported communication measures that have been used with RNDDs, but only six measures had validation data for at least one RNDD. High quality evidence is accumulating, with all validation studies in this review published between 2020 to 2023. Modifications of existing measures may be required to assess communication for RNDDs. What are the clinical implications of this work? This systematic review catalogues the available psychometric data for communication measures and indicates an ongoing need for new validation studies to ensure they are fit-for-purpose for upcoming clinical trials in RNDDs. This review will inform the selection of communication measures for clinical trials and research studies.

Psychometric properties of QI-Disability in CDKL5 Deficiency Disorder: Establishing readiness for clinical trials.

CDKL5 Deficiency Disorder (CDD) is a rare genetic disorder with symptoms of epilepsy, developmental impairments, and other comorbidities. Currently, there are no outcome measures for CDD with comprehensive evidence of validation. This study aimed to evaluate the psychometric properties of the Quality of Life Inventory-Disability (QI-Disability) in CDD. Quality of Life Inventory-Disability was administered to 152 parent caregivers registered with the International CDKL5 Disorder Database (ICDD). Confirmatory factor analysis was conducted and the goodness of fit of the factor structure was assessed. Fixed-effects linear regression models examined the responsiveness of QI-Disability to reported changes in child health. A subset of parent caregivers (n = 56) completed QI-Disability, as well as additional health-related questions, on two occasions separated by four weeks to evaluate test-retest reliability. Test-retest reliability was assessed using intra-class correlations (ICCs) calculated from QI-Disability scores. Based upon adjustments for changes in child health, ICCs were recalculated to estimate responsiveness to change. Confirmatory factor analysis, internal consistency, and divergent validity were mostly satisfactory, except divergent validity was not satisfactory for the Social Interactions and Independence domains. The Physical Health, Social Interactions, Leisure, and Total scores responded to changes in the child's Physical health, and the Negative Emotions and Leisure domains responded to changes in the child's behavior. Unadjusted and adjusted ICC values were above 0.8 for the Positive Emotions, Negative Emotions, Social Interactions, Leisure, Independence domains and Total score, and above 0.6 for the Physical Health domain. Findings suggest that QI-Disability is suitable to assess the quality of life of children and adults with CDD and could be of value for upcoming clinical trials.

Early-life seizures modify behavioral response to ultrasonic vocalization playback in adult rats.

Early-life seizures (ELS) are associated with autism spectrum disorder (ASD); however, due to a lack of effective treatments for ELS, it is not clear whether ELS plays a causal role, potentiates the ASD phenotype, or is the result of a common pathophysiology. Deficits in communications are a core feature of ASD. To isolate the impact of ELS on communication, we probed the behavioral consequences of a single episode of kainic acid-induced early-life seizures (KA-ELS) in male and female Sprague-Dawley (CD) rats. Deficits in auditory communication were observed in adult male rats as assessed by behavioral response to ultrasonic vocalization (USV) playback. Ultrasonic vocalizations are classified into two major categories - 50-kHz (positive) calls and 22-kHz (aversive) calls. Behavioral response was assessed via rat preference for different USV playback in a radial arm maze. Response to 22-kHz calls was not impacted by ELS while response to 50-kHz calls was impacted. All rats demonstrated positional preference for the arms adjacent to where 50-kHz calls were playing compared to background noise; however, male ELS rats demonstrated a greater positional preference for the arms adjacent to where 50-kHz calls were playing compared to male control rats. These studies demonstrate that responses to socially relevant auditory cues are chronically altered in adult male rats following a single episode of ELS. We speculate that these changes contribute to previously reported social deficits associated with ELS.

Whole-exome sequencing and adrenocorticotropic hormone therapy in individuals with infantile spasms.

AIM: To identify additional genes associated with infantile spasms using a cohort with defined infantile spasms. METHOD: Whole-exome sequencing (WES) was performed on 21 consented individuals with infantile spasms and their unaffected parents (a trio-based study). Clinical history and imaging were reviewed. Potentially deleterious exonic variants were identified and segregated. To refine potential candidates, variants were further prioritized on the basis of evidence for relevance to disease phenotype or known associations with infantile spasms, epilepsy, or neurological disease. RESULTS: Likely pathogenic de novo variants were identified in NR2F1, GNB1, NEUROD2, GABRA2, and NDUFAF5. Suggestive dominant and recessive candidate variants were identified in PEMT, DYNC1I1, ASXL1, RALGAPB, and STRADA; further confirmation is required to support their relevance to disease etiology. INTERPRETATION: This study supports the utility of WES in uncovering the genetic etiology in undiagnosed individuals with infantile spasms with an overall yield of five out of 21. High-priority candidates were identified in an additional five individuals. WES provides additional support for previously described disease-associated genes and expands their already broad mutational and phenotypic spectrum.

Exploring genotype-phenotype relationships in the CDKL5 deficiency disorder using an international dataset.

Characterized by early-onset seizures, global developmental delay and severe motor deficits, CDKL5 deficiency disorder is caused by pathogenic variants in the cyclin-dependent kinase-like 5 gene. Previous efforts to investigate genotype-phenotype relationships have been limited due to small numbers of recurrent mutations and small cohort sizes. Using data from the International CDKL5 Disorder Database we examined genotype-phenotype relationships for 13 recurrent CDKL5 variants and the previously analyzed historic variant groupings. We have applied the CDKL5 Developmental Score (CDS) and an adapted version of the CDKL5 Clinical Severity Assessment (CCSA), to grade the severity of phenotype and developmental outcomes for 285 individuals with CDKL5 variants. Comparisons of adapted CCSA and CDS between recurrent variants and variant groups were performed using multiple linear regression adjusting for age and sex. Individuals with the missense variant, p.Arg178Trp, had the highest mean adapted CCSA and lowest mean developmental scores. Other variants producing severe phenotypes included p.Arg559* and p.Arg178Gln. Variants producing milder phenotypes included p.Arg134*, p.Arg550*, and p.Glu55Argfs*20. There are observed differences in phenotype severity and developmental outcomes for individuals with different CDKL5 variants. However, the historic variant groupings did not seem to reflect differences in phenotype severity or developmental outcomes as clearly as analyzed by individual variants.

Phenotypic features in MECP2 duplication syndrome: Effects of age.

BACKGROUND: MECP2 Duplication syndrome (MDS) is a rare X-linked genomic disorder that is caused by interstitial chromosomal duplications at Xq28 encompassing the MECP2 gene. Although phenotypic features in MDS have been described, there is a limited understanding of the range of severity of these features, and how they evolve with age. METHODS: The cross-sectional results of N = 69 participants (ages 6 months-33 years) enrolled in a natural history study of MDS are presented. Clinical severity was assessed using a clinician-report measure as well as a parent-report measure. Data was also gathered related to the top 3 concerns of parents as selected from the most salient symptoms related to MDS. The Child Health Questionnaire was also utilized to obtain parental reports of each child's quality of life to establish disease burden. RESULTS: The results of linear regression from the clinician-reported measure show that overall clinical severity scores, motor dysfunction, and functional skills are significantly worse with increasing age. Top concerns rated by parents included lack of effective communication, abnormal walking/balance issues, constipation, and seizures. Higher levels of clinical severity were also related to lower physical health quality of life scores as reported by parents. CONCLUSIONS: The data suggest that increasing levels of clinical severity are noted with older age, and this is primarily attributable to motor dysfunction, and functional skills. The results provide an important foundation for creating an MDS-specific severity scale highlighting the most important domains to target for treatment trials and will help clinicians and researchers define clinically meaningful changes.

CDKL5 deficiency disorder: Relationship between genotype, epilepsy, cortical visual impairment, and development.

OBJECTIVE: The cyclin-dependent kinase like 5 (CDKL5) gene is a known cause of early onset developmental and epileptic encephalopathy, also known as CDKL5 deficiency disorder (CDD). We sought to (1) provide a description of seizure types in patients with CDD, (2) provide an assessment of the frequency of seizure-free periods and cortical visual impairment (CVI), (3) correlate these features with genotype and gender, and (4) correlate these features with developmental milestones. METHODS: This is a cohort study of patients with CDD. Phenotypic features were explored and correlated with gene variant grouping and gender. A developmental score was created based on achieving seven primary milestones. Phenotypic variables were correlated with the developmental score to explore markers of better developmental outcomes. Multivariate linear regression was used to account for age at last visit. RESULTS: Ninety-two patients with CDD were seen during the enrollment period. Eighteen were male (19%); median age at last visit was 5 years (interquartile range = 2.0-11.0). Eighty-one percent of patients developed epileptic spasms, but only 47% of those also had hypsarrhythmia. Previously described hypermotor-tonic-spasms sequence was seen in only 24% of patients, but 56% of patients had seizures with multiple phases (often tonic and spasms). Forty-three percent of patients experienced a seizure-free period ranging from 1 to >12 months, but only 6% were still seizure-free at the last visit. CVI was present in 75% of all CDD patients. None of these features was associated with genotype group or gender. CVI was correlated with reduced milestone achievement after adjusting for age at last visit and a history of hypsarrhythmia. SIGNIFICANCE: The most common seizure types in CDD are epileptic spasms (often without hypsarrhythmia) and tonic seizures that may cluster together. CVI is a common feature in CDD and is correlated with achieving fewer milestones.

The CaMKII/GluN2B Protein Interaction Maintains Synaptic Strength.

Learning, memory, and cognition are thought to require normal long-term potentiation (LTP) of synaptic strength, which in turn requires binding of the Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) to the NMDA-type glutamate receptor (NMDAR) subunit GluN2B. For LTP induction, many additional required players are known. Here we tested the hypothesis that CaMKII/GluN2B binding also mediates the more elusive maintenance of synaptic strength. Intriguingly, the CaMKII inhibitor tatCN21 reduces synaptic strength only at high concentrations necessary for CaMKII/NMDAR disruption (20 µm) but not at lower concentrations sufficient for kinase inhibition (5 µm). However, increased concentration also causes unrelated effects. Thus, to distinguish between correlation and causality, we used a pharmacogenetic approach. In a mouse with a mutant NMDAR GluN2B subunit that is CaMKII binding-incompetent, any tatCN21 effects that are specific to the CaMKII/GluN2B interaction should be abolished, and any remaining tatCN21 effects have to be nonspecific (i.e. mediated by other targets). The results showed that the persistent reduction of synaptic strength by transient application of 20 µm tatCN21 had a nonspecific presynaptic component (on fiber volley amplitude) that was unrelated to the CaMKII/GluN2B interaction or CaMKII activity. However, the remaining component of the persistent tatCN21 effect was almost completely abolished in the GluN2B mutant mouse. These results highlight the requirement for stringent pharmacogenetic approaches to separate specific on-target effects from nonspecific off-target effects. Importantly, they also demonstrate that the CaMKII/GluN2B interaction is required not only for normal LTP induction but also for the maintenance of synaptic strength.

Developmental restoration of LTP deficits in heterozygous CaMKIIα KO mice.

The Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a major mediator of long-term potentiation (LTP) and depression (LTD), two opposing forms of synaptic plasticity underlying learning, memory and cognition. The heterozygous CaMKIIα isoform KO (CaMKIIα+/-) mice have a schizophrenia-related phenotype, including impaired working memory. Here, we examined synaptic strength and plasticity in two brain areas implicated in working memory, hippocampus CA1 and medial prefrontal cortex (mPFC). Young CaMKIIα+/- mice (postnatal days 12-16; corresponding to a developmental stage well before schizophrenia manifestation in humans) showed impaired hippocampal CA1 LTP. However, this LTP impairment normalized over development and was no longer detected in older CaMKIIα+/- mice (postnatal weeks 9-11; corresponding to young adults). By contrast, the CaMKIIα+/- mice failed to show the developmental increase of basal synaptic transmission in the CA1 seen in wild-type (WT) mice, resulting in impaired basal synaptic transmission in the older CaMKIIα+/- mice. Other electrophysiological parameters were normal, including mPFC basal transmission, LTP, and paired-pulse facilitation, as well as CA1 LTD, depotentiation, and paired-pulse facilitation at either age tested. Hippocampal CaMKIIα levels were ∼60% of WT in both the older CaMKIIα+/- mice and in the younger WT mice, resulting in ∼30% of adult WT expression in the younger CaMKIIα+/- mice; levels in frontal cortex were the same as in hippocampus. Thus, in young mice, ∼30% of adult CaMKIIα expression is sufficient for normal LTD and depotentiation, while normal LTP requires higher levels, with ∼60% of CaMKIIα expression sufficient for normal LTP in adult mice.

Enhanced long term potentiation and decreased AMPA receptor desensitization in the acute period following a single kainate induced early life seizure.

Neonatal seizures are associated with long term disabilities including epilepsy and cognitive deficits. Using a neonatal seizure rat model that does not develop epilepsy, but develops a phenotype consistent with other models of intellectual disability (ID) and autism spectrum disorders (ASD), we sought to isolate the acute effects of a single episode of early life seizure on hippocampal CA1 synaptic development and plasticity. We have previously shown chronic changes in glutamatergic synapses, loss of long term potentiation (LTP) and enhanced long term depression (LTD), in the adult male rat ~50days following kainic acid (KA) induced early life seizure (KA-ELS) in post-natal (P) 7day old male Sprague-Dawley rats. In the present work, we examined the electrophysiological properties and expression levels of glutamate receptors in the acute period, 2 and 7days, post KA-ELS. Our results show for the first time enhanced LTP 7days after KA-ELS, but no change 2days post KA-ELS. Additionally, we report that ionotropic α-amino-3-hydroxy-5-methyl-isoxazole-propionic acid type glutamate receptor (AMPAR) desensitization is decreased in the same time frame, with no changes in AMPAR expression, phosphorylation, or membrane insertion. Inappropriate enhancement of the synaptic connections in the acute period after the seizure could alter the normal patterning of synaptic development in the hippocampus during this critical period and contribute to learning deficits. Thus, this study demonstrates a novel mechanism by which KA-ELS alters early network properties that potentially lead to adverse outcomes.

Behavioral changes following a single episode of early-life seizures support the latent development of an autistic phenotype.

We probed the developmental and behavioral consequences of a single episode of kainic acid-induced early-life seizures (KA-ELS) in the rat on postnatal day 7. Correlates of developmental trajectory were not altered, demonstrating that long-term consequences following KA-ELS are not initiated by secondary causes, such as malnourishment or alterations in maternal care. We report reduced marble burying in adult rats, suggestive of restricted interests, a trait common to experimental and clinical autism. We did not detect increased repetitive grooming during habituated cage behavior. However, we did detect reduced grooming in adult KA-ELS rats in the presence of an unfamiliar rat, supporting altered social anxiety following KA-ELS. Reanalysis of a social approach task further indicated abnormal social interactions. Taken together with previous physiological and behavioral data, these data support the hypothesis that KA-ELS lead to a latent autistic phenotype in adult rats not attributable to other early alterations in development.

Deep postnatal phenotyping of a new mouse model of nonketotic hyperglycinemia.

Nonketotic hyperglycinemia due to deficient glycine cleavage enzyme activity causes a severe neonatal epileptic encephalopathy. Current therapies based on mitigating glycine excess have only limited impact. An animal model with postnatal phenotyping is needed to explore new therapeutic approaches. We developed a Gldc p.Ala394Val mutant model and bred it to congenic status in 2 colonies on C57Bl/6J (B6) and J129X1/SvJ (J129) backgrounds. Mutant mice had reduced P-protein and enzyme activity indicating a hypomorphic mutant. Glycine levels were increased in blood and brain regions, exacerbated by dietary glycine, with higher levels in female than male J129 mice. Birth defects were more prevalent in mutant B6 than J129 mice, and hydrocephalus was more frequent in B6 (40%) compared to J129 (none). The hydrocephalus rate was increased by postnatal glycine challenge in B6 mice, more so when delivered from the first neonatal week than from the fourth. Mutant mice had reduced weight gain following weaning until the eighth postnatal week, which was exacerbated by glycine loading. The electrographic spike rate was increased in mutant mice following glycine loading, but no seizures were observed. The alpha/delta band intensity ratio was decreased in the left cortex in female J129 mice, which were less active in an open field test and explored less in a Y-maze, suggesting an encephalopathic effect. Mutant mice showed no evidence of memory dysfunction. This partial recapitulation of human symptoms and biochemistry will facilitate the evaluation of new therapeutic approaches with an early postnatal time window likely most effective. Take home message: A mouse model of nonketotic hyperglycinemia is described that shows postnatal abnormalities in glycine levels, neural tube defects, body weight, electroencephalographic recordings, and in activity in young mice making it amenable for the evaluation of novel treatment interventions. Author contributions: Study concept and design: JVH, MHM, NB, KNMAnimal study data: MAS, HJ, NB, MHM, JC, CBBiochemical and genetic studies: MAS, RAVH, MWFStatistical analysis: NB, JVHFirst draft writing: JVH, NB, MHMCritical rewriting: MAS, NB, MHM, TAB, JC, MWF, KNM, JVHFinal responsibility, guarantor, and communicating author: JVH. Competing interest statement: The University of Colorado (JVH, MS, KNM, HJ) has the intention to file Intellectual property protection for certain biochemical treatments of NKH. Otherwise, the authors have stated that they had no interests that might be perceived as posing a conflict or bias to this subject matter. Funding support: Financial support is acknowledged form the NKH Crusaders, Brodyn's Friends, Nora Jane Almany Foundation, the Dickens Family Foundation, the Lucas John Foundation, Les Petits Bourdons, Joseph's Fund, the Barnett Family, Maud & Vic Foundation, Lucy's BEElievers fund, Hope for NKH, Madi's Mission NKH fund, and from Dr. and Ms. Shaw, and the University of Colorado Foundation NKH research fund. The study was supported by a grant (CNS-X-19-103) from the University of Colorado School of Medicine and the Colorado Clinical Translational Science Institute, which is supported by NIH/NCATS Colorado CTSA Grant Number UL1 TR002535. Contents are the authors' sole responsibility and do not necessarily represent official NIH views. All funding sources had no role in the design or execution of the study, the interpretation of data, or the writing of the study. Ethics approval on Laboratory Animal Studies: Mouse studies were carried out with approval from the Institutional Animal Care and Use Committee of the University of Colorado Anschutz Medical Campus (IACUC# 00413). Data sharing statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.

Modification of a parent-report sleep scale for individuals with CDKL5 deficiency disorder: a psychometric study.

STUDY OBJECTIVES: Sleep difficulties are common in CDKL5 deficiency disorder (CDD), a developmental and epileptic encephalopathy (DEE). This study evaluated the factor structure of the Disorders of Initiating and Maintaining Sleep (DIMS), Disorders of Excessive Daytime Somnolence (DOES) and Sleep Breathing Disorders (SBD) domains of the Sleep Disturbance Scale for Children (SDSC) for CDD. METHODS: A cross-sectional psychometric study design was used. Data were collected for 125 individuals aged 3 years or older who attended a US Centers of Excellence clinic or registered with the International CDKL5 Disorder Database. RESULTS: The median age was 10.3 years (range 3.2 - 40.7 years) and 105 (84%) were female. Two of the three SBD items related were not observed by most respondents and analysis was restricted to the DIMS and DOES domains. Using all items in the initial confirmatory factor analysis, two items in the DIMS domain and one item in the DOES domain loaded poorly. After deleting these items and repeating the analysis, item loading (0.524-0.814) and internal consistency (DIMS: 0.78, DOES: 0.76) statistics were good. The square of the inter-domain correlation coefficient was 0.17, less than Average Variance Extracted values for both domains and indicating good discriminant validity. The Tucker-Lewis and Comparative Fit indices were slightly lower than the threshold of >0.9 for establishing goodness of fit. CONCLUSIONS: The modified DIMS and DOES domains from the SDSC could be suitable clinical outcome assessments of insomnia and related impairments in CDD and potentially other DEE conditions.