An adolescent case of ASXL3-related disorder with delayed onset of feeding difficulty.

BACKGROUND: ASXL3-related disorder, first described in 2013, is a genetic disorder with an autosomal dominant inheritance that is caused by a heterozygous loss-of-function variant in ASXL3. The most characteristic feature is neurodevelopmental delay with consistently limited speech. Feeding difficulty is a main symptom observed in infancy. However, no adolescent case has been reported. CASE PRESENTATION: A 14-year-old girl with ASXL3-related syndrome was referred to our hospital with subacute onset of emotional lability. Limbic encephalitis was ruled out by examination; however, the patient gradually showed a lack of interest in eating, with decreased diet volume. Consequently, she experienced significant weight loss. She experienced no symptoms of bulimia, or food allergy; therefore, avoidant/restrictive food intake disorder (ARFID) was clinically suspected. CONCLUSIONS: We reported the first case of ASXL3-related disorder with adolescent onset of feeding difficulty. ARFID was considered a cause of the feeding difficulty.

Impact of maternal immune activation and sex on placental and fetal brain cytokine and gene expression profiles in a preclinical model of neurodevelopmental disorders.

Maternal inflammation during gestation is associated with a later diagnosis of neurodevelopmental disorders including autism spectrum disorder (ASD). However, the specific impact of maternal immune activation (MIA) on placental and fetal brain development remains insufficiently understood. This study aimed to investigate the effects of MIA by analyzing placental and brain tissues obtained from the offspring of pregnant C57BL/6 dams exposed to polyinosinic: polycytidylic acid (poly I: C) on embryonic day 12.5. Cytokine and mRNA content in the placenta and brain tissues were assessed using multiplex cytokine assays and bulk-RNA sequencing on embryonic day 17.5. In the placenta, male MIA offspring exhibited higher levels of GM-CSF, IL-6, TNFα, and LT-α, but there were no differences in female MIA offspring. Furthermore, differentially expressed genes (DEG) in the placental tissues of MIA offspring were found to be enriched in processes related to synaptic vesicles and neuronal development. Placental mRNA from male and female MIA offspring were both enriched in synaptic and neuronal development terms, whereas females were also enriched for terms related to excitatory and inhibitory signaling. In the fetal brain of MIA offspring, increased levels of IL-28B and IL-25 were observed with male MIA offspring and increased levels of LT-α were observed in the female offspring. Notably, we identified few stable MIA fetal brain DEG, with no male specific difference whereas females had DEG related to immune cytokine signaling. Overall, these findings support the hypothesis that MIA contributes to the sex- specific abnormalities observed in ASD, possibly through altered neuron developed from exposure to inflammatory cytokines. Future research should aim to investigate how interactions between the placenta and fetal brain contribute to altered neuronal development in the context of MIA.

Neurodevelopmental outcome in preterm infants with intraventricular hemorrhages: the potential of quantitative brainstem MRI.

OBJECTIVES: This retrospective study aimed to identify quantitative magnetic resonance imaging markers in the brainstem of preterm neonates with intraventricular hemorrhages. It delves into the intricate associations between quantitative brainstem magnetic resonance imaging metrics and neurodevelopmental outcomes in preterm infants with intraventricular hemorrhage, aiming to elucidate potential relationships and their clinical implications. MATERIALS AND METHODS: Neuroimaging was performed on preterm neonates with intraventricular hemorrhage using a multi-dynamic multi-echo sequence to determine T1 relaxation time, T2 relaxation time, and proton density in specific brainstem regions. Neonatal outcome scores were collected using the Bayley Scales of Infant and Toddler Development. Statistical analysis aimed to explore potential correlations between magnetic resonance imaging metrics and neurodevelopmental outcomes. RESULTS: Sixty preterm neonates (mean gestational age at birth 26.26 ± 2.69 wk; n = 24 [40%] females) were included. The T2 relaxation time of the midbrain exhibited significant positive correlations with cognitive (r = 0.538, P < 0.0001, Pearson's correlation), motor (r = 0.530, P < 0.0001), and language (r = 0.449, P = 0.0008) composite scores at 1 yr of age. CONCLUSION: Quantitative magnetic resonance imaging can provide valuable insights into neurodevelopmental outcomes after intraventricular hemorrhage, potentially aiding in identifying at-risk neonates. Multi-dynamic multi-echo sequence sequences hold promise as an adjunct to conventional sequences, enhancing the sensitivity of neonatal magnetic resonance neuroimaging and supporting clinical decision-making for these vulnerable patients.

Debugging neurodevelopment disorders.

Gut bacteria are thought to contribute to neurodevelopmental disorders, but whether they are causal or predictive of disease remains unclear. In a prospective longitudinal study of thousands of children, Ahrens et al. generate evidence for the role of the gut microbiome in neurodevelopmental disorders while highlighting important open questions.

Spectrum of NMDA Receptor Variants in Neurodevelopmental Disorders and Epilepsy.

N-methyl-D-aspartate receptors (NMDAR) are ligand-gated ion channels mediating excitatory neurotransmission and are important for normal brain development, cognitive abilities, and motor functions. Pathogenic variants in the Glutamate receptor Ionotropic N-methyl-D-aspartate (GRIN) genes (GRIN1, GRIN2A-D) encoding NMDAR subunits have been associated with a wide spectrum of neurodevelopmental disorders and epilepsies ranging from treatable focal epilepsies to devastating early-onset developmental and epileptic encephalopathies. Genetic variants in NMDA receptor genes can cause a range of complex alterations to receptor properties resulting in various degrees of loss-of-function, gain-of-function, or mixtures thereof. Understanding how genetic variants affect the function of the receptors, therefore, represents an important first step in the ongoing development towards targeted therapies. Currently, targeted treatment options for GRIN-related diseases are limited. However, treatment with memantine has been reported to significantly reduce seizure frequency in a few individuals with developmental and epileptic encephalopathies harboring de novo gain-of-function GRIN2A missense variants, and supplementary treatment with L-serine has been associated with improved motor and cognitive performance as well as reduced seizure frequency in patients with GRIN2B loss-of-function missense variants as well as GRIN2A and GRIN2B null variants.

Early Neurodevelopmental Assessments for Predicting Long-Term Outcomes in Infants at High Risk of Cerebral Palsy.

Importance: Studies suggest that early neurodevelopmental assessments are beneficial for identifying cerebral palsy, yet their effectiveness in practical scenarios and their ability to detect cognitive impairment are limited. Objective: To assess the effectiveness of early neurodevelopmental assessments in identifying cerebral palsy and cognitive and other neurodevelopmental impairments, including their severity, within a multidisciplinary clinic. Design, Setting, and Participants: This diagnostic study was conducted at Monash Children's Hospital, Melbourne, Australia. Participants were extremely preterm infants born at less than 28 weeks' gestation or extremely low birth weight infants less than 1000 g and term encephalopathic infants who received therapeutic hypothermia, attending the early neurodevelopmental clinic between January 2019 and July 2021. Data were analyzed from December 2023 to January 2024. Exposures: Early cerebral palsy or high risk of cerebral palsy, the absence of fidgety movements, and Hammersmith Infant Neurological Examination (HINE) scores at corrected age (CA) 3 to 4 months. Early cerebral palsy or high risk of cerebral palsy diagnosis was based on absent fidgety movements, a low HINE score (<57), and medical neurological examination. Main Outcome and Measures: The outcomes of interest were cerebral palsy, cognitive and neurodevelopmental impairments and their severity, diagnosed at 24 to 36 months' CA. Results: A total of 116 infants (median [IQR] gestational age, 27 [25-29] weeks; 65 [56%] male) were included. Diagnosis of early cerebral palsy or high risk of cerebral palsy demonstrated a sensitivity of 92% (95% CI, 63%-99%) and specificity of 84% (95% CI, 76%-90%) for predicting cerebral palsy and 100% (95% CI, 59%-100%) sensitivity and 80% (95% CI, 72%-87%) specificity for predicting moderate to severe cerebral palsy. Additionally, the accuracy of diagnosis of early cerebral palsy or high risk of cerebral palsy was 85% (95% CI, 77%-91%) for predicting cerebral palsy and 81% (95% CI, 73%-88%) for predicting moderate to severe cerebral palsy. Similarly, the absence of fidgety movements had an 81% (95% CI, 73%-88%) accuracy in predicting cerebral palsy, and HINE scores exhibited good discriminatory power with an area under the curve of 0.88 (95% CI, 0.79-0.97) for cerebral palsy prediction. However, for cognitive impairment, the predictive accuracy was 44% (95% CI, 35%-54%) for an early cerebral palsy or high risk of cerebral palsy diagnosis and 45% (95% CI, 36%-55%) for the absence of fidgety movements. Similarly, HINE scores showed poor discriminatory power for predicting cognitive impairment, with an area under the curve of 0.62 (95% CI, 0.51-0.73). Conclusions and Relevance: In this diagnostic study of infants at high risk for cerebral palsy or other cognitive or neurodevelopmental impairment, early neurodevelopmental assessments at 3 to 4 months' CA reliably predicted cerebral palsy and its severity at 24 to 36 months' CA, signifying its crucial role in facilitating early intervention. However, for cognitive impairment, longer-term assessments are necessary for accurate identification.

Is neurodevelopment impaired in Brazilian children with intestinal failure on prolonged parenteral nutrition? A single center study.

PURPOSE: To assess the neurodevelopment outcomes of children younger than 42 months of age with intestinal failure (IF) using prolonged parenteral nutrition (PN) followed by a Pediatric Multidisciplinary Intestinal Rehabilitation Program from a public tertiary hospital in Brazil. METHODS: Bayley III scale was administered in children aged 2 to 42 months with IF and receiving PN for more than 60 days. Composite scores in cognitive, motor, and language domains were analyzed. Developmental delay was defined as a performance 2 standard deviations (SD) below the average at the 3 domains. Association between Bayley III composite scores and clinical variables related to IF were tested. RESULTS: Twenty-four children with median (IQR) age of 17.5 months (9-28.5) were studied, 58.3% were male. Developmental delay was found in 34%, 33% and 27% of the patients in cognitive, motor, and language domains, respectively. There was no significant association between the Bayley-III composite scores and length of hospitalization, prematurity, and number of surgical procedures with anesthesia. CONCLUSION: The study demonstrated impairments in the cognitive, motor and language domains in approximately one-third of young patients with IF on prolonged PN.

Whole-exome-based single nucleotide variants and copy number analysis for prenatal diagnosis of compound heterozygosity of SMPD4.

BACKGROUND: Biallelic loss-of-function variants in SMPD4 cause a rare and severe neurodevelopmental disorder. These variants have been identified in a group of children with neurodevelopmental disorders with microcephaly, arthrogryposis, and structural brain anomalies. SMPD4 encodes a sphingomyelinase that hydrolyzes sphingomyelin into ceramide at neutral pH and can thereby affect membrane lipid homeostasis. SMPD4 localizes to the membranes of the endoplasmic reticulum and nuclear envelope and interacts with nuclear pore complexes. MATERIALS AND METHODS: For the efficient prenatal diagnosis of rare and undiagnosed diseases, the parallel detection of copy number variants (CNVs) and single nucleotide variants using whole-exome analysis is required. A physical examination of the parents was performed. Karyotype and whole-exome analysis were performed for the fetus and the parents. RESULTS: A fetus with microcephaly and arthrogryposis; biallelic null variants (c.387-1G>A; Chr2[GRCh38]: g.130142742_130202459del) were detected by whole-exome sequencing (WES). We have reported for the first time the biallelic loss-of-function mutations in SMPD4 in patients born to unrelated parents in China. CONCLUSION: WES could replace chromosomal microarray analysis and copy number variation sequencing as a more cost-effective genetic test for detecting CNVs and diagnosing highly heterogeneous conditions.

The wide world of technological telerehabilitation for pediatric neurologic and neurodevelopmental disorders - a systematic review.

Introduction: The use of Information and Communication Technology (ICT) for assessing and treating cognitive and motor disorders is promoting home-based telerehabilitation. This approach involves ongoing monitoring within a motivating context to help patients generalize their skills. It can also reduce healthcare costs and geographic barriers by minimizing hospitalization. This systematic review focuses on investigating key aspects of telerehabilitation protocols for children with neurodevelopmental or neurological disorders, including technology used, outcomes, caregiver involvement, and dosage, to guide clinical practice and future research. Method: This systematic review adhered to PRISMA guidelines and was registered in PROSPERO. The PICO framework was followed to define the search strategy for technology-based telerehabilitation interventions targeting the pediatric population (aged 0-18) with neurological or neurodevelopmental disorders. The search encompassed Medline/PubMed, EMBASE, and Web of Science databases. Independent reviewers were responsible for selecting relevant papers and extracting data, while data harmonization and analysis were conducted centrally. Results: A heterogeneous and evolving situation emerged from our data. Our findings reported that most of the technologies adopted for telerehabilitation are commercial devices; however, research prototypes and clinical software were also employed with a high potential for personalization and treatment efficacy. The efficacy of these protocols on health or health-related domains was also explored by categorizing the outcome measures according to the International Classification of Functioning, Disability, and Health (ICF). Most studies targeted motor and neuropsychological functions, while only a minority of papers explored language or multi-domain protocols. Finally, although caregivers were rarely the direct target of intervention, their role was diffusely highlighted as a critical element of the home-based rehabilitation setting. Discussion: This systematic review offers insights into the integration of technological devices into telerehabilitation programs for pediatric neurologic and neurodevelopmental disorders. It highlights factors contributing to the effectiveness of these interventions and suggests the need for further development, particularly in creating dynamic and multi-domain rehabilitation protocols. Additionally, it emphasizes the importance of promoting home-based and family-centered care, which could involve caregivers more actively in the treatment, potentially leading to improved clinical outcomes for children with neurological or neurodevelopmental conditions. Systematic review registration: PROSPERO (CRD42020210663).

Adolescent Neurodevelopmental Variance Across Social Strata.

This cohort study explores variability in neurodevelopment across sociodemographic factors among youths.

PURA syndrome-causing mutations impair PUR-domain integrity and affect P-body association.

Mutations in the human PURA gene cause the neurodevelopmental PURA syndrome. In contrast to several other monogenetic disorders, almost all reported mutations in this nucleic acid-binding protein result in the full disease penetrance. In this study, we observed that patient mutations across PURA impair its previously reported co-localization with processing bodies. These mutations either destroyed the folding integrity, RNA binding, or dimerization of PURA. We also solved the crystal structures of the N- and C-terminal PUR domains of human PURA and combined them with molecular dynamics simulations and nuclear magnetic resonance measurements. The observed unusually high dynamics and structural promiscuity of PURA indicated that this protein is particularly susceptible to mutations impairing its structural integrity. It offers an explanation why even conservative mutations across PURA result in the full penetrance of symptoms in patients with PURA syndrome.

PURA syndrome is a neurodevelopmental disorder that affects about 650 patients worldwide, resulting in a range of symptoms including neurodevelopmental delays, intellectual disability, muscle weakness, seizures, and eating difficulties. The condition is caused by a mutated gene that codes for a protein called PURA. PURA binds RNA ­ the molecule that carries genetic information so it can be translated into proteins ­ and has roles in regulating the production of new proteins. Contrary to other conditions that result from mutations in a single gene, PURA syndrome patients show 'high penetrance', meaning almost every reported mutation in the gene leads to symptoms. Proske, Janowski et al. wanted to understand the molecular basis for this high penetrance. To find out more, the researchers first examined how patient mutations affected the location of the PURA in the cell, using human cells grown in the laboratory. Normally, PURA travels to P-bodies, which are groupings of RNA and proteins involved in regulating which genes get translated into proteins. The researchers found that in cells carrying PURA syndrome mutations, PURA failed to move adequately to P-bodies. To find out how this 'mislocalization' might happen, Proske, Janowski et al. tested how different mutations affected the three-dimensional folding of PURA. These analyses showed that the mutations impair the protein's folding and thereby disrupt PURA's ability to bind RNA, which may explain why mutant PURA cannot localize correctly. Proske, Janowski et al. describe the molecular abnormalities of PURA underlying this disorder and show how molecular analysis of patient mutations can reveal the mechanisms of a disease at the cell level. The results show that the impact of mutations on the structural integrity of the protein, which affects its ability to bind RNA, are likely key to the symptoms of the syndrome. Additionally, their approach used establishes a way to predict and test mutations that will cause PURA syndrome. This may help to develop diagnostic tools for this condition.

The research landscape concerning environmental factors in neurodevelopmental disorders: Endocrine disrupters and pesticides-A review.

In recent years, environmental epidemiology and toxicology have seen a growing interest in the environmental factors that contribute to the increased prevalence of neurodevelopmental disorders, with the purpose of establishing appropriate prevention strategies. A literature review was performed, and 192 articles covering the topic of endocrine disruptors and neurodevelopmental disorders were found, focusing on polychlorinated biphenyls, polybrominated diphenyl ethers, bisphenol A, and pesticides. This study contributes to analyzing their effect on the molecular mechanism in maternal and infant thyroid function, essential for infant neurodevelopment, and whose alteration has been associated with various neurodevelopmental disorders. The results provide scientific evidence of the association that exists between the environmental neurotoxins and various neurodevelopmental disorders. In addition, other possible molecular mechanisms by which pesticides and endocrine disruptors may be associated with neurodevelopmental disorders are being discussed.

Functional myelin in cognition and neurodevelopmental disorders.

In vertebrates, oligodendrocytes (OLs) are glial cells of the central nervous system (CNS) responsible for the formation of the myelin sheath that surrounds the axons of neurons. The myelin sheath plays a crucial role in the transmission of neuronal information by promoting the rapid saltatory conduction of action potentials and providing neurons with structural and metabolic support. Saltatory conduction, first described in the peripheral nervous system (PNS), is now generally recognized as a universal evolutionary innovation to respond quickly to the environment: myelin helps us think and act fast. Nevertheless, the role of myelin in the central nervous system, especially in the brain, may not be primarily focused on accelerating conduction speed but rather on ensuring precision. Its principal function could be to coordinate various neuronal networks, promoting their synchronization through oscillations (or rhythms) relevant for specific information processing tasks. Interestingly, myelin has been directly involved in different types of cognitive processes relying on brain oscillations, and myelin plasticity is currently considered to be part of the fundamental mechanisms for memory formation and maintenance. However, despite ample evidence showing the involvement of myelin in cognition and neurodevelopmental disorders characterized by cognitive impairments, the link between myelin, brain oscillations, cognition and disease is not yet fully understood. In this review, we aim to highlight what is known and what remains to be explored to understand the role of myelin in high order brain processes.

The effectiveness of a dialogical family guidance intervention regarding child treatment response in families with a child with neurodevelopmental disorders.

BACKGROUND: Children with neurodevelopmental disorders (NDD) can have emotional and behavioral symptoms affecting not only the child, but the whole family. Since family members have a strong impact on each other, studies highlight the need to offer effective family interventions to strengthen the wellbeing of the family. The aim of the current study is to clarify whether there is a difference between parents` opinions regarding their child`s emotional and behavioral condition immediately after Dialogical Family Guidance (DFG) has ended and after a three and six month follow-up. METHOD: Fifty families with a child with NDD were randomized into two groups. Group 1 received DFG with an immediate starting point, and Group 2 received DFG after a three-month waiting period. Parent experiences of treatment response regarding their children`s emotional and behavioral symptoms were estimated before and after DFG using the parent version of the Strengths and Difficulties Questionnaire (SDQ-p) at baseline, and after three and six months. Additionally, comparisons between boys and girls, and the age of the child were analyzed. RESULTS: The total difficulties score between Group 1 and Group 2 showed no difference immediately after DFG, or after three months. Regarding subdomains boys had more peer problems than girls, and at baseline, children between 3 and 6 years appeared to have more conduct problems than children between 7 and 13 years. Subdomain prosocial behavior increased statistically significantly during the study period in Group 1. Other SDQ-p subdomains remained constant in both groups between baseline and three and six month follow-up. CONCLUSIONS: The result does not show any differences between parents` opinions regarding their child immediately after or three months after DFG regarding SDQ-p total difficulties scores in either group. The difference between younger and older children regarding conduct problems at baseline, and the difference between boys and girls regarding peer problems is worth paying attention to in the clinical setting. Because of the small sample, it is not possible to draw relevant conclusions regarding the intervention`s effect regarding the child`s mental health dimensions, gender, or age. Nevertheless, Dialogical family Guidance represents one intervention that can be used. TRIAL REGISTRATION: ClinicalTrials.gov NCT04892992 (retrospectively registered May 18th 2021).

Trastornos del sueño en niños con epilepsia / Sleep disorders in children with epilepsy

Introducción: Los niños con epilepsia tienen más trastornos del sueño (TS) que la población sana. Es fundamental su diagnóstico, ya que la epilepsia y los TS tienen una relación bidireccional. Objetivo: Determinar la incidencia de TS y malos hábitos de sueño en niños con epilepsia. Método: Estudio transversal de pacientes menores de 18 años con epilepsia sobre TS, mediante la versión española de Sleep Disturbance Scale for Children (SDSC), y sobre hábitos de sueño, mediante cuestionario de elaboración propia. Resultados: La muestra incluyó 153 pacientes. El 84% de la población estudiada presentaba alterado algún aspecto del sueño. Lo más frecuente fueron las alteraciones en la transición sueño-vigilia (53%), en el inicio-mantenimiento del sueño (47,7%) y la somnolencia diurna (44,4%). Un 70% de los padres de los pacientes referían que su hijo «dormía bien», pero en este grupo se detectaron TS hasta en el 75,7%. Muchos de los pacientes tenían hábitos de sueño poco saludables, como dormirse con dispositivos electrónicos (16,3%), precisar presencia familiar para dormirse (39%) o dormir en colecho o cohabitación (23,5 y 30,5%, respectivamente). Aquellos con epilepsias generalizadas, refractarias, crisis nocturnas y discapacidad intelectual presentaron mayor probabilidad de presentar TS. En cambio, los malos hábitos de sueño fueron frecuentes independientemente de las características de la epilepsia. Conclusiones: Los TS y los malos hábitos de sueño son frecuentes en niños con epilepsia. Su tratamiento puede conllevar una mejoría en la calidad de vida del paciente y su familia, así como una mejoría en el pronóstico de la epilepsia.(AU)

Introduction: Children with epilepsy present greater prevalence of sleep disorders than the general population. Their diagnosis is essential, since epilepsy and sleep disorders have a bidirectional relationship. Objective: Determine the incidence of sleep disorders and poor sleep habits in children with epilepsy. Methods: We conducted a cross-sectional study of patients under 18 years of age with epilepsy, assessing sleep disorders using the Spanish-language version of the Sleep Disturbance Scale for Children (SDSC), and sleep habits using an original questionnaire. Results: The sample included 153 patients. Eighty-four percent of our sample presented some type of sleep alteration. The most frequent alterations were sleep-wake transition disorders (53%), sleep initiation and maintenance disorders (47.7%), and daytime sleepiness (44.4%). In 70% of cases, the patients’ parents reported that their child “slept well,” although sleep disorders were detected in up to 75.7% of these patients. Many patients had poor sleep habits, such as using electronic devices in bed (16.3%), requiring the presence of a family member to fall asleep (39%), or co-sleeping or sharing a room (23.5% and 30.5%, respectively). Those with generalised epilepsy, refractory epilepsy, nocturnal seizures, and intellectual disability were more likely to present sleep disorders. In contrast, poor sleep habits were frequent regardless of seizure characteristics. Conclusions: Sleep disorders and poor sleep habits are common in children with epilepsy. Their treatment can lead to an improvement in the quality of life of the patient and his/her family, as well as an improvement in the prognosis of epilepsy.(AU)

Neurodevelopmental defects in a mouse model of O-GlcNAc transferase intellectual disability.

The addition of O-linked ß-N-acetylglucosamine (O-GlcNAc) to proteins (referred to as O-GlcNAcylation) is a modification that is crucial for vertebrate development. O-GlcNAcylation is catalyzed by O-GlcNAc transferase (OGT) and reversed by O-GlcNAcase (OGA). Missense variants of OGT have recently been shown to segregate with an X-linked syndromic form of intellectual disability, OGT-linked congenital disorder of glycosylation (OGT-CDG). Although the existence of OGT-CDG suggests that O-GlcNAcylation is crucial for neurodevelopment and/or cognitive function, the underlying pathophysiologic mechanisms remain unknown. Here we report a mouse line that carries a catalytically impaired OGT-CDG variant. These mice show altered O-GlcNAc homeostasis with decreased global O-GlcNAcylation and reduced levels of OGT and OGA in the brain. Phenotypic characterization of the mice revealed lower body weight associated with reduced body fat mass, short stature and microcephaly. This mouse model will serve as an important tool to study genotype-phenotype correlations in OGT-CDG in vivo and for the development of possible treatment avenues for this disorder.

Not Just a Mood Disorder─Is Depression a Neurodevelopmental, Cognitive Disorder? Focus on Prefronto-Thalamic Circuits.

Depression is one of the most burdensome psychiatric disorders, affecting hundreds of millions of people worldwide. The disease is characterized not only by severe emotional and affective impairments, but also by disturbed vegetative and cognitive functions. Although many candidate mechanisms have been proposed to cause the disease, the pathophysiology of cognitive impairments in depression remains unclear. In this article, we aim to assess the link between cognitive alterations in depression and possible developmental changes in neuronal circuit wiring during critical periods of susceptibility. We review the existing literature and propose a role of serotonin signaling during development in shaping the functional states of prefrontal neuronal circuits and prefronto-thalamic loops. We discuss how early life insults affecting the serotonergic system could be important in the alterations of these local and long-range circuits, thus favoring the emergence of neurodevelopmental disorders, such as depression.

Clinical and molecular outcomes from the 5-Year natural history study of SSADH Deficiency, a model metabolic neurodevelopmental disorder.

BACKGROUND: Succinic semialdehyde dehydrogenase deficiency (SSADHD) represents a model neurometabolic disease at the fulcrum of translational research within the Boston Children's Hospital Intellectual and Developmental Disabilities Research Centers (IDDRC), including the NIH-sponsored natural history study of clinical, neurophysiological, neuroimaging, and molecular markers, patient-derived induced pluripotent stem cells (iPSC) characterization, and development of a murine model for tightly regulated, cell-specific gene therapy. METHODS: SSADHD subjects underwent clinical evaluations, neuropsychological assessments, biochemical quantification of γ-aminobutyrate (GABA) and related metabolites, electroencephalography (standard and high density), magnetoencephalography, transcranial magnetic stimulation, magnetic resonance imaging and spectroscopy, and genetic tests. This was parallel to laboratory molecular investigations of in vitro GABAergic neurons derived from induced human pluripotent stem cells (hiPSCs) of SSADHD subjects and biochemical analyses performed on a versatile murine model that uses an inducible and reversible rescue strategy allowing on-demand and cell-specific gene therapy. RESULTS: The 62 SSADHD subjects [53% females, median (IQR) age of 9.6 (5.4-14.5) years] included in the study had a reported symptom onset at ∼ 6 months and were diagnosed at a median age of 4 years. Language developmental delays were more prominent than motor. Autism, epilepsy, movement disorders, sleep disturbances, and various psychiatric behaviors constituted the core of the disorder's clinical phenotype. Lower clinical severity scores, indicating worst severity, coincided with older age (R= -0.302, p = 0.03), as well as age-adjusted lower values of plasma γ-aminobutyrate (GABA) (R = 0.337, p = 0.02) and γ-hydroxybutyrate (GHB) (R = 0.360, p = 0.05). While epilepsy and psychiatric behaviors increase in severity with age, communication abilities and motor function tend to improve. iPSCs, which were differentiated into GABAergic neurons, represent the first in vitro neuronal model of SSADHD and express the neuronal marker microtubule-associated protein 2 (MAP2), as well as GABA. GABA-metabolism in induced GABAergic neurons could be reversed using CRISPR correction of the pathogenic variants or mRNA transfection and SSADHD iPSCs were associated with excessive glutamatergic activity and related synaptic excitation. CONCLUSIONS: Findings from the SSADHD Natural History Study converge with iPSC and animal model work focused on a common disorder within our IDDRC, deepening our knowledge of the pathophysiology and longitudinal clinical course of a complex neurodevelopmental disorder. This further enables the identification of biomarkers and changes throughout development that will be essential for upcoming targeted trials of enzyme replacement and gene therapy.

Investigating the role of common cis-regulatory variants in modifying penetrance of putatively damaging, inherited variants in severe neurodevelopmental disorders.

Recent work has revealed an important role for rare, incompletely penetrant inherited coding variants in neurodevelopmental disorders (NDDs). Additionally, we have previously shown that common variants contribute to risk for rare NDDs. Here, we investigate whether common variants exert their effects by modifying gene expression, using multi-cis-expression quantitative trait loci (cis-eQTL) prediction models. We first performed a transcriptome-wide association study for NDDs using 6987 probands from the Deciphering Developmental Disorders (DDD) study and 9720 controls, and found one gene, RAB2A, that passed multiple testing correction (p = 6.7 × 10-7). We then investigated whether cis-eQTLs modify the penetrance of putatively damaging, rare coding variants inherited by NDD probands from their unaffected parents in a set of 1700 trios. We found no evidence that unaffected parents transmitting putatively damaging coding variants had higher genetically-predicted expression of the variant-harboring gene than their child. In probands carrying putatively damaging variants in constrained genes, the genetically-predicted expression of these genes in blood was lower than in controls (p = 2.7 × 10-3). However, results for proband-control comparisons were inconsistent across different sets of genes, variant filters and tissues. We find limited evidence that common cis-eQTLs modify penetrance of rare coding variants in a large cohort of NDD probands.

Shared and divergent mental health characteristics of ADNP-, CHD8- and DYRK1A-related neurodevelopmental conditions.

BACKGROUND: Neurodevelopmental conditions such as intellectual disability (ID) and autism spectrum disorder (ASD) can stem from a broad array of inherited and de novo genetic differences, with marked physiological and behavioral impacts. We currently know little about the psychiatric phenotypes of rare genetic variants associated with ASD, despite heightened risk of psychiatric concerns in ASD more broadly. Understanding behavioral features of these variants can identify shared versus specific phenotypes across gene groups, facilitate mechanistic models, and provide prognostic insights to inform clinical practice. In this paper, we evaluate behavioral features within three gene groups associated with ID and ASD - ADNP, CHD8, and DYRK1A - with two aims: (1) characterize phenotypes across behavioral domains of anxiety, depression, ADHD, and challenging behavior; and (2) understand whether age and early developmental milestones are associated with later mental health outcomes. METHODS: Phenotypic data were obtained for youth with disruptive variants in ADNP, CHD8, or DYRK1A (N = 65, mean age = 8.7 years, 40% female) within a long-running, genetics-first study. Standardized caregiver-report measures of mental health features (anxiety, depression, attention-deficit/hyperactivity, oppositional behavior) and developmental history were extracted and analyzed for effects of gene group, age, and early developmental milestones on mental health features. RESULTS: Patterns of mental health features varied by group, with anxiety most prominent for CHD8, oppositional features overrepresented among ADNP, and attentional and depressive features most prominent for DYRK1A. For the full sample, age was positively associated with anxiety features, such that elevations in anxiety relative to same-age and same-sex peers may worsen with increasing age. Predictive utility of early developmental milestones was limited, with evidence of early language delays predicting greater difficulties across behavioral domains only for the CHD8 group. CONCLUSIONS: Despite shared associations with autism and intellectual disability, disruptive variants in ADNP, CHD8, and DYRK1A may yield variable psychiatric phenotypes among children and adolescents. With replication in larger samples over time, efforts such as these may contribute to improved clinical care for affected children and adolescents, allow for earlier identification of emerging mental health difficulties, and promote early intervention to alleviate concerns and improve quality of life.