[Treatment of sleep disorders in neurodevelopmental disorders]. / Abordaje de los trastornos del sueño en los trastornos del neurodesarrollo.

Sleep disorders are common in children and affect neurological development with important cognitive, emotional and behavioral repercussions. There is a high prevalence of sleep disorders (SD) in neurodevelopmental disorders (NDD) such as autism spectrum disorder (ASD) and attention-deficit hyperactivity disorder (ADHD). Sleep disorders in pediatric population have a prevalence of 6-25%, while in children with NDD this number rises to 50-80%. In NDDs, higher rates of difficulties in falling asleep, nocturnal awakenings and daytime sleepiness are observed. Disturbances in the circadian rhythm as well as respiratory sleep disorders are also observed. Consequently, there is a decrease in alertness for daytime activities with increased behavioral disorders, emotional problems and academic difficulties associated with executive and memory dysfunctions. Sleep assessment has to be a systemic part in the clinical evaluation of children with NDDs, so as to give a convenient diagnosis and treatment in each case, allowing to improve the quality of life of children and their families.

Los trastornos del sueño son frecuentes en niños y afectan al desarrollo neurológico, con importante repercusión cognitiva, emocional y conductual. Existe una alta prevalencia de trastornos del sueño (TS) en los trastornos del neurodesarrollo (TND), como trastorno del espectro autista (TEA) y trastorno por déficit de atención con hiperactividad (TDAH). Los TS en población pediátrica tienen una prevalencia del 6-25%, mientras que en los niños con TND esta cifra asciende al 50-80%. En los TND se observa un incremento de las dificultades para conciliar el sueño, de los despertares nocturnos y de la somnolencia diurna. Así mismo, presentan alteraciones del ritmo circadiano y trastornos respiratorios del sueño. Como consecuencia se produce una reducción de la alerta para las actividades diarias con incremento de trastornos conductuales, problemas emocionales y dificultades académicas asociadas a disfunciones ejecutivas y de memoria. La evaluación del sueño debe formar parte sistemática en la valoración clínica de los niños con TND, con el fin de realizar un diagnóstico y un tratamiento adecuados a cada caso, permitiendo mejorar la calidad de vida del niño y de su familia.

A cohort study of neurodevelopmental disorders and/or congenital anomalies using high resolution chromosomal microarrays in southern Brazil highlighting the significance of ASD.

Chromosomal microarray (CMA) is the reference in evaluation of copy number variations (CNVs) in individuals with neurodevelopmental disorders (NDDs), such as intellectual disability (ID) and/or autism spectrum disorder (ASD), which affect around 3-4% of the world's population. Modern platforms for CMA, also include probes for single nucleotide polymorphisms (SNPs) that detect homozygous regions in the genome, such as long contiguous stretches of homozygosity (LCSH). These regions result from complete or segmental chromosomal homozygosis and may be indicative of uniparental disomy (UPD), inbreeding, population characteristics, as well as replicative DNA repair events. In this retrospective study, we analyzed CMA reading files requested by geneticists and neurologists for diagnostic purposes along with available clinical data. Our objectives were interpreting CNVs and assess the frequencies and implications of LCSH detected by Affymetrix CytoScan HD (41%) or 750K (59%) platforms in 1012 patients from the south of Brazil. The patients were mainly children with NDDs and/or congenital anomalies (CAs). A total of 206 CNVs, comprising 132 deletions and 74 duplications, interpreted as pathogenic, were found in 17% of the patients in the cohort and across all chromosomes. Additionally, 12% presented rare variants of uncertain clinical significance, including LPCNVs, as the only clinically relevant CNV. Within the realm of NDDs, ASD carries a particular importance, owing to its escalating prevalence and its growing repercussions for individuals, families, and communities. ASD was one clinical phenotype, if not the main reason for referral to testing, for about one-third of the cohort, and these patients were further analyzed as a sub-cohort. Considering only the patients with ASD, the diagnostic rate was 10%, within the range reported in the literature (8-21%). It was higher (16%) when associated with dysmorphic features and lower (7%) for "isolated" ASD (without ID and without dysmorphic features). In 953 CMAs of the whole cohort, LCSH (≥ 3 Mbp) were analyzed not only for their potential pathogenic significance but were also explored to identify common LCSH in the South Brazilians population. CMA revealed at least one LCSH in 91% of the patients. For about 11.5% of patients, the LCSH suggested consanguinity from the first to the fifth degree, with a greater probability of clinical impact, and in 2.8%, they revealed a putative UPD. LCSH found at a frequency of 5% or more were considered common LCSH in the general population, allowing us to delineate 10 regions as potentially representing ancestral haplotypes of neglectable clinical significance. The main referrals for CMA were developmental delay (56%), ID (33%), ASD (33%) and syndromic features (56%). Some phenotypes in this population may be predictive of a higher probability of indicating a carrier of a pathogenic CNV. Here, we present the largest report of CMA data in a cohort with NDDs and/or CAs from the South of Brazil. We characterize the rare CNVs found along with the main phenotypes presented by each patient and show the importance and usefulness of LCSH interpretation in CMA results that incorporate SNPs, as well as we illustrate the value of CMA to investigate CNV in ASD.

Pediatrician and parental evaluation of child neurodevelopment at 2 years of age.

BACKGROUND: The early identification of infants with a risk for neurodevelopmental disorders in the first few years of life is essential for better developmental outcomes. Screenings should be carried out by combining the family pediatricians' and parents' perspectives, the two fundamental sources of information on children's health. The present study has three aims: (a) to test the feasibility of parent-report instruments to detect warning signs in their children's development; (b) to ascertain whether there is an agreement between the family pediatricians' (FP) clinical judgments of warning signs and the parental perceptions; (c) to determine whether there is a link between parents' distress and child development. METHODS: Within the NASCITA birth cohort, in addition to the family pediatrician's clinical evaluation with routine tools, the Modified Checklist for Autism in Toddlers, Revised (M-CHAT-R) was completed by parents to assess the child's language, social skills, behavior, and sensory areas. Parents were also asked to complete the Parenting Stress Index, Short Form (PSI-SF) to verify the magnitude of stress in the parent-child system. Univariate and multivariate analyses were performed to evaluate the association between child and parental characteristics and the presence of warning signs. RESULTS: The follow-up assessment was completed for 435 infants: 69 (15.8%) presented warning signs: 43 in the pediatrician's assessment and 36 in the M-CHAT-R (10 in both). A total of 16 children (14 with warning signs) received a diagnosis after a specialist evaluation. Being male (OR 2.46, 95%CI: 1.23-4.91) and having sleep disorders (OR 2.43, 95% CI 1.17-5.04) was associated with a greater likelihood of warning signs in the multivariate analysis, while reading aloud was a protective factor (not exposed versus exposed (OR = 3.14; 95% CI 1.60-6.17). For 73 children (18.4%), at least one parent tested positive for PSI-SF. An increased prevalence of parental distress was observed in children with warning signs (OR 2.36, 95% CI 1.27-4.37). CONCLUSIONS: Integrating physician and parental perspectives during well-child visits and in clinical practice appears feasible and can improve the identification of children at risk of developmental disorders.

Differential Diagnosis of Autism and Other Neurodevelopmental Disorders.

This article discusses the diagnostic criteria for autism spectrum disorder (ASD), as well as other neurodevelopmental disorders that may be confused with or co-occur with ASD. Practitioners involved in diagnostic assessment of ASD must be well versed in the features that differentiate ASD from other conditions and be familiar with how co-occurring conditions may manifest in the context of ASD. ASD symptoms present differently across development, underscoring the need for training about typical developmental expectations for youth. Periodic reevaluations throughout development are also important because support needs for individuals with autism change over time.

Improving care for rare genetic neurodevelopmental disorders: A systematic review and critical appraisal of clinical practice guidelines using AGREE II.

PURPOSE: Rare genetic neurodevelopmental disorders associated with intellectual disability require lifelong multidisciplinary care. Clinical practice guidelines may support healthcare professionals in their daily practice, but guideline development for rare conditions can be challenging. In this systematic review, the characteristics and methodological quality of internationally published recommendations for this population are described to provide an overview of current guidelines and inform future efforts of European Reference Network ITHACA (Intellectual disability, TeleHealth, Autism, and Congenital Anomalies). METHODS: MEDLINE, Embase, and Orphanet were systematically searched to identify guidelines for conditions classified as "rare genetic intellectual disability" (ORPHA:183757). Methodological quality was assessed using the Appraisal of Guidelines, Research, and Evaluation II tool. RESULTS: Seventy internationally published guidelines, addressing the diagnosis and/or management of 28 conditions, were included. The methodological rigor of development was highly variable with limited reporting of literature searches and consensus methods. Stakeholder involvement and editorial independence varied as well. Implementation was rarely addressed. CONCLUSION: Comprehensive, high-quality guidelines are lacking for many rare genetic neurodevelopmental disorders. Use and transparent reporting of sound development methodologies, active involvement of affected individuals and families, robust conflict of interest procedures, and attention to implementation are vital for enhancing the impact of clinical practice recommendations.

A novel de novo truncating variant in a Hungarian patient with CTNNB1 neurodevelopmental disorder.

PURPOSE: We aimed to elucidate the underlying disease in a Hungarian family, with only one affected family member, a 16-year-old male Hungarian patient, who developed global developmental delay, cognitive impairment, behavioral problems, short stature, intermittent headaches, recurrent dizziness, strabismus, hypermetropia, complex movement disorder and partial pituitary dysfunction. After years of detailed clinical investigations and careful pediatric care, the exact diagnosis of the patient and the cause of the disease was still unknown. METHODS: We aimed to perform whole exome sequencing (WES) in order to investigate whether the affected patient is suffering from a rare monogenic disease. RESULTS: Using WES, we identified a novel, de novo frameshift variant (c.1902dupG, p.Ala636SerfsTer12) of the catenin beta-1 (CTNNB1) gene. Assessment of the novel CTNNB1 variant suggested that it is a likely pathogenic one and raised the diagnosis of CTNNB1 neurodevelopmental disorder (OMIM 615,075). CONCLUSIONS: Our manuscript may contribute to the better understanding of the genetic background of the recently discovered CTNNB1 neurodevelopmental disorder and raise awareness among clinicians and geneticists. The affected Hungarian family demonstrates that based on the results of the clinical workup is difficult to establish the diagnosis and high-throughput genetic screening may help to solve these complex cases.

Consensus Statement of the IAP - Neurodevelopmental Chapter On Neurodevelopmental Disorders Habilitation Process: Strategic Plan for Prevention, Early Detection and Early Intervention.

JUSTIFICATION: Neurodevelopmental disorders, as per DSM-V, are described as a group of conditions with onset in the development period of childhood. There is a need to distinguish the process of habilitation and rehabilitation, especially in a developing country like India, and define the roles of all stakeholders to reduce the burden of neurodevelopmental disorders. PROCESS: Subject experts and members of Indian Academy of Pediatrics (IAP) Chapter of Neurodevelopmental Pediatrics, who reviewed the literature on the topic, developed key questions and prepared the first draft on guidelines. The guidelines were then discussed by the whole group through online meetings, and the contentious issues were discussed until a general consensus was arrived at. Following this, the final guidelines were drafted by the writing group and approved by all contributors. OBJECTIVES: These guidelines aim to provide practical clinical guidelines for pediatricians on the prevention, early diagnosis and management of neurodevelopmental disorders (NDDs) in the Indian settings. It also defines the roles of developmental pediatricians and development nurse counselor. STATEMENT: There is a need for nationwide studies with representative sampling on epidemiology of babies with early NDD in the first 1000 days in India. Specific learning disability (SLD) has been documented as the most common NDD after 6 years in India, and special efforts should be made to establish the epidemiology of infants and toddlers at risk for SLD, where ever measures are available. Preconception counseling as part of focusing on first 1000 days; Promoting efforts to organize systematic training programs in Newborn Resuscitation Program (NRP); Lactation management; Developmental follow-up and Early stimulation for SNCU/ NICU graduates; Risk stratification of NICU graduates, Newborn Screening; Counseling parents; Screening for developmental delay by trained professionals using simple validated Indian screening tools at 4, 8, 12, 18 and 24 months; Holistic assessment of 10 NDDs at child developmental clinics (CDCs) / district early intervention centre (DEICs) by multidisciplinary team members; Confirmation of diagnosis by developmental pediatrician/developmental neurologist/child psychiatrist using clinical/diagnostic tools; Providing parent guided low intensity multimodal therapies before 3 years age as a center-based or home-based or community-based rehabilitation; Developmental pediatrician to seek guidance of pediatric neurologist, geneticist, child psychiatrist, physiatrist, and other specialists, when necessary; and Need to promote ongoing academic programs in clinical child development for capacity building of community based therapies, are the chief recommendations.

Gestational diabetes mellitus and risk of neurodevelopmental disorders in young offspring: does the risk differ by race and ethnicity?

BACKGROUND: Previous studies examined the associations of gestational diabetes mellitus with autism spectrum disorder and attention deficit hyperactivity disorder. However, the associations between gestational diabetes mellitus and other neurodevelopmental disorders, such as the common speech/language disorder and developmental coordination disorder, are rarely studied, and whether the associations vary by race/ethnicity remains unknown. OBJECTIVE: This study aimed to examine the associations of gestational diabetes mellitus with individual neurodevelopmental disorders in young offspring, and to investigate whether the associations vary by race/ethnicity. STUDY DESIGN: This retrospective cohort study (Glucose in Relation to Women and Babies' Health [GrownB]) included 14,480 mother-offspring pairs in a large medical center in the United States from March 1, 2013 to August 31, 2021. We ascertained gestational diabetes mellitus using the validated ICD (International Classification of Diseases) codes (ICD-9: 648.8x; ICD-10: O24.4x), and identified neurodevelopmental disorders (speech/language disorder, developmental coordination disorder, autism spectrum disorder, and other neurodevelopmental disorders [attention deficit hyperactivity disorder, behavioral disorder, intellectual disability, and learning difficulty]) and their combinations using validated algorithms. We compared the hazard of neurodevelopmental disorders during the entire follow-up period between offspring born to mothers with and without gestational diabetes mellitus using multivariable Cox regression models. RESULTS: Among all mothers, 19.9% were Asian, 21.8% were Hispanic, 41.0% were non-Hispanic White, and 17.3% were of other/unknown race/ethnicity. During the median follow-up of 3.5 years (range, 1.0-6.3 years) after birth, 8.7% of offspring developed at least 1 neurodevelopmental disorder. Gestational diabetes mellitus was associated with a higher risk of speech/language disorder (adjusted hazard ratio, 1.59 [95% confidence interval, 1.07-2.35]), developmental coordination disorder (2.36 [1.37-4.04]), autism spectrum disorder (3.16 [1.36-7.37]), other neurodevelopmental disorders (3.12 [1.51-6.47]), any neurodevelopmental disorder (1.86 [1.36-2.53]), the combination of speech/language disorder and autism spectrum disorder (3.79 [1.35-10.61]), and the combination of speech/language disorder and developmental coordination disorder (4.22 [1.69-10.51]) among offspring born to non-Hispanic White mothers. No associations between gestational diabetes mellitus and any neurodevelopmental disorders or their combinations were observed among offspring born to mothers of other racial/ethnic groups. CONCLUSION: We observed an elevated risk of neurodevelopmental disorders among young offspring born to non-Hispanic White mothers with gestational diabetes mellitus, but not among other racial/ethnic groups.

Episignatures in practice: independent evaluation of published episignatures for the molecular diagnostics of ten neurodevelopmental disorders.

Variants of uncertain significance (VUS) are a significant issue for the molecular diagnosis of rare diseases. The publication of episignatures as effective biomarkers of certain Mendelian neurodevelopmental disorders has raised hopes to help classify VUS. However, prediction abilities of most published episignatures have not been independently investigated yet, which is a prerequisite for an informed and rigorous use in a diagnostic setting. We generated DNA methylation data from 101 carriers of (likely) pathogenic variants in ten different genes, 57 VUS carriers, and 25 healthy controls. Combining published episignature information and new validation data with a k-nearest-neighbour classifier within a leave-one-out scheme, we provide unbiased specificity and sensitivity estimates for each of the signatures. Our procedure reached 100% specificity, but the sensitivities unexpectedly spanned a very large spectrum. While ATRX, DNMT3A, KMT2D, and NSD1 signatures displayed a 100% sensitivity, CREBBP-RSTS and one of the CHD8 signatures reached <40% sensitivity on our dataset. Remaining Cornelia de Lange syndrome, KMT2A, KDM5C and CHD7 signatures reached 70-100% sensitivity at best with unstable performances, suffering from heterogeneous methylation profiles among cases and rare discordant samples. Our results call for cautiousness and demonstrate that episignatures do not perform equally well. Some signatures are ready for confident use in a diagnostic setting. Yet, it is imperative to characterise the actual validity perimeter and interpretation of each episignature with the help of larger validation sample sizes and in a broader set of episignatures.

Addressing the Gap in Research Training in Child Psychiatry and Neurodevelopment.

Psychiatric and neurodevelopmental conditions in children are common, often co-occur, and can be highly impairing. Moreover, psychiatric disorders that typically do not fully manifest until adulthood, such as schizophrenia, have their roots in early development, with atypical brain and behavioral patterns arising well before a clinical diagnosis is made. The relevance of brain development to improving outcomes of psychiatric and neurodevelopmental conditions underscores the need to cultivate a pipeline of investigators with the necessary training to conduct rigorous, developmentally focused research.

Comprehensive evaluation of the implementation of episignatures for diagnosis of neurodevelopmental disorders (NDDs).

Episignatures are popular tools for the diagnosis of rare neurodevelopmental disorders. They are commonly based on a set of differentially methylated CpGs used in combination with a support vector machine model. DNA methylation (DNAm) data often include missing values due to changes in data generation technology and batch effects. While many normalization methods exist for DNAm data, their impact on episignature performance have never been assessed. In addition, technologies to quantify DNAm evolve quickly and this may lead to poor transposition of existing episignatures generated on deprecated array versions to new ones. Indeed, probe removal between array versions, technologies or during preprocessing leads to missing values. Thus, the effect of missing data on episignature performance must also be carefully evaluated and addressed through imputation or an innovative approach to episignatures design. In this paper, we used data from patients suffering from Kabuki and Sotos syndrome to evaluate the influence of normalization methods, classification models and missing data on the prediction performances of two existing episignatures. We compare how six popular normalization methods for methylarray data affect episignature classification performances in Kabuki and Sotos syndromes and provide best practice suggestions when building new episignatures. In this setting, we show that Illumina, Noob or Funnorm normalization methods achieved higher classification performances on the testing sets compared to Quantile, Raw and Swan normalization methods. We further show that penalized logistic regression and support vector machines perform best in the classification of Kabuki and Sotos syndrome patients. Then, we describe a new paradigm to build episignatures based on the detection of differentially methylated regions (DMRs) and evaluate their performance compared to classical differentially methylated cytosines (DMCs)-based episignatures in the presence of missing data. We show that the performance of classical DMC-based episignatures suffers from the presence of missing data more than the DMR-based approach. We present a comprehensive evaluation of how the normalization of DNA methylation data affects episignature performance, using three popular classification models. We further evaluate how missing data affect those models' predictions. Finally, we propose a novel methodology to develop episignatures based on differentially methylated regions identification and show how this method slightly outperforms classical episignatures in the presence of missing data.

Early detection of neurodevelopmental disorders in African children living in informal settlements in Nairobi.

BACKGROUND: Children in low-income and middle-income countries (LMICs) are at a substantially increased risk of delayed physical, emotional and sociocognitive outcomes, with consequential neurodevelopmental disorders. Evidence based, cost-effective and culturally appropriate screening tools are recommended for early identification of developmental disorders. METHODS: The present study aims to assess the feasibility of early screening for neurodevelopmental disorders in children living in informal settlements in Nairobi, Kenya (Korogocho). The selected tools (ie, the CDC checklist and the Modified Checklist for Autism in Toddlers, Revised (M-CHAT-R)), widely used in high-income countries, are applied in two different populations: one from Kenya (LMIC) and one from Italy, to compare the different scores. RESULTS: Of 509 children screened, 8.6% were classified at-risk based on the results of the screening tools. Significant risk factors are history of low birth weight and Apgar score, presence of neurological disorders, malnutrition and/or rickets, younger age of the child and older age of the mother. Caesarean section delivery, first pregnancy and mothers' older age were common risk factors among the Kenyan and the Italian samples. The Italian sample had a significantly greater rate of missed milestones. CONCLUSIONS: Our data demonstrate the feasibility of using the CDC and M-CHAT-R tools in informal settlement dwellers. Further studies are needed to explore the opportunity for early diagnosis of developmental disorders in LMICs.

Autistic traits at neurodevelopmental assessment for very preterm infants.

Aim The aim of this study was to establish the prevalence of autistic traits at childhood neurodevelopmental assessment in a premature cohort and to assess associated perinatal exposures. Methods An observational retrospective case-control study was conducted in a single tertiary neonatal unit. All infants born weighing =1500 grams and/or =32/40 weeks who attended for neurodevelopmental assessment in 2019 were eligible. Results 96 preterm infants met the inclusion criteria. 22 (23%) in the case group demonstrated clinical features of autism at early childhood assessment. The remaining 74 acted as a control group. In the case group 18 (82%) were male. There was no difference in rate of multiple births between the groups. There was no statistically significant difference in maternal age or indication for delivery. Male phenotype (p=0.003), non-Irish ethnicity (p=0.005), vaginal delivery (p=0.005) and abnormal cranial ultrasound (p=0.009) occurred more frequently in the case group. Use of assistive reproductive technologies occurred less frequently in the case group (p=0.047). In the case group, 10/14 of the composite scores measured on Bayleys-3 at a median (IQR) age of 32 (31-35) months showed statistically significant differences (p<0.003). Discussion Our study strongly supports increasing awareness of the association between prematurity and autism. It highlights the need for targeted neurodevelopmental follow-up to support early detection of autism, allowing for timely intervention. Further investigation in a larger prospective cohort may further delineate the various perinatal risk factors for autism.

Utility of the 21-month neurodevelopmental outcome for predicting neurodevelopmental impairment at 36 months for preterm infants <29 weeks gestation.

OBJECTIVE: To determine the sensitivity and specificity of the 21-month neurodevelopmental outcome for predicting the presence of neurodevelopmental impairment at 36 months corrected age in a population of preterm infants under 29 weeks gestation. STUDY DESIGN: This is a retrospective observational cohort study. Preterm infants born under 29 weeks gestation who were followed up at both 18-21 months and 36 months corrected age with outcome data available were enrolled. RESULTS: Overall, 713 preterm infants <29 weeks gestation and were included in the final analysis. The specificity of the 21-month assessment for predicting neurodevelopmental impairment at 36 months corrected age was 66% (95% confidence interval[CI] 62-71%) with a positive predictive value of 61% (95% CI 56-66%). CONCLUSION: In preterm neonates born <29 weeks gestation, the 18-21 months corrected neurodevelopmental outcome had low specificity and positive predictive value for predicting the presence of neurodevelopmental impairment at 36 months corrected age.

Methodology of a Natural History Study of a Rare Neurodevelopmental Disorder: Alternating Hemiplegia of Childhood as a Prototype Disease.

Here, we describe the process of development of the methodology for an international multicenter natural history study of alternating hemiplegia of childhood as a prototype disease for rare neurodevelopmental disorders. We describe a systematic multistep approach in which we first identified the relevant questions about alternating hemiplegia of childhood natural history and expected challenges. Then, based on our experience with alternating hemiplegia of childhood and on pragmatic literature searches, we identified solutions to determine appropriate methods to address these questions. Specifically, these solutions included development and standardization of alternating hemiplegia of childhood-specific spell video-library, spell calendars, adoption of tailored methodologies for prospective measurement of nonparoxysmal and paroxysmal manifestations, unified data collection protocols, centralized data platform, adoption of specialized analysis methods including, among others, Cohen kappa, interclass correlation coefficient, linear mixed effects models, principal component, propensity score, and ambidirectional analyses. Similar approaches can, potentially, benefit in the study of other rare pediatric neurodevelopmental disorders.

Genetic Diagnosis of Children With Neurodevelopmental Disorders Using Whole Genome Sequencing.

BACKGROUND: Neurodevelopmental disorders (NDDs) have diverse phenotypes. Their genetic diagnoses are often challenged by difficulties of targeting causative genes due to heterogeneous genetic etiologies. The objective of this study was to perform genetic diagnosis of children with NDDs using whole genome sequencing. METHODS: This study included 78 pediatric patients with NDDs and their 152 family members for whole genome sequencing (WGS). All cases except one were families with at least two members. Seventy-five patients had previously undergone other genetic tests besides WGS. Detected variants were classified according to the guidelines of the American College of Medical Genetics and Genomics. RESULTS: Among 78 probands, 26 patients were genetically diagnosed with NDDs through WGS, showing a diagnostic rate of 33.3%. Of them, 22 cases had de novo variants (DNVs) identified through trio analysis. Of these DNVs, half were novel variants. Three structural variants, including a multiexon deletion, a contiguous gene deletion involving 13 Mb, and a retrotransposon insertion, were revealed by WGS. All cases except one had defects in different genes, consistent with the phenotypically diverse nature of NDDs. In addition, three patients were inconclusive, two of them had one likely pathogenic variant in a gene associated with autosomal recessive disease and the other one had no clinical phenotypes associated with the detected DNV. CONCLUSIONS: Our experience demonstrates the advantage of WGS in the diagnosis of NDDs, including detection of copy number variations and also the advantage of trio sequencing for interpretation of DNVs.

Aromatic L-Amino-Acid Decarboxylase Deficiency Screening by Analysis of 3-O-Methyldopa in Dried Blood Spots: Results of a Multicentric Study in Neurodevelopmental Disorders.

Aromatic L-amino acid decarboxylase deficiency (AADCd) is a rare recessive metabolic disorder caused by pathogenic homozygous or compound heterozygous variants in the dopa decarboxylase (DDC) gene. Adeno-associated viral vector-mediated gene transfer of the human DDC gene injected into the putamen is available. The typical presentation is characterized by early-onset hypotonia, severe developmental delay, movement disorders, and dysautonomia. Recently, mild and even atypical phenotypes have been reported, increasing the diagnostic challenge. The aim of this multicentric study is to identify the prevalence of AADCd in a population of patients with phenotypic clusters characterized by neurodevelopmental disorders (developmental delay/intellectual disability, and/or autism) by 3-O-methyldopa (3-OMD) detection in dried blood spots (DBS). It is essential to identify AADCd promptly, especially within non-typical phenotypic clusters, because better results are obtained when therapy is quickly started in mild-moderate phenotypes. Between 2021 and 2023, 390 patients with non-specific phenotypes possibly associated with AADCd were tested; none resulted in a positive result. This result highlights that the population to be investigated for AADCd should have more defined clinical characteristics: association with common signs (hypotonia) and/or pathognomonic symptoms (oculogyric crisis and dysautonomia). It is necessary to continue to screen selected clusters for reaching diagnosis and improving long-term outcomes through treatment initiation. This underscores the role of newborn screening in identifying AADCd.