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Keywords = syndromic complex neurodevelopmental disorder

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17 pages, 519 KB  
Systematic Review
Sleep Disorders in Patients with Tics: Towards Personalized Care for Tourette Syndrome
by Kashish K. Qureshi and Andrea E. Cavanna
J. Pers. Med. 2026, 16(6), 309; https://doi.org/10.3390/jpm16060309 - 6 Jun 2026
Viewed by 273
Abstract
Background/Objectives: Tourette syndrome and other chronic tic disorders are neurodevelopmental conditions characterized by intermittent motor/phonic tics and frequent behavioral comorbidity. Poor sleep quality is often reported by patients with tic disorders; however, little is known about the prevalence and clinical correlates of [...] Read more.
Background/Objectives: Tourette syndrome and other chronic tic disorders are neurodevelopmental conditions characterized by intermittent motor/phonic tics and frequent behavioral comorbidity. Poor sleep quality is often reported by patients with tic disorders; however, little is known about the prevalence and clinical correlates of disruption in sleep physiology. Methods: We conducted a systematic literature review of clinical studies evaluating sleep using at least one validated sleep outcome (questionnaire, polysomnography, or coded clinical diagnosis). Results: Despite high heterogeneity in age ranges, diagnostic formulations, outcome measures, and confounder handling, converging evidence across designs indicated a significantly higher prevalence of sleep disturbance in patients with Tourette syndrome and other chronic tic disorders compared to controls. Specifically, registries showed significantly greater insomnia rates (aOR 6–7); case–control studies revealed a 9-fold increase in night-waking, bedtime resistance, parasomnias, and daytime drowsiness; polysomnography studies demonstrated sleep fragmentation, with decreased efficiency, longer latency, and more awakenings. Conclusions: Sleep disorders are relatively common in patients with Tourette syndrome and other chronic tic disorders, with clinical implications for both arousal instability and sleep initiation/maintenance issues. Further research is needed to better understand the complex interplay between altered sleep patterns and tic expression, as well as the impact of behavioral comorbidities. Our findings highlight a need for personalized treatment interventions focusing on sleep problems in the context of tic disorders. Full article
(This article belongs to the Special Issue Personalized Diagnosis and Treatment for Neurological Diseases)
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23 pages, 785 KB  
Review
Neuroglia and Artificial Intelligence in Pediatric Neurodevelopmental Disorders: Integrating Biological Mechanisms with Precision Diagnostics
by Nikola Ilić and Adrijan Sarajlija
Neuroglia 2026, 7(2), 16; https://doi.org/10.3390/neuroglia7020016 - 29 May 2026
Viewed by 187
Abstract
Pediatric neurodevelopmental disorders (NDDs) encompass a highly heterogeneous group of conditions characterized by complex interactions among genetic, molecular, developmental, and environmental factors. Growing evidence increasingly supports an important role for neuroglial dysfunction, including disturbances in astrocytic, microglial, and oligodendroglial biology, in the pathophysiology [...] Read more.
Pediatric neurodevelopmental disorders (NDDs) encompass a highly heterogeneous group of conditions characterized by complex interactions among genetic, molecular, developmental, and environmental factors. Growing evidence increasingly supports an important role for neuroglial dysfunction, including disturbances in astrocytic, microglial, and oligodendroglial biology, in the pathophysiology of disorders such as autism spectrum disorder, global developmental delay, intellectual disability, and rare neurogenetic syndromes. At the same time, artificial intelligence (AI)-assisted analytical approaches are becoming increasingly relevant in pediatric diagnostics through integration of multidimensional datasets, including clinical phenotypes, neuroimaging, genomic sequencing, and molecular biomarkers. This review examines the evolving intersection of neuroglial biology and AI-based analytical methods in pediatric NDDs. Current understanding of neuroglial mechanisms underlying disease vulnerability and developmental heterogeneity is discussed alongside emerging applications of machine learning, deep phenotyping platforms, radiogenomics, and large language models in diagnostic interpretation and clinical decision support. Important translational and ethical challenges, including algorithmic bias, interpretability limitations, data governance, and disparities in data accessibility, are also considered. Overall, integration of neuroglial research with AI-assisted analytical frameworks may contribute to more biologically informed interpretation of pediatric neurodevelopmental disorders and support ongoing development of increasingly individualized diagnostic approaches. Full article
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11 pages, 4623 KB  
Case Report
From Suspected Congenital Cytomegalovirus Infection to Malan Syndrome: Delayed Genetic Diagnosis Due to Diagnostic Anchoring
by Gordana Kovacevic, Sanja Cirkovic, Gordana Petrovic, Maja Stanojevic, Tanja Lalic, Nikola Ilic, Slavica Ostojic, Marina Siljic, Biljana Alimpic, Milanka Tesic, Predrag Ilic, Jovana Krstic, Jana Cirkovic and Adrijan Sarajlija
Diseases 2026, 14(6), 191; https://doi.org/10.3390/diseases14060191 - 28 May 2026
Viewed by 381
Abstract
Background: Diagnostic anchoring to a presumed infectious etiology may delay recognition of underlying genetic disorders in children with neurodevelopmental impairment. Case presentation: A case of a child with sensorineural hearing loss, visual impairment, and developmental delay is reported; cytomegalovirus (CMV) infection was identified [...] Read more.
Background: Diagnostic anchoring to a presumed infectious etiology may delay recognition of underlying genetic disorders in children with neurodevelopmental impairment. Case presentation: A case of a child with sensorineural hearing loss, visual impairment, and developmental delay is reported; cytomegalovirus (CMV) infection was identified at 6 months of age based on positive serology and detection of viral DNA in serum and urine. Given the timing of testing, congenital CMV infection (cCMV) could not be definitively confirmed. Antiviral therapy with valganciclovir was administered. Despite antiviral treatment, severe neurodevelopmental impairment and hearing loss persisted, associated with facial dysmorphism, bilateral cryptorchidism, pectus excavatum, and optic nerve hypoplasia, findings not fully attributable to CMV infection. Brain magnetic resonance imaging (MRI) showed nonspecific findings. Chromosomal microarray analysis (CMA) performed at 4.5 years of age identified a heterozygous 908 kb de novo microdeletion at 19p13.2p13.13 containing NFIX (MIM *164005) and other morbid genes. The de novo variant was confirmed by parental testing, and the unifying genetic diagnosis of NFIX-related Malan syndrome (MIM#614753) was established. Conclusions: This case emphasizes the importance of reconsidering the initial diagnosis when the clinical phenotype is not fully consistent with an infectious etiology. Early genomic testing, including CMA, may facilitate timely recognition of underlying genetic syndromes in children with complex neurodevelopmental presentations. Full article
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13 pages, 10234 KB  
Case Report
Wiedemann–Steiner Syndrome (WSS): A Neonatal Case Report Expanding the Phenotypic Spectrum of a Previously Reported Missense Variant
by Myrto Poulou, Thessalia Kamilari, Eirini Nikaina, Eleftheria Dikoglou-Tzanetatou, Christina Kanaka-Gantenbein, Aggeliki Kolialexi and Tania Siahanidou
Int. J. Mol. Sci. 2026, 27(10), 4163; https://doi.org/10.3390/ijms27104163 - 7 May 2026
Viewed by 520
Abstract
We present a neonatal case of Wiedemann–Steiner syndrome (WSS) with a de novo, previously reported KMT2A missense variant (c.3464G>A; p.Cys1155Tyr; NM_001197104.2), and provide a focused literature review of this specific variant. WSS (OMIM#605130) is a rare neurodevelopmental disorder caused by heterozygous variants in [...] Read more.
We present a neonatal case of Wiedemann–Steiner syndrome (WSS) with a de novo, previously reported KMT2A missense variant (c.3464G>A; p.Cys1155Tyr; NM_001197104.2), and provide a focused literature review of this specific variant. WSS (OMIM#605130) is a rare neurodevelopmental disorder caused by heterozygous variants in the KMT2A gene, which encodes a histone H3 lysine K4 (H3K4) methyltransferase involved in transcriptional regulation. Clinically, the syndrome is characterized by developmental delay, distinctive facial features, short stature, hypertrichosis, and neurological manifestations such as hypotonia and seizures. In this single-patient report, we describe additional clinical findings, including interstitial lung disease and hypertrophic pyloric stenosis requiring surgical intervention. These may represent rare manifestations of WSS that require confirmation in further reports before a formal expansion of the phenotypic spectrum can be established. Most pathogenic KMT2A variants arise de novo and are typically nonsense or frameshift; however, missense variants have also been reported and may have complex functional consequences. Haploinsufficiency is considered the primary pathogenic mechanism, leading to the disruption of chromatin modification and transcriptional regulation. While emerging genotype–phenotype correlations are being identified, considerable variability remains. Given the single-patient nature of this study, these observations should be considered hypothesis-generating and require confirmation in additional cases. Full article
(This article belongs to the Section Molecular Genetics and Genomics)
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19 pages, 563 KB  
Review
Functional Motor Assessment and Rehabilitation in Joubert Syndrome: A Narrative Review and Conceptual Framework for Pediatric Neurorehabilitation
by Łukasz Mański, Aleksandra Moluszys and Jolanta Wierzba
Children 2026, 13(4), 512; https://doi.org/10.3390/children13040512 - 7 Apr 2026
Cited by 1 | Viewed by 664
Abstract
Background/Objectives: Joubert syndrome (JS) is a rare neurodevelopmental disorder characterized by cerebellar and brainstem malformations, resulting in a complex and heterogeneous motor phenotype. Despite increasing clinical recognition, functional assessment and physiotherapy strategies in this population remain insufficiently characterized. This study aimed to [...] Read more.
Background/Objectives: Joubert syndrome (JS) is a rare neurodevelopmental disorder characterized by cerebellar and brainstem malformations, resulting in a complex and heterogeneous motor phenotype. Despite increasing clinical recognition, functional assessment and physiotherapy strategies in this population remain insufficiently characterized. This study aimed to synthesize current rehabilitation evidence and to propose a conceptual framework for functional motor assessment in children with JS. Methods: A structured narrative review was conducted across PubMed, Scopus, Web of Science, EBSCOhost, the Cochrane Library, and PEDro databases, including studies published between 2000 and 2026. Eligible studies involved pediatric patients (0–18 years) with JS and reported physiotherapy or motor-related outcomes. Data were synthesized descriptively, and recurring functional domains were identified to inform the development of a conceptual framework. Results: Ten studies (eight case reports and two case series) were included. Rehabilitation approaches were heterogeneous and predominantly multidisciplinary, focusing on postural control, trunk stability, and motor milestone acquisition. Functional improvements were reported across studies; however, outcome measures were primarily based on generic pediatric tools such as GMFM-88 and WeeFIM. These tools did not fully capture the multidimensional nature of motor impairment, particularly in relation to regulatory and sensorimotor domains. Evidence also suggested that postural control and gross motor performance may not fully correspond, highlighting additional functional components such as axial control and thoracoabdominal organization. Given the absence of formal risk-of-bias assessment and the low methodological quality of included studies, all findings should be interpreted as exploratory. Conclusions: Current functional assessment in JS may not adequately reflect the interaction between regulatory processes, sensorimotor integration, and motor control. The proposed conceptual framework provides a multidimensional, hypothesis-generating perspective that may support clinical reasoning and physiotherapy planning. Further research is required to validate this framework and to develop more sensitive, syndrome-specific assessment tools. Full article
(This article belongs to the Section Pediatric Neurology & Neurodevelopmental Disorders)
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12 pages, 1485 KB  
Article
Novel Perspectives on ATP8A2 Regulation: Evidence for Parental Imprinting and Chimeric Transcript Formation
by Abdelhamid Bouramtane, Badreddine Elmakhzen, Amal Ouskri, Mohamed Ahakoud, Laila Bouguenouch, Karim Ouldim and Omar Askander
Epigenomes 2026, 10(2), 26; https://doi.org/10.3390/epigenomes10020026 - 6 Apr 2026
Viewed by 666
Abstract
Background: Parental imprinting plays a crucial role in epigenetic regulation and is increasingly recognized for its involvement in neurodevelopmental disorders. Although ATP8A2 is considered a non-imprinted gene; However, the marked phenotypic variability observed across related disorders suggests that additional regulatory layers may [...] Read more.
Background: Parental imprinting plays a crucial role in epigenetic regulation and is increasingly recognized for its involvement in neurodevelopmental disorders. Although ATP8A2 is considered a non-imprinted gene; However, the marked phenotypic variability observed across related disorders suggests that additional regulatory layers may influence its expression. Methods: We investigated the imprinting-like status of ATP8A2 through functional analyses of a splicing variant (c.1580-3C>G) identified in a patient diagnosed with Cerebellar Ataxia, Mental Retardation, and Disequilibrium syndrome type 4 (CAMRQ4). Sanger sequencing was used to assess allelic expression and identify aberrant transcripts. Results: Our analyses revealed an allelic expression imbalance suggestive of parental imprinting of ATP8A2. Moreover, Sanger sequencing led to the identification of a novel ATP8A2RAB3GAP2 chimeric transcript, pointing to a previously unreported transcriptional event, the functional relevance of which remains to be determined. Conclusions: These findings indicate that ATP8A2 may be subject to imprinting-like regulation and involved in atypical splicing events with unknown significance. This highlights the need for further investigation into the epigenetic and transcriptional complexity of ATP8A2-related neurodevelopmental disorders. Full article
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12 pages, 255 KB  
Article
Co-Occurring Genetic Mutations in Rett Syndrome and MECP2-Related Disorders—Clinical and Diagnostic Implications from a Case Series
by Jatinder Singh, Samiya Chishti and Paramala Santosh
Genes 2026, 17(3), 274; https://doi.org/10.3390/genes17030274 - 27 Feb 2026
Viewed by 779
Abstract
Background/Objectives: Factors modulating phenotypic variability in Rett syndrome (RTT, OMIM 312750) include X chromosome inactivation (XCI), type of MECP2 variant, and/or disease modifiers. Emerging evidence also points to multi-locus genetic variants. Understanding the phenotypic variability associated with multi-locus genetic diagnoses in individuals [...] Read more.
Background/Objectives: Factors modulating phenotypic variability in Rett syndrome (RTT, OMIM 312750) include X chromosome inactivation (XCI), type of MECP2 variant, and/or disease modifiers. Emerging evidence also points to multi-locus genetic variants. Understanding the phenotypic variability associated with multi-locus genetic diagnoses in individuals with RTT and MECP2-related disorders would be important not only for accurate diagnosis, risk stratification and clinical management but also to explain symptoms that might not be typically associated with RTT. Methods: We present a case series of five individuals with a diagnosis of RTT or an MECP2-related disorder with co-occurring genetic findings, including pathogenic variants, variants of unknown significance and chromosome duplications. Clinical features such as neurodevelopmental history and comorbid medical conditions were assessed alongside the genetic findings. Results: A review of 200 cases with RTT identified five cases (all females aged 7–27 years) with a co-occurring genetic finding. Each case harboured at least one additional genetic variant that included a beta thalassaemia trait, Calmodulin 3 (CALM3) missense variant, maternally inherited 22q12.3 to q13.1 duplication, 7p14.3 and Dynein Cytoplasmic 1 Heavy Chain 1 (DYNC1H1) variants of uncertain significance and a pathogenic Set Domain-containing protein 5 (SETD5) variant. A rare triple genetic finding was illustrated in a single case, combining MECP2, CALM3, and DYNC1H1 variants. Conclusions: This case series supports the premise that RTT and MECP2-related disorders exist in a more complex neurogenetic spectrum than previously defined. It also emphasises the complexity within MECP2-related disorders. They are not static, and in the context of severe treatment resistant epilepsy, MECP2 disorders can evolve over time, necessitating diagnostic reclassification. Although the co-occurrence of multiple genetic disorders in RTT and MECP2-related disorders is rare, these cases underscore the importance of considering cumulative genetic burden when evaluating individuals with atypical features or evolving neurodevelopmental phenotypes. Full article
(This article belongs to the Special Issue Feature Papers in "Neurogenetics and Neurogenomics": 2026)
18 pages, 401 KB  
Review
Neuropsychiatric Phenotype and Treatment Challenges in 47,XYY Syndrome: A Narrative Review with a Case Series of Adolescents
by Maria Giulia D’Acunto, Chiara Bosetti, Deianira Rinaldi, Marika Ricci, Stefano Berloffa, Gabriele Masi and Maria Mucci
Brain Sci. 2026, 16(2), 232; https://doi.org/10.3390/brainsci16020232 - 15 Feb 2026
Viewed by 1987
Abstract
Background: 47,XYY syndrome is a relatively common sex chromosome aneuploidy that remains largely underdiagnosed. While its somatic phenotype is often mild, growing evidence indicates a substantial burden of neurodevelopmental and psychiatric morbidity. However, the characterization of the neuropsychiatric phenotype across development, particularly during [...] Read more.
Background: 47,XYY syndrome is a relatively common sex chromosome aneuploidy that remains largely underdiagnosed. While its somatic phenotype is often mild, growing evidence indicates a substantial burden of neurodevelopmental and psychiatric morbidity. However, the characterization of the neuropsychiatric phenotype across development, particularly during adolescence, and the associated treatment challenges remain incomplete. Objectives: To provide a comprehensive narrative review of the neuropsychiatric phenotype of 47,XYY syndrome and to illustrate clinical complexity and treatment response through a case series of adolescents. Methods: A narrative review of the literature was conducted focusing on genetics, neurodevelopmental and psychiatric features, neuroimaging and neurophysiology findings, clinical course, and management strategies in 47,XYY syndrome. This review is complemented by a case series of adolescents with confirmed 47,XYY karyotype, evaluated for developmental history, psychiatric comorbidity and response to pharmacological and non-pharmacological interventions. Results: The literature consistently describes increased risks of language impairment, executive dysfunction, ADHD, autism spectrum traits, and emotional and behavioral dysregulation in males with 47,XYY syndrome. Psychiatric vulnerability appears to increase during adolescence and adulthood, with elevated rates of mood, psychotic, and substance use disorders. The presented cases illustrate a convergent clinical trajectory marked by early developmental delays, progressive behavioral dysregulation in adolescence and limited or inconsistent response to multiple classes of psychotropic medications, suggesting a pattern of pharmacoresistance in a subset of patients. Conclusions: 47,XYY syndrome is associated with a distinct and heterogeneous neuropsychiatric phenotype that extends beyond early neurodevelopmental disorders. Early diagnosis alone may be insufficient to prevent severe psychiatric outcomes, highlighting the need for long-term monitoring and integrated, multidisciplinary management. Further research is required to identify early predictors of high-risk trajectories and to optimize treatment strategies for this population. Full article
(This article belongs to the Special Issue Rethinking Neurodevelopmental Disorders: Beyond One-Size-Fits-All)
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12 pages, 1239 KB  
Case Report
A Complex Case of Langer–Giedion Syndrome, Cornelia de Lange Syndrome Type 4, and Hereditary Multiple Osteochondromas with Mosaic 8q23.1–q24.12 Deletion
by Samuel David Amio Valientes and Hua Wang
Genes 2026, 17(2), 175; https://doi.org/10.3390/genes17020175 - 31 Jan 2026
Viewed by 974
Abstract
Langer–Giedion syndrome (LGS), also known as trichorhinophalangeal syndrome type II (TRPS II; OMIM #150230), is a contiguous-gene deletion disorder caused by haploinsufficiency of TRPS1 and EXT1. Cornelia de Lange syndrome (CdLS) is genetically heterogeneous; heterozygous variants in RAD21 cause the milder CdLS [...] Read more.
Langer–Giedion syndrome (LGS), also known as trichorhinophalangeal syndrome type II (TRPS II; OMIM #150230), is a contiguous-gene deletion disorder caused by haploinsufficiency of TRPS1 and EXT1. Cornelia de Lange syndrome (CdLS) is genetically heterogeneous; heterozygous variants in RAD21 cause the milder CdLS type 4 phenotype (OMIM #614701). Because RAD21 lies between TRPS1 and EXT1, overlapping phenotypes may arise when all three genes are deleted. We report a unique case of a 4-year-old female presenting with a blended phenotype of Langer–Giedion Syndrome (LGS) and Cornelia de Lange Syndrome (CdLS) type 4. This case is distinct from previously reported 8q deletions in three key aspects: (1) Complex Genomic Architecture: Chromosomal microarray revealed a novel complex rearrangement consisting of a 13.01 Mb mosaic interstitial deletion at 8q23.1–q24.12, flanked by two large duplications (21.5 Mb at 8q11.23–q23.1 and 25.78 Mb at 8q24.12–q24.3). (2) Rare Mosaicism: This represents only the second reported case of mosaicism affecting this contiguous gene region. Notably, the patient demonstrates a “mosaic rescue” effect, where the mosaicism appears to have mitigated the neurodevelopmental phenotype (the patient is bilingual and ambulatory) while failing to protect the skeleton. (3) First Bone-Specific Therapy: The patient suffered from severe, recurrent fractures due to a synergistic “double hit” of TRPS1-related osteopenia and EXT1-related exostoses. We report the first successful use of bisphosphonate therapy (pamidronate) in this specific mosaic profile, which resulted in a complete cessation of fractures during a 12-month follow-up. This case underscores the utility of detailed microarray analysis in complex phenotypes and suggests bisphosphonates as a viable rescue therapy for refractory syndromic osteoporosis. Full article
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9 pages, 208 KB  
Review
Genomics of Complex Neurodevelopmental Disorders with Variable Epilepsy Phenotypes: A Clinical Review of Dup15q Syndrome
by Drew Thodeson, Trevor Lockard and Sookyong Koh
Genes 2026, 17(2), 163; https://doi.org/10.3390/genes17020163 - 30 Jan 2026
Viewed by 1153
Abstract
Background: Complex neurodevelopmental disorders frequently reflect multiple neurologic symptoms which have shared molecular and network level mechanisms. Advances in genomic medicine have redefined these conditions as overlapping manifestations of brain circuit dysfunction with significant variability. This review examines the intersection of genomics, epilepsy, [...] Read more.
Background: Complex neurodevelopmental disorders frequently reflect multiple neurologic symptoms which have shared molecular and network level mechanisms. Advances in genomic medicine have redefined these conditions as overlapping manifestations of brain circuit dysfunction with significant variability. This review examines the intersection of genomics, epilepsy, and neurodevelopment in complex neurodevelopmental disorders, emphasizing Dup15q syndrome as a model for understanding phenotypic variability. Methods: Authors conducted a clinical (non-systematic) review of the literature based on their experience with three patients with Dup15q who responded dramatically to neurostimulation. We synthesized current literature on genomic mechanisms underlying complex neurodevelopmental disorders focusing on Dup15q syndrome and its subtypes—int15, idic15, and mosaic idic15. We integrated clinical, electrophysiologic, and molecular data to illustrate the spectrum of epilepsy phenotypes and their mechanistic underpinnings. Results: Dup15q syndrome demonstrates marked heterogeneity in epilepsy severity and seizure semiology, reflecting variable gene dosing effects, maternal imprinting of UBE3A, and altered GABAergic signaling. While idic15 is more strongly associated with refractory epilepsy and SUDEP, both idic15 and int15 subtypes show overlapping developmental and behavioral phenotypes. There is a well-known differential response to anti-seizure medications and emerging evidence for neurostimulation and precision medicine. Conclusion: Dup15q syndrome exemplifies the convergence of genomic, neurophysiologic, and developmental pathways in epilepsy. As genomic discovery expands, precision therapies will increasingly rely on collaborative research networks. Understanding the genomic architecture of Dup15q syndrome may inform personalized strategies for epilepsy treatment and prevention. Full article
(This article belongs to the Section Neurogenomics)
12 pages, 630 KB  
Case Report
A Clinical Practice Example of Smith–Magenis Syndrome in the Neuropediatric Clinic: Etiology, Clinical Presentation, Diagnostics and Therapeutic Approaches—A Case Report
by Oleksandr Shevchenko
Children 2026, 13(2), 179; https://doi.org/10.3390/children13020179 - 28 Jan 2026
Viewed by 779
Abstract
Background/Objectives: Smith–Magenis syndrome (SMS) is a rare neurogenetic disorder caused by a microdeletion in chromosome region 17p11.2 or by pathogenic variants in the RAI1 gene. The syndrome is characterized by a distinctive neurobehavioral profile, including cognitive deficits, sleep disturbances, self-injurious behavior, and typical [...] Read more.
Background/Objectives: Smith–Magenis syndrome (SMS) is a rare neurogenetic disorder caused by a microdeletion in chromosome region 17p11.2 or by pathogenic variants in the RAI1 gene. The syndrome is characterized by a distinctive neurobehavioral profile, including cognitive deficits, sleep disturbances, self-injurious behavior, and typical dysmorphic features. A characteristic diagnostic hallmark is paradoxical melatonin secretion, with increased daytime levels instead of the normal nocturnal peak. This article aims to summarize current knowledge on the etiology, diagnostics, EEG findings, therapy, and prognosis of SMS from a neuropediatric perspective. Methods: A narrative review of the literature on Smith–Magenis syndrome was conducted, focusing on genetic background, clinical features, diagnostic approaches, EEG characteristics, therapeutic strategies, and prognosis. In addition, a detailed clinical case of a 16-year-old female patient with SMS is presented. Results: The reviewed data confirm that SMS is associated with characteristic neurobehavioral abnormalities and sleep–wake rhythm disturbances. EEG findings may include epileptiform activity without overt epilepsy. In the presented case, “Rolandic-type” spike–sharp wave complexes were observed on EEG and are interpreted as an expression of congenital disturbances in brain maturation processes. Therapeutic recommendations addressing behavioral symptoms and sleep regulation are discussed. Conclusions: Smith–Magenis syndrome represents a complex neurodevelopmental disorder with distinctive clinical, neurophysiological, and genetic features. Early recognition of characteristic signs, including sleep disturbances and EEG abnormalities, is essential for appropriate management. A multidisciplinary, individualized therapeutic approach may improve quality of life and long-term outcomes. Full article
(This article belongs to the Special Issue Current Advances in Paediatric Sleep Medicine (2nd Edition))
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14 pages, 4301 KB  
Article
Transcriptome- and Epigenome-Wide Association Studies of Tic Spectrum Disorder in Discordant Monozygotic Twins
by Jonas Dalsberg, Cathrine Jespersgaard, Amanda M. Levy, Anna Maria Asplund, Frederik Otzen Bagger, Nanette M. Debes, Qihua Tan, Zeynep Tümer and Mathis Hildonen
Genes 2026, 17(1), 97; https://doi.org/10.3390/genes17010097 - 18 Jan 2026
Viewed by 820
Abstract
Background: Tic spectrum disorder (TSD), encompassing Tourette syndrome and chronic tic disorder, is a childhood-onset neurodevelopmental condition with complex genetic and environmental contributions. Heritable components have been implicated in TSD, but no clear genetic mechanisms have been identified. Significant aspects of TSD [...] Read more.
Background: Tic spectrum disorder (TSD), encompassing Tourette syndrome and chronic tic disorder, is a childhood-onset neurodevelopmental condition with complex genetic and environmental contributions. Heritable components have been implicated in TSD, but no clear genetic mechanisms have been identified. Significant aspects of TSD etiology remain unclear, with key uncertainties concerning the role of environmental influences in its development. In this study, we aimed to identify environmentally induced epigenomic and transcriptomic changes contributing to TSD pathology by investigating genetically similar monozygotic twins discordant for TSD. Methods: To investigate environmentally driven mechanisms, we analyzed peripheral blood from eleven monozygotic twin pairs, either discordant or concordant for TSD, using RNA sequencing and DNA methylation analysis. Results: Differential expression analysis identified a dozen differentially expressed genes between TSD and non-TSD individuals, most of which were long non-coding RNAs or pseudogenes. Expression of the small RNA gene RNY1 was significantly associated with tic severity, suggesting involvement of immune-related processes. DNA methylation (DNAm) analysis revealed ~30,000 probes with a nominal p < 0.05, however none of these were significant after multiple testing correction. Expression quantitative trait methylation (eQTM) analysis identified 236 methylation-associated genes. Gene set enrichment analysis demonstrated broad downregulation in TSD individuals for pathways related to translation, RNA processing, and neurobiological functions, with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways including ribosome, nucleocytoplasmic transport, pluripotency signaling, and nicotine addiction. Conclusions: These results suggest that environmentally influenced gene expression may contribute to TSD pathogenesis through dysregulation of immune and neuronal pathways. Despite a small sample size, the monozygotic twin design provides strong control for genetic background and identifies significant differences that contribute to the understanding of the underlying molecular mechanisms of TSD. Full article
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13 pages, 1015 KB  
Case Report
Adams–Oliver Syndrome Type 3: A Case Report of Concurrent RBPJ, CACNA1A, and Double-Heterozygous MTHFR Variants
by Grațian Cosmin Damian, Valerica Belengeanu, Cristina Popescu, Diana Marian, Ramona Amina Popovici and Carolina Cojocariu
Diagnostics 2026, 16(2), 274; https://doi.org/10.3390/diagnostics16020274 - 15 Jan 2026
Viewed by 681
Abstract
Background and Clinical Significance: Adams–Oliver syndrome type 3 (AOS3) is a rare congenital disorder typically characterised by terminal transverse limb defects and variable involvement of other organ systems. Although pathogenic variants in RBPJ are well established in AOS3, associated neurodevelopmental or psychiatric [...] Read more.
Background and Clinical Significance: Adams–Oliver syndrome type 3 (AOS3) is a rare congenital disorder typically characterised by terminal transverse limb defects and variable involvement of other organ systems. Although pathogenic variants in RBPJ are well established in AOS3, associated neurodevelopmental or psychiatric features have been only sporadically documented. Case Presentation: We describe a male patient first evaluated at the age of 10 years and subsequently re-evaluated at 14 years, with AOS3 presenting terminal limb defects together with autistic-like behaviour, cognitive difficulties, dyslexia, and recurrent depressive symptoms. Whole-exome sequencing (WES) identified a heterozygous pathogenic variant in RBPJ (c.505A>G; p.Lys169Glu), confirming the molecular diagnosis of autosomal dominant AOS3. Additional findings included a heterozygous missense variant in CACNA1A (p.Arg1678Cys), a gene linked to neurological disorders with broad phenotypic variability. Because of elevated homocysteine levels, the patient was also tested for MTHFR variants and was found to be heterozygous for C677T and A1298C. Conclusions: This case illustrates a rare combination of a validated AOS3-associated RBPJ variant, along with additional CACNA1A and MTHFR variants that may influence the patient’s neurocognitive and psychiatric characteristics. The results underscore the importance of comprehensive genetic testing in atypical AOS presentations and highlight the complexity of interpreting overlapping genetic factors. Full article
(This article belongs to the Section Medical Imaging and Theranostics)
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8 pages, 901 KB  
Case Report
Beyond Neurodevelopmental Delay: BICRA-Related Coffin–Siris Syndrome 12 with Severe Intestinal Dysmotility and Recurrent Pneumothorax
by Hua Wang
Genes 2026, 17(1), 81; https://doi.org/10.3390/genes17010081 - 11 Jan 2026
Viewed by 1148
Abstract
Background: Coffin–Siris syndrome 12 (CSS12) is a recently described neurodevelopmental disorder caused by heterozygous pathogenic variants in BICRA, a gene encoding a core subunit of the non-canonical BAF (ncBAF) chromatin-remodeling complex. The condition is characterized by developmental delay, hypotonia, hypertrichosis, and joint [...] Read more.
Background: Coffin–Siris syndrome 12 (CSS12) is a recently described neurodevelopmental disorder caused by heterozygous pathogenic variants in BICRA, a gene encoding a core subunit of the non-canonical BAF (ncBAF) chromatin-remodeling complex. The condition is characterized by developmental delay, hypotonia, hypertrichosis, and joint laxity. However, long-term data remain limited, and systemic manifestations are incompletely defined. Case Description: We report a 22-year-old male with a de novo BICRA frameshift variant, c.2479_2480delinsA (p.Ala827Thrfs*15), previously included in the original cohort reported by Barish et al. Longitudinal follow-up revealed an expanded phenotype extending beyond neurodevelopmental features. Early findings included global developmental delay, growth hormone deficiency, short stature, and joint hypermobility. In adolescence and adulthood, he developed severe intestinal dysmotility requiring total colectomy, recurrent spontaneous pneumothoraces from bilateral apical bullous disease, and portal-vein thrombosis, representing visceral and vascular complications not previously emphasized in BICRA-related disorders. The identified BICRA variant truncates the coiled-coil domain critical for BRD9/BRD4 interaction, consistent with a loss-of-function mechanism. The patient’s systemic features suggest that BICRA haploinsufficiency affects not only neurodevelopmental pathways but also smooth-muscle and connective-tissue integrity. Conclusions: This case expands the phenotypic spectrum of BICRA-related CSS12, demonstrating that visceral and vascular involvement can occur alongside neurodevelopmental and connective-tissue features. Recognition of these broader manifestations underscores the need for lifelong multidisciplinary surveillance and contributes to understanding the diverse biological roles of the ncBAF complex in human development. Full article
(This article belongs to the Section Genetic Diagnosis)
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18 pages, 6272 KB  
Article
Using Virtual Reality to Promote Cognitive Engagement in Rett Syndrome: Eye-Tracking Evidence from Immersive Forest Tasks
by Rosa Angela Fabio, Michela Perina, Andrea Nucita, Giancarlo Iannizzotto and Martina Semino
Appl. Sci. 2026, 16(2), 626; https://doi.org/10.3390/app16020626 - 7 Jan 2026
Viewed by 941
Abstract
Rett syndrome (RTT) is a rare neurodevelopmental disorder that causes severe motor and cognitive impairments, limiting voluntary communication. Gaze-based technologies and virtual reality (VR) offer innovative ways to assess and enhance attention, happiness, and learning in individuals with minimal motor control. This study [...] Read more.
Rett syndrome (RTT) is a rare neurodevelopmental disorder that causes severe motor and cognitive impairments, limiting voluntary communication. Gaze-based technologies and virtual reality (VR) offer innovative ways to assess and enhance attention, happiness, and learning in individuals with minimal motor control. This study investigated and compared visual-attentional and emotional engagement in girls with RTT and typically developing (TD) peers during exploration of a virtual forest presented in 2D and immersive 3D (VR) formats across four progressively complex tasks. Twelve girls with RTT and 12 TD peers completed eye-tracking tasks measuring reaction time, fixation duration, disengagement events, and observed happiness. Girls with RTT showed slower responses and more disengagements overall, but VR significantly improved attentional efficiency in both groups, resulting in faster reaction times (η2p = 0.36), longer fixations (η2p = 0.31), and fewer disengagements (η2p = 0.27). These effects were stronger in the RTT group. Both groups also showed greater happiness in VR settings (RTT: p = 0.011; TD: p = 0.015), and in participants with RTT, peaks in attention coincided with peak happiness, indicating a link between happiness and cognitive engagement. Immersive VR thus appears to enhance attention and affect in RTT, supporting its integration into personalized neurorehabilitation. Full article
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