Search

Neurofibromatosis type 1 (NF1) is a neurocutaneous genetic disorder with a broad spectrum of associated signs and symptoms, including skeletal anomalies. The association of NF1 with anterior chest wall deformities has been recently reported, especially the pectus excavatum (PE). Over the years, several authors have suggested loss of heterozygosity (LOH) as the possible pathogenic mechanism underlying the development of the typical NF1 skeletal features. Here, we report a NF1 patient with severe chest deformity and harboring the germline heterozygous pathogenic NF1 variant NM_001042492.3: c.4271delC p.(Ala1424Glufs ∗ 4). Through next-generation sequencing (NGS), we investigated the affected cartilage from the PE deformity and identified the additional frameshift variant NM_001042492.3: c.2953delC p.(Gln985Lysfs ∗ 7), occurring as a somatic NF1 second hit mutation. Exome sequencing confirmed the absence of additional variants of potential pathogenic relevance. Western blot analysis showed the absence of wild-type NF1 protein in the cartilage of the patient, consistent with a somatic double inactivation (SDI) of NF1. Taken together, our findings support the role of SDI in NF1-related PE, widening the spectrum of the pathophysiological mechanisms involved in NF1-related skeletal features.

Background and ObjectivesClinical manifestations in STXBP1 developmental and epileptic encephalopathy (DEE) vary in severity and outcome, and the genotypic spectrum is diverse. We aim to trace the neurodevelopmental trajectories in individuals with STXBP1-DEE and dissect the relationship between neurodevelopment and epilepsy.MethodsRetrospective standardized clinical data were collected through international collaboration. A composite neurodevelopmental score system compared the developmental trajectories in STXBP1-DEE.ResultsForty-eight patients with de novo STXBP1 variants and a history of epilepsy were included (age range at the time of the study: 10 months to 35 years, mean 8.5 years). At the time of inclusion, 65% of individuals (31/48) had active epilepsy, whereas 35% (17/48) were seizure free, and 76% of those (13/17) achieved remission within the first year of life. Twenty-two individuals (46%) showed signs of developmental impairment and/or neurologic abnormalities before epilepsy onset. Age at seizure onset correlated with severity of developmental outcome and the developmental milestones achieved, with a later seizure onset associated with better developmental outcome. In contrast, age at seizure remission and epilepsy duration did not affect neurodevelopmental outcomes. Overall, we did not observe a clear genotype-phenotype correlation, but monozygotic twins with de novo STXBP1 variant showed similar phenotype and parallel disease course.DiscussionThe disease course in STXBP1-DEE presents with 2 main trajectories, with either early seizure remission or drug-resistant epilepsy, and a range of neurodevelopmental outcomes from mild to profound intellectual disability. Age at seizure onset is the only epilepsy-related feature associated with neurodevelopment outcome. These findings can inform future dedicated natural history studies and trial design.

EEG anomalies and epilepsy are a not so rare clinical manifestation in patients with Phosphatase and tensin homolog (PTEN) variants. The main aim of this study is to analyze the characteristics of EEG traces, neuroimaging findings and epilepsy to better define the neurological aspects in a set of patients with PTEN variants collected in four Italian Centres. As a secondary aim, we describe the neurodevelopmental profile and the psychiatric comorbidities of this cohort.Patients with PTEN variants, identified by Sanger sequencing or target resequencing, were enrolled. For each subjects, clinical data were retrospectively extracted from medical charts, with a focus on epilepsy and neuroimaging data.54 patients with PTEN variants were enrolled, with a mean age of 18.8 years. 72.2% have at least one psychiatric diagnosis, being Autism Spectrum Disorder and Intellectual Disability the most frequent diagnosis (29 and 25 cases, respectively). 22 subjects show an abnormal EEG and 8 received a diagnosis of epilepsy, mainly focal epilepsy (7/8), with a mean age at seizure onset of 3.8 years. 3/8 subjects have a drug resistant epilepsy, independently from the underlying neuroimaging pattern. The finding of a Focal cortical dysplasia is significantly associated with both an abnormal EEG (p = 0.02) and the occurrence of seizures (p = 0.002).EEG should be taken into consideration in the first-line diagnostic flowchart of subjects with PTEN variants. The onset of a focal epilepsy, independently from its response to antiepileptic drugs, highly recommends to carry out a neuroimaging exam.

Alternative splicing (AS) is crucial for cell-type-specific gene transcription and plays a critical role in neuronal differentiation and synaptic plasticity. De novo frameshift variants in NOVA2, encoding a neuron-specific key splicing factor, have been recently associated with a new neurodevelopmental disorder (NDD) with hypotonia, neurological features, and brain abnormalities. We investigated eight unrelated individuals by exome sequencing (ES) and identified seven novel pathogenic NOVA2 variants, including two with a novel localization at the KH1 and KH3 domains. In addition to a severe NDD phenotype, novel clinical features included psychomotor regression, attention deficit-hyperactivity disorder (ADHD), dyspraxia, and urogenital and endocrinological manifestations. To test the effect of the variants on splicing regulation, we transfected HeLa cells with wildtype and mutant NOVA2 complementary DNA (cDNA). The novel variants NM_002516.4:c.754_756delCTGinsTT p.(Leu252Phefs*144) and c.1329dup p.(Lys444Glnfs*82) all negatively affected AS events. The distal p.(Lys444Glnfs*82) variant, causing a partial removal of the KH3 domain, had a milder functional effect leading to an intermediate phenotype. Our findings expand the molecular and phenotypic spectrum of NOVA2-related NDD, supporting the pathogenic role of AS disruption by truncating variants and suggesting that this is a heterogeneous condition with variable clinical course.

Contactin-associated protein-like 2 (CNTNAP2) gene encodes for CASPR2, a presynaptic type 1 transmembrane protein, involved in cell–cell adhesion and synaptic interactions. Biallelic CNTNAP2 loss has been associated with “Pitt-Hopkins-like syndrome-1” (MIM#610042), while the pathogenic role of heterozygous variants remains controversial. We report 22 novel patients harboring mono- (n = 2) and bi-allelic (n = 20) CNTNAP2 variants and carried out a literature review to characterize the genotype–phenotype correlation. Patients (M:F 14:8) were aged between 3 and 19 years and affected by global developmental delay (GDD) (n = 21), moderate to profound intellectual disability (n = 17) and epilepsy (n = 21). Seizures mainly started in the first two years of life (median 22.5 months). Antiseizure medications were successful in controlling the seizures in about two-thirds of the patients. Autism spectrum disorder (ASD) and/or other neuropsychiatric comorbidities were present in nine patients (40.9%). Nonspecific midline brain anomalies were noted in most patients while focal signal abnormalities in the temporal lobes were noted in three subjects. Genotype–phenotype correlation was performed by also including 50 previously published patients (15 mono- and 35 bi-allelic variants). Overall, GDD (p p p = 0.012), ASD (p = 0.009), language impairment (p = 0.020) and severe cognitive impairment (p = 0.031) were significantly associated with the presence of biallelic versus monoallelic variants. We have defined the main features associated with biallelic CNTNAP2 variants, as severe cognitive impairment, epilepsy and behavioral abnormalities. We propose CASPR2-deficiency neurodevelopmental disorder as an exclusively recessive disease while the contribution of heterozygous variants is less likely to follow an autosomal dominant inheritance pattern.

PURPOSECoffin-Siris and Nicolaides-Baraitser syndromes, are recognisable neurodevelopmental disorders caused by germline variants in BAF complex subunits. TheSMARCC2BAFopathy was recently reported. Herein, we present clinical and molecular data on a large cohort.METHODSClinical symptoms for 41 novel and 24 previously published cases were analyzed using the Human Phenotype Ontology. For genotype-phenotype correlation, molecular data were standardized and grouped into non-truncating and likely gene-disrupting variants (LGD). Missense variant protein expression and BAF subunit interactions were examined using 3D protein modeling, co-immunoprecipitation, and proximity-ligation assays.RESULTSNeurodevelopmental delay with intellectual disability, muscular hypotonia and behavioral disorders were the major manifestations. Clinical hallmarks of BAFopathies were rare. Clinical presentation differed significantly, with LGD variants being predominantly inherited and associated with mildly reduced or normal cognitive development, while non-truncating variants were mostlyde novoand presented with severe developmental delay. These distinct manifestations and non-truncating variant clustering in functional domains suggest different pathomechanisms.In vitrotesting showed decreased protein expression for N-terminal missense variants similar to LGD.CONCLUSIONThis study improvedSMARCC2variant classification and identified discernibleSMARCC2-associated phenotypes for LGD and non-truncating variants, which were distinct from other BAFopathies. The pathomechanism of most non-truncating variants has yet to be investigated.

Neurofibromatosis type 1 (NF1) is a neurocutaneous disorder caused by mutations in NF1 gene, coding for neurofibromin 1. NF1 can be associated with Moyamoya disease (MMD), and this association, typical of paediatric patients, is referred to as Moyamoya syndrome (MMS). MMD is a cerebral arteriopathy characterized by the occlusion of intracranial arteries and collateral vessel formation, which increase the risk of ischemic and hemorrhagic events. RNF213 gene mutations have been associated with MMD, so we investigated whether rare variants of RNF213 could act as genetic modifiers of MMS phenotype in a pediatric cohort of 20 MMS children, 25 children affected by isolated MMD and 47 affected only by isolated NF1. By next-generation re-sequencing (NGS) of patients’ DNA and gene burden tests, we found that RNF213 seems to play a role only for MMD occurrence, while it does not appear to be involved in the increased risk of Moyamoya for MMS patients. We postulated that the loss of neurofibromin 1 can be enough for the excessive proliferation of vascular smooth muscle cells, causing Moyamoya arteriopathy associated with NF1. Further studies will be crucial to support these findings and to elucidate the possible role of other genes, enhancing our knowledge about pathogenesis and treatment of MMS.

Chromatinopathy; Syndromic neurodevelopmental disorder; Syndromic obesity Cromatinopatia; Trastorn sindròmic del neurodesenvolupament; Obesitat sindròmica Cromatinopatía; Trastorno sindrómico del neurodesarrollo; Obesidad sindrómica Purpose Protein arginine methyltransferase 7 (PRMT7) is a member of a family of enzymes that catalyzes the methylation of arginine residues on several protein substrates. Biallelic pathogenic PRMT7 variants have previously been associated with a syndromic neurodevelopmental disorder characterized by short stature, brachydactyly, intellectual developmental disability, and seizures. To our knowledge, no comprehensive study describes the detailed clinical characteristics of this syndrome. Thus, we aim to delineate the phenotypic spectrum of PRMT7-related disorder. Methods We assembled a cohort of 51 affected individuals from 39 different families, gathering clinical information from 36 newly described affected individuals and reviewing data of 15 individuals from the literature. Results The main clinical characteristics of the PRMT7-related syndrome are short stature, mild to severe developmental delay/intellectual disability, hypotonia, brachydactyly, and distinct facial morphology, including bifrontal narrowing, prominent supraorbital ridges, sparse eyebrows, short nose with full/broad nasal tip, thin upper lip, full and everted lower lip, and a prominent or squared-off jaw. Additional variable findings include seizures, obesity, nonspecific magnetic resonance imaging abnormalities, eye abnormalities (i.e., strabismus or nystagmus), and hearing loss. Conclusion This study further delineates and expands the molecular, phenotypic spectrum and natural history of PRMT7-related syndrome characterized by a neurodevelopmental disorder with skeletal, growth, and endocrine abnormalities. The authors thank all patients and families for participation in this study. Part of this research was possible thanks to the Deciphering Developmental Disorders study. The Deciphering Developmental Disorders study presents independent research commissioned by the Health Innovation Challenge Fund (grant number HICF-1009-003). This study makes use of DECIPHER (http://www.deciphergenomics.org), which is funded by Wellcome. See www.ddduk.org/access.html for full acknowledgment. This study was also supported by the Wellcome Trust (WT093205MA and WT104033AIA to H.H. and 203141/Z/16/Z to M.P.F. and J.C.T.), Medical Research Council (H.H.), European Community’s Seventh Framework Programme (FP7/2007-2013, under grant agreement No. 2012-305121 to H.H.), the National Institute for Health Research (NIHR), University College London Hospitals, Biomedical Research Centre, and Fidelity Foundation. The Yale Center for Mendelian Genomics (UM1HG006504) is funded by the National Human Genome Research Institute. D.B. is supported by NIHR Research Professorship (RP-2016-07-011). F.L. and A.G. received funding from European Union and Région Normandie in the context of Recherche Innovation Normandie 2018. Europe gets involved in Normandie with the European Regional Development Fund. The authors thank the families and KFMC Research Centre for the partial support (Intramural Research Fund; Demography of Recessive Diseases in KSA; Grant No. 019-052). This work was also supported by King Salman Center for Disability research through Research Group RG-2022-010.

Early-onset myopathy, areflexia, respiratory distress, and dysphagia (EMARDD) is caused by homozygous or compound heterozygous mutation in the

ADGRL1/latrophilin-1, a well-characterized adhesion G protein-coupled receptor, has been implicated in synaptic development, maturation and activity. However, the role of ADGRL1 in human disease has been elusive. Here, we describe 10 individuals with variable neurodevelopmental features including developmental delay, intellectual disability, attention deficit hyperactivity and autism spectrum disorders, and epilepsy, all featuring heterozygous variants in ADGRL1. In vitro, human ADGRL1 variants expressed in neuroblastoma cells showed faulty ligand-induced regulation of intracellular Ca2+ influx, consistent with haploinsufficiency. In vivo, Adgrl1 was knocked out in mice and studied on two genetic backgrounds. On a non-permissive background, mice carrying a heterozygous Adgrl1 null allele exhibited neurological and developmental abnormalities while homozygous mice were non-viable. On a permissive background, the null allele also appeared at sub-Mendelian frequency, but many Adgrl1 null mice survived the gestation and reached adulthood. The Adgrl1-/- mice demonstrated stereotypic behaviors, sexual dysfunction, bimodal extremes of locomotion, augmented startle reflex and attenuated pre-pulse inhibition, which responded to risperidone. Ex vivo synaptic preparations displayed increased spontaneous exocytosis of dopamine, acetylcholine and glutamate, but Adgrl1-/- neurons formed synapses in vitro poorly. Overall, our findings demonstrate that ADGRL1 haploinsufficiency leads to consistent developmental, neurological and behavioral abnormalities in mice and humans.

© The Author(s) 2022. Open Access This article is licensed under a Creative Commons Attri- bution 4.0 International License, which permits use, sharing, adapta- tion, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/., Purpose: There is limited data concerning neuroimaging findings and longitudinal evaluation of familial cerebral cavernous malformations (FCCM) in children. Our aim was to study the natural history of pediatric FCCM, with an emphasis on symptomatic hemorrhagic events and associated clinical and imaging risk factors. Methods: We retrospectively reviewed all children diagnosed with FCCM in four tertiary pediatric hospitals between January 2010 and March 2022. Subjects with first available brain MRI and [Formula: see text] 3 months of clinical follow-up were included. Neuroimaging studies were reviewed, and clinical data collected. Annual symptomatic hemorrhage risk rates and cumulative risks were calculated using survival analysis and predictors of symptomatic hemorrhagic identified using regression analysis. Results: Forty-one children (53.7% males) were included, of whom 15 (36.3%) presenting with symptomatic hemorrhage. Seven symptomatic hemorrhages occurred during 140.5 person-years of follow-up, yielding a 5-year annual hemorrhage rate of 5.0% per person-year. The 1-, 2-, and 5-year cumulative risks of symptomatic hemorrhage were 7.3%, 14.6%, and 17.1%, respectively. The latter was higher in children with prior symptomatic hemorrhage (33.3%), CCM2 genotype (33.3%), and positive family history (20.7%). Number of brainstem (adjusted hazard ratio [HR] = 1.37, P = 0.005) and posterior fossa (adjusted HR = 1.64, P = 0.004) CCM at first brain MRI were significant independent predictors of prospective symptomatic hemorrhage. Conclusion: The 5-year annual and cumulative symptomatic hemorrhagic risk in our pediatric FCCM cohort equals the overall risk described in children and adults with all types of CCM. Imaging features at first brain MRI may help to predict potential symptomatic hemorrhage at 5-year follow-up.

© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2022, Purpose: The aim of the study was to assess the prevalence and characteristics of spinal cord cavernous malformations (SCCM) and intraosseous spinal vascular malformations (ISVM) in a pediatric familial cerebral cavernous malformation (FCCM) cohort and evaluate clinico-radiological differences between children with (SCCM +) and without (SCCM-) SCCM. Methods: All patients with a pediatric diagnosis of FCCM evaluated at three tertiary pediatric hospitals between January 2010 and August 2021 with [Formula: see text] 1 whole spine MR available were included. Brain and spine MR studies were retrospectively evaluated, and clinical and genetic data collected. Comparisons between SCCM + and SCCM- groups were performed using student-t/Mann-Whitney or Fisher exact tests, as appropriate. Results: Thirty-one children (55% boys) were included. Baseline spine MR was performed (mean age = 9.7 years) following clinical manifestations in one subject (3%) and as a screening strategy in the remainder. Six SCCM were detected in five patients (16%), in the cervico-medullary junction (n = 1), cervical (n = 3), and high thoracic (n = 2) regions, with one appearing during follow-up. A tendency towards an older age at first spine MR (P = 0.14) and [Formula: see text] 1 posterior fossa lesion (P = 0.13) was observed in SCCM + patients, lacking statistical significance. No subject demonstrated ISVM. Conclusion: Although rarely symptomatic, SCCM can be detected in up to 16% of pediatric FCCM patients using diverse spine MR protocols and may appear de novo. ISVM were instead absent in our cohort. Given the relative commonality of asymptomatic SCCM, serial screening spine MR should be considered in FCCM starting in childhood.

Contains fulltext : 283128.pdf (Publisher’s version ) (Open Access) Developmental and epileptic encephalopathy 35 (DEE 35) is a severe neurological condition caused by biallelic variants in ITPA, encoding inosine triphosphate pyrophosphatase, an essential enzyme in purine metabolism. We delineate the genotypic and phenotypic spectrum of DEE 35, analyzing possible predictors for adverse clinical outcomes. We investigated a cohort of 28 new patients and reviewed previously described cases, providing a comprehensive characterization of 40 subjects. Exome sequencing was performed to identify underlying ITPA pathogenic variants. Brain MRI (magnetic resonance imaging) scans were systematically analyzed to delineate the neuroradiological spectrum. Survival curves according to the Kaplan-Meier method and log-rank test were used to investigate outcome predictors in different subgroups of patients. We identified 18 distinct ITPA pathogenic variants, including 14 novel variants, and two deletions. All subjects showed profound developmental delay, microcephaly, and refractory epilepsy followed by neurodevelopmental regression. Brain MRI revision revealed a recurrent pattern of delayed myelination and restricted diffusion of early myelinating structures. Congenital microcephaly and cardiac involvement were statistically significant novel clinical predictors of adverse outcomes. We refined the molecular, clinical, and neuroradiological characterization of ITPase deficiency, and identified new clinical predictors which may have a potentially important impact on diagnosis, counseling, and follow-up of affected individuals.

Major Facilitator Superfamily Domain containing 2a (MFSD2A) is an essential endothelial lipid transporter at the blood-brain barrier. Biallelic variants affecting function in MFSD2A cause autosomal recessive primary microcephaly 15 (MCPH15, OMIM# 616486). We sought to expand our knowledge of the phenotypic spectrum of MCPH15 and demonstrate the underlying mechanism of inactivation of the MFSD2A transporter. We carried out detailed analysis of the clinical and neuroradiological features of a series of 27 MCPH15 cases, including eight new individuals from seven unrelated families. Genetic investigation was performed through exome sequencing (ES). Structural insights on the human Mfsd2a model and in-vitro biochemical assays were used to investigate the functional impact of the identified variants. All patients had primary microcephaly and severe developmental delay. Brain MRI showed variable degrees of white matter reduction, ventricular enlargement, callosal hypodysgenesis, and pontine and vermian hypoplasia. ES led to the identification of six novel biallelic MFSD2A variants (NG_053084.1, NM_032793.5: c.556+1G>A, c.748G>T; p.(Val250Phe), c.750_753del; p.(Cys251SerfsTer3), c.977G>A; p.(Arg326His), c.1386_1435del; p.(Gln462HisfsTer17), and c.1478C>T; p.(Pro493Leu)) and two recurrent variants (NM_032793.5: c.593C>T; p.(Thr198Met) and c.476C>T; p.(Thr159Met)). All these variants and the previously reported NM_032793.5: c.490C>A; p.(Pro164Thr) resulted in either reduced MFSD2A expression and/or transport activity. Our study further delineates the phenotypic spectrum of MCPH15, refining its clinical and neuroradiological characterization and supporting that MFSD2A deficiency causes early prenatal brain developmental disruption. We also show that poor MFSD2A expression despite normal transporter activity is a relevant pathomechanism in MCPH15.

The clinical and radiological spectrum of spondylocostal dysostosis syndromes encompasses distinctive costo-vertebral anomalies. RIPPLY2 biallelic pathogenic variants were described in two distinct cervical spine malformation syndromes: Klippel–Feil syndrome and posterior cervical spine malformation. RIPPLY2 is involved in the determination of rostro-caudal polarity and somite patterning during development. To date, only four cases have been reported. The current report aims at further delineating the posterior malformation in three new patients. Three patients from two unrelated families underwent clinical and radiological examination through X-ray, 3D computed tomography and brain magnetic resonance imaging. After informed consent was obtained, family-based whole exome sequencing (WES) was performed. Complex vertebral segmentation defects in the cervico-thoracic spine were observed in all patients. WES led to the identification of the homozygous splicing variant c.240-4T>G in all subjects. This variant is predicted to result in aberrant splicing of Exon 4. The current report highlights a subtype of cervical spine malformation with major atlo-axoidal malformation compromising spinal cord integrity. This distinctive mutation-specific pattern of malformation differs from Klippel–Feil syndrome and broadens the current classification, defining a sub-type of RIPPLY2-related skeletal disorder. Of note, the phenotype of one patient overlaps with oculo-auriculo-vertebral spectrum disorder.

Disease gene discovery on chromosome (chr) X is challenging owing to its unique modes of inheritance. We undertook a systematic analysis of human chrX genes. We observe a higher proportion of disorder-associated genes and an enrichment of genes involved in cognition, language, and seizures on chrX compared to autosomes. We analyze gene constraints, exon and promoter conservation, expression and paralogues, and report 127 genes sharing one or more attributes with known chrX disorder genes. Using a neural network trained to distinguish disease-associated from dispensable genes, we classify 235 genes, including 121 of the 127, as having high probability of being disease-associated. We provide evidence of an excess of variants in predicted genes in existing databases. Finally, we report damaging variants in CDK16 and TRPC5 in patients with intellectual disability or autism spectrum disorders. This study predicts large-scale gene-disease associations that could be used for prioritization of X-linked pathogenic variants.

We investigated an early adolescent female with intellectual disability, drug-responsive epilepsy and white matter abnormalities. Through exome sequencing, we identified the novel de novo variant (NM_005052.3): c.83TC (p.Phe28Ser) inIn vitro analyses revealed that the p.F28S variant was spontaneously activated by substantially increased intrinsic GTP/GDP-exchange activity and bound to downstream effectors tested, such as PAK1 and MLK2. The variant suppressed the differentiation of primary cultured hippocampal neurons and caused cell rounding with lamellipodia. In vivo analyses using in utero electroporation showed that acute expression of the p.F28S variant caused migration defects of excitatory neurons and axon growth delay during corticogenesis. Notably, defective migration was rescued by a dominant negative version of PAK1 but not MLK2.Our results indicate that RAC3 is critical for brain development and the p.F28S variant causes morphological and functional defects in cortical neurons, likely due to the hyperactivation of PAK1.

Background: Heterozygous POLR2A variants have been recently reported in patients with a neurodevelopmental syndrome characterized by profound infantile-onset hypotonia. POLR2A encodes the highly conserved RBP1 protein, an essential subunit of the DNA-dependent RNA polymerase II.Case presentation: We investigated a 12-year-old girl presenting with an early-onset encephalopathy characterized by psychomotor delay, facial dysmorphism, refractory epilepsy with variable seizure types, behavioural abnormalities, and sleep disorder. Brain MRI showed a slowly progressive cerebellar atrophy. Trio-exome sequencing (Trio-ES) revealed the de novo germline variant NM_000937.5:c.1370T>C; p.(Ile457Thr) in POLR2A. This variant was previously reported in a subject with profound generalized hypotonia and muscular atrophy by Haijes et al. Our patient displayed instead a severe epileptic phenotype with refractory hypotonic seizures with impaired consciousness, myoclonic jerks, and drop attacks.Conclusion: This case expands the clinical spectrum of POLR2A-related syndrome, highlighting its phenotypic variability and supporting the relevance of epilepsy as a core feature of this emerging condition. (c) 2022 The Japanese Society of Child Neurology Published by Elsevier B.V. All rights reserved.

Background: Poirier–Bienvenu Neurodevelopmental Syndrome (POBINDS) is a rare disease linked to mutations of the CSNK2B gene, which encodes for a subunit of caseinkinase CK2 involved in neuronal growth and synaptic transmission. Its main features include early-onset epilepsy and intellectual disability. Despite the lack of cases described, it appears that POBINDS could manifest with a wide range of phenotypes, possibly related to the different mutations of CSNK2B. Methods: Our multicentric, retrospective study recruited nine patients with POBINDS, detected using next-generation sequencing panels and whole-exome sequencing. Clinical, laboratory, and neuroimaging data were reported for each patient in order to assess the severity of phenotype, and eventually, a correlation with the type of CSNK2B mutation. Results: We reported nine unrelated patients with heterozygous de novo mutations of the CSNK2B gene. All cases presented epilepsy, and eight patients were associated with a different degree of intellectual disability. Other features detected included endocrinological and vascular abnormalities and dysmorphisms. Genetic analysis revealed six new variants of CSNK2B that have not been reported previously. Conclusion: Although it was not possible to assess a genotype–phenotype correlation in our patients, our research further expands the phenotype spectrum of POBINDS patients, identifying new mutations occurring in the CSNK2B gene.

Neurodevelopmental disorders are highly heterogenous conditions resulting from abnormalities of brain architecture and/or function. FBXW7 (F-box and WD-repeat-domain-containing 7), a recognized developmental regulator and tumor suppressor, has been shown to regulate cell-cycle progression and cell growth and survival by targeting substrates including CYCLIN E1/2 and NOTCH for degradation via the ubiquitin proteasome system. We used a genotype-first approach and global data-sharing platforms to identify 35 individuals harboring de novo and inherited FBXW7 germline monoallelic chromosomal deletions and nonsense, frameshift, splice-site, and missense variants associated with a neurodevelopmental syndrome. The FBXW7 neurodevelopmental syndrome is distinguished by global developmental delay, borderline to severe intellectual disability, hypotonia, and gastrointestinal issues. Brain imaging detailed variable underlying structural abnormalities affecting the cerebellum, corpus collosum, and white matter. A crystal-structure model of FBXW7 predicted that missense variants were clustered at the substrate-binding surface of the WD40 domain and that these might reduce FBXW7 substrate binding affinity. Expression of recombinant FBXW7 missense variants in cultured cells demonstrated impaired CYCLIN E1 and CYCLIN E2 turnover. Pan-neuronal knockdown of the Drosophila ortholog, archipelago, impaired learning and neuronal function. Collectively, the data presented herein provide compelling evidence of an F-Box protein-related, phenotypically variable neurodevelopmental disorder associated with monoallelic variants in FBXW7.

PurposeHeterozygous variants in BCL11A underlie an intellectual developmental disorder with persistence of fetal hemoglobin (BCL11A-IDD, a.k.a. Dias-Logan syndrome). We sought to delineate the genotypic and phenotypic spectrum of BCL11A-IDD.MethodsWe performed an in-depth analysis of 42 patients with BCL11A-IDD ascertained through a collaborative network of clinical and research colleagues. We also reviewed 33 additional affected individuals previously reported in the literature or available through public repositories with clinical information.ResultsMolecular and clinical data analysis of 75 patients with BCL11A-IDD identified 60 unique variants (30 frameshift, 7 missense, 6 splice-site, 17 stop-gain) and 8 unique CNVs (microdeletions involving BCL11A only). We redefined the most frequent manifestations of the condition: intellectual disability, hypotonia, behavioral abnormalities, postnatal microcephaly and autism spectrum disorder. Two thirds of patients have brain MRI abnormalities, and we identified a recurrent posterior fossa phenotype of vermian hypoplasia and/or small brainstem. Truncating BCL11A variants, particularly those affecting the long (BCL11A-L) and extra-long (-XL) isoforms, sparing the short (-S) isoform, were associated with increased severity.ConclusionsWe expand the clinical delineation of BCL11A-IDD and identify a potential isoform-specific genotype-phenotype correlation. We show that BCL11A-IDD is associated with posterior fossa anomalies and highlight the differences between BCL11A-IDD and 2p16.1p15 microdeletion syndrome.

WIPI2 is a member of the human WIPI protein family (seven-bladed b-propeller proteins binding phosphatidylinositols, PROPPINs), which play a pivotal role in autophagy and has been implicated in the pathogenesis of several neurological conditions. The homozygous WIPI2 variant c.745G>A; p.(Val249Met) (NM_015610.4) has recently been associated with a neurodevelopmental disorder in a single family. Using exome sequencing and Sanger segregation analysis, here, two novel homozygous WIPI2 variants [c.551T>G; p.(Val184Gly) and c.724C>T; p.(Arg242Trp) (NM_015610.4)] were identified in four individuals of two consanguineous families. Additionally, follow-up clinical data were sought from the previously reported family. Three non-ambulant affected siblings of the first family harbouring the p.(Val184Gly) missense variant presented with microcephaly, profound global developmental delay/intellectual disability, refractory infantile/childhood-onset epilepsy, progressive tetraplegia with joint contractures and dyskinesia. In contrast, the proband of the second family carrying the p.(Arg242Trp) missense variant, similar to the initially reported WIPI2 cases, presented with a milder phenotype, encompassing moderate intellectual disability, speech and visual impairment, autistic features, and an ataxic gait. Brain MR imaging in five patients showed prominent white matter involvement with a global reduction in volume, posterior corpus callosum hypoplasia, abnormal dentate nuclei and hypoplasia of the inferior cerebellar vermis. To investigate the functional impact of these novel WIPI2 variants, we overexpressed both in WIPI2-knockout HEK293A cells. In comparison to wildtype, expression of the Val166Gly WIPI2b mutant resulted in a deficient rescue of LC3 lipidation whereas Arg224Trp mutant increased LC3 lipidation, in line with the previously reported Val231Met variant. These findings support a dysregulation of the early steps of the autophagy pathway. Collectively, our findings provide evidence that biallelic WIPI2 variants cause a neurodevelopmental disorder of variable severity and disease course. Our report expands the clinical spectrum and establishes WIPI2-related disorder as a congenital disorders of autophagy., Maroofian et al. reported two novel homozygous WIPI2 variants [c.551T>G; p.(Val184Gly) and c.724C>T; p.(Arg242Trp) (NM_015610.4)] in four individuals of two consanguineous families with neurodevelopmental disorder and brain abnormalities. Expression of the Val184Gly mutant in WIPI2-knockout HEK293A cells resulted in a deficient LC3 lipidation rescue whereas Arg242Trp mutant increased LC3 lipidation., Graphical Abstract Graphical Abstract

INTRODUCTION: The acronym VATER/VACTERL refers to the rare non-random association of the following component features (CFs): vertebral defects (V), anorectal malformations (ARM) (A), cardiac anomalies (C), tracheoesophageal fistula with or without esophageal atresia (TE), renal malformations (R), and limb anomalies (L). For the clinical diagnosis the presence of at least three CFs is required, individuals presenting with only two CFs have been categorized as VATER/VACTERL-like. The majority of VATER/VACTERL individuals displays a renal phenotype. Hitherto, variants in FGF8, FOXF1, HOXD13, LPP, TRAP1, PTEN and ZIC3 have been associated with the VATER/VACTERL association; however, large-scale re-sequencing could only confirm TRAP1 and ZIC3 as VATER/VACTERL disease genes, both associated with a renal phenotype. METHODS: In this study, we performed exome sequencing in 21 individuals and their families with a renal VATER/VACTERL or VATER/VACTERL-like phenotype to identify potentially novel genetic causes. RESULTS: Exome analysis identified biallelic and X-chromosomal hemizygous potentially pathogenic variants in six individuals (29%) in B9D1, FREM1, ZNF157, SP8, ACOT9, and TTLL11, respectively. The online tool GeneMatcher revealed another individual with a variant in ZNF157. CONCLUSION: Our study suggests six biallelic and X-chromosomal hemizygous VATER/VACTERL disease gene implicating all six genes in the expression of human renal malformations.

GRIN1 encodes the obligate subunit (GluN1) of glutamate N-methyl-d-aspartate receptor (NMDAr). Pathogenic variants in GRIN1 are a well-known cause of infantile encephalopathy characterized by profound developmental delay (DD), variable epileptic phenotypes, and distinctive behavioral abnormalities. Recently, GRIN1 has also been implicated in the pathogenesis of polymicrogyria (PMG). We investigated two patients presenting with severe intellectual disability (ID), epilepsy, stereotyped movements, and abnormal ocular movements. They showed distinctive circadian rhythm alterations and sleep-wake patterns anomalies characterized by recurrent cyclic crying or laughing spells. Genetic analysis led to the identification of two distinct de novo variants in GRIN1 affecting the same amino acid residue of an important functional protein domain. Recent advances in circadian rhythm and sleep regulation suggest that abnormal GluN1 function might play a relevant pathogenetic role for the peculiar behavioral abnormalities observed in GRIN1 patients. Our cases highlight the relevance of circadian rhythm abnormalities in epileptic children as a clue toward GRIN1 encephalopathy and expand the complex phenotypic spectrum of this severe genetic disorder.

Background The genetic causes of abnormal pituitary development have been extensively studied in the last few years. ROBO1 is involved in neurogenesis and axon guidance. Loss-of-function variants in ROBO1 have been associated with pituitary stalk interruption syndrome (PSIS), suggesting that its haploinsufficiency could impair the guidance of hypothalamic axons to the pituitary gland leading to developmental abnormalities. Case presentation We report a 4.5-year-old girl with anterior pituitary hypoplasia and pituitary stalk duplication in the ventral-dorsal direction. Her father had a similar pituitary phenotype, characterized by anterior pituitary hypoplasia combined with ectopic posterior pituitary. Comparative genomic hybridization (CGH) microarray analysis identified a 343.7 kb deletion of 3p12.3 encompassing ROBO1 in both individuals. Conclusions We report the first familial ROBO1 deletion in two individuals with peculiar pituitary anomalies, including the rare pituitary stalk duplication in the ventral-dorsal direction. These findings widen the spectrum of the phenotypes associated with ROBO1 haploinsufficiency and support its role in human pituitary development.