Menstrual management using the etonogestrel implant in individuals with intellectual disabilities in Joinville, Brazil.

OBJECTIVE: This study aimed to describe the use of etonogestrel (ENG) implants for menstrual management (i.e., management of bleeding and symptoms associated with menstruation) in individuals with intellectual disabilities. METHODS: This study retrospectively analyzed a cohort of individuals with intellectual disabilities who began using ENG implants between 2003 and 2018, in Joinville, Brazil. We collected sociodemographic, clinical, and reproductive data from the medical records, along with information related to ENG implant use. RESULTS: In total, 369 implants were placed in 130 individuals with intellectual disabilities. The median age at the first implant was 20 (interquartile range [IQR], 17-26) years, and 43.8% of the patients were adolescents. By December 2018, 90 patients had received two or more subsequent implants. The median duration of current ENG implant use was 19 (IQR, 12.8-22) months. More than 40% of the patients had comorbidities, with epilepsy being the most common. During the use of the current implant, 80% of the patients had a favorable bleeding profile (no bleeding or ≤1 bleeding episode per month), and 53.8% (70/130) had no bleeding within 3 months before their last medical visit. Among patients experiencing dysmenorrhea and premenstrual syndrome (PMS), 79% (64/81) and 82% (54/66) reported complete improvement, respectively. The premature implant removal rate was 8.9% (33/369). Unfavorable bleeding was the main reason for premature implant removal (20 out 33 removals). CONCLUSIONS: ENG implants might be a suitable option for individuals with intellectual disabilities who require management of menstrual bleeding and symptoms associated with menstruation. Most patients had a favorable bleeding profile and experienced significant improvements in dysmenorrhea and PMS, contributing to the high continuation rates of ENG implants.

Microduplications of ARID1A and ARID1B cause a novel clinical and epigenetic distinct BAFopathy.

BACKGROUND: ARID1A/ARID1B haploinsufficiency leads to Coffin-Siris syndrome, duplications of ARID1A lead to a distinct clinical syndrome, whilst ARID1B duplications have not yet been linked to a phenotype. METHODS: We collected patients with duplications encompassing ARID1A and ARID1B duplications. RESULTS: 16 ARID1A and 13 ARID1B duplication cases were included with duplication sizes ranging from 0.1-1.2 Mb(1-44 genes) for ARID1A and 0.9-10.3 Mb(2-101 genes) for ARID1B. Both groups shared features, with ARID1A patients having more severe intellectual disability, growth delay and congenital anomalies. DNA methylation analysis showed that ARID1A patients had a specific methylation pattern in blood, which differed from controls and from patients with ARID1A or ARID1B loss-of-function variants. ARID1B patients appeared to have a distinct methylation pattern, similar to ARID1A duplication patients, but further research is needed to validate these results. Five cases with duplications including ARID1A or ARID1B initially annotated as duplications of uncertain significance were evaluated using PhenoScore and DNA methylation re-analysis, resulting in the reclassification of two ARID1A and two ARID1B duplications as pathogenic. CONCLUSION: Our findings reveal that ARID1B duplications manifest a clinical phenotype and ARID1A duplications have a distinct episignature that overlaps with that of ARID1B duplications, providing further evidence for a distinct and emerging BAFopathy caused by whole gene duplication rather than haploinsufficiency.

Novel Splice Site Pathogenic Variant in STXBP1 Gene in a Child with Intellectual Disability, Epilepsy, and Autism Spectrum Disorder: A Case Report.

Introduction: Pathogenic variants in the STXBP1 gene are associated to a large spectrum of severe early onset developmental and epileptic encephalopathies (OMIM #612164). They were also identified in various other neurodevelopmental disorders. This gene encodes for the syntaxin-binding protein 1, a member of the SEC-1 family of membrane-transport proteins that modulate the presynaptic vesicular fusion by interacting with soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). However, the physiopathology of STXBP1 pathogenic variants is not yet fully understood. Case Presentation: Herein, we report a patient presenting intellectual disability, early onset seizures, and autism. Clinical exome sequencing identified a novel monoallelic splice pathogenic variant STXBP1(NM_001032221.6):c.38-2A>G. Discussion: Splice-site pathogenic variants in the STXBP1 gene are mostly associated with West syndrome, early onset epilepsy and encephalopathy, and Ohtahara syndrome. Our findings extend clinical and molecular spectrum of STXBP1 gene variants by reporting the first splice-site variant associated with autism along with early onset epilepsy and, and intellectual disability in a patient.

Cicchetti's organizational-developmental perspective of Down syndrome: Contributions to the emergence of developmental psychopathology and the study of persons with neurodevelopmental conditions.

Dante Cicchetti's earliest work, his studies of social-emotional development in infants and children with Down syndrome, set the stage for the emergence of the larger field of developmental psychopathology. By applying basic developmental principles, methodologies, and questions to the study of persons with Down syndrome, Dante took on the challenge of searching for patterns in atypical development. In doing so, he extended traditional developmental theory and introduced a more "liberal" approach that both continues to guide developmentally based research with persons with neurodevelopmental conditions (NDCs), including Down syndrome. We highlight five themes from Dante's work: (1) appreciating the importance of developmental level; (2) prioritizing the organization of development; (3) examining whether developmental factors work similarly in those with known genetic conditions; (4) rethinking narratives about ways of being; and (5) examining the influence of multiple levels of the environment on the individual's functioning. We highlight ways that these essential lessons anticipated present-day research with persons with a variety of NDCs, including Down syndrome, other genetic syndromes associated with intellectual disability, and autism. We conclude with visions to the future for research with these populations as well as for the field of developmental psychopathology more generally.

Clinical, developmental and serotonemia phenotyping of a sample of 70 Italian patients with Phelan-McDermid Syndrome.

BACKGROUND: Phelan-McDermid syndrome (PMS) is caused by monoallelic loss or inactivation at the SHANK3 gene, located in human chr 22q13.33, and is often associated with Autism Spectrum Disorder (ASD). OBJECTIVES: To assess the clinical and developmental phenotype in a novel sample of PMS patients, including for the first time auxometric trajectories and serotonin blood levels. METHODS: 70 Italian PMS patients were clinically characterized by parental report, direct medical observation, and a thorough medical and psychodiagnostic protocol. Serotonin levels were measured in platelet-rich plasma by HPLC. RESULTS: Our sample includes 59 (84.3%) cases with chr. 22q13 terminal deletion, 5 (7.1%) disruptive SHANK3 mutations, and 6 (8.6%) ring chromosome 22. Intellectual disability was present in 69 (98.6%) cases, motor coordination disorder in 65 (92.9%), ASD in 20 (28.6%), and lifetime bipolar disorder in 12 (17.1%). Prenatal and postnatal complications were frequent (22.9%-48.6%). Expressive and receptive language were absent in 49 (70.0%) and 19 (27.1%) cases, respectively. Decreased pain sensitivity was reported in 56 (80.0%), hyperactivity in 49 (80.3%), abnormal sleep in 45 (64.3%), congenital dysmorphisms in 35 (58.3%), chronic stool abnormalities and especially constipation in 29 (41.4%). Parents reported noticing behavioral abnormalities during early childhood immediately after an infective episode in 34 (48.6%) patients. Brain MRI anomalies were observed in 53 (79.1%), EEG abnormalities in 16 (23.5%), kidney and upper urinary tract malformations in 18 (28.1%). Two novel phenotypes emerged: (a) a subgroup of 12/44 (27.3%) PMS patients displays smaller head size at enrollment (mean age 11.8 yrs) compared to their first year of neonatal life, documenting a deceleration of head growth (p < 0.001); (b) serotonin blood levels are significantly lower in 21 PMS patients compared to their 21 unaffected siblings (P < 0.05), and to 432 idiopathic ASD cases (p < 0.001). CONCLUSIONS: We replicate and extend the description of many phenotypic characteristics present in PMS, and report two novel features: (1) growth trajectories are variable and head growth appears to slow down during childhood in some PMS patients; (2) serotonin blood levels are decreased in PMS, and not increased as frequently occurs in ASD. Further investigations of these novel features are under way.

Identification of a Novel Frameshift variant of the ATRX gene: a Case Report and Review of the genotype-phenotype relationship.

BACKGROUND: X-linked intellectual disability-hypotonic facies syndrome-1 (MRXHF1) and Alpha-thalassemia X-linked intellectual disability (ATR-X) syndrome are caused by pathogenic variant in the ATRX gene, a member of the switch/sucrose non-fermentable (SWI-SNF) protein family that exhibits chromatin remodeling activity. These syndromes show a wide spectrum of clinical manifestations, such as distinctive dysmorphic features, mild-to-profound intellectual disability, motor development delay, seizures, urogenital abnormalities, and gastrointestinal disorders. CASE PRESENTATION AND LITERATURE REVIEW: A 3-year-old boy from a Chinese non-consanguineous family was diagnosed with MRXHF1 by whole-exome sequencing. Comprehensive family history information was obtained. The Medline database was searched until 1st Aug 2023 for articles related to ATRX pathogenic variant. Data on gene/protein mutations and clinical symptoms were extracted. The proband showed intellectual disability, motor development delay, typical facial abnormalities, urogenital defect, behavior problems, and optical nerve dysplasia. A novel frameshift mutation c.399_400dup, (p.Leu134Cysfs*2) in the ATRX gene was the primary cause, which occurs right before the ATRXDNMT3-DNMT3L (ADD) domain of ATRX protein. Missense mutation is the most common variation type. The ADD and helicase-like domains are the most frequently affected domains. Epilepsy, congenital heart disease, urogenital defect, acoustic defect, and optical defect are more prevalent in patients with frameshift mutations compared to those with missense mutations. There are more urogenital defects with C-terminal frameshift mutations than with N-terminal frameshift mutations. CONCLUSION: We described a novel frameshift mutation in the ATRX gene in a patient with MRXHF1 syndrome and summarized the genotype-phenotype relationship of ATRX pathogenic variant by variation type and affected protein domain. The regulatory mechanism underlying ATRX variant requires comprehensive analysis in future studies.

A systematic review of attachment interventions for people with intellectual disability and their caregivers.

OBJECTIVE: The current mixed-methods systematic review evaluated available literature to find out which attachment-based interventions have been implemented for people with intellectual disability and whether they are efficacious and acceptable. METHODS: Five databases were searched (in July 2023 and April 2024), using terms related to intellectual disability and attachment-based interventions. The search yielded 793 papers; 15 papers (13 studies) met inclusion criteria. Relevant data was extracted from each study. Paper quality was appraised using the Mixed Methods Appraisal Tool. Findings were synthesised in an integrative review. RESULTS: Of the included studies, 7 had people with intellectual disability as participants and 6 had their caregivers. Interventions included education, psychotherapy, technology assisted therapy, video interaction guidance/feedback and circle of security. Research methods varied. CONCLUSIONS: Evidence for efficacy and acceptability of interventions was mixed but promising. Most studies had limited generalisability. Therefore, further research is required. Pre-registration with PROSPERO [351287].

Novel loss-of-function variants in WDR26 cause Skraban-Deardorff syndrome in two Chinese patients.

Introduction: Mutations in the protein WD repeat structural domain 26 (WDR26, MIM 617424) have been identified as the cause of autosomal dominant Skraban-Deardorff syndrome, a rare genetic disorder characterized by intellectual disability (ID), developmental delay (DD), hypotonia, epilepsy, infant feeding difficulties, gait abnormalities and distinctive facial features. The objective of this study is to investigate the genetic factors that may contribute to the development of Skraban-Deardorff syndrome in affected individuals. Methods: In this study, we used whole-exome sequencing (WES) to analyze pathogenic and likely pathogenic variants in two unrelated Chinese patients with DD and ID. We confirmed the origin of the variants by conducting Sanger sequencing and classified them according to ACMG/AMP guidelines. Results: Here, two novel de novo variants (c.1797delC(p.His599fs*11) and c.1414C>T(p.Gln472*)) in the WDR26 gene have been identified in two Chinese patients with Skraban-Deardorff syndrome. These patients exhibit a range of symptoms, including varying degrees of ID, DD, speech delay, an abnormal wide-foot and/or stiff-legged gait, facial dysmorphism, behavioural abnormalities, with or without seizures. Conclusions: In this study, We report two unrelated Chinese patients with Skraban-Deardorff syndrome caused by novel de novo pathogenic variants of the WDR26 gene. These patients showed a clinical phenotype similar to that of patients with the WDR26 variant. Compared to reported cases with WDR26 pathogenic variants, patient 2 presented a novel complication of severe behavioural problems, including hyperactivity, social anxiety, self-mutilation, impulsivity and violent behaviour. This research broadens the range of genetic and clinical features of Skraban-Deardorff syndrome. In addition, the symptoms may become more pronounced as the patient ages. Furthermore, our report highlights the clinical diversity of Skraban-Deardorff syndrome. The findings may assist healthcare professionals in providing more accurate genetic testing and counselling to affected families and improving the overall management of the condition.

Case report: A novel FBXW7 gene variant causes global developmental delay.

Objective: To investigate a case of neurodevelopmental disorder caused by mutation of FBXW7. Methods: Clinical data were collected from the patient, trio-WES (whole-exome sequencing) was performed on the patient and his parents (trio), and the results were verified by Sanger sequencing. RESULTS: The patient was a 2-year and 1-month old male who presented with facial dysmorphism (prominent forehead, ocular hypertelorism, and low nasal bridge), global developmental delay, language impairment, hypertonia, labial hemangioma, hydrocele, and overgrowth. The trio-WES confirmed that the child had a pathogenic de novo FBXW7 gene variant, c.1612C>T (p.G1n538*), a heretofore unreported locus. Conclusion: This case of developmental delay, hypotonia, and impaired language (OMIM: #620012) related to a mutation in FBXW7, is a rare genetic disorder, newly identified in recent years, and seldom reported. The presence of hypertonia, labial hemangioma, and hydrocele in this child suggests significant phenotypic heterogeneity of the disease, and the discovery of new mutant loci enriches the spectrum of pathogenic variants of the disease.

The effect of motor dual-task training on gait and mobility performances in children with intellectual disabilities.

The study investigated the impact of motor dual-task training on gait and mobility in children with intellectual disabilities. Performance was assessed using the Timed Up and Go Test (TUGT) and the 10-Meter Walking Test (TMWT) before and after an 8-week training period, with participants divided into a Trained Group (n=12) and a Control Group (n=14). Results indicated that, across both groups and regardless of session, TUGT and TMWT scores were significantly higher (p < 0.001) in the motor dual-task condition compared to the single-task condition. Post-training, TUGT scores significantly decreased (p < 0.05) in the single-task condition. The Trained Group showed significant improvements in second motor-task performance on both TUGT (p < 0.05) and TMWT (p < 0.001) under dual-task conditions, while the Control Group showed no change. The study demonstrated the effectiveness of motor dual-task training in enhancing mobility in children with intellectual disabilities.

Clozapine for persons with neurodevelopmental disorders: a systematic review and expert recommendations for clinical practice.

INTRODUCTION: We aimed to synthesize the information on the risks and benefits of clozapine prescription for resistant challenging behavior in persons with neurodevelopmental disorders. METHODS: Articles were identified with MEDLINE, Web of Sciences, and PsycINFO search from inception through January 2024. The review was restricted to persons with intellectual disability (ID) and/or autism spectrum disorder (ASD) without comorbid psychotic or affective disorder. Data were synthesized narratively. RESULTS: We identified 24 articles (13 case reports, eight chart studies, two controlled studies, one pharmaco-epidemiological study) including 296 patients with ID (n = 222) or ASD (n = 74) (10% aged ≤ 18 years). After clozapine initiation, a decreased frequency of challenging behavior persisting over time was reported in most participants included in clinical studies, and a significant reduction in the number of admissions in the population-based two-year mirror-image study. Adverse drug reactions were those commonly observed with clozapine, i.e. constipation, sedation, and weight gain. CONCLUSIONS: Since only four participants were included in the controlled studies, the benefits of clozapine in neurodevelopmental disorders are supported by a body of evidence exclusively drawn from observational studies. Further studies are required to clarify the indications of clozapine with respect to the unmet need induced by resistant challenging behavior. REGISTRATION: PROSPERO database registration number CRD42024522343.

A Strong Candidate Gene for Nonsyndromic Intellectual Disability Phenotype: SGSM3.

SGSM proteins are small modulator proteins interacting with proteins in the RAS signaling pathway. Studies with mouse and human tissues indicated that SGSM genes were highly expressed in the brain and could be expressed at different levels at different stages of development in fetal and adult brain tissue. It was first reported by Birnbaum et al. that the SGSM3 gene might be associated with a Mendelian inherited disease in families of Ashkenazi Jews with clinical manifestations of intellectual disability (ID). In this study, a novel homozygous stop-gain (NM_015705.6: c.1576C>T: p.(Arg526Ter)) variation was detected in the SGSM3 gene in two siblings with short stature and ID findings. The report of two cases with bi-allelic LOF variants in the SGSM3 gene from different populations with similar clinical manifestations strengthens the potential of this gene as a candidate gene for the nonsyndromic ID phenotype. Functional studies are required to investigate the signaling pathways affected by SGSM3 gene variations to produce the ID phenotype and their effect on the functioning of neurons.

Case report: IORT as an alternative treatment option for breast cancer patients with difficulty staying still.

Background: Administering radiation therapy to individuals with intellectual disabilities (ID) and psychiatric patients taking antipsychotics poses challenges, especially with whole breast irradiation (WBI) due to difficulty staying still (DSS). In such scenarios, intraoperative radiotherapy (TARGIT-IORT) provides an alternative. Although prior studies have shown its applicability in special cases where WBI may be contraindicated, there is a paucity of literature emphasizing its role in patients with ID and psychiatric conditions who have DSS. Therefore, our case series aims to highlight the applicability of administering TARGIT-IORT in such patients. Case reports: Four breast cancer patients underwent lumpectomy and TARGIT-IORT. Among them, two patients had ID, with one experiencing a decreased range of motion. The other two had psychiatric disorders, including schizophrenia and bipolar disorder, both manifesting involuntary movements and DSS. Three patients had invasive ductal carcinoma (IDC), and one had invasive lobular carcinoma (ILC). All patients undergoing TARGIT-IORT tolerated the procedure well. Notably, none of the patients exhibited evidence of disease on follow-up. Conclusion: Our study underscores the potential use of TARGIT-IORT as a viable treatment option for breast cancer patients with intellectual and psychiatric disabilities. Unlike traditional EBRT, TARGIT-IORT offers a single radiation dose, addressing challenges associated with compliance or DSS. Our findings demonstrate positive outcomes and tolerance, especially in patients where standard oncologic procedures are difficult to achieve. TARGIT-IORT could also benefit breast cancer patients with concurrent movement disorders like Parkinson's disease and other movement disorders. Nonetheless, future studies are needed to reinforce its applicability for patients with DSS.

Promoting multistep requesting through systematic instruction and facilitated iPad-based intervention with children with intellectual disability.

A lack of multistep requesting among children with intellectual disability can be an indicator of complex communication and social challenges. This study aims to determine the effect of a systematic instruction (differential reinforcement, progressive time delay, and least-to-most prompting) using an iPad with the "GoTalk Now" app on the acquisition and maintenance of multistep requesting. Using a multiple-probe across-participants design, three children between the ages of nine and 10 diagnosed with intellectual disability participated in this study. The findings revealed that the intervention was effective in both the intervention and maintenance phases. In two participants, the change in performance occurred immediately, while in the other participant, it took more sessions to reach the acquisition criteria. Social validity data were obtained from participants' teachers. Implications and future directions are discussed according to the findings.

The use of iPads, evidence-based practices, and systematic instruction can enhance communication skills, specifically multistep requesting, among children with moderate intellectual disability.The intervention package (GoTalk Now app on iPad and systematic instruction) was effective and help the three children gain and maintain multistep requesting skills.The positive change in children's performance may encourage more usage of the iPad and systematic instruction for enhancing different skills among children with intellectual disability.This study may prove useful to teachers and specialists who teach or work with children with intellectual disability.

Ubiquitin ligase signalling networks shape presynaptic development, function and disease.

Ubiquitin ligases are important regulators of nervous system development, function and disease. To date, numerous ubiquitin ligases have been discovered that regulate presynaptic biology. Here, we discuss recent findings on presynaptic ubiquitin ligases that include members from the three major ubiquitin ligase classes: RING, RBR and HECT. Several themes emerge based on findings across a range of model systems. A cadre of ubiquitin ligases is required presynaptically to orchestrate development and transmission at synapses. Multiple ubiquitin ligases deploy both enzymatic and non-enzymatic mechanisms, and act as hubs for signalling networks at the synapse. Both excitatory and inhibitory presynaptic terminals are influenced by ligase activity. Finally, there are several neurodevelopmental disorders and neurodegenerative diseases associated with presynaptic ubiquitin ligases. These findings highlight the growing prominence and biomedical relevance of the presynaptic ubiquitin ligase network.

Minocycline prevents early age-related cognitive decline in a mouse model of intellectual disability caused by ZBTB18/RP58 haploinsufficiency.

Haploinsufficiency of the transcriptional repressor ZBTB18/RP58 is associated with intellectual disability. However, the mechanisms causing this disability are unknown, and preventative measures and treatments are not available. Here, we assessed multiple behaviors in Zbtb18/Rp58 heterozygous-knockout mice, and examined local field potentials, DNA fragmentation, mitochondrial morphology, and performed histochemical and transcriptome analyses in the hippocampus to evaluate chronic inflammation. In wild-type mice, object location memory was present at a similar level at 2 and 4-5 months of age, and became impaired at 12-18 months. In contrast, Zbtb18/Rp58 heterozygous-knockout mice displayed early onset impairments in object location memory by 4-5 months of age. These mice also exhibited earlier accumulation of DNA and mitochondrial damage, and activated microglia in the dentate gyrus, which are associated with defective DNA repair. Notably, chronic minocycline therapy, which has neuroprotective and anti-inflammatory effects, attenuated age-related phenotypes, including accumulation of DNA damage, increased microglial activation, and impairment of object location memory. Our results suggest that Zbtb18/Rp58 activity is required for DNA repair and its reduction results in DNA and mitochondrial damage, increased activation of microglia, and inflammation, leading to accelerated declines in cognitive functions. Minocycline has potential as a therapeutic agent for the treatment of ZBTB18/RP58 haploinsufficiency-associated cognitive dysfunction.

Does adapting a self-report instrument to improve its cognitive accessibility for people with intellectual disability result in a better measure? - A cognitive interview study.

BACKGROUND AND AIMS: We investigated whether improving the cognitive accessibility of a widely used self-report measure leads to better understanding and more accurate answers in a sample of adults with mild intellectual disability and borderline intellectual functioning. METHODS AND PROCEDURES: We undertook a series of cognitive interviews before and after adaptation of the instructions and selected items of an existing self-report measure of adaptive functioning. Interview results and participant feedback were supplemented with quantitative comparisons between participant and carer scores. OUTCOMES AND RESULTS: Adaptation based on participant experiences and preferences combined with evidence-informed guidelines improved understanding and accuracy. Self-report and carer-report scores showed greater convergence after adaptation; this occurred because people with intellectual disabilities appeared to understand the self-report measure more effectively. CONCLUSIONS AND IMPLICATIONS: The results show that adaptation of the self-report instrument to suit the needs and preferences of people with mild intellectual disability or borderline intellectual functioning leads to a more accessible measure and more reliable and valid results. Results also highlight the importance of complementing proxy reports with a first-person perspective in assessment as clients and informants may differ in their assessment of behavior and skills.

A Scoping Review of Outcomes Measured and Involvement of People With Intellectual Disabilities in Active Support Research.

BACKGROUND: Active Support is a staff practice that aims to increase engagement of people with intellectual disabilities. This study seeks to: (1) identify the outcomes of staff using Active Support and how these are measured; (2) identify how the views of people with intellectual disabilities have been included in Active Support research. METHOD: A scoping review was conducted of peer-reviewed articles about Active Support published between 2009 and 2023. RESULTS: Sixteen articles were identified. Outcomes included engagement, the quality of staff support, choice and challenging behaviour. Structured observations were the most frequently used measurement method. Only two studies explored people with intellectual disabilities' perspectives about Active Support. CONCLUSIONS: Consistent use of similar measures is a strength of Active Support research. Including perspectives of people with intellectual disabilities may provide insight into dimensions of support not been measured and assist in further developing these measures and Active Support practice.

Cohen syndrome: Can early-onset recurrent infections and hypotonia provide early diagnosis and intervention for intellectual disability?

INTRODUCTION: Cohen syndrome is a rare disease associated with neurodevelopmental disorders, especially intellectual disability (ID), neutropenia and recurrent infections are consistently reported in cases. Neutropenia is an important part of the syndrome, as well as ID. Homozygous variants in the VPS13B gene, located on chromosome 8q22 and containing 62 exons, have been found to cause Cohen syndrome. Cohen syndrome is commonly diagnosed when dysmorphological findings and developmental delay become more apparent. However, the identification of some findings with increasing age has caused the diagnosis of Cohen syndrome to be delayed. METHODS: Cases diagnosed with ID were evaluated using whole-exome sequencing/clinical exome sequencing method. Family segregation analysis was performed using Sanger sequencing. We presented the clinical and genetic findings of three cases diagnosed with Cohen syndrome and their parents in detail. RESULTS: In this study, we presented the occurrence of symptoms in different age groups, and the prognosis of three cases carrying the VPS13B gene variants, including three different variant types: missense, frameshift and nonsense. Although our cases had different variant types, they shared important similarities on the onset period and prognosis of the symptoms. All cases presented hypotonia, difficulties in swallowing, recurrent respiratory tract infections, neutropenia, delay in motor development, ID and hyperactivity. Our cases did not have a diagnosis of autism spectrum disorder. All cases had increased willingness to engage in social communication. CONCLUSION: We emphasize the importance of early-onset recurrent infections and hypotonia for early diagnosis and preventive genetic counselling in Cohen syndrome.

CTNND2 moderates the pace of synaptic maturation and links human evolution to synaptic neoteny.

Human-specific genes are potential drivers of brain evolution. Among them, SRGAP2C has contributed to the emergence of features characterizing human cortical synapses, including their extended period of maturation. SRGAP2C inhibits its ancestral copy, the postsynaptic protein SRGAP2A, but the synaptic molecular pathways differentially regulated in humans by SRGAP2 proteins remain largely unknown. Here, we identify CTNND2, a protein implicated in severe intellectual disability (ID) in Cri-du-Chat syndrome, as a major partner of SRGAP2. We demonstrate that CTNND2 slows synaptic maturation and promotes neuronal integrity. During postnatal development, CTNND2 moderates neuronal excitation and excitability. In adults, it supports synapse maintenance. While CTNND2 deficiency is deleterious and results in synaptic loss of SYNGAP1, another major ID-associated protein, the human-specific protein SRGAP2C, enhances CTNND2 synaptic accumulation in human neurons. Our findings suggest that CTNND2 regulation by SRGAP2C contributes to synaptic neoteny in humans and link human-specific and ID genes at the synapse.