Intellectual Disability Patients Research Articles

GWO-SVM: AN APPROACH TO IMPROVING SVM PERFORMANCE USING GREY WOLF OPTIMIZER IN INTELLECTUAL DISABILITY CLASSIFICATION

Intellectual disability (ID) is a neurodevelopmental disorder that requires early and accurate diagnosis. This study aims to improve the efficiency of ID diagnosis using a machine learning approach. A Support Vector Machine (SVM) model optimized with Grey Wolf Optimizer (GWO) was developed and trained using data from questionnaires completed by 101 families/guardians of ID patients at RSUD Dr. Soetomo Surabaya. The features used include family history, cognitive abilities, and adaptive behaviors. The results showed that the GWO-SVM model achieved an accuracy of 95% in classifying ID patients, an improvement of 5% compared to the conventional SVM. The GWO algorithm successfully optimized the parameters in SVM, resulting in a model with the best performance. These findings indicate the potential of GWO-SVM as an effective and efficient tool for assisting in the diagnosis of ID.

Non‐pharmacological interventions in ID patients with challenging behaviours

The STOMP (stopping over‐medication of people with a learning disability, autism or both with psychotropic medicines) initiative and NICE guidelines regarding the management of challenging behaviour in adults with intellectual disability (ID) promote the use of non‐pharmacological approaches ahead of medication, with an emphasis also on reducing dosage or stopping medication where appropriate. Here the authors report on the findings of a service evaluation looking at how often a community intellectual disability psychiatry clinic initiates non‐pharmacological approaches in cases referred for challenging behaviour, and importantly whether this impacts the dosages of medication subsequently prescribed.

Evidence for the additivity of rare and common variant burden throughout the spectrum of intellectual disability

Intellectual disability (ID) is a common disorder, yet there is a wide spectrum of impairment from mild to profoundly affected individuals. Mild ID is seen as the low extreme of the general distribution of intelligence, while severe ID is often seen as a monogenic disorder caused by rare, pathogenic, highly penetrant variants. To investigate the genetic factors influencing mild and severe ID, we evaluated rare and common variation in the Northern Finland Intellectual Disability cohort (n = 1096 ID patients), a cohort with a high percentage of mild ID (n = 550) and from a population bottleneck enriched in rare, damaging variation. Despite this enrichment, we found only a small percentage of ID was due to recessive Finnish-enriched variants (0.5%). A larger proportion was linked to dominant variation, with a significant burden of rare, damaging variation in both mild and severe ID. This rare variant burden was enriched in more severe ID (p = 2.4e-4), patients without a relative with ID (p = 4.76e-4), and in those with features associated with monogenic disorders. We also found a significant burden of common variants associated with decreased cognitive function, with no difference between mild and more severe ID. When we included common and rare variants in a joint model, the rare and common variants had additive effects in both mild and severe ID. A multimodel inference approach also found that common and rare variants together best explained ID status (ΔAIC = 16.8, ΔBIC = 10.2). Overall, we report evidence for the additivity of rare and common variant burden throughout the spectrum of intellectual disability.

Virtual-Reality-Based Supermarket for Intellectual Disability Classification, Diagnostics, and Assessment

Possible symptoms of intellectual disability (ID) include delayed physical development that becomes more pronounced as the disability progresses, delayed development of gross and fine motor skills, sensory perception problems, and difficulty grasping the integrity of objects. Although there is no cure or reversal, research has shown that extensive training and learning can lead to easier social integration, but the human demands of diagnosis and the cost of training often result in overburdened families of origin, an unmanageable workload for teachers, and high social costs. Therefore, it is important to conduct efficient, effective, and economical assessments in a safe and reproducible training environment. Currently, the assessment of intellectual disability relies on intelligence tests such as the Wechsler Intelligence Scale (WIS) and the Vineland Adaptive Behavior Scale (VABS). With the rapid development of virtual reality (VR) and machine learning (ML), we created a virtual supermarket and then collected data in three areas, including eye movements, brain waves, and behaviors. We also propose an intelligent executive function evaluation using ML to develop a more objective and automatic evaluation model based on real data through physiological data obtained from user reflections. Statistical analysis of the obtained data showed that some data metrics derived from behavioral information differed significantly between ID patients and healthy participants. This shows that it is possible to perform classification through neural networks, even at multiple levels, which may prove effective for vocational training through VR.

Comparative Transcriptomics Data Profiling Reveals E2F Targets as an Important Biological Pathway Overexpressed in Intellectual Disability Disorder.

Intellectual disability (ID) is an early childhood neurodevelopmental disorder that is characterized by impaired intellectual functioning and adaptive behavior. It is one of the major concerns in the field of neurodevelopmental disorders across the globe. Diversified approaches have been put forward to overcome this problem. Among all these approaches, high throughput transcriptomic analysis has taken an important dimension. The identification of genes causing ID rapidly increased over the past 3 to 5 years owing to the use of sophisticated high throughput sequencing platforms. Early monitoring and preventions are much important for such disorder as their progression occurs during fetal development. This study is an attempt to identify differentially expressed genes (DEGs) and upregulated biological processes involved in development of ID patients through comparative analysis of available transcriptomics data. A total of 7 transcriptomic studies were retrieved from National Center for Biotechnology Information (NCBI) and were subjected to quality check and trimming prior to alignment. The normalization and differential expression analysis were carried out using DESeq2 and EdgeR packages of Rstudio to identify DEGs in ID. In progression of the study, functional enrichment analysis of the results obtained from both DESeq2 and EdgeR was done using gene set enrichment analysis (GSEA) tool to identify major upregulated biological processes involved in ID. Our findings concluded that monitoring the level of E2F targets, estrogen, and genes related to oxidative phosphorylation, DNA repair, and glycolysis during the developmental stage of an individual can help in the early detection of ID disorder.

Loss of NDST1 N-sulfotransferase activity is associated with autosomal recessive intellectual disability.

Intellectual Disability (ID) is the major cause of handicap, affecting nearly 3% of the general population, and is highly genetically heterogenous with more than a thousand genes involved. Exome sequencing performed in two independent families identified the same missense variant, p.(Gly611Ser), in the NDST1 (N-deacetylase/N-sulfotransferase member 1) gene. This variant had been previously found in ID patients of two other families but has never been functionally characterized. The NDST1 gene encodes a bifunctional enzyme that catalyzes both N-deacetylation and N-sulfation of N-acetyl-glucosamine residues during heparan sulfate (HS) biosynthesis. This step is essential because it influences the downstream enzymatic modifications and thereby determines the overall structure and sulfation degree of the HS polysaccharide chain. To discriminate between a rare polymorphism and a pathogenic variant, we compared the enzymatic properties of wild-type and mutant NDST1 proteins. We found that the p.(Gly611Ser) variant results in a complete loss of N-sulfotransferase activity while the N-deacetylase activity is retained. NDST1 shows the highest and the most homogeneous expression in the human cerebral structures compared to the other members of the NDST gene family. These results indicate that a loss of NDST1 N-sulfation activity is associated with impaired cognitive functions.

Identification and functional characterization of de novo variant in the SYNGAP1 gene causing intellectual disability.

Background: Intellectual disability (ID) is defined by cognitive and social adaptation defects. Variants in the SYNGAP1 gene, which encodes the brain-specific cytoplasmic protein SYNGAP1, are commonly associated with ID. The aim of this study was to identify novel SYNGAP1 gene variants in Chinese individuals with ID and evaluate the pathogenicity of the detected variants. Methods: Whole exome sequencing (WES) was performed on 113 patients diagnosed with ID. In the study, two de novo variants in SYNGAP1 were identified. Sanger sequencing was used to confirm these variants. Minigene assays were used to verify whether the de novo intronic variant in SYNGAP1 influenced the normal splicing of mRNA. Results: Two de novo heterozygous pathogenic variants in SYNGAP1, c.333del and c.664-2A>G, were identified in two ID patients separately. The c.333del variant has been reported previously as a de novo finding in a child with ID, while the c.664-2A>G variant was novel de novo intronic variant, which has not been reported in the literature. Functional studies showed that c.664-2A>G could cause aberrant splicing, resulting in exon 7 skipping and a 16bp deletion within exon 7. Conclusion: We identified two de novo pathogenic heterozygous variants in SYNGAP1 in two patients with ID, among which the c.664-2A>G variant was a novel de novo pathogenic variant. Our findings further enrich the variant spectrum of the SYNGAP1 gene and provide a research basis for the genetic diagnosis of ID.

Whole Exome Sequencing Reveals Two Novel Homozygous Variants in the TRAPPC9 and PLOD3 Genes Leading to Intellectual Disability and Bone Fragility with Contractures

Salt and Pepper’ syndrome is an autosomal recessive condition characterized by severe intellectual disability (ID), epilepsy, scoliosis, choreoathetosis, dysmorphic facial features, and altered dermal pigmentation. IDs are heterogeneous group of disorders prevalent in highly consanguineous populations and genetically variable condition of cognitive impairment linked with behavioral, syndromic, or dysmorphic features. Trafficking protein particle complex subunit 9 ( TRAPPC9) (MIM 611966) is an important gene, and mutations in this gene have been reported to be involved in ID conditions. Lysyl hydroxylase 3 (encoded by ( PLOD3)) is a multifunctional enzyme responsible for catalyzing hydroxylation of lysyl residues and O-glycosylation of hydroxylysyl residues, an important step during posttranslational modifications for collagen biosynthesis. In this study, whole exome sequencing was done for a family member having ID, microcephaly, included joint contractures, low bone mineral density, and dysmorphic feature. We identified a novel missense variant (NM_001160372.3) c.3211G>A, p.G1071S in the exon 22 of TRAPPC9 causing ID and other missense variant c.346G>A, p.V116M (NM_001084.4) in the exon 4 of the PLOD3 gene causing bone fragility with contractures in the affected member of the family. The obtained results were further validated by using Sanger sequencing analysis. The identified variant has not been reported in either gnomAD or Exac databases. Both parents were heterozygous (carriers) to these identified mutations. Our results for the first time suggest that identified novel TRAPPC9 and PLOD3 gene mutations are the main cause of the disease leading to the ID-associated conditions along with cognitive deficits along with microcephaly. This is the first study to report patients with TRAPPC9- and PLOD3-related disorder from Saudi Arabia. This study will add to the literature of the disease and will enable the creation of a database that will provide a strong base to understanding the critical genomic regions to control ID and related disorders in Saudi patients.

A novel heterozygous ZBTB18 missense mutation in a family with non-syndromic intellectual disability.

Intellectual disability (ID) is a common neurodevelopmental disorder characterized by significantly impaired adaptive behavior and cognitive capacity. High throughput sequencing approaches have revealed the genetic etiologies for 25-50% of ID patients, while inherited genetic mutations were detected in <5% cases. Here, we investigated the genetic cause for non-syndromic ID in a Han Chinese family. Whole genome sequencing was performed on identical twin sisters diagnosed with ID, their respective children, and their asymptomatic parents. Data was filtered for rare variants, and in silico prediction tools were used to establish pathogenic alleles. Candidate mutations were validated by Sanger sequencing. In silico modeling was used to evaluate the mutation's effects on the protein encoded by a candidate coding gene. A novel heterozygous variant in the ZBTB18 gene c.1323C>G (p.His441Gln) was identified. This variant co-segregated with affected individuals in an autosomal dominant pattern and was not detected in asymptomatic family members. Molecular studies reveal that a p.His441Gln substitution disrupts zinc binding within the second zinc finger and disrupts the capacity for ZBTB18 to bind DNA. This is the first report of an inherited ZBTB18 mutation for ID. This study further validates WGS for the accurate molecular diagnosis of ID.

Pathogenic SCN2A variants cause early-stage dysfunction in patient-derived neurons.

Pathogenic heterozygous variants in SCN2A, which encodes the neuronal sodium channel NaV1.2, cause different types of epilepsy or intellectual disability (ID)/autism without seizures. Previous studies using mouse models or heterologous systems suggest that NaV1.2 channel gain-of-function typically causes epilepsy, whereas loss-of-function leads to ID/autism. How altered channel biophysics translate into patient neurons remains unknown. Here, we investigated iPSC-derived early-stage cortical neurons from ID patients harboring diverse pathogenic SCN2A variants [p.(Leu611Valfs*35); p.(Arg937Cys); p.(Trp1716*)] and compared them with neurons from an epileptic encephalopathy (EE) patient [p.(Glu1803Gly)] and controls. ID neurons consistently expressed lower NaV1.2 protein levels. In neurons with the frameshift variant, NaV1.2 mRNA and protein levels were reduced by ~ 50%, suggesting nonsense-mediated decay and haploinsufficiency. In other ID neurons, only protein levels were reduced implying NaV1.2 instability. Electrophysiological analysis revealed decreased sodium current density and impaired action potential (AP) firing in ID neurons, consistent with reduced NaV1.2 levels. In contrast, epilepsy neurons displayed no change in NaV1.2 levels or sodium current density, but impaired sodium channel inactivation. Single-cell transcriptomics identified dysregulation of distinct molecular pathways including inhibition of oxidative phosphorylation in neurons with SCN2A haploinsufficiency and activation of calcium signaling and neurotransmission in epilepsy neurons. Together, our patient iPSC-derived neurons reveal characteristic sodium channel dysfunction consistent with biophysical changes previously observed in heterologous systems. Additionally, our model links the channel dysfunction in ID to reduced NaV1.2 levels and uncovers impaired AP firing in early-stage neurons. The altered molecular pathways may reflect a homeostatic response to NaV1.2 dysfunction and can guide further investigations.

Identifying Genetic Etiology in Patients with Intellectual Disability: An Experience in Public Health Services in Northeastern Brazil.

Intellectual disability (ID) is considered a common neuropsychiatric disorder that affects up to 3% of the population. The etiologic origin of ID may be genetic, environmental, and multifactorial. Chromosomopathies are relatively common among the genetic causes of ID, especially in the most severe cases and those associated with dysmorphic features. Currently, the application of new molecular cytogenetics technologies has increasingly allowed the identification of microdeletions, microduplications, and unbalanced translocations as causes of ID. The objective of this study was to investigate the etiology of ID in patients admitted to a public hospital in Northeastern Brazil. In total, 119 patients with ID who had normal karyotypes and fragile X exams participated in this study. The patients were initially physically examined for microdeletion syndromes and then tested using fluorescence in situ hybridization (FISH), multiplex ligation-dependent probe amplification (MLPA), methylation-sensitive polymerase chain reaction (MS-PCR), and chromosome microarray analysis (CMA), according to clinical suspicion. Patients with no diagnoses after FISH, MLPA, and/or MS-PCR evaluations were subsequently tested by CMA. The rate of etiologic diagnoses of ID in the current study was 28%. FISH diagnosed 25 out of 79 tested (31%), MLPA diagnosed 26 out of 79 tested (32%), MS-PCR diagnosed 7 out of 20 tested (35%), and the single nucleotide polymorphism array diagnosed 6 out of 27 tested (22%). Although the CMA is the most complete and recommended tool for the diagnosis of microdeletions, microduplications, and unbalance translocations in patients with ID, FISH, MLPA, and MS-PCR testing can be used as the first tests for specific syndromes, as long as the patients are first physically screened clinically, especially in the public health networks system in Brazil, where resources are scarce.

Genetic etiology of adult intellectual disability (ID) of unknown cause in Qatar: a retrospective study.

Background: Intellectual disability (ID) is a common condition that consists of a heterogeneous group of clinical conditions with different etiologies, including genetic conditions. Identifying those with a genetic cause results in better clinical management.Aim: To identify the genetic etiology of ID in adult patients with unknown etiology presenting to a specialist learning disability service in Qatar.Methods: Retrospective review of chart notes of patients referred for ID service from January 1, 2015 to January 1, 2020.Results: Of the 228 patients, 82 had a known cause of ID and did not require genetic testing, 22 had an unknown cause and underwent genetic testing, and 124 had an unknown cause and did not undergo genetic testing. Of the 82 patients with a known cause of ID, about one-half had an autistic spectrum disorder (ASD) and 18 patients had a genetic disorder. Of the 22 patients who underwent genetic testing, 2 were positive for the Fragile-X mental retardation 1 gene, 3 underwent chromosomal microarray, and 7 underwent whole-exome sequencing. Seven abnormal genes were identified.Conclusions: Identifying the underlying genetic etiology of patients with ID has major implications for diagnostic and therapeutic approaches. Additionally, it guides a prediction of the natural history of the disease and makes it possible to test at-risk family members.

Incidence of Psychiatric Disorders in Children affected with Intellectual Disability

Intellectual disability is caused by environmental influences, genetic disorders and infections including perinatal, postnatal and neonatal infections. Physical disabilities are also associated with intellectual disability (ID) children.Identification of ID patients occurred by test of intellectual disfunctioning. A cross sectional and analytical study was performed from September 2019 to March 2020on intellectually disabled children on the Pakistan Air Force (PAF) children school Lahore, Fountain house in Sargodha and Shadab institute of special education, Punjab, Pakistan. The level of intellectual disability was based on the intelligence quotient (IQ). In present study, out of 200 children, 80 children were suffered from this disease, 56 were males and 24 were females. Cases related to intellectual disability were identified with in different age groups such as age group 0-5 (N = 13), 6-10 (N = 27), 11-15 (N = 27), 16-20 (N = 10), 21-25 (N = 3) and 26-30 (N = 3). A total of 33.75% were belong to 6-10 years of age group. Out of 80 children 27.50% (N = 22) were affected due to malnutrition in pregnancy, 16.25% (N = 13) children had folic acid deficiency, 15% (N = 12) children were due to exposure to the chemicals or radiations in pregnancy, 21.25% (N = 17) children had hypothyroidism and 16% (N = 20) children had other gene disorder associated with intellectual disability. Proper recognition of disorder can play an important role in dealing with psychiatrists patients.

Aberrant hippocampal transmission and behavior in mice with a stargazin mutation linked to intellectual disability

Mutations linked to neurodevelopmental disorders, such as intellectual disability (ID), are frequently found in genes that encode for proteins of the excitatory synapse. Transmembrane AMPA receptor regulatory proteins (TARPs) are AMPA receptor auxiliary proteins that regulate crucial aspects of receptor function. Here, we investigate a mutant form of the TARP family member stargazin, described in an ID patient. Molecular dynamics analyses predicted that the ID-associated stargazin variant, V143L, weakens the overall interface of the AMPAR:stargazin complex and impairs the stability of the complex. Knock-in mice harboring the V143L stargazin mutation manifest cognitive and social deficits and hippocampal synaptic transmission defects, resembling phenotypes displayed by ID patients. In the hippocampus of stargazin V143L mice, CA1 neurons show impaired spine maturation, abnormal synaptic transmission and long-term potentiation specifically in basal dendrites, and synaptic ultrastructural alterations. These data suggest a causal role for mutated stargazin in the pathogenesis of ID and unveil a new role for stargazin in the development and function of hippocampal synapses.

Novel variants underlying autosomal recessive neurodevelopmental disorders with intellectual disability in Iranian consanguineous families

BackgroundIntellectual disability (ID) is a heterogeneous group of neurodevelopmental disorders that is characterized by significant impairment in intellectual and adaptive functioning with onset during the developmental period. Whole‐exome sequencing (WES)‐based studies in the consanguineous families with individuals affected with ID have shown a high burden of relevant variants. So far, over 700 genes have been reported in syndromic and non‐syndromic ID. However, genetic causes in more than 50% of ID patients still remain unclear.MethodsWhole‐exome sequencing was applied for investigation of various variants of ID, then Sanger sequencing and in silico analysis in ten patients from five Iranian consanguineous families diagnosed with autosomal recessive neurodevelopmental disorders, intellectual disability, performed for confirming the causative mutation within the probands. The most patients presented moderate‐to‐severe intellectual disability, developmental delay, seizure, speech problem, high level of lactate, and onset before 10 years.ResultsFiltering the data identified by WES, two novel homozygous missense variants in FBXO31 and TIMM50 genes and one previously reported mutation in the CEP290 gene in the probands were found. Sanger sequencing confirmed the homozygote variant's presence of TIMM50 and FBXO31 genes in six patients and two affected siblings in their respective families. Our computational results predicted that the variants are located in the conserved regions across different species and have the impacts on the protein stability.ConclusionHence, we provide evidence for the pathogenicity of two novel variants in the patients which will expand our knowledge about potential mutation involved in the heterogeneous disease.

Neurodevelopmental phenotype in 36 new patients with 8p inverted duplication-deletion: Genotype-phenotype correlation for anomalies of the corpus callosum.

Inverted duplication deletion 8p [invdupdel(8p)] is a complex and rare chromosomal rearrangement that combines a distal deletion and an inverted interstitial duplication of the short arm of chromosome 8. Carrier patients usually have developmental delay and intellectual disability (ID), associated with various cerebral and extra-cerebral malformations. Invdupdel(8p) is the most common recurrent chromosomal rearrangement in ID patients with anomalies of the corpus callosum (AnCC). Only a minority of invdupdel(8p) cases reported in the literature to date had both brain cerebral imaging and chromosomal microarray (CMA) with precise breakpoints of the rearrangements, making genotype-phenotype correlation studies for AnCC difficult. In this study, we report the clinical, radiological, and molecular data from 36 new invdupdel(8p) cases including three fetuses and five individuals from the same family, with breakpoints characterized by CMA. Among those, 97% (n=32/33) of patients presented with mild to severe developmental delay/ID and 34% had seizures with mean age of onset of 3.9 years (2 months-9 years). Moreover, out of the 24 patients with brain MRI and 3 fetuses with neuropathology analysis, 63% (n=17/27) had AnCC. We review additional data from 99 previously published patients with invdupdel(8p) and compare data of 17 patients from the literature with both CMA analysis and brain imaging to refine genotype-phenotype correlations for AnCC. This led us to refine a region of 5.1 Mb common to duplications of patients with AnCC and discuss potential candidate genes within this region.

Clinical characterization of a novel RAB39B nonstop mutation in a family with ASD and severe ID causing RAB39B downregulation and study of a Rab39b knock down mouse model.

Autism spectrum disorder (ASD) and intellectual disability (ID) often exist together in patients. The RAB39B gene has been reported to be mutated in ID patients with additional clinical features ranging from ASD, macrocephaly, seizures and/or early-onset parkinsonism. Here, we describe a novel RAB39B nonstop mutation [Xq28; c.640 T > C; p.(*214Glnext*21)] in a family with ASD, severe ID and poor motor coordination, and we assessed the pathogenicity of the mutation. A heterologous cell system and a Rab39b knockdown (KD) murine model, which mimic the nonstop mutation, were used to validate the deleterious effect of the RAB39B mutation. The mutation led to RAB39B protein instability, resulting in its increased degradation and consequent downregulation. Using a Rab39b KD mouse model, we demonstrated that the downregulation of RAB39B led to increased GluA2 lacking Ca2+-permeable AMPAR composition at the hippocampal neuronal surface and increased dendritic spine density that remained in an immature filopodia-like state. These phenotypes affected behavioural performance in a disease-specific manner. Rab39b KD mice revealed impaired social behaviour but intact social recognition. They also showed normal anxiety-like, exploratory and motivational behaviours but impaired working and associative memories. In conclusion, we found a novel RAB39B nonstop variant that segregated in a family with a clinical phenotype including ID, ASD and poor motor coordination. The pathogenicity of mutations causing the downregulation of RAB39B proteins, impacting AMPAR trafficking and dendritic spine morphogenesis, reinforced the idea that AMPAR modulation and dendritic spine assets could be considered hallmarks of neurodevelopmental disorders.

Understanding inequalities in COVID-19 outcomes following hospital admission for people with intellectual disability compared to the general population: a matched cohort study in the UK

ObjectivesThis study explores the hospital journey of patients with intellectual disabilities (IDs) compared with the general population after admission for COVID-19 during the first wave of the pandemic (when demand...

A Tiered Genetic Screening Strategy for the Molecular Diagnosis of Intellectual Disability in Chinese Patients.

Objective: Intellectual disability (ID) is one of the most common developmental disabilities. To identify the genetic etiology of IDs in Chongqing, we conducted a multistage study in Chinese Han patients. Methods: We collected the clinical and etiological data of 1665 ID patients, including 1,604 from the disabled children evaluation center and 61 from the pediatric rehabilitation unit. Routine genetic screening results were obtained, including karyotype and candidate gene analysis. Then 105 idiopathic cases with syndromic and severe ID/developmental delay (DD) were selected and tested by chromosomal microarray (CMA) and whole exome sequencing (WES) sequentially. The pathogenicity of the CNVs and SNVs were evaluated according to ACMG guidelines. Results: Molecular diagnosis was made by routine genetic screening in 216 patients, including 196 chromosomal syndromes. Among the 105 idiopathic patients, 49 patients with pathogenic/likely pathogenic CNVs and 21 patients with VUS were identified by CMA. Twenty-six pathogenic CNVs underlying well-known syndromic cases, such as Williams-Beuren syndrome, were confirmed by multiplex ligation-dependent probe amplification (MLPA). Nine novel mutations were identified by WES in thirty-fix CNV-negative ID cases. Conclusions: The study illustrated the genetic aberrations distribution of a large ID cohort in Chongqing. Compared with conventional or single methods, a tiered high-throughput diagnostic strategy was developed to greatly improve the diagnostic yields and extend the variation spectrum for idiopathic syndromic ID cases.

Altered Gene Expression Profiles in Neural Stem Cells Derived from Duchenne Muscular Dystrophy Patients with Intellectual Disability.

Intellectual disability (ID) is a neurodevelopmental disorder defined by below-average intelligence (intelligence quotient of <70) accompanied by adaptive behavior deficits. Defects in the functions of neural stem cells during brain development are closely linked to the pathogenesis of ID. To understand the molecular etiology of ID, we examined neural stem cells from individuals with Duchenne muscular dystrophy (DMD), a genetic disorder in which approximately one-third of the patients exhibit ID. In this study, we generated induced pluripotent stem cells from peripheral blood mononuclear cells from a normal individual and DMD patients with and without ID to identify ID-specific functional and molecular abnormalities. We found defects in neural ectoderm formation in the group of DMD patients with ID. Our transcriptome analysis of patient-derived neural stem cells revealed altered expression of genes related to the hippo signaling pathway and neuroactive ligand-receptor interaction, implicating these in the pathogenesis of ID in patients with DMD.