Publications by authors named "Mehdi Zarrei"

Article Synopsis
  • - The study investigates the genetic relationship between Adolescent Idiopathic Scoliosis (AIS) and Schizophrenia (SCZ), particularly focusing on the 22q11.2 deletion syndrome, which greatly increases the risk for both conditions in adolescents.
  • - Researchers utilized data from three genome-wide association studies (GWAS) to analyze single nucleotide polymorphisms (SNPs) linked to both AIS and SCZ, while also examining gene networks related to the 22q11.2 region.
  • - Findings showed a significant genetic overlap between AIS and SCZ, with the most impactful SNPs forming a meaningful enrichment cluster, indicating a potential shared biological pathway.
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We performed whole-genome sequencing (WGS) in 327 children with cerebral palsy (CP) and their biological parents. We classified 37 of 327 (11.3%) children as having pathogenic/likely pathogenic (P/LP) variants and 58 of 327 (17.

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The genetic correlates of extreme impulsive violence are poorly understood, and there have been few studies that have characterized a large group of affected individuals both clinically and genetically. We performed whole exome sequencing (WES) in 290 males with the life-course-persistent, extremely impulsively violent form of antisocial personality disorder (APD) and analyzed the spectrum of rare protein-truncating variants (rPTVs). Comparisons were made with 314 male controls and publicly available genotype data.

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Background: We present genomic and phenotypic findings of a transgenerational family consisting of three male offspring, each with a maternally inherited distal 220 kb deletion at locus 16p11.2 (BP2-BP3). Genomic analysis of all family members was prompted by a diagnosis of autism spectrum disorder (ASD) in the eldest child, who also presented with a low body mass index.

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De novo variants (DNVs) analysis has proven to be a powerful approach to gene discovery in Autism Spectrum Disorder (ASD), which has not yet been shown in a Brazilian ASD cohort. The relevance of inherited rare variants has also been suggested, particularly in oligogenic models. We hypothesized that three-generation analyses of DNVs could provide new insights into the relevance of de novo and inherited variants across generations.

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Article Synopsis
  • - The study examined gene copy number variation (CNV) in a large group of 7,100 children and youth, focusing on its impact on mental health, cognitive functioning, and physical health.
  • - Clinically relevant CNVs were found in 3.9% of participants and were linked to higher ADHD traits, cognitive deficits, and increased occurrence of specific mental health diagnoses like ADHD, autism spectrum disorder, and learning disorders.
  • - The research highlights the role of rare genetic deletions in brain-related gene sets, suggesting they contribute to ADHD characteristics, and sets a baseline for understanding genetic factors in mental health issues among youth during a growing crisis.
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Background: The X-linked PTCHD1 locus is strongly associated with autism spectrum disorder (ASD). Males who carry chromosome microdeletions of PTCHD1 antisense long non-coding RNA (PTCHD1-AS)/DEAD-box helicase 53 (DDX53) have ASD, or a sub-clinical form called Broader Autism Phenotype. If the deletion extends beyond PTCHD1-AS/DDX53 to the next gene, PTCHD1, which is protein-coding, the individuals typically have ASD and intellectual disability (ID).

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Copy number variants (CNVs) represent major etiologic factors in rare genetic diseases. Current clinical CNV interpretation workflows require extensive back-and-forth with multiple tools and databases. This increases complexity and time burden, potentially resulting in missed genetic diagnoses.

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Article Synopsis
  • Full understanding of autism spectrum disorder (ASD) genetics requires whole-genome sequencing (WGS), highlighted by the latest Autism Speaks MSSNG resource that includes data from over 11,000 individuals.
  • The study found ASD-associated rare genetic variants in about 14% of individuals with ASD, examining data from MSSNG and the Simons Simplex Collection, which suggests similar prevalence in both datasets.
  • The identified variants were mostly nuclear (98%) with a small fraction being mitochondrial, and the research aims to help explore genetic links to ASD traits and identify causes for the 85% of ASD cases that currently lack identified genetic causes.
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Article Synopsis
  • Research identifies distinct genetic subtypes of autism spectrum disorder (ASD) by analyzing physical traits, categorizing 325 Canadian children with ASD into dysmorphic and nondysmorphic groups.
  • A novel genome-wide rare variant score (GRVS) was developed to assess genetic variants, revealing that children with dysmorphic ASD exhibit significantly higher GRVS than those without physical anomalies.
  • Additional analysis using a polygenic transmission test showed that common ASD variants are more prevalent in nondysmorphic probands, supporting a new classification approach based on morphology to guide treatment strategies.
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Oligogenic inheritance of autism spectrum disorder (ASD) has been supported by several studies. However, little is known about how the risk variants interact and converge on causative neurobiological pathways. We identified in an ASD proband deleterious compound heterozygous missense variants in the Reelin (RELN) gene, and a de novo splicing variant in the Cav3.

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Cerebral organoids have emerged as robust models for neurodevelopmental and pathological processes, as well as a powerful discovery platform for less-characterized neurobiological programs. Toward this prospect, we leverage mass-spectrometry-based proteomics to molecularly profile precursor and neuronal compartments of both human-derived organoids and mid-gestation fetal brain tissue to define overlapping programs. Our analysis includes recovery of precursor-enriched transcriptional regulatory proteins not found to be differentially expressed in previous transcriptomic datasets.

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Autism Spectrum Disorder (ASD) is characterized by impaired social communication, restricted interests, and repetitive and stereotyped behaviors. The TRPC6 (transient receptor potential channel 6) represents an ASD candidate gene under an oligogenic/multifactorial model based on the initial description and cellular characterization of an individual with ASD bearing a de novo heterozygous mutation disrupting TRPC6, together with the enrichment of disruptive TRPC6 variants in ASD cases as compared to controls. Here, we perform a clinical re-evaluation of the initial non-verbal patient, and also present eight newly reported individuals ascertained for ASD and bearing predicted loss-of-function mutations in TRPC6.

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Copy number variants (CNVs) are recognized as a crucial genetic cause of neurodevelopmental disorders (NDDs). Chromosomal microarray analysis (CMA), the first-tier diagnostic test for individuals with NDDs, has been utilized to detect CNVs in clinical practice, but most reports are still from populations of European ancestry. To contribute more worldwide clinical genomics data, we investigated the genetic etiology of 410 Han Chinese patients with NDDs (151 with autism and 259 with unexplained intellectual disability (ID) and developmental delay (DD)) using CMA (Affymetrix) after G-banding karyotyping.

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This study examines 2 gene-level metrics of variation constraint against protein-truncating variants—probability of loss-of-function intolerance and loss-of-function observed/expected upper bound fraction—and their association with the psychiatric consequences of both recurrent and nonrecurrent gene deletions.

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Background: In recent years, several hundred autism spectrum disorder (ASD) implicated genes have been discovered impacting a wide range of molecular pathways. However, the molecular underpinning of ASD, particularly from the point of view of 'brain to behaviour' pathogenic mechanisms, remains largely unknown.

Methods: We undertook a study to investigate patterns of spatiotemporal and cell type expression of ASD-implicated genes by integrating large-scale brain single-cell transcriptomes (> million cells) and de novo loss-of-function (LOF) ASD variants (impacting 852 genes from 40,122 cases).

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In more than one-third of primary immunodeficiency (PID) patients, extensive genetic analysis including whole-exome sequencing (WES) fails to identify the genetic defect. Whole-genome sequencing (WGS) is able to detect variants missed by other genomics platforms, enabling the molecular diagnosis of otherwise unresolved cases. Here, we report two siblings, offspring of consanguineous parents, who experienced similar severe events encompassing early onset of colitis, lymphoproliferation, and hypogammaglobulinemia, typical of lipopolysaccharide-responsive and beige-like anchor (LRBA) or cytotoxic T lymphocyte antigen 4 (CTLA4) deficiencies.

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Article Synopsis
  • - Autism Spectrum Disorder (ASD) is influenced by a complex array of genetic factors, with around 100 known copy number variants and genes associated with the condition, prompting researchers to explore specific damaging mutations in affected genes.
  • - The study identified a common mutation in the SHANK3 gene (c.3679dup; p.Ala1227Glyfs*69) present in 18 individuals from 16 families, which is found in about 0.08% of those with ASD, with many individuals having new mutations while some inherited it through somatic mosaicism.
  • - Analysis of individuals with the SHANK3 mutation revealed that all tested had an ASD diagnosis, but the expression of core ASD features varied significantly
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Prediction of pathogenicity of rare copy number variations (CNVs), a genomic alteration known to contribute to the etiology of autism spectrum disorder (ASD), represents a serious limitation to interpreting genetic tests, particularly for genetic counseling purposes. Chromosomal microarray analysis (CMA) was conducted in a unique collection of 144 Brazilian individuals with ASD of strong European and African ancestries. Rare CNVs were detected in 39 patients: 41 of unknown significance (VUS), four pathogenic and one likely pathogenic CNVs (clinical yield of 4.

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Purpose: Much of the heredity of melanoma remains unexplained. We sought predisposing germline copy-number variants using a rare disease approach.

Methods: Whole-genome copy-number findings in patients with melanoma predisposition syndrome congenital melanocytic nevus were extrapolated to a sporadic melanoma cohort.

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Mendelian and early-onset severe psychiatric phenotypes often involve genetic variants having a large effect, offering opportunities for genetic discoveries and early therapeutic interventions. Here, the index case is an 18-year-old boy, who at 14 years of age had a decline in cognitive functioning over the course of a year and subsequently presented with catatonia, auditory and visual hallucinations, paranoia, aggression, mood dysregulation, and disorganized thoughts. Exome sequencing revealed a stop-gain mutation in RCL1 (NM_005772.

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Recent genome-wide studies of rare genetic variants have begun to implicate novel mechanisms for tetralogy of Fallot (TOF), a severe congenital heart defect (CHD). To provide statistical support for case-only data without parental genomes, we re-analyzed genome sequences of 231 individuals with TOF ( = 175) or related CHD. We adapted a burden test originally developed for variants to assess ultra-rare variant burden in individual genes, and in gene-sets corresponding to functional pathways and mouse phenotypes, accounting for highly correlated gene-sets and for multiple testing.

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Background: Pediatric high-grade gliomas (pHGGs) are incurable malignant brain cancers. Clear somatic genetic drivers are difficult to identify in the majority of cases. We hypothesized that this may be due to the existence of germline variants that influence tumor etiology and/or progression and are filtered out using traditional pipelines for somatic mutation calling.

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Autism spectrum disorder (ASD) is a relatively common childhood onset neurodevelopmental disorder with a complex genetic etiology. While progress has been made in identifying the de novo mutational landscape of ASD, the genetic factors that underpin the ASD's tendency to run in families are not well understood. In this study, nine extended pedigrees each with three or more individuals with ASD, and others with a lesser autism phenotype, were phenotyped and genotyped in an attempt to identify heritable copy number variants (CNVs).

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Chromosome 15q24 microdeletion syndrome is characterized by developmental delay, facial dysmorphism, hearing loss, hypotonia, recurrent infection, and other congenital malformations including microcephaly, scoliosis, joint laxity, digital anomalies, as well as sometimes having autism spectrum disorder (ASD) and attention deficit hyperactivity disorder. Here, we report a boy with a 2.58-Mb de novo deletion at chromosome 15q24.

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