Publications by authors named "Neelroop Parikshak"

Microglia are the resident immune cells of the central nervous system and are involved in brain development, homeostasis, and disease. New imaging and genomics technologies are revealing microglial complexity across developmental and functional states, brain regions, and diseases. We curated a set of publicly available gene expression datasets from human microglia spanning disease and health to identify sets of genes reflecting physiological and pathological microglial states.

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  • The genetic factors contributing to stroke risk in South Asians remain largely unstudied, with a recent study examining 75,000 Pakistanis using exome-wide sequencing.
  • A specific genetic variant, NOTCH3 p.Arg1231Cys, was found to be more common in South Asians (0.58%) compared to Western Europeans (0.019%) and was significantly linked to hemorrhagic and overall stroke risk.
  • This variant accounts for about 2.0% of hemorrhagic strokes and 1.1% of all strokes in South Asians, emphasizing the importance of including diverse populations in genetic research for better understanding and treatment of stroke.
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Anterior Uveitis (AU) is the inflammation of the anterior part of the eye, the iris and ciliary body and is strongly associated with HLA-B*27. We report AU exome sequencing results from eight independent cohorts consisting of 3,850 cases and 916,549 controls. We identify common genome-wide significant loci in HLA-B (OR = 3.

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Radial glial (RG) development is essential for cerebral cortex growth and organization. In humans, the outer radial glia (oRG) subtype is expanded and gives rise to diverse neurons and glia. However, the mechanisms regulating oRG differentiation are unclear.

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Human genetic studies of smoking behavior have been thus far largely limited to common variants. Studying rare coding variants has the potential to identify drug targets. We performed an exome-wide association study of smoking phenotypes in up to 749,459 individuals and discovered a protective association in CHRNB2, encoding the β2 subunit of the α4β2 nicotine acetylcholine receptor.

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Clonal haematopoiesis involves the expansion of certain blood cell lineages and has been associated with ageing and adverse health outcomes. Here we use exome sequence data on 628,388 individuals to identify 40,208 carriers of clonal haematopoiesis of indeterminate potential (CHIP). Using genome-wide and exome-wide association analyses, we identify 24 loci (21 of which are novel) where germline genetic variation influences predisposition to CHIP, including missense variants in the lymphocytic antigen coding gene LY75, which are associated with reduced incidence of CHIP.

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Neuropsychiatric disorders classically lack defining brain pathologies, but recent work has demonstrated dysregulation at the molecular level, characterized by transcriptomic and epigenetic alterations. In autism spectrum disorder (ASD), this molecular pathology involves the upregulation of microglial, astrocyte and neural-immune genes, the downregulation of synaptic genes, and attenuation of gene-expression gradients in cortex. However, whether these changes are limited to cortical association regions or are more widespread remains unknown.

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  • SARS-CoV-2 can infect a variety of cell types, severely affecting respiratory function and causing neurological symptoms in about one-third of COVID-19 cases.
  • Research using stem-cell-derived cortical organoids and human cortical tissue revealed that SARS-CoV-2 predominantly infects astrocytes in the brain, leading to increased inflammation and cellular stress.
  • Despite the lack of ACE2 expression in astrocytes, the presence of coreceptors CD147 and DPP4 is linked to the infection's severity, indicating that manipulating these coreceptors could influence the infection rate.
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The development of autoimmune antibody panels has improved the diagnosis of paraneoplastic neurological disorders (PNDs) of the brain and spinal cord. Here, we present a case of a woman with a history of breast cancer who presented with a subacute sensory ataxia that progressed over 18 months. Her examination and diagnostic studies were consistent with a myelopathy.

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(Gandal et al., "Shared molecular neuropathology across major psychiatric disorders parallels polygenic overlap" Science 09 Feb 2018:Vol. 359, Issue 6376, pp.

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  • - The study investigates the role of DNA methylation in Autism Spectrum Disorder (ASD) by analyzing brain tissue samples from 43 ASD patients and 38 control donors, focusing on three brain regions: the prefrontal cortex, temporal cortex, and cerebellum.
  • - Significant differences in DNA methylation patterns were found in individuals with idiopathic ASD (iASD) and in those with a specific genetic subtype of ASD (dup15q), highlighting distinct molecular changes linked to the disorder.
  • - The findings indicate that both iASD and dup15q share common methylomic signatures related to genes tied to the immune system and neuronal functioning, representing a comprehensive analysis of how DNA methylation is associated with ASD across different
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Background: Williams syndrome (WS) is a neurodevelopmental disorder that has been attributed to heterozygous deletions in chromosome 7q11.23 and exhibits a variety of physical, cognitive, and behavioral features. However, the genetic basis of this phenotypic variability is unclear.

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  • Common genetic factors contribute to autism spectrum disorder (ASD) through risk gene variants that have minimal individual effects, alongside environmental influences that disrupt neurodevelopment.
  • Cytoplasmic polyadenylation element binding proteins (CPEB1-4) are crucial for regulating the translation of specific mRNAs during development, and CPEB4 is particularly linked to many high-confidence ASD risk genes.
  • In individuals with idiopathic ASD, imbalances in CPEB4 transcripts lead to shorter poly(A)-tails and reduced expression of ASD risk gene proteins, and similar disruptions in mice produce ASD-like characteristics, implicating CPEB4 as a key regulator in ASD.
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Change history: In this Letter, the labels for splicing events A3SS and A5SS were swapped in column D of Supplementary Table 3a and b. This has been corrected online.

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A fundamental question in the biology of sex differences has eluded direct study in humans: How does sex-chromosome dosage (SCD) shape genome function? To address this, we developed a systematic map of SCD effects on gene function by analyzing genome-wide expression data in humans with diverse sex-chromosome aneuploidies (XO, XXX, XXY, XYY, and XXYY). For sex chromosomes, we demonstrate a pattern of obligate dosage sensitivity among evolutionarily preserved X-Y homologs and update prevailing theoretical models for SCD compensation by detecting X-linked genes that increase expression with decreasing X- and/or Y-chromosome dosage. We further show that SCD-sensitive sex-chromosome genes regulate specific coexpression networks of SCD-sensitive autosomal genes with critical cellular functions and a demonstrable potential to mediate previously documented SCD effects on disease.

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Background: Genetic studies in autism have pinpointed a heterogeneous group of loci and genes. Further, environment may be an additional factor conferring susceptibility to autism. Transcriptome studies investigate quantitative differences in gene expression between patient-derived tissues and control.

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The predisposition to neuropsychiatric disease involves a complex, polygenic, and pleiotropic genetic architecture. However, little is known about how genetic variants impart brain dysfunction or pathology. We used transcriptomic profiling as a quantitative readout of molecular brain-based phenotypes across five major psychiatric disorders-autism, schizophrenia, bipolar disorder, depression, and alcoholism-compared with matched controls.

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Autism spectrum disorder (ASD) involves substantial genetic contributions. These contributions are profoundly heterogeneous but may converge on common pathways that are not yet well understood. Here, through post-mortem genome-wide transcriptome analysis of the largest cohort of samples analysed so far, to our knowledge, we interrogate the noncoding transcriptome, alternative splicing, and upstream molecular regulators to broaden our understanding of molecular convergence in ASD.

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The association of histone modification changes with autism spectrum disorder (ASD) has not been systematically examined. We conducted a histone acetylome-wide association study (HAWAS) by performing H3K27ac chromatin immunoprecipitation sequencing (ChIP-seq) on 257 postmortem samples from ASD and matched control brains. Despite etiological heterogeneity, ≥68% of syndromic and idiopathic ASD cases shared a common acetylome signature at >5,000 cis-regulatory elements in prefrontal and temporal cortex.

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Hundreds of genetic loci increasing risk for neuropsychiatric disorders have recently been identified. This success, perhaps paradoxically, has posed challenges for therapeutic development, which are amplified by the highly polygenic and pleiotropic nature of these genetic contributions. Success requires understanding the biological impact of single genetic variants and predicting their effects within an individual.

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Three-dimensional physical interactions within chromosomes dynamically regulate gene expression in a tissue-specific manner. However, the 3D organization of chromosomes during human brain development and its role in regulating gene networks dysregulated in neurodevelopmental disorders, such as autism or schizophrenia, are unknown. Here we generate high-resolution 3D maps of chromatin contacts during human corticogenesis, permitting large-scale annotation of previously uncharacterized regulatory relationships relevant to the evolution of human cognition and disease.

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Genetic variants conferring risk for autism spectrum disorder (ASD) have been identified, but the role of post-transcriptional mechanisms in ASD is not well understood. We performed genome-wide microRNA (miRNA) expression profiling in post-mortem brains from individuals with ASD and controls and identified miRNAs and co-regulated modules that were perturbed in ASD. Putative targets of these ASD-affected miRNAs were enriched for genes that have been implicated in ASD risk.

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Autism spectrum disorder (ASD) is more prevalent in males, and the mechanisms behind this sex-differential risk are not fully understood. Two competing, but not mutually exclusive, hypotheses are that ASD risk genes are sex-differentially regulated, or alternatively, that they interact with characteristic sexually dimorphic pathways. Here we characterized sexually dimorphic gene expression in multiple data sets from neurotypical adult and prenatal human neocortical tissue, and evaluated ASD risk genes for evidence of sex-biased expression.

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