Browsing by Subject "Neurodevelopmental disorder"

Now showing 1 - 7 of 7
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    Deoxyhypusine synthase deficiency syndrome zebrafish model: aberrant morphology, epileptiform activity, and reduced arborization of inhibitory interneurons
    (Springer Nature, 2024-09-27) Shojaeinia, Elham; Mastracci, Teresa L.; Soliman, Remon; Devinsky, Orrin; Esguerra, Camila V.; Crawford, Alexander D.; Biology, School of Science
    DHPS deficiency syndrome is an ultra-rare neurodevelopmental disorder (NDD) which results from biallelic mutations in the gene encoding the enzyme deoxyhypusine synthase (DHPS). DHPS is essential to synthesize hypusine, a rare amino acid formed by post-translational modification of a conserved lysine in eukaryotic initiation factor 5 A (eIF5A). DHPS deficiency syndrome causes epilepsy, cognitive and motor impairments, and mild facial dysmorphology. In mice, a brain-specific genetic deletion of Dhps at birth impairs eIF5AHYP-dependent mRNA translation. This alters expression of proteins required for neuronal development and function, and phenotypically models features of human DHPS deficiency. We studied the role of DHPS in early brain development using a zebrafish loss-of-function model generated by knockdown of dhps expression with an antisense morpholino oligomer (MO) targeting the exon 2/intron 2 (E2I2) splice site of the dhps pre-mRNA. dhps knockdown embryos exhibited dose-dependent developmental delay and dysmorphology, including microcephaly, axis truncation, and body curvature. In dhps knockdown larvae, electrophysiological analysis showed increased epileptiform activity, and confocal microscopy analysis revealed reduced arborisation of GABAergic neurons. Our findings confirm that hypusination of eIF5A by DHPS is needed for early brain development, and zebrafish with an antisense knockdown of dhps model features of DHPS deficiency syndrome.
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    HNRNPC haploinsufficiency affects alternative splicing of intellectual disability-associated genes and causes a neurodevelopmental disorder
    (Elsevier, 2023) Niggl, Eva; Bouman, Arjan; Briere, Lauren C.; Hoogenboezem, Remco M.; Wallaard, Ilse; Park, Joohyun; Admard, Jakob; Wilke, Martina; Harris-Mostert, Emilio D. R. O.; Elgersma, Minetta; Bain, Jennifer; Balasubramanian, Meena; Banka, Siddharth; Benke, Paul J.; Bertrand, Miriam; Blesson, Alyssa E.; Clayton-Smith, Jill; Ellingford, Jamie M.; Gillentine, Madelyn A.; Goodloe, Dana H.; Haack, Tobias B.; Jain, Mahim; Krantz, Ian; Luu, Sharon M.; McPheron, Molly; Muss, Candace L.; Raible, Sarah E.; Robin, Nathaniel H.; Spiller, Michael; Starling, Susan; Sweetser, David A.; Thiffault, Isabelle; Vetrini, Francesco; Witt, Dennis; Woods, Emily; Zhou, Dihong; Genomics England Research Consortium; Undiagnosed Diseases Network; Elgersma, Ype; van Esbroeck, Annelot C. M.; Medical and Molecular Genetics, School of Medicine
    Heterogeneous nuclear ribonucleoprotein C (HNRNPC) is an essential, ubiquitously abundant protein involved in mRNA processing. Genetic variants in other members of the HNRNP family have been associated with neurodevelopmental disorders. Here, we describe 13 individuals with global developmental delay, intellectual disability, behavioral abnormalities, and subtle facial dysmorphology with heterozygous HNRNPC germline variants. Five of them bear an identical in-frame deletion of nine amino acids in the extreme C terminus. To study the effect of this recurrent variant as well as HNRNPC haploinsufficiency, we used induced pluripotent stem cells (iPSCs) and fibroblasts obtained from affected individuals. While protein localization and oligomerization were unaffected by the recurrent C-terminal deletion variant, total HNRNPC levels were decreased. Previously, reduced HNRNPC levels have been associated with changes in alternative splicing. Therefore, we performed a meta-analysis on published RNA-seq datasets of three different cell lines to identify a ubiquitous HNRNPC-dependent signature of alternative spliced exons. The identified signature was not only confirmed in fibroblasts obtained from an affected individual but also showed a significant enrichment for genes associated with intellectual disability. Hence, we assessed the effect of decreased and increased levels of HNRNPC on neuronal arborization and neuronal migration and found that either condition affects neuronal function. Taken together, our data indicate that HNRNPC haploinsufficiency affects alternative splicing of multiple intellectual disability-associated genes and that the developing brain is sensitive to aberrant levels of HNRNPC. Hence, our data strongly support the inclusion of HNRNPC to the family of HNRNP-related neurodevelopmental disorders.
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    Initial analysis of peripheral lymphocytic extracellular signal related kinase activation in autism
    (Elsevier, 2017-01) Erickson, Craig A.; Ray, Balmiki; Wink, Logan K.; Bayon, Baindu L.; Pedapat, Ernest V.; Shaffer, Rebecca; Schaefer, Tori L.; Lahiri, Debomoy K.; Psychiatry, School of Medicine
    BACKGROUND: Dysregulation of extracellular signal-related kinase (ERK) activity has been potentially implicated in the pathophysiology of autistic disorder (autism). ERK is part of a central intracellular signaling cascade responsible for a myriad of cellular functions. ERK is expressed in peripheral blood lymphocytes, and measurement of activated (phosphorylated) lymphocytic ERK is commonly executed in many areas of medicine. We sought to conduct the first study of ERK activation in humans with autism by utilizing a lymphocytic ERK activation assay. We hypothesized that ERK activation would be enhanced in peripheral blood lymphocytes from persons with autism compared to those of neurotypical control subjects. METHOD: We conducted an initial study of peripheral lymphocyte ERK activation in 45 subjects with autism and 26 age- and gender-matched control subjects (total n = 71). ERK activation was measured using a lymphocyte counting method (primary outcome expressed as lymphocytes staining positive for cytosolic phosphorylated ERK divided by total cells counted) and additional Western blot analysis of whole cell phosphorylated ERK adjusted for total ERK present in the lymphocyte lysate sample. RESULTS: Cytosolic/nuclear localization of pERK activated cells were increased by almost two-fold in the autism subject group compared to matched neurotypical control subjects (cell count ratio of 0.064 ± 0.044 versus 0.034 ± 0.031; p = 0.002). Elevated phosphorylated ERK levels in whole cell lysates also showed increased activated ERK in the autism group compared to controls (n = 54 total) in Western blot analysis. CONCLUSIONS: The results of this first in human ERK activation study are consistent with enhanced peripheral lymphocytic ERK activation in autism, as well as suggesting that cellular compartmentalization of activated ERK may be altered in this disorder. Future work will be required to explore the impact of concomitant medication use and other subject characteristics such as level of cognitive functioning on ERK activation.
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    Neuron-specific ablation of eIF5A or deoxyhypusine synthase leads to impairments in growth, viability, neurodevelopment, and cognitive functions in mice
    (Elsevier, 2021) Kar, Rajesh Kumar; Hanner, Ashleigh S.; Starost, Matthew F.; Springer, Danielle; Mastracci, Teresa L.; Mirmira, Raghavendra G.; Park, Myung Hee; Biology, School of Science
    Eukaryotic initiation factor 5A (eIF5A)†, ‡ is an essential protein that requires a unique amino acid, hypusine, for its activity. Hypusine is formed exclusively in eIF5A post-translationally via two enzymes, deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase. Each of the genes encoding these proteins, Eif5a, Dhps, and Dohh, is required for mouse embryonic development. Variants in EIF5A or DHPS were recently identified as the genetic basis underlying certain rare neurodevelopmental disorders in humans. To investigate the roles of eIF5A and DHPS in brain development, we generated four conditional KO mouse strains using the Emx1-Cre or Camk2a-Cre strains and examined the effects of temporal- and region-specific deletion of Eif5a or Dhps. The conditional deletion of Dhps or Eif5a by Emx1 promotor–driven Cre expression (E9.5, in the cortex and hippocampus) led to gross defects in forebrain development, reduced growth, and premature death. On the other hand, the conditional deletion of Dhps or Eif5a by Camk2a promoter–driven Cre expression (postnatal, mainly in the CA1 region of the hippocampus) did not lead to global developmental defects; rather, these KO animals exhibited severe impairment in spatial learning, contextual learning, and memory when subjected to the Morris water maze and a contextual learning test. In both models, the Dhps-KO mice displayed more severe impairment than their Eif5a-KO counterparts. The observed defects in the brain, global development, or cognitive functions most likely result from translation errors due to a deficiency in active, hypusinated eIF5A. Our study underscores the important roles of eIF5A and DHPS in neurodevelopment.
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    Recessive Rare Variants in Deoxyhypusine Synthase, an Enzyme Involved in the Synthesis of Hypusine, Are Associated with a Neurodevelopmental Disorder
    (Elsevier, 2019-02-07) Ganapathi, Mythily; Padgett, Leah R.; Yamada, Kentaro; Devinsky, Orrin; Willaert, Rebecca; Person, Richard; Au, Ping-Yee Billie; Tagoe, Julia; McDonald, Marie; Karlowicz, Danielle; Wolf, Barry; Lee, Joanna; Shen, Yufeng; Okur, Volkan; Deng, Liyong; LeDuc, Charles A.; Wang, Jiayao; Hanner, Ashleigh; Mirmira, Raghavendra G.; Park, Myung Hee; Mastracci, Teresa L.; Chung, Wendy K.; Pediatrics, School of Medicine
    Hypusine is formed post-translationally from lysine and is found in a single cellular protein, eukaryotic translation initiation factor-5A (eIF5A), and its homolog eIF5A2. Biosynthesis of hypusine is a two-step reaction involving the enzymes deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase (DOHH). eIF5A is highly conserved throughout eukaryotic evolution and plays a role in mRNA translation, cellular proliferation, cellular differentiation, and inflammation. DHPS is also highly conserved and is essential for life, as Dhps-null mice are embryonic lethal. Using exome sequencing, we identified rare biallelic, recurrent, predicted likely pathogenic variants in DHPS segregating with disease in five affected individuals from four unrelated families. These individuals have similar neurodevelopmental features that include global developmental delay and seizures. Two of four affected females have short stature. All five affected individuals share a recurrent missense variant (c.518A>G [p.Asn173Ser]) in trans with a likely gene disrupting variant (c.1014+1G>A, c.912_917delTTACAT [p.Tyr305_Ile306del], or c.1A>G [p.Met1?]). cDNA studies demonstrated that the c.1014+1G>A variant causes aberrant splicing. Recombinant DHPS enzyme harboring either the p.Asn173Ser or p.Tyr305_Ile306del variant showed reduced (20%) or absent in vitro activity, respectively. We co-transfected constructs overexpressing HA-tagged DHPS (wild-type or mutant) and GFP-tagged eIF5A into HEK293T cells to determine the effect of these variants on hypusine biosynthesis and observed that the p.Tyr305_Ile306del and p.Asn173Ser variants resulted in reduced hypusination of eIF5A compared to wild-type DHPS enzyme. Our data suggest that rare biallelic variants in DHPS result in reduced enzyme activity that limits the hypusination of eIF5A and are associated with a neurodevelopmental disorder.
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    The clinical and genetic spectrum of inherited glycosylphosphatidylinositol deficiency disorders
    (Oxford University Press, 2024) Sidpra, Jai; Sudhakar, Sniya; Biswas, Asthik; Massey, Flavia; Turchetti, Valentina; Lau, Tracy; Cook, Edward; Alvi, Javeria Raza; Elbendary, Hasnaa M.; Jewell, Jerry L.; Riva, Antonella; Orsini, Alessandro; Vignoli, Aglaia; Federico, Zara; Rosenblum, Jessica; Schoonjans, An-Sofie; de Wachter, Matthias; Alvarez, Ignacio Delgado; Felipe-Rucián, Ana; Haridy, Nourelhoda A.; Haider, Shahzad; Zaman, Mashaya; Banu, Selina; Anwaar, Najwa; Rahman, Fatima; Maqbool, Shazia; Yadav, Rashmi; Salpietro, Vincenzo; Maroofian, Reza; Patel, Rajan; Radhakrishnan, Rupa; Prabhu, Sanjay P.; Lichtenbelt, Klaske; Stewart, Helen; Murakami, Yoshiko; Löbel, Ulrike; D'Arco, Felice; Wakeling, Emma; Jones, Wendy; Hay, Eleanor; Bhate, Sanjay; Jacques, Thomas S.; Mirsky, David M.; Whitehead, Matthew T.; Zaki, Maha S.; Sultan, Tipu; Striano, Pasquale; Jansen, Anna C.; Lequin, Maarten; de Vries, Linda S.; Severino, Mariasavina; Edmondson, Andrew C.; Menzies, Lara; Campeau, Philippe M.; Houlden, Henry; McTague, Amy; Efthymiou, Stephanie; Mankad, Kshitij; Radiology and Imaging Sciences, School of Medicine
    Inherited glycosylphosphatidylinositol deficiency disorders (IGDs) are a group of rare multisystem disorders arising from pathogenic variants in glycosylphosphatidylinositol anchor pathway (GPI-AP) genes. Despite associating 24 of at least 31 GPI-AP genes with human neurogenetic disease, prior reports are limited to single genes without consideration of the GPI-AP as a whole and with limited natural history data. In this multinational retrospective observational study, we systematically analyse the molecular spectrum, phenotypic characteristics and natural history of 83 individuals from 75 unique families with IGDs, including 70 newly reported individuals; the largest single cohort to date. Core clinical features were developmental delay or intellectual disability (DD/ID, 90%), seizures (83%), hypotonia (72%) and motor symptoms (64%). Prognostic and biologically significant neuroimaging features included cerebral atrophy (75%), cerebellar atrophy (60%), callosal anomalies (57%) and symmetric restricted diffusion of the central tegmental tracts (60%). Sixty-one individuals had multisystem involvement including gastrointestinal (66%), cardiac (19%) and renal (14%) anomalies. Though dysmorphic features were appreciated in 82%, no single dysmorphic feature had a prevalence >30%, indicating substantial phenotypic heterogeneity. Follow-up data were available for all individuals, 15 of whom were deceased at the time of writing. Median age at seizure onset was 6 months. Individuals with variants in synthesis stage genes of the GPI-AP exhibited a significantly shorter time to seizure onset than individuals with variants in transamidase and remodelling stage genes of the GPI-AP (P = 0.046). Forty individuals had intractable epilepsy. The majority of individuals experienced delayed or absent speech (95%), motor delay with non-ambulance (64%), and severe-to-profound DD/ID (59%). Individuals with a developmental epileptic encephalopathy (51%) were at greater risk of intractable epilepsy (P = 0.003), non-ambulance (P = 0.035), ongoing enteral feeds (P < 0.001) and cortical visual impairment (P = 0.007). Serial neuroimaging showed progressive cerebral volume loss in 87.5% and progressive cerebellar atrophy in 70.8%, indicating a neurodegenerative process. Genetic analyses identified 93 unique variants (106 total), including 22 novel variants. Exploratory analyses of genotype-phenotype correlations using unsupervised hierarchical clustering identified novel genotypic predictors of clinical phenotype and long-term outcome with meaningful implications for management. In summary, we expand both the mild and severe phenotypic extremities of the IGDs, provide insights into their neurological basis, and vitally, enable meaningful genetic counselling for affected individuals and their families.
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    Trajectory Analysis for Identifying Classes of Attention Deficit Hyperactivity Disorder (ADHD) in Children of the United States
    (Bentham Open, 2024-05-21) Lee, Yu-Sheng; Sprong, Matthew Evan; Shrestha, Junu; Smeltzer, Matthew P.; Hollender, Heaven; Health Sciences, School of Health and Human Sciences
    Background: Attention Deficit Hyperactivity Disorder (ADHD) is a mental health disorder that affects attention and behavior. People with ADHD frequently encounter challenges in social interactions, facing issues, like social rejection and difficulties in interpersonal relationships, due to their inattention, impulsivity, and hyperactivity. Methods: A National Longitudinal Survey of Youth (NLSY) database was employed to identify patterns of ADHD symptoms. The children who were born to women in the NLSY study between 1986 and 2014 were included. A total of 1,847 children in the NLSY 1979 cohort whose hyperactivity/inattention score was calculated when they were four years old were eligible for this study. A trajectory modeling method was used to evaluate the trajectory classes. Sex, baseline antisocial score, baseline anxiety score, and baseline depression score were adjusted to build the trajectory model. We used stepwise multivariate logistic regression models to select the risk factors for the identified trajectories. Results: The trajectory analysis identified six classes for ADHD, including (1) no sign class, (2) few signs since preschool being persistent class, (3) few signs in preschool but no signs later class, (4) few signs in preschool that magnified in elementary school class, (5) few signs in preschool that diminished later class, and (6) many signs since preschool being persistent class. The sensitivity analysis resulted in a similar trajectory pattern, except for the few signs since preschool that magnified later class. Children's race, breastfeeding status, headstrong score, immature dependent score, peer conflict score, educational level of the mother, baseline antisocial score, baseline anxious/depressed score, and smoking status 12 months prior to the birth of the child were found to be risk factors in the ADHD trajectory classes. Conclusion: The trajectory classes findings obtained in the current study can (a) assist a researcher in evaluating an intervention (or combination of interventions) that best decreases the long-term impact of ADHD symptoms and (b) allow clinicians to better assess as to which class a child with ADHD belongs so that appropriate intervention can be employed.