Medical Sciences Commons^™

Genetics Of Cerebrotendinous Xanthomatosis, Jennifer Hanson, Penelope E Bonnen

Faculty, Staff and Students Publications

Cerebrotendinous xanthomatosis (CTX) is rare, autosomal recessive inborn error of metabolism caused by biallelic pathogenic variants in CYP27A1, which encodes sterile 27 hydroxylase, a key enzyme in bile acid biosynthesis. Enzyme deficiency results in reduced cholic and chenodeoxycholic acid synthesis with accumulation of cholestanol, bile acid intermediates, and bile alcohols, producing a progressive multisystem disorder characterized by chronic diarrhea, juvenile-onset cataracts, tendons xanthomas, and neurological dysfunction. Although CTX typically begins in childhood, diagnosis is frequently delayed until adulthood, limiting the benefit of effective disease modifying therapy with chenodeoxycholic acid. Since the identification of CYP27A1, more than 200 pathogenic variants have …

Functional Characterization Of Uhrf1 Variants In Facilitating Dna Methylation, Bigang Liu, Kaila Nayvelt, Swanand Hardikar, Kimie Kondo, Marcos R Estecio, Xiaodong Cheng, Taiping Chen

The Brown Foundation: Institute of Molecular Medicine

Ubiquitin-like with plant homeodomain (PHD) and really interesting new gene (RING) finger domains 1 (UHRF1) is essential for DNA methylation inheritance. However, the functional impacts of several natural and engineered UHRF1 variants are either insufficiently characterized or obscured by conflicting results, with some discrepancies likely stemming from cellular toxicity and adaptive responses induced by DNA methylation changes. In this study, we utilized mouse embryonic stem cells (mESCs)-which uniquely tolerate the complete loss of DNA methylation-to evaluate the functional consequences of clinical mutations, isoform variation, and epitope tagging. Using rescue experiments in Uhrf1-deficient mESCs, we characterized two UHRF1 mutations identified in …

Single-Nucleus Profiling Reveals A Core Disease Signature And Cell Type-Specific Vulnerabilities In Early Rett Syndrome, Yan Li, Ashley G Anderson, Guantong Qi, Sih-Rong Wu, Jean-Pierre Revelli, Hu Chen, Zhandong Liu, Huda Y Zoghbi

Faculty, Staff and Students Publications

Rett syndrome (RTT) is an X-linked neurological disorder caused by MECP2 mutations, creating distinct cellular environments in females (mosaic) versus males (nonmosaic). Despite female patients representing most cases, how mosaicism contributes molecularly to RTT pathogenesis, particularly in presymptomatic stages, remains poorly understood. To address this question, we profiled hippocampal transcriptomes of young female and male RTT mice using bulk and single-nucleus RNA sequencing. We identified a core disease signature of consistently dysregulated genes only in MeCP2− cells across RTT models. Moreover, we uncovered non–cell autonomous effects exclusively in female MeCP2+ excitatory neurons, suggesting that these circuits are more vulnerable early …

Monoclonal Antibodies Targeting Pcdh7 Inhibit Tumor Growth And Enhance Immune Responses In Kras-Mutant Non-Small Cell Lung Cancer, Nicole Novaresi, Poorva Ghosh, Shayna Thomas-Jardin, Hui Deng, Xuejun Fan, Zhiqiang Ku, Wei Xiong, Xiaorong Zhou, Jingfei Zhu, Huiyu Li, Mahesh S Padanad, Bethany Smith, Chul Ahn, John D Minna, Zhiqiang An, Ningyan Zhang, Kathryn A O'Donnell

The Brown Foundation: Institute of Molecular Medicine

We identified an important oncogenic role for protocadherin 7 (PCDH7), a cell surface protein frequently overexpressed in lung adenocarcinoma and associated with poor clinical outcome. Pcdh7 depletion reduces tumor burden and prolongs survival in KrasLSL-G12D; Tp53fl/fl mice. These findings nominate this cell surface protein as an actionable therapeutic target and highlight the therapeutic potential of PCDH7 inhibition for non–small cell lung cancer. We report the development and characterization of high-affinity anti-PCDH7 monoclonal antibodies (mAbs) that inhibit downstream mitogen-activated protein kinase (MAPK) pathway activation and suppress tumor growth in multiple mutant KRAS–driven models. A lead mAb (mAb7) sensitized tumors …

Non-Isolated Dandy-Walker Malformation: Exome Sequencing Efficacy And Phenotypic Expansions, Sarah Araji, Xiaonan Zhao, Jill A Rosenfeld, Seema R Lalani, Daryl A Scott

Faculty, Staff and Students Publications

Dandy-Walker malformation (DWM) is a rare congenital abnormality of the posterior fossa and the cerebellum and has an incidence of 1 in 10 000 to 30 000 births. Although DWM can present in isolation, it is often associated with other central nervous system (CNS) abnormalities or extra-CNS anomalies (DWM+). A molecular cause is not identified in the majority of individuals with DWM+. This is due, in part, to uncertainty regarding optimal testing strategies and an incomplete understanding of the genetic causes of DWM+. In this study, we analyzed clinical exome sequencing (cES) data from 91 individuals with DWM+ to determine …

Coxfa4l2 Upregulation Preserves Residual Cytochrome C Oxidase Activity In Coxfa4-Related Leigh-Like Encephalopathy, Micol Falabella, Sandra Lopez Calcerrada, Jana Aref, Jiaze Gao, William L Macken, Chiara Pizzamiglio, Renata Kabiljo, Anna Lucia Francavilla, Pauline Gaignard, Antoine Pouzet, Jonathan Levy, Giulia Barcia, Jamie K Leighton, Efstathia Chronopoulou, Germaine Pierre, Riza Köksal Özgül, Ali Dursun, Rebecca Halligan, Helen Mundy, Javeria Raza Alvi, Tipu Sultan, William James Craigen, Lisa Emrick, Jill A Rosenfeld, Gehad Elmakkawy, Jihye Kim, Joseph J Gleeson, Aboulfazl Rad, Gabriela Oprea, Maqbool Hussain, Khalil Ur Rehman, Sadia Riaz, Robert W Taylor, Vincent Procaccio, Maha S Zaki, Erika Fernandez-Vizarra, Ciro Leonardo Pierri, Michael G Hanna, Henry Houlden, Reza Maroofian, Cristina Ugalde, Jan-Willem Taanman, Robert D S Pitceathly

Faculty, Staff and Students Publications

Primary mitochondrial diseases (PMDs) affect approximately 1 in 4300 individuals and cause early-onset neuromuscular and multisystem dysfunction with reduced lifespan. They result from pathogenic variants in mitochondrial or nuclear DNA that impair oxidative phosphorylation. Cytochrome c oxidase (COX; complex IV) deficiency is a well-established cause of PMD, leading to a broad spectrum of phenotypes. COXFA4 (cytochrome c oxidase subunit FA4), formerly NDUFA4, is a nuclear-encoded COX subunit, but its role in disease remains poorly defined. We report the largest genetically confirmed cohort of COXFA4-related PMD to date, comprising 13 individuals from 12 families with biallelic pathogenic COXFA4 variants. All present …

The Ramification Of Mutations In Sonic Hedgehog Gene On The Occurrence Of Deformities In The Course Of The Embryonic Development Stage, Umalbaneen Hilal Hadi, Safa J. Al-Yassiri

Al-Nisour Journal for Medical Sciences

Sonic Hedgehog (SHH) is one of the most significant genes regulating embryonic development in mammals, playing a pivotal role in cell differentiation, tissue fate determination, and regulating lateral symmetry of the embryo. The results of this research show that any mutation whether, a loss of function or a change in the regulation of gene expression in SHH gene leads to severe and highly complex consequences for embryonic development.as a result for that, severe disorders of CNS development SHH is a morphogen essential for germline formation and neuronal differentiation. Mutations in this gene result in failure to develop properly the cerebellum, …

Natural History Of Ngly1 Deficiency: Motor Function & Clinical Features, Grace Morrison, Selina Dwight, Hal Landy, William F Mueller, Pam Ventola, Regina Deck, Becky Schweighardt, Matt Wilsey, Kevin J Lee, Bernhard Suter

Faculty, Staff and Students Publications

N-glycanase 1 (NGLY1) Deficiency is an ultra-rare neurodevelopmental disorder caused by biallelic loss-of-function mutations in the NGLY1 gene, leading to severe impairments in neurocognitive and motor function abilities in the affected patient population. Its core clinical features include global developmental delay, hyperkinetic movement disorders, elevation of liver transaminases, (hypo)alacrima, and progressive sensorimotor neuropathy. Due to the range of phenotypes and severity within the confirmed patient population, ongoing characterization of the disease is critical. A prospective natural history study (NHS) was conducted to further elucidate disease phenotypes and examine any changes in neurocognitive or motor function over a one-year period. Fifteen …

Large-Scale Genetic Characterization Of Parkinson’S Disease In The African And African Admixed Populations, Fulya Akçimen, Kimberly Paquette, Peter Wild Crea, Kathryn Step, Emily Waldo, Mathew J Koretsky, Paula Saffie-Awad, Charles Achoru, Funmilola Taiwo, Simon Ozomma, Gerald Onwuegbuzie, Marzieh Khani, Spencer Grant, Lukman Owolabi, Chiamaka Okereke, Olajumoke Oshinaike, Emmanuel Iwuozo, Suleyman Can Akerman, Paul Suhwan Lee, Shyngle Oyakhire, Nosakhare Osemwegie, Kensuke Daida, Sani Abubakar, Adedunni Olusanya, Mariam Isayan, Christiane Alvarez, Rami Traurig, Adebimpe Ogunmodede, Sarah Samuel, Mary B Makarious, Fadimatu Sa'ad, Rashidat Olanigan, Kristin Levine, Ewere Marie Ogbimi, Dan Vitale, Francis Odiase, Francis Ojini, Olanike Odeniyi, Zih-Hua Fang, Nkechi Obianozie, Deborah A Hall, Ernest Nwazor, Tao Xie, Francesca Nwaokorie, Mahesh Padmanaban, Paul Nwani, Ejaz A Shamim, Alero Nnama, David Standaert, Morenikeji Komolafe, Marissa Dean, Godwin Osaigbovo, Elizabeth Disbrow, Ismaila Ishola, Ashley Rawls, Frank Imarhiagbe, Shivika Chandra, Cyril Erameh, Vanessa Hinson, Naomi Louie, Ahmed Idowu, J Solle, Scott A Norris, Abdullahi Ibrahim, Camilla Kilbane, Gauthaman Sukumar, Lisa M Shulman, Daniel Ezuduemoih, Julia Staisch, Sarah Breaux, Clifton Dalgard, Erin R Foster, Abiodun Bello, Andrew Ameri, Raquel Real, Erica Ikwenu, Huw R Morris, Roosevelt Anyanwu, Erin Furr Stimming, Kimberley Billingsley, Wemimo Alaofin, Pilar Alvarez Jerez, Osigwe Agabi, Dena G Hernandez, Rufus Akinyemi, Sampath Arepalli, Laksh Malik, Raymond Owolabi, Yakub Nyandaiti, Hampton L Leonard, Kolawole Wahab, Oladunni Abiodun, Carlos F Hernandez, Fatima Abdulai, Hirotaka Iwaki, Soraya Bardien, Christine Klein, John Hardy, Henry Houlden, Kamalini Ghosh Galvelis, Mike A Nalls, Nabila Dahodwala, Whitley Aamodt, Emily Hill, Alberto Espay, Stewart Factor, Chantale Branson, Cornelis Blauwendraat, Andrew B Singleton, Oluwadamilola Ojo, Lana M Chahine, Njideka Okubadejo, Sara Bandres-Ciga

Faculty, Staff and Student Publications

Elucidating the genetic contributions to Parkinson's disease aetiology across diverse ancestries is a critical priority for the development of targeted therapies in a global context. We conducted the largest sequencing characterization of potentially disease-causing, protein-altering and splicing mutations in 710 cases and 11 827 controls from genetically predicted African or African admixed ancestries. We explored copy number variants (CNVs) and runs of homozygosity in prioritized early onset and familial cases. Our study identified rare GBA1 coding variants to be the most frequent mutations among patients with Parkinson's disease, with a frequency of 4% in our case cohort. Of the 18 …

Dolutegravir Developmental Toxicity Is Mitigated By Magnesium And Folate In Zebrafish Embryos, Robert M Cabrera, Ahmed Mohamed, Ryoko Minowa, Katheryn A Neugebauer, Daniel A Gorelick

Faculty, Staff and Students Publications

Integrase strand transfer inhibitors have transformed human immunodeficiency virus (HIV) therapy, yet the widely prescribed drug dolutegravir (DTG) has been linked to developmental toxicity, and its teratogenic mechanism remains unclear. Here, we used zebrafish to dissect DTG toxicity during early vertebrate development. DTG exposure from 2-4 h post-fertilization (hpf) to 24 hpf produced high mortality and abnormal morphology. Co-treatment with folates partially restored normal morphology, whereas calcium had no effect. Strikingly, supplementation with magnesium (Mg) partially rescued DTG-exposed embryos, implicating Mg availability in protection. In competitive binding assays, Mg increased binding of folate to purified folate receptor (FOLR1) by 30% …

Expanding The Mutation Spectrum Of Non-Syndromic Retinitis Pigmentosa In Consanguineous Pakistani Families: Unraveling Novel Pathogenic Variants In Rp1, Pde6b, And Prcd Genes For Precision Diagnosis, Tayyaba Shan, Nimra Mukhtar, Sayyed Hammad Ullah, Asad Ullah, Asfandyar Ahmad Khan, Yumei Li, Meng Wang, Raeesa Tehreem, Amtul Aziz, Kiran Afshan, Rui Chen, Sabika Firasat

Faculty, Staff and Students Publications

No abstract provided.

Rhesus Macaques With An Opa1 Mutation Demonstrate Features Of Autosomal Dominant Optic Atrophy, Tracy N Jaggers, Ana Ripolles-Garcia, Ala Moshiri, Brett D Story, Jun Wang, Rui Chen, Lucy G Moore, Leandro B C Teixeira, Jaeho Shim, Ana C Raposo, Maria Isabel Casanova, Sophie M Le, Sangwan Park, Laura J Young, Soohyun Kim, Karolina P Roszak, Vanessa Ureno, Paige M Karpinen, Nayeli Echeverria, Monica Ardon, Brian C Leonard, Marguerite Knipe, Eliza Bliss-Moreau, Brad Fortune, J Timothy Stout, Jeffrey Rogers, Nicholas Marsh-Armstrong, Sara M Thomasy

Faculty, Staff and Students Publications

Autosomal dominant optic atrophy (ADOA) is an inherited optic neuropathy primarily caused by mutations in OPA1. We identified and defined a spontaneous nonhuman primate (NHP) model of ADOA using rhesus macaques heterozygous for a missense mutation (OPA1A8S). With ocular examinations, ophthalmic imaging, electroretinography, histopathology, immunohistochemistry, and transmission electron microscopy (TEM), we documented retinal nerve fiber layer (RNFL) thinning, retinal ganglion cell (RGC) loss and dysfunction, OPA1 mislocalization, and reduced axonal mitochondrial density in affected macaques. Our investigation revealed substantial phenotypic variability among affected macaques, shedding light on the pathogenesis of ADOA. The retinas were evaluated using techniques …

Functional Requirement For Dicer Helicase Arginine Methylation In 26 G Sirna Biogenesis And Oocyte Meiotic Program, Nick Newkirk, Shin-Yu Chen, Tokiko Furuta, Kenneth A Trimmer, Leilei Shi, Sabrina Stratton, Hongyuan Li, Xiaodong Cheng, Mark T Bedford, Swathi Arur

The Brown Foundation: Institute of Molecular Medicine

Spatiotemporal regulation of Dicer is essential for small RNA biogenesis and fertility, yet how its helicase domain is controlled remains unclear. Using Caenorhabditis elegans, we identify a regulatory role for the arginine-rich GRARR motif within helicase domain motif VI of DCR-1. Mutating conserved arginines in this sequence disrupts maternal 26 G endo-siRNA production, impairs oocyte meiosis I and II, and reduces fertility. Biochemically, an asymmetrically dimethylated DCR-1 GRA[R495*]R peptide enhances interaction with ERI-5, a tandem-Tudor protein in the ERIC complex, while loss of DCR-1(R495) diminishes this interaction in vivo. Genetically, eri-5 deletion phenocopies the dcr-1 R495K mutant, supporting a functional …

Contributing Factors Of Contralateral Breast Cancer In Patients With Brca Mutation (On-Brca Ii Study, Korea-Bsg 11), Seon-Hi Shin, Sung Gwe Ahn, Jai Min Ryu, Sae Byul Lee, Hyung Seok Park, Eun-Shin Lee, Janghee Lee, Byeongju Kang, Sanghwa Kim, Eun Young Kim, Young-Joon Kang, Sun Young Min, Moohyun Lee, Se-Kang Kim, Hong-Kyu Kim, Chihwan David Cha

Faculty, Staff and Students Publications

Background: The cumulative risk of contralateral breast cancer (CBC) in BRCA1/2 carriers is remarkably higher than in non-carriers. This study aimed to investigate the clinicopathological predictors associated with the risk of metachronous CBC among breast cancer patients with BRCA1/2 mutations using correspondence analysis.

Methods: This retrospective study included patients who underwent BRCA testing between January 2008 and December 2018. The inclusion criterion was patients being between 20 and 80-years-old with invasive breast cancer (pT1-3, N0-3). We performed univariate and multivariate survival analyses to assess the risks associated with BRCA mutations, and conducted correspondence analysis to identify contributing factors for CBC …

Bi-Allelic Variants In Ap5z1 And Ap5b1 Lead To Retinal Degeneration, Hafiz Muhammad Jafar Hussain, Meng Wang, Paul Yang, Behnoosh Tasharrofi, Yumei Li, Rebecca Lynn Clark, Emma Fale-Olsen, Grace Waldow, Mohammad Keramatipour, Mostafa Asadollahi, Mark E Pennesi, Rui Chen

Faculty, Staff and Students Publications

Inherited retinal diseases (IRDs) comprise a diverse group of disorders that frequently lead to progressive vision impairment and blindness. Despite advances in genetic testing, a significant number of IRD cases remain genetically unsolved, often due to unidentified disease-associated genes or variants. This study reports additional cases for the newly discovered IRD genes of the AP-5 complex. A comprehensive ophthalmological evaluation was performed for all patients, including retinal imaging (multimodal imaging), visual field testing, and electroretinogram (ERG) testing. Whole-genome and -exome sequencing (WGS and WES) were performed for clinically unsolved IRD patients, and data were analyzed to identify underlying causal variants. …

Novel Variants Identified In Families With Snx27 -Related Neurodevelopmental Disorder, Aiding In Characterizing Its Genotypic And Phenotypic Spectrum, Tayyaba Shan, Abrar Hussain, Anushree Acharya, Mulazim Hussain, Yumei Li, Hafiz Muhammad Jafar Hussain, Kiran Afshan, Suzanne M Leal, Rui Chen, Asif Mir, Isabelle Schrauwen, Sabika Firasat

Faculty, Staff and Students Publications

Background:

Sorting Nexin 27 (SNX27), a key regulator of synaptic receptor trafficking and endosomal recycling, has been implicated in maintaining synaptic homeostasis and cognitive function. To date, variants in SNX27 have been reported in a small number of patients across three publications with severe neurodevelopmental phenotypes. However, the genetic and functional landscape of SNX27-related disorders remains poorly understood, and further evidence is needed to confirm its association with disease and to better delineate the associated phenotype.

Methods and Results:

Two unrelated Pakistani families with a total of five affected individuals segregating a neurodevelopmental disorder were investigated via exome …

Ins-17 Acts As A Nutrient Deprivation Signal To Mediate Adult Iis-Regulated Associative Behaviors In C. Elegans, Emily J Leptich, Priyadharshini Vijayakumar, Edward W Pietryk, Meredith I Williams, Rachana Rajupalem, Rachel N Arey

Faculty, Staff and Students Publications

Insulin/Insulin-like growth factor 1 (IGF-1) signaling (IIS) is a pleiotropic signaling pathway that functions across tissues to coordinate phenotypic changes in response to nutrient status. Thus, the ubiquity of the IIS pathway hinders efforts to elucidate the mechanisms driving specific IIS-related phenotypes. Previous research in the nematode worm C. elegans has demonstrated that loss of function of the IIS transmembrane receptor (IR) ortholog, DAF-2, results in a doubled lifespan and enhanced learning and memory behaviors in young and aged animals. However, these findings are the result of reducing DAF-2 receptor function rather than modulating ligand-receptor interactions. In the current study, …

Baseline Parp-1 Pet Imaging In Patients With Advanced Solid Tumors With Dna Damage Response Mutations, Tarek Daoud, Jiansong Chen, Peng Wei, Franklin Wong, Timothy A Yap, Lilie L Lin

Faculty, Staff and Student Publications

Purpose: Inhibitors of poly(ADP-ribose) polymerase (PARP), an enzyme with numerous roles in DNA damage response signaling, represent a class of anti-cancer drugs approved for treating solid tumors with defects in the DNA damage response. However, additional methods for identifying patients who would benefit from the use of PARP inhibitors are urgently needed. We evaluated a novel radiotracer, 18F-FluorThanatrace ([18F]-FTT), to noninvasively assess PARP activity with PET/CT before treatment and determine associations between uptake, tumor mutation status, and prior receipt of therapy including PARP inhibitors.

Methods: Fifty-two patients with solid tumors underwent whole-body (skull base to thigh) [18F]-FTT PET/CT scans before …

Unraveling The Nexus: Tumor Mutational Burden, Pd-L1 Expression, And Oncogenic Alterations In Non-Small Cell Lung Cancer Cytology Specimens, Min Dai, Francis Anthony San Lucas, Hector Alvarez, Leomar Ballester, Hui Chen, Keyur P Patel, Asif Rashid, Shun Rao, Mark J Routbort, Gloria Sura, Keith Sweeney, Gokce Toruner, Peng Wei, Richard Yang, Hyvan Dang, Rajyalakshmi Luthra, Sinchita Roy-Chowdhuri

Faculty, Staff and Student Publications

Background: PD-L1 expression and tumor mutational burden (TMB) are biomarkers for immune checkpoint inhibitor (ICI) therapy in non-small cell lung cancer (NSCLC); however, patients harboring oncogenic alterations have limited benefit from ICIs. The impact of oncogenic alterations on TMB and PD-L1 tumor proportion score in lung cytology specimens is poorly understood. Herein, the association between oncogenic alterations, TMB, and PD-L1 in NSCLC cytology specimens is explored.

Methods: Next-generation sequencing results from 312 NSCLC cytology specimens were retrospectively reviewed that interrogate 610 genes and select immuno-oncology signatures. TMB and PD-L1 immunohistochemical expression across oncogenic alterations were analyzed to explore associations.

Results: …

Functional And Structural Basis Of A Hypermorphic Trpc3 Variant, Briar Bell, Angela M Jaramillo-Granada, Luis O Romero, Irene A Gutierrez, Venkata K P S Mallampalli, Guizhen Fan, Sameer Varma, Matthew L Baker, Irina I Serysheva, Valeria Vásquez, Julio F Cordero-Morales

Faculty, Staff and Student Publications

Cerebellar ataxias are characterized by impaired motor coordination resulting from neuronal dysfunction within the cerebellum. The mechanisms underlying this pathology and its cerebellar-specific neurodegeneration remain unknown. We uncover how a gain-of-function canonical transient receptor potential member 3 (TRPC3) mutation, coupled with a cerebellum-specific isoform, stabilizes the channel’s open state, resists the leading inhibitor Pyr3, and drives calcium-dependent cell death. Restoring calcium homeostasis by expressing a Purkinje cell calcium pump improves cell viability. Transgenic expression of the TRPC3 hypermorphic variant in Caenorhabditis elegans induces neurodegeneration, confirming its pathogenicity across species. Cryo–electron microscopy and molecular simulations reveal the structural basis for the …

Modulating Alternative Splicing Of Mecp2 Is A Potential Therapeutic Strategy For Rett Syndrome, Harini P Tirumala, Li Wang, Yan Li, Sameer S Bajikar, Ashley G Anderson, Wei Wang, Alexander J Trostle, Mahla Zahabiyon, Aleksandar Bajic, Jean J Kim, Hu Chen, Zhandong Liu, Huda Y Zoghbi

Faculty, Staff and Students Publications

Rett syndrome (RTT) is a neurological disorder caused by loss-of-function mutations in methyl CpG binding protein 2 (MECP2), a transcriptional regulator essential for maintenance of normal neuronal function. The current FDA-approved treatment for RTT, Trofinetide, mildly alleviates some symptoms. In contrast, re-introducing MeCP2 or increasing its amount through transgenesis in mouse RTT models improves most neurological phenotypes and enhances survival. Here, we devised a therapeutic strategy to moderately increase MeCP2 protein by modulating the alternative splicing of MECP2 to switch the less efficiently translated e2 to the more efficiently translated e1 isoform. We deleted Mecp2 exon 2 (unique …

Lonp1 Variants Are Associated With Clinically Diverse Phenotypes, Randee E Young, Lu Qiao, Rebecca Hernan, David A Sweetser, Jessica L Waxler, Daryl A Scott, Tiana M Scott, Seema R Lalani, Mahshid S Azamian, Jill A Rosenfeld, Bret Bostwick, Lindsay C Burrage, Lance H Rodan, Bianca E Russell, Marina Dutra-Clarke, Michael Kruer, Somayeh Bakhtiarim, Hossein Darvish, David J Amor, Shamima Rahman, Karen Stals, Lisa Bradley, Susan Byrne, Leandra K Tolusso, Beatrix Wong, Laura Benedict, Kimberly Wallis, Kestutis Micke, Cindy Colson, Thomas Smol, Sabrina V Southwick, Kristen A Miller, Michelle L Kush, Odelia Chorin, Annick Rothschild, Wei Wang, Yufeng Shen, Wendy K Chung

Faculty, Staff and Students Publications

LONP1 encodes a mitochondrial protease essential for protein quality control and metabolism. Variants in LONP1 are associated with a diverse and expanding spectrum of disorders, including Cerebral, Ocular, Dental, Auricular, and Skeletal anomalies syndrome (CODAS), congenital diaphragmatic hernia (CDH), and neurodevelopmental disorders (NDD), with some individuals exhibiting features of mitochondrial encephalopathy. We report 16 novel LONP1 variants identified in 16 individuals (11 with NDD, 5 with CDH), further expanding the clinical spectrum. Structural mapping of disease-associated missense variants revealed phenotype-specific clustering, with CODAS variants enriched in the proteolytic chamber and NDD variants more broadly distributed. CODAS is caused by biallelic …

Impact Of Mutational Landscape And Burden On Rbc Transfusion Response In Patients With Lower-Risk Myelodysplastic Syndromes (Lr-Mds) In The Commands Study, Rami S Komrokji, Sheida Hayati, Manuel Ugidos, Guillermo Garcia-Manero, Matteo Giovanni Della Porta, Amer M Zeidan, Valeria Santini, Uwe Platzbecker, Anita K Gandhi, Rajasekhar N V S Suragani

Faculty, Staff and Student Publications

The COMMANDS trial established luspatercept as a first‐line treatment for anemia in transfusion‐dependent lower‐risk (LR) myelodysplastic syndromes (MDS). Here we report red blood cell (RBC) transfusion response analysis based on somatic mutations profile and disease risk for patients treated with luspatercept or epoetin alfa in the COMMANDS trial. Of 350 evaluable patients, 238 (68.0%) had MDS with multiple lineage dysplasia and ring sideroblasts (RS) according to World Health Organization 2016 criteria, and 320 (91.4%) had somatic mutations in ≥ 1 gene (median, 2) with median variant allele frequencies (VAF) of 2%–59%. Mutation profiles were similar in the treatment groups. Luspatercept …

Quantifying Rate-Limiting Genetic Variation In Breast And Ovarian Tumourigenesis, Kathleen E Houlahan, Mahad Bihie, Yves Greatti, Julián Grandvallet Contreras, Daniel J Fulop, Gonzalo Lopez, Marc Williams, Hsin-Hsiung Huang, Peter Van Loo, Paul C Boutros, Kuan-Lin Huang

Faculty, Staff and Student Publications

Background: The number and type of genetic alterations required to initiate breast and ovarian cancer remain unclear. While germline BRCA1/2 carriers show markedly elevated cancer risk, it is uncertain whether point mutations or copy number alterations constitute the rate-limiting events of tumourigenesis.

Methods: We developed a statistical framework extending prior incidence-mutation models to estimate the minimal number and type of driver events required for cancer initiation. Somatic mutation and copy-number data from >3000 breast and ovarian cancers in TCGA and METABRIC were compared between germline BRCA1/2 carriers and non-carriers matched on subtypes. Results were validated through analyses of evolutionary timing …

Risk Stratification Of Low-Dose Cytarabine And Venetoclax In Patients With Aml Ineligible For Intensive Chemotherapy, Andrew H Wei, Panayiotis Panayiotidis, Pau Montesinos, Kamel Laribi, Vladimir Ivanov, Inho Kim, Jan Novak, Rebecca Champion, Walter Fiedler, Maria Pagoni, Julie Bergeron, Stephen B Ting, Jing-Zhou Hou, Takahiro Yamauchi, Jianxiang Wang, Stephen A Strickland, Michael R Savona, Tara L Lin, Anoop Enjeti, Ing Soo Tiong, Sangmin Lee, Gail J Roboz, Relja Popovic, Qi Jiang, Zihuan Liu, Yan Sun, Wellington Mendes, Brenda Chyla, Courtney D Dinardo

Faculty, Staff and Student Publications

Prognostic risk categorization aids treatment selection for patients with acute myeloid leukemia (AML). Although the European LeukemiaNet (ELN) classifications (2017 and 2022) for AML have been used to stratify outcomes for patients receiving intensive chemotherapy, their application to patients receiving less intensive therapy, such as azacitidine plus venetoclax, has been less satisfactory. In response, a 4-gene classifier that stratifies older patients with AML unfit for intensive chemotherapy into those with higher benefit (wild type), intermediate benefit (FLT3-internal tandem duplication [ITD] or NRAS/KRAS mutation), or lower benefit (TP53 mutation) after azacitidine plus venetoclax treatment was developed. We hypothesized that this 4-gene …

Supt16h-Associated Neurodevelopmental Disorder And Neurocristopathy: Genetic And Phenotypic Spectrum, Eunhye Lee, Seungmin Sim, Hee-Jung Choi, Eugene Y Liang, Carolyn Le, Roya Bina, Ryan Cohen, Elizabeth George, Soo Yeon Kim, Gifty Bhat, Erin Falsey, Richard Sidlow, Kristin Clinard, Shay Ben-Shachar, Eleina England, Beatriz Menendez, Isabella Herman, Shelly Nielsen, Jaya Punetha, Priya Bhola, J Austin Hamm, Megan A Keeney, Nike Sitzman, Sara Berger, Lakshmi Mehta, Alison J Conn, Lilian Downie, Myla Ashfaq, Hope Northrup, Ange-Line Bruel, Sylvie Odent, Justin O Szot, Noelia Nunez Martinez, Sunju Park, Julie Refkin, Jean-Marc Good, Fabienne Maurer, Cédric Le Caignec, David J Coman, Erin Anderson, Linda J Richards, Ryan J Dean, Caleb Yang, Chulwon Choi, Byung Joon Hwang, Jin Sook Lee, William B Dobyns, Murim Choi, Elliott H Sherr, Jong-Hee Chae, Yun Kee, Emanuela Argilli

Faculty, Staff and Student Publications

SUPT16H encodes a subunit of the FACT (FAcilitates Chromatin Transcription) complex, a histone chaperone essential for maintaining chromatin integrity during transcription, replication, and DNA repair. Pathogenic de novo SUPT16H missense variants have previously been linked to neurodevelopmental disorders in eight individuals. Here, we expand the genotypic and phenotypic spectrum by identifying 24 additional individuals harboring ultrarare heterozygous missense or truncating variants, who share overlapping clinical features including intellectual disability, autism spectrum disorder, hypotonia, and characteristic craniofacial dysmorphism. To elucidate the underlying mechanisms, we generated a supt16h knockout zebrafish model using CRISPR/Cas9. The supt16h loss-of-function (LOF) model recapitulated key patient phenotypes …

Human Microglia In Brain Assembloids Display Region-Specific Diversity And Respond To Hyperexcitable Neurons Carrying Scn2a Mutation, Jiaxiang Wu, Xiaoling Chen, Jingliang Zhang, Kyle Wettschurack, Morgan Robinson, Weihao Li, Yuanrui Zhao, Ye-Eun Yoo, Brody A Deming, Yue Shu, Akila D Abeyaratna, Zhefu Que, Dongshu Du, Matthew Tegtmeyer, Chongli Yuan, William C Skarnes, Zhong-Yin Zhang, Jean-Christophe Rochet, Long-Jun Wu, Yang Yang

The Brown Foundation: Institute of Molecular Medicine

Microglia critically shape neuronal circuit development and function, yet their region-specific properties and roles in distinct circuits of the human brain remain poorly understood. In this study, we generated region-specific brain organoids (cortical, striatal, and midbrain), each integrated with human microglia, to fill this critical gap. Single-cell RNA sequencing uncovered six distinct microglial subtypes exhibiting unique regional signatures, including a subtype highly enriched for the GABAB receptor gene within striatal organoids. To investigate the contributions of microglia to neural circuitry, we created microglia-incorporated midbrain-striatal assembloids, modeling a core circuit node for many neuropsychiatric disorders, including autism. Using chemogenetics to activate …

Unbalanced Chromatin Binding Of Polycomb Complexes Drives Neurodevelopmental Disorders, Rodrigo L Borges, Gretter González-Blanco, Harikumar Arigela, Yingyu Huang, Lucas D Caeiro, Nikolai Fattakhov, Stefano Lepore, Liliana Garcia-Martinez, Matea Maurice, Pushti D Mehta, Emily J Park, Kailynn Macgillivray, Jevithen Nehru, Matthew Chau, Maria C Robayo, Clemer Abad, Alicia Bilbao-Martinez, Fabiola Monteiro, Xi Luo, Song Tan, Daniel Bilbao, Simone Sidoli, Bruno Di Stefano, Katherina Walz, Arneet L Saltzman, Ramiro E Verdun, Ramin Shiekhattar, Lluis Morey

Faculty, Staff and Students Publications

The prevalence of neurodevelopmental disorders (NDDs) in children is increasing, yet their underlying causes remain largely unknown. We identified heterozygous mutations in the Polycomb repressive complex 1 (PRC1) E3 ligases RING1 and RNF2 in individuals with NDDs and revealed distinct mechanisms by which they compromise PRC1 activity. We developed cellular and mouse models carrying the Ring1b

Bi-Allelic Variants In Neuronal Adhesion Molecule Astrotactin 1 Gene Astn1 Cause Diverse Neurodevelopmental Disorders, Jesse M Levine, Daniel G Calame, Riccardo Sangermano, Haowei Du, Ahmed Saad, Jasmin Lisfeld, Tatjana Bierhals, Jonas Denecke, Eyyup Uctepe, Merve Yoldas Celik, Ahmet Yesilyurt, Hilal Yildiz Er, Elif Yilmaz Gulec, Aziza Mushiba, Naif Almontashiri, Pawel Gawlinski, Wojciech Wiszniewski, Ender Karaca, Lama Alabdi, Davut Pehlivan, Dana Marafi, Maha S Zaki, Fowzan S Alkuraya, Joseph G Gleeson, Shalini N Jhangiani, Richard A Gibbs, Jennifer E Posey, Kinga M Bujakowska, James R Lupski

Faculty, Staff and Students Publications

ASTN1 encodes astrotactin 1, a neuronal-glial ligand in the developing brain that promotes neuronal migration along radial glia in brain structures with laminar organization, such as the cerebral cortex, hippocampus, and cerebellum. In mouse models, disruption of Astn1 results in neuronal migration deficits, a mild reduction in cerebellar volume, and balance and coordination deficits. In humans, bi-allelic ASTN1 variants have been identified in nine individuals with neurodevelopmental disorders (NDDs) with or without brain malformations. ASTN1 additionally interacts with astrotactin 2 (ASTN2) to implement neuronal migration; ASTN2 deletions associate with NDDs with reduced penetrance. Here, we describe eighteen individuals with NDDs …

Mutations Altering The Dna Binding Domains Of The Human Rad52 Protein Exert Distinct Effects On Homologous Recombination Repair In Saccharomyces Cerevisiae, Glenn M. Manthey, Elise W. Wolf, Jason Xu, M. Cristina Negritto, Renee A. Bouley, Ruben C. Petreaca, Adam M. Bailis

College of Health Professions Faculty Papers

RAD52 is a conserved member of the homologous recombination repair (HRR) apparatus from yeast to humans. Mutating conserved amino acids in the internal and external DNA binding domains of the human RAD52 protein (HsRAD52) has discrete effects in vitro. Previous studies have shown that HsRAD52 supports multiple mechanisms of HRR in budding yeast, suggesting the utility of this model system for exploring the correspondence between losses of HsRAD52 function in vitro and their impact in vivo. We report that disrupting the internal and external DNA binding domains of HsRAD52 produced distinct effects on the repair of genomic DNA double-strand breaks …