1
|
Ng R, Bjornsson HT, Fahrner JA, Harris J. Associations Between Executive Functioning, Behavioral Functioning, and Adaptive Functioning Difficulties in Wiedemann-Steiner Syndrome. Arch Clin Neuropsychol 2024; 39:186-195. [PMID: 37565480 PMCID: PMC10879922 DOI: 10.1093/arclin/acad060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 07/06/2023] [Accepted: 07/08/2023] [Indexed: 08/12/2023] Open
Abstract
OBJECTIVES Wiedemann-Steiner syndrome (WSS) is a neurogenetic disorder caused by heterozygous variants in KMT2A. Recent investigations suggest increased anxiety and behavior regulation challenges among those with WSS although the neurobehavioral phenotype remains largely unknown. This study aims to examine the pattern of and associations between executive functioning (EF) and behavior functioning among those with WSS. METHOD This study involved utilizing caregiver-report inventories (Behavior Rating Inventory of Executive Function 2nd Edition, BRIEF-2; Adaptive Behavior Assessment 3rd Edition, ABAS-3; Strengths and Difficulties Questionnaire, SDQ) to assess day-to-day behavior functioning among those with WSS (N = 24; mean age = 10.68 years, SD = 3.19). Frequency of clinical elevations in daily difficulties in EF, adaptive behaviors, and behavior regulation were reported. Correlations and hierarchical linear regressions were used to determine the relationships between EF with behavior and adaptive functioning. RESULTS Out of our sample, 63% met clinical levels of executive functioning difficulties on the BRIEF-2, and 75% with Hyperactivity and 54% with Emotional Problems on the SDQ. In addition, 33% were rated >2 SD below the normative mean in overall adaptive functioning on the ABAS-3. Elevated ratings in BRIEF-2 Shift, reflective of challenges with mental flexibility, predicted more Emotional Problems and accounted for 33.5% of its variance. More difficulties in Emotional Control were related to greater adaptive deficits, accounting for 33.3% of its variance. CONCLUSIONS Those with WSS are at risk for EF deficits, hyperactivity, and emotional dysregulation. EF correlates with adaptive and affective behaviors, highlighting the promise of behavioral interventions to target cognitive flexibility, emotional awareness, and reactivity in this population.
Collapse
Affiliation(s)
- Rowena Ng
- Kennedy Krieger Institute, Baltimore, MD, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hans Tomas Bjornsson
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland
- Landspitali University Hospital, Reykjavik, Iceland
| | - Jill A Fahrner
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jacqueline Harris
- Kennedy Krieger Institute, Baltimore, MD, USA
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| |
Collapse
|
2
|
Klemenzdottir EO, Arnadottir GA, Jensson BO, Jonasdottir A, Katrinardottir H, Fridriksdottir R, Jonasdottir A, Sigurdsson A, Gudjonsson SA, Jonsson JJ, Stefansdottir V, Danielsen R, Palsdottir A, Jonsson H, Helgason A, Magnusson OT, Thorsteinsdottir U, Bjornsson HT, Stefansson K, Sulem P. A population-based survey of FBN1 variants in Iceland reveals underdiagnosis of Marfan syndrome. Eur J Hum Genet 2024; 32:44-51. [PMID: 37684520 PMCID: PMC10772070 DOI: 10.1038/s41431-023-01455-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 08/18/2023] [Accepted: 08/30/2023] [Indexed: 09/10/2023] Open
Abstract
Marfan syndrome (MFS) is an autosomal dominant condition characterized by aortic aneurysm, skeletal abnormalities, and lens dislocation, and is caused by variants in the FBN1 gene. To explore causes of MFS and the prevalence of the disease in Iceland we collected information from all living individuals with a clinical diagnosis of MFS in Iceland (n = 32) and performed whole-genome sequencing of those who did not have a confirmed genetic diagnosis (27/32). Moreover, to assess a potential underdiagnosis of MFS in Iceland we attempted a genotype-based approach to identify individuals with MFS. We interrogated deCODE genetics' database of 35,712 whole-genome sequenced individuals to search for rare sequence variants in FBN1. Overall, we identified 15 pathogenic or likely pathogenic variants in FBN1 in 44 individuals, only 22 of whom were previously diagnosed with MFS. The most common of these variants, NM_000138.4:c.8038 C > T p.(Arg2680Cys), is present in a multi-generational pedigree, and was found to stem from a single forefather born around 1840. The p.(Arg2680Cys) variant associates with a form of MFS that seems to have an enrichment of abdominal aortic aneurysm, suggesting that this may be a particularly common feature of p.(Arg2680Cys)-associated MFS. Based on these combined genetic and clinical data, we show that MFS prevalence in Iceland could be as high as 1/6,600 in Iceland, compared to 1/10,000 based on clinical diagnosis alone, which indicates underdiagnosis of this actionable genetic disorder.
Collapse
Affiliation(s)
| | - Gudny Anna Arnadottir
- deCODE Genetics/Amgen, Inc., Reykjavik, Iceland
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | | | | | | | | | | | | | | | - Jon Johannes Jonsson
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland
- Department of Genetics, Landspitali Universtity Hospital, Reykjavik, Iceland
| | | | - Ragnar Danielsen
- Department of Cardiology, Landspitali University Hospital, Reykjavik, Iceland
| | - Astridur Palsdottir
- Institute for Experimental Pathology at Keldur, University of Iceland, Reykjavik, Iceland
| | | | - Agnar Helgason
- deCODE Genetics/Amgen, Inc., Reykjavik, Iceland
- Department of Anthropology, University of Iceland, Reykjavik, Iceland
| | | | - Unnur Thorsteinsdottir
- deCODE Genetics/Amgen, Inc., Reykjavik, Iceland
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Hans Tomas Bjornsson
- Department of Pediatrics, Landspitali University Hospital, Reykjavik, Iceland
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland
- Department of Genetics, Landspitali Universtity Hospital, Reykjavik, Iceland
- McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kari Stefansson
- deCODE Genetics/Amgen, Inc., Reykjavik, Iceland.
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
| | | |
Collapse
|
3
|
Goodman SJ, Luperchio TR, Ellegood J, Chater-Diehl E, Lerch JP, Bjornsson HT, Weksberg R. Peripheral blood DNA methylation and neuroanatomical responses to HDACi treatment that rescues neurological deficits in a Kabuki syndrome mouse model. Clin Epigenetics 2023; 15:172. [PMID: 37884963 PMCID: PMC10605417 DOI: 10.1186/s13148-023-01582-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 10/08/2023] [Indexed: 10/28/2023] Open
Abstract
BACKGROUND Recent findings from studies of mouse models of Mendelian disorders of epigenetic machinery strongly support the potential for postnatal therapies to improve neurobehavioral and cognitive deficits. As several of these therapies move into human clinical trials, the search for biomarkers of treatment efficacy is a priority. A potential postnatal treatment of Kabuki syndrome type 1 (KS1), caused by pathogenic variants in KMT2D encoding a histone-lysine methyltransferase, has emerged using a mouse model of KS1 (Kmt2d+/βGeo). In this mouse model, hippocampal memory deficits are ameliorated following treatment with the histone deacetylase inhibitor (HDACi), AR-42. Here, we investigate the effect of both Kmt2d+/βGeo genotype and AR-42 treatment on neuroanatomy and on DNA methylation (DNAm) in peripheral blood. While peripheral blood may not be considered a "primary tissue" with respect to understanding the pathophysiology of neurodevelopmental disorders, it has the potential to serve as an accessible biomarker of disease- and treatment-related changes in the brain. METHODS Half of the KS1 and wildtype mice were treated with 14 days of AR-42. Following treatment, fixed brain samples were imaged using MRI to calculate regional volumes. Blood was assayed for genome-wide DNAm at over 285,000 CpG sites using the Illumina Infinium Mouse Methylation array. DNAm patterns and brain volumes were analyzed in the four groups of animals: wildtype untreated, wildtype AR-42 treated, KS1 untreated and KS1 AR-42 treated. RESULTS We defined a DNAm signature in the blood of KS1 mice, that overlapped with the human KS1 DNAm signature. We also found a striking 10% decrease in total brain volume in untreated KS1 mice compared to untreated wildtype, which correlated with DNAm levels in a subset KS1 signature sites, suggesting that disease severity may be reflected in blood DNAm. Treatment with AR-42 ameliorated DNAm aberrations in KS1 mice at a small number of signature sites. CONCLUSIONS As this treatment impacts both neurological deficits and blood DNAm in mice, future KS clinical trials in humans could be used to assess blood DNAm as an early biomarker of therapeutic efficacy.
Collapse
Affiliation(s)
| | - Teresa Romeo Luperchio
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Jacob Ellegood
- Mouse Imaging Centre (MICe), Hospital for Sick Children, Toronto, Canada
| | - Eric Chater-Diehl
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Canada
| | - Jason P Lerch
- Mouse Imaging Centre (MICe), Hospital for Sick Children, Toronto, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Wellcome Centre for Integrative Neuroimaging, The University of Oxford, Oxford, UK
- Nuffield Department of Clinical Neuroscience, The University of Oxford, Oxford, UK
| | - Hans Tomas Bjornsson
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, USA
- Faculty of Medicine, University of Iceland, Reykjavík, Iceland
- Landspitali University Hospital, Reykjavík, Iceland
| | - Rosanna Weksberg
- Genetics and Genome Biology, Hospital for Sick Children, Toronto, Canada.
- Division of Clinical and Metabolic Genetics, Hospital for Sick Children, Toronto, Canada.
- Department of Molecular Genetics, University of Toronto, Toronto, Canada.
- Institute of Medical Science, University of Toronto, Toronto, Canada.
- Department of Paediatrics, University of Toronto, Toronto, ON, Canada.
| |
Collapse
|
4
|
Ng R, Kalinousky A, Fahrner JA, Bjornsson HT, Harris J. The social phenotype associated with Wiedemann-Steiner syndrome: Autistic traits juxtaposed with high social drive and prosociality. Am J Med Genet A 2023; 191:2591-2601. [PMID: 37470210 DOI: 10.1002/ajmg.a.63351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 06/13/2023] [Accepted: 06/28/2023] [Indexed: 07/21/2023]
Abstract
The aim of this study was to provide a descriptive overview of the social characteristics associated with Wiedemann-Steiner syndrome (WSS). A total of 24 parents of children/adults with WSS (11F, mean age = 12.94 years, SD = 8.00) completed the Social Responsiveness Scale 2nd Edition (SRS-2); Colorado Learning Difficulties Questionnaire (CLDQ) and Strengths and Difficulties Questionnaire (SDQ). Almost half our sample reported a diagnosis of autism spectrum disorder (ASD) and 70% had intellectual disability. On the SDQ, over 90% of participants were rated in borderline/clinical ranges in Peer Problems, yet the majority fell within normal limits in Prosocial Behaviors. Most fell in the moderate/severe difficulties ranges across SRS-2 Social Cognition, Communication, and Restricted/Repetitive Behaviors scales (all >70%); whereas substantially less participants met these ranges for deficits in Social Awareness (50%) and Social Motivation (33.33%). A pattern of relatively strong prosocial skills and social drive in the context of difficulties with inflexible behaviors, social cognition, and communication was observed, regardless of gender, ASD or intellectual disability diagnosis. The social phenotype associated with WSS is characterized by some autistic features paired with unusually high social motivation and prosocial tendencies.
Collapse
Affiliation(s)
- Rowena Ng
- Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Allison Kalinousky
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jill A Fahrner
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hans Tomas Bjornsson
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland
- Landspitali University Hospital, Reykjavik, Iceland
| | - Jacqueline Harris
- Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| |
Collapse
|
5
|
Rafnsdottir S, Jang K, Halldorsdottir ST, Tomasdottir A, Vinod M, Möller K, Reynisdottir T, Atladottir LH, Allison KE, He J, Zhang L, Northington FJ, Chavez-Valdez R, Anderson KJ, Bjornsson HT. SMYD5 is a novel epigenetic gatekeeper of the mild hypothermia response. bioRxiv 2023:2023.05.11.540170. [PMID: 37333301 PMCID: PMC10274674 DOI: 10.1101/2023.05.11.540170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Organisms have homeostatic mechanisms to respond to cold temperature to ensure survival including the activation of the mammalian neuroprotective mild hypothermia response (MHR) at 32°C. We show activation of the MHR at euthermia by an FDA-approved medication Entacapone, proof-of-principle that the MHR can be medically manipulated. Utilizing a forward CRISPR-Cas9 mutagenesis screen, we identify the histone lysine methyltransferase SMYD5 as an epigenetic gatekeeper of the MHR. SMYD5 represses the key MHR gene SP1 at euthermia but not at 32°C. This repression is mirrored by temperature-dependent levels of H3K36me3 at the SP1-locus and globally indicating that the mammalian MHR is regulated at the level of histone modifications. We identified 45 additional SMYD5-temperature dependent genes suggesting a broader MHR-related role for SMYD5. Our study provides an example of how the epigenetic machinery integrates environmental cues into the genetic circuitry of mammalian cells and suggests novel therapeutic avenues for neuroprotection after catastrophic events.
Collapse
Affiliation(s)
- Salvor Rafnsdottir
- Louma G. Laboratory of Epigenetic Research, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Kijin Jang
- Louma G. Laboratory of Epigenetic Research, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Sara Tholl Halldorsdottir
- Louma G. Laboratory of Epigenetic Research, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Arnhildur Tomasdottir
- Louma G. Laboratory of Epigenetic Research, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Meghna Vinod
- Louma G. Laboratory of Epigenetic Research, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Katrin Möller
- Louma G. Laboratory of Epigenetic Research, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Tinna Reynisdottir
- Louma G. Laboratory of Epigenetic Research, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Laufey Halla Atladottir
- Louma G. Laboratory of Epigenetic Research, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | | | - Jin He
- Department of Biochemistry and Molecular Biology, College of Natural Science, Michigan State University, MI, USA
| | - Li Zhang
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, MD, USA
| | - Frances J. Northington
- Division of Neonatology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Raul Chavez-Valdez
- Division of Neonatology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kimberley Jade Anderson
- Louma G. Laboratory of Epigenetic Research, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Hans Tomas Bjornsson
- Louma G. Laboratory of Epigenetic Research, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, MD, USA
- Department of Pediatrics, Johns Hopkins University, MD, USA
- Department of Genetics and Molecular Medicine, Landspitali University Hospital, Reykjavik, Iceland
| |
Collapse
|
6
|
Ng R, Bjornsson HT, Fahrner JA, Harris J. Unique profile of academic learning difficulties in Wiedemann-Steiner syndrome. J Intellect Disabil Res 2023; 67:101-111. [PMID: 36437529 PMCID: PMC9839653 DOI: 10.1111/jir.12993] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 09/06/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Wiedemann-Steiner syndrome (WSS) is a rare genetic disorder caused by heterozygous variants in KMT2A. To date, the cognitive profile associated with WSS remains largely unknown, although emergent case series implicate increased risk of non-verbal reasoning and visual processing deficits. This study examines the academic and learning concerns associated with WSS based on a parent-report screening measure. PARTICIPANTS AND METHODS A total of 25 parents of children/adults with a molecularly-confirmed diagnosis of WSS (mean age = 12.85 years, SD = 7.82) completed the Colorado Learning Difficulties Questionnaire (CLDQ), a parent-screening measure of learning and academic difficulties. Parent ratings were compared to those from a normative community sample to determine focal areas in Math, Reading and Spatial skills that may be weaker within this clinical population. RESULTS On average, parent ratings on the Math (mean Z = -3.08, SD = 0.87) and Spatial scales (mean Z = -2.52, SD = 0.85) were significantly more elevated than that of Reading (mean Z = -1.31, SD = 1.46) (Wilcoxon sign rank test Z < -3.83, P < 0.001), reflecting relatively more challenges observed in these areas. Distribution of parent ratings in Math items largely reflect a positively skewed distribution with most endorsing over three standard deviations below a community sample. In contrast, distributions of parent ratings in Reading and Spatial domains were more symmetric but flat. Ratings for Reading items yielded much larger variance than the other two domains, reflecting a wider range of performance variability. CONCLUSIONS Parent ratings on the CLDQ suggest more difficulties with Math and Spatial skills among those with WSS within group and relative to a community sample. Study results are consistent with recent case reports on the neuropsychological profile associated with WSS and with Kabuki syndrome, which is caused by variants in the related gene KMT2D. Findings lend support for overlapping cognitive patterns across syndromes, implicating potential common disease pathogenesis.
Collapse
Affiliation(s)
- Rowena Ng
- Kennedy Krieger Institute
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine
| | - Hans Tomas Bjornsson
- Department of Genetic Medicine, Johns Hopkins University School of Medicine
- Department of Pediatrics, Johns Hopkins University School of Medicine
- Faculty of Medicine, University of Iceland, Reykjavik
- Landspitali University Hospital
| | - Jill A. Fahrner
- Department of Genetic Medicine, Johns Hopkins University School of Medicine
- Department of Pediatrics, Johns Hopkins University School of Medicine
| | - Jacqueline Harris
- Kennedy Krieger Institute
- Department of Genetic Medicine, Johns Hopkins University School of Medicine
- Department of Pediatrics, Johns Hopkins University School of Medicine
- Department of Neurology, Johns Hopkins University School of Medicine
| |
Collapse
|
7
|
Ng R, Bjornsson HT, Fahrner JA, Harris J. Anxiety in Wiedemann-Steiner syndrome. Am J Med Genet A 2023; 191:437-444. [PMID: 36373844 PMCID: PMC9907226 DOI: 10.1002/ajmg.a.63040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 10/22/2022] [Accepted: 10/27/2022] [Indexed: 11/16/2022]
Abstract
This study examined anxiety in Wiedemann-Steiner syndrome (WSS). Eighteen caregivers and participants with WSS completed the parent- and self-report versions of the Screen for Child Anxiety Related Disorder or the adapted version of the Screen for Adult Anxiety Related Disorder. Approximately 33.33% of parents and 65% of participants with WSS rated in the clinical range for overall anxiety. Across anxiety subtypes, parents primarily indicated concerns with Separation Anxiety (72%), which was also endorsed by the majority of participants with WSS (82%). The emergent trend showed Total Anxiety increased with age based on parent-informant ratings. The behavioral phenotype of WSS includes elevated anxiety. Clinical management should include incorporating early behavioral interventions to bolster emotion regulation given the observed risk of anxiety with age.
Collapse
Affiliation(s)
- Rowena Ng
- Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hans Tomas Bjornsson
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland
- Landspitali University Hospital, Reykjavik, Iceland
| | - Jill A. Fahrner
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jacqueline Harris
- Kennedy Krieger Institute, Baltimore, Maryland, USA
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| |
Collapse
|
8
|
Koenig MK, Russo SN, McBride KL, Bjornsson HT, Gunnarsdottir BB, Goldstein A, Falk SA. Use of Elamipretide in patients assigned treatment in the compassionate use program: Case series in pediatric patients with rare orphan diseases. JIMD Rep 2023; 64:65-70. [PMID: 36636586 PMCID: PMC9830009 DOI: 10.1002/jmd2.12335] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 08/12/2022] [Accepted: 09/06/2022] [Indexed: 01/16/2023] Open
Abstract
Several mitochondrial diseases are caused by pathogenic variants that impair membrane phospholipid remodeling, with no FDA-approved therapies. Elamipretide targets the inner mitochondrial membrane where it binds to cardiolipin, resulting in improved membrane stability, cellular respiration, and ATP production. In clinical trials, elamipretide produced clinical and functional improvements in adults and adolescents with mitochondrial disorders, such as primary mitochondrial myopathy and Barth syndrome; however, experience in younger patients is limited and to our knowledge, these are the first case reports on the safety and efficacy of elamipretide treatment in children under 12 years of age. We describe the use of elamipretide in patients with mitochondrial disorders to provide dosing parameters in patients aged <12 years.
Collapse
Affiliation(s)
- Mary Kay Koenig
- The University of Texas McGovern Medical School, Center for the Treatment of Pediatric Neurodegenerative DiseaseHoustonTexasUSA
| | - Sam Nick Russo
- The University of Texas McGovern Medical School, Center for the Treatment of Pediatric Neurodegenerative DiseaseHoustonTexasUSA
| | - Kim L. McBride
- Division of Genetic and Genomic Medicine and the Heart Center Nationwide Children's Hospital, Department of Pediatrics College of MedicineOhio State UniversityColumbusOhioUSA
| | - Hans Tomas Bjornsson
- Landspitali University HospitalReykjavikIceland
- Faculty of MedicineUniversity of IcelandReykjavikIceland
- Mckusick‐Nathans Department of Genetic MedicineJohns Hopkins UniversityBaltimoreMarylandUSA
| | | | - Amy Goldstein
- Children's Hospital of PhiladelphiaPhiladelphiaPennsylvaniaUSA
| | - Scott A. Falk
- Perelman School of Medicine of the University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| |
Collapse
|
9
|
Kalinousky AJ, Rapp T, Hijazi H, Johnson J, Bjornsson HT, Harris JR. Neurobehavioral phenotype of Kabuki syndrome: Anxiety is a common feature. Front Genet 2022; 13:1007046. [PMID: 36276984 PMCID: PMC9582441 DOI: 10.3389/fgene.2022.1007046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/20/2022] [Indexed: 11/18/2022] Open
Abstract
Kabuki syndrome (KS) is a Mendelian Disorder of the Epigenetic Machinery (MDEM) caused by loss of function variants in either of two genes involved in the regulation of histone methylation, KMT2D (34–76%) or KDM6A (9–13%). Previously, representative neurobehavioral deficits of KS were recapitulated in a mouse model, emphasizing the role of KMT2D in brain development, specifically in ongoing hippocampal neurogenesis in the granule cell layer of the dentate gyrus. Interestingly, anxiety, a phenotype that has a known association with decreased hippocampal neurogenesis, has been anecdotally reported in individuals with KS. In this study, anxiety and behavior were assessed in a cohort of 60 individuals with molecularly confirmed KS and 25 unaffected biological siblings, via questionnaires (SCARED/GAS-ID and CBCL/ABCL). Participant age ranged from 4 to 43 years old, with 88.3% of participants having a pathogenic variant in KMT2D, and the rest having variants in KDM6A. In addition, data was collected on adaptive function and positive affect/quality of life in participants with KS using appropriate online surveys including ABAS-III and PROMIS Positive Affect. Survey scores were compared within the KS participants across age groups and between KS participants and their unaffected siblings. We found that children with KS have significantly higher anxiety scores and total behavior problem scores than their unaffected siblings (p = 0.0225, p < 0.0001). Moreover, a large proportion of affected individuals (22.2% of children and 60.0% of adults) surpassed the established threshold for anxiety; this may even be an underestimate given many patients are already treated for anxiety. In this sample, anxiety levels did not correlate with level of cognitive or adaptive function in any KS participants, but negatively correlated with positive affect in children with KS (p = 0.0005). These findings indicate that anxiety is a common neurobehavioral feature of KS. Providers should therefore carefully screen individuals with KS for anxiety as well as other behavioral issues in order to allow for prompt intervention. Neurobehavioral anxiety measures may also prove to be important outcome measures for clinical trials in KS.
Collapse
Affiliation(s)
- Allison J. Kalinousky
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Tyler Rapp
- University of North Carolina School of Medicine, University of North Carolina, Chapel Hill, NC, United States
| | - Hadia Hijazi
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | | | - Hans Tomas Bjornsson
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Faculty of Medicine, University of Iceland, Reykjavík, Iceland
- Landspitali University Hospital, Reykjavík, Iceland
| | - Jacqueline R. Harris
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Kennedy Krieger Institute, Baltimore, MD, United States
- *Correspondence: Jacqueline R. Harris,
| |
Collapse
|
10
|
Reynisdottir T, Anderson KJ, Boukas L, Bjornsson HT. Missense variants causing Wiedemann-Steiner syndrome preferentially occur in the KMT2A-CXXC domain and are accurately classified using AlphaFold2. PLoS Genet 2022; 18:e1010278. [PMID: 35727845 PMCID: PMC9249231 DOI: 10.1371/journal.pgen.1010278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 07/01/2022] [Accepted: 05/27/2022] [Indexed: 11/19/2022] Open
Abstract
Wiedemann-Steiner syndrome (WDSTS) is a neurodevelopmental disorder caused by de novo variants in KMT2A, which encodes a multi-domain histone methyltransferase. To gain insight into the currently unknown pathogenesis of WDSTS, we examined the spatial distribution of likely WDSTS-causing variants across the 15 different domains of KMT2A. Compared to variants in healthy controls, WDSTS variants exhibit a 61.9-fold overrepresentation within the CXXC domain–which mediates binding to unmethylated CpGs–suggesting a major role for this domain in mediating the phenotype. In contrast, we find no significant overrepresentation within the catalytic SET domain. Corroborating these results, we find that hippocampal neurons from Kmt2a-deficient mice demonstrate disrupted histone methylation (H3K4me1 and H3K4me3) preferentially at CpG-rich regions, but this has no systematic impact on gene expression. Motivated by these results, we combine accurate prediction of the CXXC domain structure by AlphaFold2 with prior biological knowledge to develop a classification scheme for missense variants in the CXXC domain. Our classifier achieved 92.6% positive and 92.9% negative predictive value on a hold-out test set. This classification performance enabled us to subsequently perform an in silico saturation mutagenesis and classify a total of 445 variants according to their functional effects. Our results yield a novel insight into the mechanistic basis of WDSTS and provide an example of how AlphaFold2 can contribute to the in silico characterization of variant effects with very high accuracy, suggesting a paradigm potentially applicable to many other Mendelian disorders. Wiedemann-Steiner syndrome (WDSTS) is a neurodevelopmental pediatric disorder caused by the genetic disruption of the histone methyltransferase KMT2A. Since KMT2A has many different domains that perform different functions, we reasoned that by identifying the domains most enriched for WDSTS-causing genetic variants we would gain insights into the incompletely understood molecular pathogenesis of WDSTS. We discovered that the CXXC domain—which binds unmethylated CpGs—shows by far the greatest enrichment, suggesting that loss of the CpG-binding ability of KMT2A plays a central role in WDSTS. Next, to understand specific rules underlying the genetic disruption of the CXXC domain, we combined prior knowledge about the function/structure of the domain with 3D structure prediction by AlphaFold2 to develop an effect classifier for CXXC missense variants. We found that this classifier exhibits accurate performance, and we therefore applied it to provide classifications for any such variant that can possibly arise, in order to aid in the interpretation of such variants in the clinic. Our work provides novel insights into WDSTS and suggests a strategy for missense variant classification that can potentially be applied to many other pediatric genetic disorders.
Collapse
Affiliation(s)
- Tinna Reynisdottir
- Laboratory of Translational Medicine, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Kimberley Jade Anderson
- Laboratory of Translational Medicine, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| | - Leandros Boukas
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- * E-mail: (LB); (HTB)
| | - Hans Tomas Bjornsson
- Laboratory of Translational Medicine, Faculty of Medicine, University of Iceland, Reykjavik, Iceland
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Pediatrics, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Genetics and Molecular Medicine, Landspitali University Hospital, Reykjavik, Iceland
- * E-mail: (LB); (HTB)
| |
Collapse
|
11
|
Agnarsdóttir D, Sigurjónsdóttir VK, Emilsdóttir AR, Petersen E, Sigfússon G, Rögnvaldsson I, Franzson L, Vernon H, Bjornsson HT. Early cardiomyopathy without severe metabolic dysregulation in a patient with cblB-type methylmalonic acidemia. Mol Genet Genomic Med 2022; 10:e1971. [PMID: 35712814 PMCID: PMC9266587 DOI: 10.1002/mgg3.1971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 03/18/2022] [Accepted: 05/03/2022] [Indexed: 11/10/2022] Open
Abstract
Background Cardiomyopathy is a known complication of organic acidemias but generally thought to be secondary to poor metabolic control. Methods Our patient was found through biochemical testing and Sanger sequencing to harbor an Icelandic founder mutation: NM_052845.4(MMAB):c.571C > T(p.Arg191Trp), leading to an early presentation (4 h after birth) of cblB‐type methylmalonic acidemia (MMA). Biochemical testing of this patient suggested B‐12‐responsiveness and thus the patient was treated with cyanocobalamin throughout life. Informed parental consent was obtained for this report. Results Our patient had three metabolic decompensations in her life (at birth, at 1 month, and at 5 months). The first decompensation was probably linked to stress of delivery, second to rhinovirus infection, and third by co‐infection of norovirus and enterovirus. At 3 months, the patient was noted to be tachypneic, although this was attributed to her underlying metabolic acidosis. At 5 months and 10 days, the patient was admitted with minor flu‐like symptoms but developed severe diarrhea in hospital and upon rehydration had cardiac decompensation and was found to have undiagnosed dilated cardiomyopathy. Although, patient was treated aggressively with dextrose, hemodialysis, levocarnitine, and vasoactive agents, there was limited response to medications to treat cardiac failure, and eventually the patient passed away before turning 6 months old. Conclusions Other than these three mild decompensations, patient had very good metabolic control, thus demonstrating that even without frequent metabolic decompensation, cardiomyopathy can be an observed phenotype in cblB‐type MMA even very early in life, suggesting that this phenotype may be independent of metabolic control.
Collapse
Affiliation(s)
- Dagbjört Agnarsdóttir
- Department of Genetics and Molecular Medicine, Landspitali University Hospital, Reykjavik, Iceland
| | | | - Arna Rut Emilsdóttir
- Department of Genetics and Molecular Medicine, Landspitali University Hospital, Reykjavik, Iceland
| | - Erna Petersen
- Department of Nutrition, Landspitali University Hospital, Reykjavik, Iceland
| | - Gunnlaugur Sigfússon
- Hringurinn, Childrens Hospital, Landspitali University Hospital, Reykjavik, Iceland
| | | | - Leifur Franzson
- Department of Genetics and Molecular Medicine, Landspitali University Hospital, Reykjavik, Iceland
| | - Hilary Vernon
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Hans Tomas Bjornsson
- Department of Genetics and Molecular Medicine, Landspitali University Hospital, Reykjavik, Iceland.,McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, Maryland, USA.,Faculty of Medicine, University of Iceland, Reykjavik, Iceland
| |
Collapse
|
12
|
Ng R, Bjornsson HT, Fahrner JA, Harris J. Sleep disturbances correlate with behavioral problems among individuals with Wiedemann-Steiner syndrome. Front Genet 2022; 13:950082. [PMID: 36313433 PMCID: PMC9608624 DOI: 10.3389/fgene.2022.950082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Wiedemann-Steiner syndrome (WSS) is a rare genetic disorder caused by mutation in KMT2A and characterized by neurodevelopmental delay. This study is the first prospective investigation to examine the sleep and behavioral phenotypes among those with WSS through parent-informant screening inventories. A total of 24 parents of children/adults with WSS (11F, Mean age = 12.71 years, SD = 8.17) completed the Strengths and Difficulties Questionnaire (SDQ) and 22 of these caregivers also completed the Modified Simonds and Parraga Sleep Questionnaire (MSPSQ). On average, the majority of those with WSS (83%) were rated to show borderline to clinical level of behavioral difficulties on the SDQ. Approximately 83% were rated in these ranges for hyperactivity, 63% for emotional problems, and 50% for conduct problems. When applying prior published clinical cut-off for risk of sleep disturbance among those with neurodevelopmental disorders, over 80% of our sample exceeded this limit on the MSPSQ. Largely, caregivers' ratings suggested restless sleep, rigid bedtime rituals, sleep reluctance and breathing through the mouth in sleep were most consistent problems observed. Partial correlations between sleep and behavioral domains showed elevated emotional problems were associated with parasomnia characteristics after controlling for age. Daytime drowsiness and activity were associated with more hyperactivity. Those with more night waking problems and delayed sleep onset were rated to show more severe conduct problems. Overall, these findings suggest dysfunctional sleep behaviors, hyperactivity, and affective problems are part of the neurobehavioral phenotype of WSS. Routine clinical care for those affected by WSS should include close monitoring of sleep and overactive behaviors.
Collapse
Affiliation(s)
- Rowena Ng
- Kennedy Krieger Institute, Baltimore, MD, United States.,Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Hans Tomas Bjornsson
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States.,Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, United States.,Faculty of Medicine, University of Iceland, Reykjavik, Iceland.,Landspitali University Hospital, Reykjavik, Iceland
| | - Jill A Fahrner
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States.,Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Jacqueline Harris
- Kennedy Krieger Institute, Baltimore, MD, United States.,Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States.,Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, United States.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| |
Collapse
|
13
|
Zhang L, Pilarowski G, Pich EM, Nakatani A, Dunlop J, Baba R, Matsuda S, Daini M, Hattori Y, Matsumoto S, Ito M, Kimura H, Bjornsson HT. Inhibition of KDM1A activity restores adult neurogenesis and improves hippocampal memory in a mouse model of Kabuki syndrome. Mol Ther Methods Clin Dev 2021; 20:779-791. [PMID: 33738331 PMCID: PMC7940709 DOI: 10.1016/j.omtm.2021.02.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 02/14/2021] [Indexed: 12/13/2022]
Abstract
Kabuki syndrome (KS) is a rare cause of intellectual disability primarily caused by loss-of-function mutations in lysine-specific methyltransferase 2D (KMT2D), which normally adds methyl marks to lysine 4 on histone 3. Previous studies have shown that a mouse model of KS (Kmt2d+/βGeo) demonstrates disruption of adult neurogenesis and hippocampal memory. Proof-of-principle studies have shown postnatal rescue of neurological dysfunction following treatments that promote chromatin opening; however, these strategies are non-specific and do not directly address the primary defect of histone methylation. Since lysine-specific demethylase 1A (LSD1/KDM1A) normally removes the H3K4 methyl marks added by KMT2D, we hypothesized that inhibition of KDM1A demethylase activity may ameliorate molecular and phenotypic defects stemming from KMT2D loss. To test this hypothesis, we evaluated a recently developed KDM1A inhibitor (TAK-418) in Kmt2d+/βGeo mice. We found that orally administered TAK-418 increases the numbers of newly born doublecortin (DCX)+ cells and processes in the hippocampus in a dose-dependent manner. We also observed TAK-418-dependent rescue of histone modification defects in hippocampus both by western blot and chromatin immunoprecipitation sequencing (ChIP-seq). Treatment rescues gene expression abnormalities including those of immediate early genes such as FBJ osteosarcoma oncogene (Fos) and FBJ osteosarcoma oncogene homolog B (Fosb). After 2 weeks of TAK-418, Kmt2d+/βGeo mice demonstrated normalization of hippocampal memory defects. In summary, our data suggest that KDM1A inhibition is a plausible treatment strategy for KS and support the hypothesis that the epigenetic dysregulation secondary to KMT2D dysfunction plays a major role in the postnatal neurological disease phenotype in KS.
Collapse
Affiliation(s)
- Li Zhang
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Genay Pilarowski
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | | | - Atsushi Nakatani
- Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - John Dunlop
- Takeda Pharmaceutical Company Limited, London, UK
| | - Rina Baba
- Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Satoru Matsuda
- Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Masaki Daini
- Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Yasushi Hattori
- Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | | | - Mitsuhiro Ito
- Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Haruhide Kimura
- Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Hans Tomas Bjornsson
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik 101, Iceland
- Landspitali University Hospital, Reykjavik 101, Iceland
- Corresponding author: Hans Tomas Bjornsson, McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, 733 North Broadway Street, MRB 415, Baltimore, MD 21205, USA.
| |
Collapse
|
14
|
Luperchio TR, Applegate CD, Bodamer O, Bjornsson HT. Haploinsufficiency of KMT2D is sufficient to cause Kabuki syndrome and is compatible with life. Mol Genet Genomic Med 2019; 8:e1072. [PMID: 31814321 PMCID: PMC7005614 DOI: 10.1002/mgg3.1072] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Teresa Romeo Luperchio
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Carolyn D Applegate
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Olaf Bodamer
- Division of Genetics and Genomics, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.,Broad Institute of MIT and Harvard University, Cambridge, MA, USA
| | - Hans Tomas Bjornsson
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavik, Iceland.,Landspitali University Hospital, Reykjavik, Iceland
| |
Collapse
|
15
|
Harris J, Mahone EM, Bjornsson HT. Molecularly confirmed Kabuki (Niikawa-Kuroki) syndrome patients demonstrate a specific cognitive profile with extensive visuospatial abnormalities. J Intellect Disabil Res 2019; 63:489-497. [PMID: 30767315 PMCID: PMC6499655 DOI: 10.1111/jir.12596] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 12/13/2018] [Accepted: 01/07/2019] [Indexed: 05/05/2023]
Abstract
BACKGROUND Kabuki (Niikawa-Kuroki) syndrome (KS) is caused by disease-causing variants in either of two components (KMT2D and KDM6A) of the histone methylation machinery. Nearly all individuals with KS have cognitive difficulties, and most have intellectual disability. Recent studies on a mouse model of KS suggest disruption of normal adult neurogenesis in the granule cell layer of the dentate gyrus of the hippocampus. These mutant mice also demonstrate hippocampal memory defects compared with littermates, but this phenotype is rescued postnatally with agents that target the epigenetic machinery. If these findings are relevant to humans with KS, we would expect significant and disproportionate disruption of visuospatial functioning in these individuals. METHODS To test this hypothesis, we have compiled a battery to robustly explore visuospatial function. We prospectively recruited 22 patients with molecularly confirmed KS and 22 IQ-matched patients with intellectual disability. RESULTS We observed significant deficiencies in visual motor, visual perception and visual motor memory in the KS group compared with the IQ-matched group on several measures. In contrast, language function appeared to be marginally better in the KS group compared with the IQ-matched group in a sentence comprehension task. CONCLUSIONS Together, our data suggest specific disruption of visuospatial function, likely linked to the dentate gyrus, in individuals with KS and provide the groundwork for a novel and specific outcome measure for a clinical trial in a KS population.
Collapse
Affiliation(s)
- J Harris
- Department of Neurogenetics, Kennedy Krieger Institute, Baltimore, MD, USA
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, MD, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - E M Mahone
- Department of Neuropsychology, Kennedy Krieger Institute, Baltimore, MD, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - H T Bjornsson
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, MD, USA
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Faculty of Medicine, University of Iceland, Reykjavik, Iceland
- Department of Genetics and Molecular Medicine, Landspitali University Hospital, Reykjavik, Iceland
| |
Collapse
|
16
|
Abstract
The Mendelian disorders of the epigenetic machinery are genetic disorders that involve disruption of the various components of the epigenetic machinery (writers, erasers, readers, and remodelers) and are thus expected to have widespread downstream epigenetic consequences. Studying this group may offer a unique opportunity to learn about the role of epigenetics in health and disease. Among these patients, neurological dysfunction and, in particular, intellectual disability appears to be a common phenotype; however, this is often seen in association with other more specific features in respective disorders. The specificity of some of the clinical features raises the question whether specific cell types are particularly sensitive to the loss of these factors. Most of these disorders demonstrate dosage sensitivity as loss of a single allele appears to be sufficient to cause the observed phenotypes. Although the pathogenic sequence is unknown for most of these disorders, there are several examples where disrupted expression of downstream target genes accounts for a substantial portion of the phenotype; hence, it may be useful to systematically map such disease-relevant target genes. Finally, two of these disorders (Rubinstein-Taybi and Kabuki syndromes) have shown post-natal rescue of markers of the neurological dysfunction with drugs that lead to histone deacetylase inhibition, indicating that some of these disorders may be treatable causes of intellectual disability.
Collapse
Affiliation(s)
- Hans Tomas Bjornsson
- McKusick-Nathans Institute of Genetic Medicine and Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| |
Collapse
|
17
|
Palsdottir A, Helgason A, Palsson S, Bjornsson HT, Bragason BT, Gretarsdottir S, Thorsteinsdottir U, Olafsson E, Stefansson K. A drastic reduction in the life span of cystatin C L68Q carriers due to life-style changes during the last two centuries. PLoS Genet 2008; 4:e1000099. [PMID: 18566660 PMCID: PMC2409978 DOI: 10.1371/journal.pgen.1000099] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2008] [Accepted: 05/15/2008] [Indexed: 11/18/2022] Open
Abstract
Hereditary cystatin C amyloid angiopathy (HCCAA) is an autosomal dominant disease with high penetrance, manifest by brain hemorrhages in young normotensive adults. In Iceland, this condition is caused by the L68Q mutation in the cystatin C gene, with contemporary carriers reaching an average age of only 30 years. Here, we report, based both on linkage disequilibrium and genealogical evidence, that all known copies of this mutation derive from a common ancestor born roughly 18 generations ago. Intriguingly, the genealogies reveal that obligate L68Q carriers born 1825 to 1900 experienced a drastic reduction in life span, from 65 years to the present-day average. At the same time, a parent-of-origin effect emerged, whereby maternal inheritance of the mutation was associated with a 9 year reduction in life span relative to paternal inheritance. As these trends can be observed in several different extended families, many generations after the mutational event, it seems likely that some environmental factor is responsible, perhaps linked to radical changes in the life-style of Icelanders during this period. A mutation with such radically different phenotypic effects in reaction to normal variation in human life-style not only opens the possibility of preventive strategies for HCCAA, but it may also provide novel insights into the complex relationship between genotype and environment in human disease.
Collapse
Affiliation(s)
- Astridur Palsdottir
- Institute for Experimental Pathology, University of Iceland, Keldur, Reykjavik, Iceland.
| | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Bjornsson HT, Cui H, Gius D, Fallin MD, Feinberg AP. The new field of epigenomics: implications for cancer and other common disease research. Cold Spring Harb Symp Quant Biol 2005; 69:447-56. [PMID: 16117680 PMCID: PMC5434869 DOI: 10.1101/sqb.2004.69.447] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- H T Bjornsson
- Predoctoral Program in Human Genetics and Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | | | | | | | | |
Collapse
|