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Gao CW, Lin W, Riddle RC, Chopra S, Kim J, Boukas L, Hansen KD, Björnsson HT, Fahrner JA. Growth deficiency in a mouse model of Kabuki syndrome 2 bears mechanistic similarities to Kabuki syndrome 1. PLoS Genet 2024; 20:e1011310. [PMID: 38857303 PMCID: PMC11192384 DOI: 10.1371/journal.pgen.1011310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 06/21/2024] [Accepted: 05/21/2024] [Indexed: 06/12/2024] Open
Abstract
Growth deficiency is a characteristic feature of both Kabuki syndrome 1 (KS1) and Kabuki syndrome 2 (KS2), Mendelian disorders of the epigenetic machinery with similar phenotypes but distinct genetic etiologies. We previously described skeletal growth deficiency in a mouse model of KS1 and further established that a Kmt2d-/- chondrocyte model of KS1 exhibits precocious differentiation. Here we characterized growth deficiency in a mouse model of KS2, Kdm6atm1d/+. We show that Kdm6atm1d/+ mice have decreased femur and tibia length compared to controls and exhibit abnormalities in cortical and trabecular bone structure. Kdm6atm1d/+ growth plates are also shorter, due to decreases in hypertrophic chondrocyte size and hypertrophic zone height. Given these disturbances in the growth plate, we generated Kdm6a-/- chondrogenic cell lines. Similar to our prior in vitro model of KS1, we found that Kdm6a-/- cells undergo premature, enhanced differentiation towards chondrocytes compared to Kdm6a+/+ controls. RNA-seq showed that Kdm6a-/- cells have a distinct transcriptomic profile that indicates dysregulation of cartilage development. Finally, we performed RNA-seq simultaneously on Kmt2d-/-, Kdm6a-/-, and control lines at Days 7 and 14 of differentiation. This revealed surprising resemblance in gene expression between Kmt2d-/- and Kdm6a-/- at both time points and indicates that the similarity in phenotype between KS1 and KS2 also exists at the transcriptional level.
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Affiliation(s)
- Christine W. Gao
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - WanYing Lin
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Ryan C. Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Research and Development Service, Baltimore Veterans Administration Medical Center, Baltimore, Maryland, United States of America
| | - Sheetal Chopra
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Jiyoung Kim
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Leandros Boukas
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Biostatistics, Johns Hopkins University School of Public Health, Baltimore, Maryland, United States of America
| | - Kasper D. Hansen
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Biostatistics, Johns Hopkins University School of Public Health, Baltimore, Maryland, United States of America
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Hans T. Björnsson
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Faculty of Medicine, University of Iceland, Reykjavík, Iceland
- Landspítali University Hospital, Reykjavík, Iceland
| | - Jill A. Fahrner
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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Szoszkiewicz A, Bukowska-Olech E, Jamsheer A. Molecular landscape of congenital vertebral malformations: recent discoveries and future directions. Orphanet J Rare Dis 2024; 19:32. [PMID: 38291488 PMCID: PMC10829358 DOI: 10.1186/s13023-024-03040-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 01/19/2024] [Indexed: 02/01/2024] Open
Abstract
Vertebral malformations (VMs) pose a significant global health problem, causing chronic pain and disability. Vertebral defects occur as isolated conditions or within the spectrum of various congenital disorders, such as Klippel-Feil syndrome, congenital scoliosis, spondylocostal dysostosis, sacral agenesis, and neural tube defects. Although both genetic abnormalities and environmental factors can contribute to abnormal vertebral development, our knowledge on molecular mechanisms of numerous VMs is still limited. Furthermore, there is a lack of resource that consolidates the current knowledge in this field. In this pioneering review, we provide a comprehensive analysis of the latest research on the molecular basis of VMs and the association of the VMs-related causative genes with bone developmental signaling pathways. Our study identifies 118 genes linked to VMs, with 98 genes involved in biological pathways crucial for the formation of the vertebral column. Overall, the review summarizes the current knowledge on VM genetics, and provides new insights into potential involvement of biological pathways in VM pathogenesis. We also present an overview of available data regarding the role of epigenetic and environmental factors in VMs. We identify areas where knowledge is lacking, such as precise molecular mechanisms in which specific genes contribute to the development of VMs. Finally, we propose future research avenues that could address knowledge gaps.
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Affiliation(s)
- Anna Szoszkiewicz
- Department of Medical Genetics, Poznan University of Medical Sciences, Rokietnicka 8, 60-806, Poznan, Poland.
| | - Ewelina Bukowska-Olech
- Department of Medical Genetics, Poznan University of Medical Sciences, Rokietnicka 8, 60-806, Poznan, Poland
| | - Aleksander Jamsheer
- Department of Medical Genetics, Poznan University of Medical Sciences, Rokietnicka 8, 60-806, Poznan, Poland.
- Centers for Medical Genetics GENESIS, Dąbrowskiego 77A, 60-529, Poznan, Poland.
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Kalinousky AJ, Luperchio TR, Schrode KM, Harris JR, Zhang L, DeLeon VB, Fahrner JA, Lauer AM, Bjornsson HT. KMT2D Deficiency Causes Sensorineural Hearing Loss in Mice and Humans. Genes (Basel) 2023; 15:48. [PMID: 38254937 PMCID: PMC10815913 DOI: 10.3390/genes15010048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 12/19/2023] [Accepted: 12/21/2023] [Indexed: 01/24/2024] Open
Abstract
Individuals with Kabuki syndrome type 1 (KS1) often have hearing loss recognized in middle childhood. Current clinical dogma suggests that this phenotype is caused by frequent infections due to the immune deficiency in KS1 and/or secondary to structural abnormalities of the ear. To clarify some aspects of hearing loss, we collected information on hearing status from 21 individuals with KS1 and found that individuals have both sensorineural and conductive hearing loss, with the average age of presentation being 7 years. Our data suggest that while ear infections and structural abnormalities contribute to the observed hearing loss, these factors do not explain all loss. Using a KS1 mouse model, we found hearing abnormalities from hearing onset, as indicated by auditory brainstem response measurements. In contrast to mouse and human data for CHARGE syndrome, a disorder possessing overlapping clinical features with KS and a well-known cause of hearing loss and structural inner ear abnormalities, there are no apparent structural abnormalities of the cochlea in KS1 mice. The KS1 mice also display diminished distortion product otoacoustic emission levels, which suggests outer hair cell dysfunction. Combining these findings, our data suggests that KMT2D dysfunction causes sensorineural hearing loss compounded with external factors, such as infection.
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Affiliation(s)
- Allison J. Kalinousky
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (A.J.K.); (T.R.L.); (J.R.H.); (L.Z.); (J.A.F.)
| | - Teresa R. Luperchio
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (A.J.K.); (T.R.L.); (J.R.H.); (L.Z.); (J.A.F.)
| | - Katrina M. Schrode
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (K.M.S.); (A.M.L.)
| | - Jacqueline R. Harris
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (A.J.K.); (T.R.L.); (J.R.H.); (L.Z.); (J.A.F.)
- Department of Neurology, Kennedy Krieger Institute, Baltimore, MD 21205, USA
| | - Li Zhang
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (A.J.K.); (T.R.L.); (J.R.H.); (L.Z.); (J.A.F.)
| | - Valerie B. DeLeon
- Department of Anthropology, University of Florida, Gainesville, FL 32610, USA;
| | - Jill A. Fahrner
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (A.J.K.); (T.R.L.); (J.R.H.); (L.Z.); (J.A.F.)
- Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Amanda M. Lauer
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (K.M.S.); (A.M.L.)
| | - Hans T. Bjornsson
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (A.J.K.); (T.R.L.); (J.R.H.); (L.Z.); (J.A.F.)
- Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
- Landspitali University Hospital, 102 Reykjavik, Iceland
- Faculty of Medicine, University of Iceland, 101 Reykjavik, Iceland
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White-Brown A, Choufani S, Weksberg R, Dyment D. Missense variant in SRCAP with distinct DNA methylation signature associated with non-FLHS SRCAP-related neurodevelopmental disorder. Am J Med Genet A 2023; 191:2640-2646. [PMID: 37340855 DOI: 10.1002/ajmg.a.63329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 05/18/2023] [Accepted: 05/26/2023] [Indexed: 06/22/2023]
Abstract
Floating-Harbor syndrome (FLHS) is a neurodevelopmental disorder (NDD) caused by truncating variants in exons 33 and 34 of the SNF2-related CREBBP activator protein gene (SRCAP). Truncating variants proximal to this location in SRCAP result in a non-FLHS SRCAP-associated NDD; an overlapping but distinct NDD characterized by developmental delay with or without intellectual disability (ID), hypotonia, normal stature, and behavioral and psychiatric issues. Here, we report a young woman who initially presented in childhood with significant delays in speech and mild ID. In young adulthood, she developed schizophrenia. On physical examination, she had facial features suggestive of 22q11 deletion syndrome. After non-diagnostic chromosomal microarray and trio exome sequencing (ES), a re-analysis of trio ES data identified a de novo missense variant in SRCAP that was proximal to the FLHS critical region. Subsequent DNA methylation studies showed the unique methylation signature associated with pathogenic sequence variants in non-FLHS SRCAP-related NDD. This clinical report describes an individual with non-FLHS SRCAP-related NDD caused by an SRCAP missense variant, and it also demonstrates the clinical utility of ES re-analysis and DNA methylation analysis for undiagnosed patients, in particular, those with variants of uncertain significance.
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Affiliation(s)
- Alexandre White-Brown
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Sanaa Choufani
- Genetics and Genome Biology Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Rosanna Weksberg
- Genetics and Genome Biology Program, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
- Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - David Dyment
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
- Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
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