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Bosch E, Güse E, Kirchner P, Winterpacht A, Walther M, Alders M, Kerkhof J, Ekici AB, Sticht H, Sadikovic B, Reis A, Vasileiou G. The missing link: ARID1B non-truncating variants causing Coffin-Siris syndrome due to protein aggregation. Hum Genet 2024; 143:965-978. [PMID: 39028335 PMCID: PMC11303441 DOI: 10.1007/s00439-024-02688-9] [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: 04/02/2024] [Accepted: 07/07/2024] [Indexed: 07/20/2024]
Abstract
ARID1B is the most frequently mutated gene in Coffin-Siris syndrome (CSS). To date, the vast majority of causative variants reported in ARID1B are truncating, leading to nonsense-mediated mRNA decay. In the absence of experimental data, only few ARID1B amino acid substitutions have been classified as pathogenic, mainly based on clinical data and their de novo occurrence, while most others are currently interpreted as variants of unknown significance. The present study substantiates the pathogenesis of ARID1B non-truncating/NMD-escaping variants located in the SMARCA4-interacting EHD2 and DNA-binding ARID domains. Overexpression assays in cell lines revealed that the majority of EHD2 variants lead to protein misfolding and formation of cytoplasmic aggresomes surrounded by vimentin cage-like structures and co-localizing with the microtubule organisation center. ARID domain variants exhibited not only aggresomes, but also nuclear aggregates, demonstrating robust pathological effects. Protein levels were not compromised, as shown by quantitative western blot analysis. In silico structural analysis predicted the exposure of amylogenic segments in both domains due to the nearby variants, likely causing this aggregation. Genome-wide transcriptome and methylation analysis in affected individuals revealed expression and methylome patterns consistent with those of the pathogenic haploinsufficiency ARID1B alterations in CSS cases. These results further support pathogenicity and indicate two approaches for disambiguation of such variants in everyday practice. The few affected individuals harbouring EHD2 non-truncating variants described to date exhibit mild CSS clinical traits. In summary, this study paves the way for the re-evaluation of previously unclear ARID1B non-truncating variants and opens a new era in CSS genetic diagnosis.
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Affiliation(s)
- Elisabeth Bosch
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Esther Güse
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Philipp Kirchner
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Andreas Winterpacht
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Mona Walther
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Marielle Alders
- Amsterdam University Medical Center, University of Amsterdam, Department of Human Genetics, Amsterdam Reproduction and Development Research Institute, Amsterdam, The Netherlands
| | - Jennifer Kerkhof
- Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON, Canada
| | - Arif B Ekici
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Heinrich Sticht
- Division of Bioinformatics, Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Bekim Sadikovic
- Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON, Canada
- Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
| | - André Reis
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054, Erlangen, Germany
- Centre for Rare Diseases Erlangen (ZSEER), Universitätsklinikum Erlangen, Erlangen, Germany
| | - Georgia Vasileiou
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054, Erlangen, Germany.
- Centre for Rare Diseases Erlangen (ZSEER), Universitätsklinikum Erlangen, Erlangen, Germany.
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Cai M, Lin N, Fu M, Que Y, Huang H, Xu L. Fetal agenesis of corpus callosum: chromosomal copy number abnormalities and postnatal follow-up. Mol Biol Rep 2024; 51:872. [PMID: 39080034 PMCID: PMC11289215 DOI: 10.1007/s11033-024-09821-x] [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: 04/16/2024] [Accepted: 07/23/2024] [Indexed: 08/02/2024]
Abstract
OBJECTIVE Agenesis of the corpus callosum (ACC) is an anomaly that can occur in fetuses during pregnancy. However, there is currently no treatment for fetal ACC. Therefore, we conducted a retrospective analysis of obstetric outcomes of fetal ACC to explore the relationship between fetal ACC phenotypes and chromosomal copy number abnormalities. METHODS AND RESULTS Amniotic fluid or umbilical cord blood were extracted from pregnant women with fetal ACC for karyotype analysis and chromosomal microarray analysis (CMA). Among the 48 fetuses with ACC, 22 (45.8%, 22/48) had isolated ACC, and 26 (54.2%, 26/48) had non-isolated ACC. Chromosomal abnormalities were detected via karyotype analysis in four cases. In addition to the four cases of pathogenic copy number variations (CNVs) detected using karyotype analysis, CMA revealed two cases of pathogenic CNVs with 17q12 microduplication and 16p12.2 microdeletion. The obstetric outcomes of 26 patients with non-isolated ACC were followed up, and 17 chose to terminate the pregnancy. In addition, seven of the nine cases with non-isolated ACC showed no obvious abnormality during postnatal follow-up, whereas only one case with normal CMA showed an abnormal phenotype at six months. Of the 22 patients with isolated ACC, six chose to terminate the pregnancy. Postnatal follow-up of 16 isolated ACC cases revealed only one with benign CNV, presenting with intellectual disability. CONCLUSION Pregnant women with fetal ACC should be offered prenatal CMA, particularly non-isolated ACC. Patients with ACC should undergo prolonged postnatal follow-up, and appropriate intervention should be provided if necessary.
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Affiliation(s)
- Meiying Cai
- Medical Genetic Diagnosis and Therapy Center, Fujian Maternity and Child Health Hospital College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Clinical Research Center for Maternal-Fetal Medicine, Fujian Medical University, National Key Obstetric Clinical Specialty Construction Institution of China, Fuzhou, China
| | - Na Lin
- Medical Genetic Diagnosis and Therapy Center, Fujian Maternity and Child Health Hospital College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Clinical Research Center for Maternal-Fetal Medicine, Fujian Medical University, National Key Obstetric Clinical Specialty Construction Institution of China, Fuzhou, China
| | - Meimei Fu
- Medical Genetic Diagnosis and Therapy Center, Fujian Maternity and Child Health Hospital College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Clinical Research Center for Maternal-Fetal Medicine, Fujian Medical University, National Key Obstetric Clinical Specialty Construction Institution of China, Fuzhou, China
| | - Yanting Que
- Medical Genetic Diagnosis and Therapy Center, Fujian Maternity and Child Health Hospital College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Clinical Research Center for Maternal-Fetal Medicine, Fujian Medical University, National Key Obstetric Clinical Specialty Construction Institution of China, Fuzhou, China
| | - Hailong Huang
- Medical Genetic Diagnosis and Therapy Center, Fujian Maternity and Child Health Hospital College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Clinical Research Center for Maternal-Fetal Medicine, Fujian Medical University, National Key Obstetric Clinical Specialty Construction Institution of China, Fuzhou, China.
| | - Liangpu Xu
- Medical Genetic Diagnosis and Therapy Center, Fujian Maternity and Child Health Hospital College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Clinical Research Center for Maternal-Fetal Medicine, Fujian Medical University, National Key Obstetric Clinical Specialty Construction Institution of China, Fuzhou, China.
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Comeau D, Belliveau J, Bouhamdani N, Amor MB. Expanding the phenotypic spectrum for CDK8-related disease: A case report. Am J Med Genet A 2024; 194:e63537. [PMID: 38193604 DOI: 10.1002/ajmg.a.63537] [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: 08/11/2023] [Revised: 12/06/2023] [Accepted: 12/22/2023] [Indexed: 01/10/2024]
Abstract
BACKGROUND Cyclin-dependent kinase 8 (CDK8) is part of a regulatory kinase module that regulates the activity of the Mediator complex. The Mediator, a large conformationally flexible protein complex, goes on to regulate RNA polymerase II activity, consequently affecting transcriptional regulation. Thus, inactivating mutations of the genes within the kinase module cause aberrant transcriptional regulation and disease, namely, CDK8-related intellectual developmental disorder with hypotonia and behavioral abnormalities (IDDHBA). CASE PRESENTATION We describe, for the first time, a likely pathogenic heterozygous CDK8 variant c.599G>A, p.(Arg200Gln) inherited from the biological mother. The clinical presentation of the child and mother is within the described clinical spectrum for IDDHBA; however, undocumented progressive contractures of the hips and knees as well as scoliosis were also observed in the child. This phenotype was not found in the mother, highlighting a heterogenous presentation for the same variant within the same family. Furthermore, the described clinical presentation may further support the notion of a module- or Mediator-related syndrome with varying clinical presentation. CONCLUSION This case report documents the first inherited case of IDDHBA and expands the phenotypic spectrum for CDK8-related disease to include undocumented progressive contractures of the hips and knees as well as scoliosis, which may support the notion of a module- or Mediator-related syndrome with varying clinical presentation.
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Affiliation(s)
- Dominique Comeau
- Vitalité Health Network, Dr Georges-L.-Dumont University Hospital Center, Moncton, New Brunswick, Canada
| | - Jenna Belliveau
- Centre de formation médicale du New-Brunswick, Université de Sherbrooke, Moncton, New Brunswick, Canada
| | - Nadia Bouhamdani
- Vitalité Health Network, Dr Georges-L.-Dumont University Hospital Center, Moncton, New Brunswick, Canada
- Centre de formation médicale du New-Brunswick, Université de Sherbrooke, Moncton, New Brunswick, Canada
- Medical Genetics Department, Vitalité Health Network, Dr Georges-L.-Dumont University Hospital Center, Moncton, New Brunswick, Canada
| | - Mouna Ben Amor
- Medical Genetics Department, Vitalité Health Network, Dr Georges-L.-Dumont University Hospital Center, Moncton, New Brunswick, Canada
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Cnpy3 2xHA mice reveal neuronal expression of Cnpy3 in the brain. J Neurosci Methods 2023; 383:109730. [PMID: 36280087 DOI: 10.1016/j.jneumeth.2022.109730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 10/04/2022] [Accepted: 10/17/2022] [Indexed: 11/30/2022]
Abstract
BACKGROUND Identification of biallelic CNPY3 mutations in patients with epileptic encephalopathy and abnormal electroencephalography findings of Cnpy3 knock-out mice have indicated that the loss of CNPY3 function causes neurological disorders such as epilepsy. However, the basic property of CNPY3 in the brain remains unclear. NEW METHOD We generated C-terminal 2xHA-tag knock-in Cnpy3 mice by i-GONAD in vivo genome editing system to investigate the expression and function of Cnpy3 in the mouse brain. RESULTS 2xHA-tagged Cnpy3 was confirmed by immunoblot analysis using anti-HA and CNPY3 antibodies, although HA tagging caused the decreased Cnpy3 protein level. Immunohistochemical analysis of Cnpy32xHA knock-in mice showed that Cnpy3-2xHA was predominantly expressed in the neuron. In addition, Cnpy3 and Cnpy3-2xHA were both localized in the endoplasmic reticulum and synaptosome and showed age-dependent expression changes in the brain. COMPARISON WITH EXISTING METHODS Conventional Cnpy3 antibodies could not allow us to investigate the distribution of Cnpy3 expression in the brain, while HA-tagging revealed the expression of CNPY3 in neuronal cells. CONCLUSIONS Taken together, we demonstrated that Cnpy32xHA knock-in mice would be useful to further elucidate the property of Cnpy3 in brain function and neurological disorders.
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Eroğlu Y, Baykara M, Perçinel Yazici İ, Utku Yazici K, Kürşad Poyraz A. Evaluation of the corpus callosum using magnetic resonance imaging histogram analysis in autism spectrum disorder. Neuroradiol J 2022; 35:751-757. [PMID: 35523430 PMCID: PMC9626850 DOI: 10.1177/19714009221097507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Histogram analysis is a texture analysis method that can be used in medical images. Quantitative values of the intensity of images can be obtained with histogram analysis. It aimed to evaluate corpus callosum in magnetic resonance images (MRIs) using histogram analysis of pediatric patients with autism spectrum disorder (ASD) to compare them with healthy controls. METHODS This study included 29 children with ASD and 29 healthy children with normal brain MRI. High-resolution three-dimensional turbo field echo images were obtained with a 1.5 T scanner device for brain magnetic resonance imaging. On the corpus callosum in the sagittal T1-weighted images obtained, mean gray level density (mean), the standard deviation, median, minimum, maximum, entropy, variance, skewness, kurtosis, uniformity, size % L, size % M, size % U, and percentile parameters were measured. RESULTS In ASD patients, mean, standard deviation, maximum, median, variance, entropy, 25%, 75%, 90%, 97%, and 99% values were found to be lower than the control group, and size % U value was higher. In addition, the corpus callosum area was significantly lower in the ASD compared to the controls. CONCLUSION According to our study, corpus callosum of patients with ASD showed differences compared to healthy controls by histogram analysis, even though they were seen as normal in brain MRI. We think that histogram analysis can be used to evaluate possibly affected areas of brain in ASD patients.
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Affiliation(s)
- Yeşim Eroğlu
- Faculty of Medicine, Department of
Radiology, Firat University, Elazig, Turkey
| | - Murat Baykara
- Faculty of Medicine, Department of
Radiology, Firat University, Elazig, Turkey
| | - İpek Perçinel Yazici
- Faculty of Medicine, Department of
Child and Adolescent Psychiatry, Firat University, Elazig, Turkey
| | - Kemal Utku Yazici
- Faculty of Medicine, Department of
Child and Adolescent Psychiatry, Firat University, Elazig, Turkey
| | - Ahmet Kürşad Poyraz
- Faculty of Medicine, Department of
Radiology, Firat University, Elazig, Turkey
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