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Crane-Smith Z, De Castro SCP, Nikolopoulou E, Wolujewicz P, Smedley D, Lei Y, Mather E, Santos C, Hopkinson M, Pitsillides AA, Finnell RH, Ross ME, Copp AJ, Greene NDE. A non-coding insertional mutation of Grhl2 causes gene over-expression and multiple structural anomalies including cleft palate, spina bifida and encephalocele. Hum Mol Genet 2023; 32:2681-2692. [PMID: 37364051 PMCID: PMC10460492 DOI: 10.1093/hmg/ddad094] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/19/2023] [Accepted: 06/15/2023] [Indexed: 06/28/2023] Open
Abstract
Orofacial clefts, including cleft lip and palate (CL/P) and neural tube defects (NTDs) are among the most common congenital anomalies, but knowledge of the genetic basis of these conditions remains incomplete. The extent to which genetic risk factors are shared between CL/P, NTDs and related anomalies is also unclear. While identification of causative genes has largely focused on coding and loss of function mutations, it is hypothesized that regulatory mutations account for a portion of the unidentified heritability. We found that excess expression of Grainyhead-like 2 (Grhl2) causes not only spinal NTDs in Axial defects (Axd) mice but also multiple additional defects affecting the cranial region. These include orofacial clefts comprising midline cleft lip and palate and abnormalities of the craniofacial bones and frontal and/or basal encephalocele, in which brain tissue herniates through the cranium or into the nasal cavity. To investigate the causative mutation in the Grhl2Axd strain, whole genome sequencing identified an approximately 4 kb LTR retrotransposon insertion that disrupts the non-coding regulatory region, lying approximately 300 base pairs upstream of the 5' UTR. This insertion also lies within a predicted long non-coding RNA, oriented on the reverse strand, which like Grhl2 is over-expressed in Axd (Grhl2Axd) homozygous mutant embryos. Initial analysis of the GRHL2 upstream region in individuals with NTDs or cleft palate revealed rare or novel variants in a small number of cases. We hypothesize that mutations affecting the regulation of GRHL2 may contribute to craniofacial anomalies and NTDs in humans.
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Affiliation(s)
- Zoe Crane-Smith
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Sandra C P De Castro
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Evanthia Nikolopoulou
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Paul Wolujewicz
- Center for Neurogenetics, Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York 10065, USA
| | - Damian Smedley
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK
| | - Yunping Lei
- Center for Precision Environmental Health, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Emma Mather
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Chloe Santos
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Mark Hopkinson
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London NW1 0TU, UK
| | - Andrew A Pitsillides
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London NW1 0TU, UK
| | | | - Richard H Finnell
- Center for Precision Environmental Health, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - M Elisabeth Ross
- Center for Neurogenetics, Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York 10065, USA
| | - Andrew J Copp
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Nicholas D E Greene
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
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Nagaraj UD, Moudgal R, Hopkin RJ, Venkatesan C, Kline-Fath BM. Prenatal evaluation of the Sakoda complex. Pediatr Radiol 2019; 49:1843-1847. [PMID: 31384970 DOI: 10.1007/s00247-019-04491-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 06/25/2019] [Accepted: 07/29/2019] [Indexed: 11/26/2022]
Abstract
Sakoda complex is a rare but distinct combination of birth defects consisting of a basal cephalocele, agenesis of the corpus callosum, and midline cleft lip/palate. It has been reported in association with ophthalmologic abnormalities, cognitive deficits and severe epilepsy. Here we describe both prenatal and postnatal MRI findings of a classic case of Sakoda complex in a child with characteristic findings on fetal MRI; prenatal findings have not been described in the literature. Diagnosis of this entity has important implications for prenatal counseling and perinatal management, as is demonstrated in this case.
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Affiliation(s)
- Usha D Nagaraj
- Department of Radiology and Medical Imaging, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229, USA.
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
| | - Rohitha Moudgal
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Robert J Hopkin
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Charu Venkatesan
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Department of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Beth M Kline-Fath
- Department of Radiology and Medical Imaging, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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Abstract
Optic nerves are the second pair of cranial nerves and are unique as they represent an extension of the central nervous system. Apart from clinical and ophthalmoscopic evaluation, imaging, especially magnetic resonance imaging (MRI), plays an important role in the complete evaluation of optic nerve and the entire visual pathway. In this pictorial essay, the authors describe segmental anatomy of the optic nerve and review the imaging findings of various conditions affecting the optic nerves. MRI allows excellent depiction of the intricate anatomy of optic nerves due to its excellent soft tissue contrast without exposure to ionizing radiation, better delineation of the entire visual pathway, and accurate evaluation of associated intracranial pathologies.
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Affiliation(s)
- Foram Gala
- Department of Radiology, Lifescan Imaging Centre, Mumbai, Maharashtra, India; Department of Neuroradiology, University Hospital of Zurich/Children's Hospital of Zurich, Switzerland
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