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Wen J, Song J, Chen J, Feng Z, Jing Q, Gong W, Kang X, Mei L, He C, Ma L, Feng Y. Modeling of pigmentation disorders associated with MITF mutation in Waardenburg syndrome revealed an impaired melanogenesis pathway in iPS-derived melanocytes. Pigment Cell Melanoma Res 2024; 37:21-35. [PMID: 37559350 DOI: 10.1111/pcmr.13118] [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: 09/20/2022] [Revised: 06/18/2023] [Accepted: 07/26/2023] [Indexed: 08/11/2023]
Abstract
Waardenburg Syndrome (WS) is a rare genetic disorder that leads to congenital hearing loss and pigmentation defects. Microphthalmia-associated transcription factor (MITF) is one of its significant pathogenic genes. Despite the comprehensive investigation in animal models, the pathogenic mechanism is still poorly described in humans due to difficulties accessing embryonic tissues. In this work, we used induced pluripotent stem cells derived from a WS patient carrying a heterozygous mutation in the MITF gene c.626A>T (p.His209Leu), and differentiated toward melanocyte lineage, which is the most affected cell type involved in WS. Compared with the wild-type cell line, the MITFmut cell line showed a reduced expression of the characteristic melanocyte-related genes and a lesser proportion of mature, fully pigmented melanosomes. The transcriptome analysis also revealed widespread gene expression changes at the melanocyte stage in the MITFmut cell line. The differentially expressed genes were enriched in melanogenesis and cell proliferation-related pathways. Interestingly, ion transport-related genes also showed a significant difference in MITFmut -induced melanocytes, indicating that the MITF mutant may lead to the dysfunction of potassium channels and transporters produced by intermediate cells in the cochlea, further causing the associated phenotype of deafness. Altogether, our study provides valuable insights into how MITF mutation affects WS patients, which might result in defective melanocyte development and the related phenotype based on the patient-derived iPSC model.
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Affiliation(s)
- Jie Wen
- Department of Otorhinolaryngology, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Institute of Otorhinolaryngology, Head and Neck Surgery, University of South China, Changsha, China
| | - Jian Song
- Department of Otorhinolaryngology, Xiangya Hospital Central South University, Changsha, China
- Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, China
| | - Jiale Chen
- Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, China
| | - Zhili Feng
- Department of Otorhinolaryngology, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Institute of Otorhinolaryngology, Head and Neck Surgery, University of South China, Changsha, China
| | - Qiancheng Jing
- Department of Otorhinolaryngology, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Institute of Otorhinolaryngology, Head and Neck Surgery, University of South China, Changsha, China
| | - Wei Gong
- Department of Otorhinolaryngology, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Institute of Otorhinolaryngology, Head and Neck Surgery, University of South China, Changsha, China
| | - Xiaoming Kang
- Department of Otorhinolaryngology, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Institute of Otorhinolaryngology, Head and Neck Surgery, University of South China, Changsha, China
| | - Lingyun Mei
- Department of Otorhinolaryngology, Xiangya Hospital Central South University, Changsha, China
- Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, China
| | - Chufeng He
- Department of Otorhinolaryngology, Xiangya Hospital Central South University, Changsha, China
- Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, China
| | - Lu Ma
- Institute of Otorhinolaryngology, Head and Neck Surgery, University of South China, Changsha, China
- The Hengyang Key Laboratory of Cellular Stress Biology, Institute of Cytology and Genetics, Hengyang Medical School, University of South China, Hengyang, China
| | - Yong Feng
- Department of Otorhinolaryngology, The Affiliated Changsha Central Hospital, Hengyang Medical School, University of South China, Changsha, China
- Institute of Otorhinolaryngology, Head and Neck Surgery, University of South China, Changsha, China
- Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, China
- Hengyang Medical School, University of South China, Hengyang, China
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Kim SE, Chothani PJ, Shaik R, Pollard W, Finnell RH. Pax3 lineage-specific deletion of Gpr161 is associated with spinal neural tube and craniofacial malformations during embryonic development. Dis Model Mech 2023; 16:dmm050277. [PMID: 37885410 PMCID: PMC10694864 DOI: 10.1242/dmm.050277] [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: 05/02/2023] [Accepted: 10/12/2023] [Indexed: 10/28/2023] Open
Abstract
Sonic hedgehog (Shh) signaling is the morphogen signaling that regulates embryonic craniofacial and neural tube development. G protein-coupled receptor 161 (Gpr161) is a negative regulator of Shh signaling, and its inactivation in mice results in embryo lethality associated with craniofacial defects and neural tube defects. However, the structural defects of later embryonic stages and cell lineages underlying abnormalities have not been well characterized due to the limited lifespan of Gpr161 null mice. We found that embryos with Pax3 lineage-specific deletion of Gpr161 presented with tectal hypertrophy (anterior dorsal neuroepithelium), cranial vault and facial bone hypoplasia (cranial neural crest), vertebral abnormalities (somite) and the closed form of spina bifida (posterior dorsal neuroepithelium). In particular, the closed form of spina bifida was partly due to reduced Pax3 and Cdx4 gene expression in the posterior dorsal neural tubes of Gpr161 mutant embryos with decreased Wnt signaling, whereas Shh signaling was increased. We describe a previously unreported role for Gpr161 in the development of posterior neural tubes and confirm its role in cranial neural crest- and somite-derived skeletogenesis and midbrain morphogenesis in mice.
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Affiliation(s)
- Sung-Eun Kim
- Department of Pediatrics, Dell Pediatric Research Institute, Dell Medical School, University of Texas at Austin, Austin, TX 78723, USA
| | - Pooja J. Chothani
- Department of Pediatrics, Dell Pediatric Research Institute, Dell Medical School, University of Texas at Austin, Austin, TX 78723, USA
| | - Rehana Shaik
- Department of Pediatrics, Dell Pediatric Research Institute, Dell Medical School, University of Texas at Austin, Austin, TX 78723, USA
| | - Westley Pollard
- Department of Pediatrics, Dell Pediatric Research Institute, Dell Medical School, University of Texas at Austin, Austin, TX 78723, USA
| | - Richard H. Finnell
- Department of Pediatrics, Dell Pediatric Research Institute, Dell Medical School, University of Texas at Austin, Austin, TX 78723, USA
- Center for Precision Environmental Health, Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Departments of Molecular and Human Genetics and Medicine, Baylor College of Medicine, Houston, TX 77030, USA
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Kim SE, Chothani PJ, Shaik R, Pollard W, Finnell RH. Pax3 lineage-specific deletion of Gpr161 is associated with spinal neural tube and craniofacial malformations during embryonic development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.07.548129. [PMID: 37461574 PMCID: PMC10350067 DOI: 10.1101/2023.07.07.548129] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
Shh signaling is the morphogen signaling that regulates embryonic craniofacial and neural tube development. G protein-coupled receptor 161 (Gpr161) is a negative regulator of Shh signaling, and its inactivation in mice results in embryo lethality with craniofacial and neural tube defects (NTDs). However, the structural defects of later embryonic stages in Gpr161 null mice and cell lineages underlying abnormalities were not well characterized due to their limited lifespan. We found the Pax3 lineage-specific deletion of Gpr161 in mice presented with tectal hypertrophy (anterior dorsal neuroepithelium), cranial vault and facial bone hypoplasia (cranial neural crest (CNC)), vertebral abnormalities (somite), and the closed form of spina bifida (posterior dorsal neuroepithelium). In particular, the closed form of spina bifida is partly due to the reduced Pax3 and Cdx4 gene expression of the posterior dorsal neural tubes of Gpr161 mutant embryos involving decreased Wnt signaling whereas Shh signaling was increased. This study provides the novel role of Gpr161 in the posterior neural tube development and confirms its role on CNC- and somite-derived skeletogenesis and midbrain morphogenesis in mice.
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Zemet R, Krispin E, Johnson RM, Kumar NR, Westerfield LE, Stover S, Mann DG, Castillo J, Castillo HA, Nassr AA, Sanz Cortes M, Donepudi R, Espinoza J, Whitehead WE, Belfort MA, Shamshirsaz AA, Van den Veyver IB. Implication of chromosomal microarray analysis prior to in-utero repair of fetal open neural tube defect. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2023; 61:719-727. [PMID: 36610024 PMCID: PMC10238557 DOI: 10.1002/uog.26152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/11/2022] [Accepted: 12/13/2022] [Indexed: 06/03/2023]
Abstract
OBJECTIVE In-utero repair of open neural tube defects (ONTD) is an accepted treatment option with demonstrated superior outcome for eligible patients. While current guidelines recommend genetic testing by chromosomal microarray analysis (CMA) when a major congenital anomaly is detected prenatally, the requirement for an in-utero repair, based on the Management of Myelomeningocele Study (MOMS) criteria, is a normal karyotype. In this study, we aimed to evaluate if CMA should be recommended as a prerequisite for in-utero ONTD repair. METHODS This was a retrospective cohort study of pregnancies complicated by ONTD that underwent laparotomy-assisted fetoscopic repair or open-hysterotomy fetal surgery at a single tertiary center between September 2011 and July 2021. All patients met the MOMS eligibility criteria and had a normal karyotype. In a subset of the pregnancies (n = 77), CMA testing was also conducted. We reviewed the CMA results and divided the cohort into two groups according to whether clinically reportable copy-number variants (CNV) were detected (reportable-CNV group) or not (normal-CMA group). Surgical characteristics, complications, and maternal and early neonatal outcomes were compared between the two groups. The primary outcomes were fetal or neonatal death, hydrocephalus, motor function at 12 months of age and walking status at 30 months of age. Standard parametric and non-parametric statistical tests were employed as appropriate. RESULTS During the study period, 146 fetuses with ONTD were eligible for and underwent in-utero repair. CMA results were available for 77 (52.7%) patients. Of those, 65 (84%) had a normal CMA and 12 (16%) had a reportable CNV, two of which were classified as pathogenic. The first case with a pathogenic CNV was diagnosed with a 749-kb central 22q11.21 deletion spanning low-copy-repeat regions B-D of chromosome 22; the second case was diagnosed with a 1.3-Mb interstitial deletion at 1q21.1q21.2. Maternal demographics, clinical characteristics, operative data and postoperative complications were similar between those with normal CMA results and those with reportable CNVs. There were no significant differences in gestational age at delivery or any obstetric and early neonatal outcome between the study groups. Motor function at birth and at 12 months of age, and walking status at 30 months of age, were similar between the two groups. CONCLUSIONS Standard diagnostic testing with CMA should be offered when an ONTD is detected prenatally, as this approach has implications for counseling regarding prognosis and recurrence risk. Our results indicate that the presence of a clinically reportable CNV should not a priori affect eligibility for in-utero repair, as overall pregnancy outcome is similar in these cases to that of cases with normal CMA. Nevertheless, significant CMA results will require a case-by-case multidisciplinary discussion to evaluate eligibility. To generalize the conclusion of this single-center series, a larger, multicenter long-term study should be considered. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.
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Affiliation(s)
- R. Zemet
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - E. Krispin
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery and Maternal–Fetal Medicine, Baylor College of Medicine and Texas Children’s Fetal Center, Houston, TX, USA
| | - R. M. Johnson
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery and Maternal–Fetal Medicine, Baylor College of Medicine and Texas Children’s Fetal Center, Houston, TX, USA
| | - N. R. Kumar
- School of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - L. E. Westerfield
- Department of Obstetrics and Gynecology, Division of Maternal–Fetal Medicine and Reproductive and Prenatal Genetics, Baylor College of Medicine and Texas Children’s Fetal Center, Houston, TX, USA
| | - S. Stover
- Department of Obstetrics and Gynecology, Division of Maternal–Fetal Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - D. G. Mann
- Department of Pediatric Anesthesiology, Perioperative, and Pain Medicine, Clinical Ethics, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | - J. Castillo
- Division of Developmental Pediatrics, Department of Pediatrics, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | - H. A. Castillo
- Division of Developmental Pediatrics, Department of Pediatrics, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | - A. A. Nassr
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery and Maternal–Fetal Medicine, Baylor College of Medicine and Texas Children’s Fetal Center, Houston, TX, USA
| | - M. Sanz Cortes
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery and Maternal–Fetal Medicine, Baylor College of Medicine and Texas Children’s Fetal Center, Houston, TX, USA
| | - R. Donepudi
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery and Maternal–Fetal Medicine, Baylor College of Medicine and Texas Children’s Fetal Center, Houston, TX, USA
| | - J. Espinoza
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery and Maternal–Fetal Medicine, Baylor College of Medicine and Texas Children’s Fetal Center, Houston, TX, USA
| | - W. E. Whitehead
- Department of Neurosurgery, Baylor College of Medicine and Texas Children’s Hospital, Houston, TX, USA
| | - M. A. Belfort
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery and Maternal–Fetal Medicine, Baylor College of Medicine and Texas Children’s Fetal Center, Houston, TX, USA
| | - A. A. Shamshirsaz
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery and Maternal–Fetal Medicine, Baylor College of Medicine and Texas Children’s Fetal Center, Houston, TX, USA
| | - I. B. Van den Veyver
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Department of Obstetrics and Gynecology, Division of Fetal Therapy and Surgery and Maternal–Fetal Medicine, Baylor College of Medicine and Texas Children’s Fetal Center, Houston, TX, USA
- Department of Obstetrics and Gynecology, Division of Maternal–Fetal Medicine and Reproductive and Prenatal Genetics, Baylor College of Medicine and Texas Children’s Fetal Center, Houston, TX, USA
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Rai S, Leydier L, Sharma S, Katwala J, Sahu A. A quest for genetic causes underlying signaling pathways associated with neural tube defects. Front Pediatr 2023; 11:1126209. [PMID: 37284286 PMCID: PMC10241075 DOI: 10.3389/fped.2023.1126209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 02/28/2023] [Indexed: 06/08/2023] Open
Abstract
Neural tube defects (NTDs) are serious congenital deformities of the nervous system that occur owing to the failure of normal neural tube closures. Genetic and non-genetic factors contribute to the etiology of neural tube defects in humans, indicating the role of gene-gene and gene-environment interaction in the occurrence and recurrence risk of neural tube defects. Several lines of genetic studies on humans and animals demonstrated the role of aberrant genes in the developmental risk of neural tube defects and also provided an understanding of the cellular and morphological programs that occur during embryonic development. Other studies observed the effects of folate and supplementation of folic acid on neural tube defects. Hence, here we review what is known to date regarding altered genes associated with specific signaling pathways resulting in NTDs, as well as highlight the role of various genetic, and non-genetic factors and their interactions that contribute to NTDs. Additionally, we also shine a light on the role of folate and cell adhesion molecules (CAMs) in neural tube defects.
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Affiliation(s)
- Sunil Rai
- Department of Molecular Biology, Medical University of the Americas, Charlestown, Saint Kitts and Nevis
| | - Larissa Leydier
- Department of Molecular Biology, Medical University of the Americas, Charlestown, Saint Kitts and Nevis
| | - Shivani Sharma
- Department of Molecular Biology, Medical University of the Americas, Charlestown, Saint Kitts and Nevis
| | - Jigar Katwala
- Department of Molecular Biology, Medical University of the Americas, Charlestown, Saint Kitts and Nevis
| | - Anurag Sahu
- Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
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Lee C, Lo M, Chen Y, Lin P, Hsu C, Chen P, Wu C, Hsu JS. Identification of nine novel variants across PAX3, SOX10, EDNRB, and MITF genes in Waardenburg syndrome with next-generation sequencing. Mol Genet Genomic Med 2022; 10:e2082. [PMID: 36331148 PMCID: PMC9747560 DOI: 10.1002/mgg3.2082] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 09/30/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Waardenburg syndrome (WS) is a hereditary, genetically heterogeneous disorder characterized by variable presentations of sensorineural hearing impairment and pigmentation anomalies. This study aimed to investigate the clinical features of WS in detail and determine the genetic causes of patients with clinically suspected WS. METHODS A total of 24 patients from 21 Han-Taiwanese families were enrolled and underwent comprehensive physical and audiological examinations. We applied targeted next-generation sequencing (NGS) to investigate the potential causative variants in these patients and further validated the candidate variants through Sanger sequencing. RESULTS We identified 19 causative variants of WS in our cohort. Of these variants, nine were novel and discovered in PAX3, SOX10, EDNRB, and MITF genes, including missense, nonsense, deletion, and splice site variants. Several patients presented with skeletal deformities, hypotonia, megacolon, and neurological disorders that were rarely seen in WS. CONCLUSION This study revealed highly phenotypic variability in Taiwanese WS patients and demonstrated that targeted NGS allowed us to clarify the genetic diagnosis and extend the genetic variant spectrum of WS.
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Affiliation(s)
- Chen‐Yu Lee
- Department of OtolaryngologyNational Taiwan University Hospital, Hsinchu BranchHsinchuTaiwan
| | - Ming‐Yu Lo
- Department of OtolaryngologyNational Taiwan University HospitalTaipeiTaiwan,Graduate Institute of Medical Genomics and Proteomics, College of MedicineNational Taiwan UniversityTaipeiTaiwan
| | - You‐Mei Chen
- Department of Medical GeneticsNational Taiwan University HospitalTaipeiTaiwan
| | - Pei‐Hsuan Lin
- Department of OtolaryngologyNational Taiwan University HospitalTaipeiTaiwan,Department of OtolaryngologyNational Taiwan University Hospital, Yunlin BranchYunlinTaiwan
| | - Chuan‐Jen Hsu
- Department of OtolaryngologyNational Taiwan University HospitalTaipeiTaiwan,Department of OtolaryngologyBuddhist Tzuchi General Hospital, Taichung BranchTaichungTaiwan
| | - Pei‐Lung Chen
- Graduate Institute of Medical Genomics and Proteomics, College of MedicineNational Taiwan UniversityTaipeiTaiwan,Department of Medical GeneticsNational Taiwan University HospitalTaipeiTaiwan
| | - Chen‐Chi Wu
- Department of OtolaryngologyNational Taiwan University HospitalTaipeiTaiwan,Department of Medical ResearchNational Taiwan University Hospital, Hsinchu BranchHsinchuTaiwan
| | - Jacob Shujui Hsu
- Graduate Institute of Medical Genomics and Proteomics, College of MedicineNational Taiwan UniversityTaipeiTaiwan
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Li S, Qin M, Mao S, Mei L, Cai X, Feng Y, He C, Song J. A comprehensive genotype-phenotype evaluation of eight Chinese probands with Waardenburg syndrome. BMC Med Genomics 2022; 15:230. [PMID: 36329483 PMCID: PMC9632049 DOI: 10.1186/s12920-022-01379-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 10/13/2022] [Indexed: 11/06/2022] Open
Abstract
Background Waardenburg syndrome (WS) is the most common form of syndromic deafness with phenotypic and genetic heterogeneity in the Chinese population. This study aimed to clarify the clinical characteristics and the genetic cause in eight Chinese WS families (including three familial and five sporadic cases). Further genotype–phenotype relationships were also investigated. Methods All probands underwent screening for the known WS-related genes including PAX3, SOX10, MITF, EDNRB, EDN3, and SNAI2 using next-generation sequencing to identify disease-causing genes. Further validation using Sanger sequencing was performed. Relevant findings for the associated genotype–phenotype from previous literature were retrospectively analyzed. Result Disease-causing variants were detected in all eight probands by molecular genetic analysis of the WS genes (SOX10(NM_006941.4): c.544_557del, c.553 C > T, c.762delA, c.336G > A; MITF(NM_000248.3): c.626 A > T; PAX3(NM_181459.4): c.838delG, c.452-2 A > G, c.214 A > G). Six mutations (SOX10:c.553 C > T, c.544_557del, c.762delA; PAX3: c.838delG, c.214 A > G; MITF:c.626 A > T) were first reported. Clinical evaluation revealed prominent phenotypic variability in these WS patients. Twelve WS1 cases and five WS2 cases were diagnosed in total. Two probands with SOX10 mutations developed progressive changes in iris color with age, returning from pale blue at birth to normal tan. Additionally, one proband had a renal malformation (horseshoe kidneys).All cases were first described as WS cases. Congenital inner ear malformations were more common, and semicircular malformations were exclusively observed in probands with SOX10 mutations. Unilateral hearing loss occurred more often in cases with PAX3 mutations. Conclusion Our findings helped illuminate the phenotypic and genotypic spectrum of WS in Chinese populations and could contribute to better genetic counseling of WS. Supplementary Information The online version contains supplementary material available at 10.1186/s12920-022-01379-6.
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Affiliation(s)
- Sijun Li
- Department of Otorhinolaryngology, Xiangya Hospital Central South University, Changsha, Hunan, China.,Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, Hunan, China
| | - Mengyao Qin
- Department of Otorhinolaryngology, Xiangya Hospital Central South University, Changsha, Hunan, China.,Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, Hunan, China.,Department of Otolaryngology Head and Neck Surgery, The First People's Hospital of Changde City, Hunan, Changde, China
| | - Shuang Mao
- Department of Otorhinolaryngology, Xiangya Hospital Central South University, Changsha, Hunan, China.,Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, Hunan, China
| | - Lingyun Mei
- Department of Otorhinolaryngology, Xiangya Hospital Central South University, Changsha, Hunan, China.,Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, Hunan, China
| | - Xinzhang Cai
- Department of Otorhinolaryngology, Xiangya Hospital Central South University, Changsha, Hunan, China.,Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, Hunan, China
| | - Yong Feng
- Department of Otorhinolaryngology, Xiangya Hospital Central South University, Changsha, Hunan, China.,Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, Hunan, China.,Department of Otorhinolaryngology, University of South China Affiliated Changsha Central Hospital, Changsha, Hunan, China
| | - Chufeng He
- Department of Otorhinolaryngology, Xiangya Hospital Central South University, Changsha, Hunan, China. .,Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, Hunan, China.
| | - Jian Song
- Department of Otorhinolaryngology, Xiangya Hospital Central South University, Changsha, Hunan, China. .,Province Key Laboratory of Otolaryngology Critical Diseases, Changsha, Hunan, China.
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Kim K, Orvis J, Stolfi A. Pax3/7 regulates neural tube closure and patterning in a non-vertebrate chordate. Front Cell Dev Biol 2022; 10:999511. [PMID: 36172287 PMCID: PMC9511217 DOI: 10.3389/fcell.2022.999511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 08/24/2022] [Indexed: 11/29/2022] Open
Abstract
Pax3/7 factors play numerous roles in the development of the dorsal nervous system of vertebrates. From specifying neural crest at the neural plate borders, to regulating neural tube closure and patterning of the resulting neural tube. However, it is unclear which of these roles are conserved in non-vertebrate chordates. Here we investigate the expression and function of Pax3/7 in the model tunicate Ciona. Pax3/7 is expressed in neural plate border cells during neurulation, and in central nervous system progenitors shortly after neural tube closure. We find that separate cis-regulatory elements control the expression in these two distinct lineages. Using CRISPR/Cas9-mediated mutagenesis, we knocked out Pax3/7 in F0 embryos specifically in these two separate territories. Pax3/7 knockout in the neural plate borders resulted in neural tube closure defects, suggesting an ancient role for Pax3/7 in this chordate-specific process. Furthermore, knocking out Pax3/7 in the neural impaired Motor Ganglion neuron specification, confirming a conserved role for this gene in patterning the neural tube as well. Taken together, these results suggests that key functions of Pax3/7 in neural tube development are evolutionarily ancient, dating back at least to the last common ancestor of vertebrates and tunicates.
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Schobers G, Schieving JH, Yntema HG, Pennings M, Pfundt R, Derks R, Hofste T, de Wijs I, Wieskamp N, van den Heuvel S, Galbany JC, Gilissen C, Nelen M, Brunner HG, Kleefstra T, Kamsteeg EJ, Willemsen MAAP, Vissers LELM. Reanalysis of exome negative patients with rare disease: a pragmatic workflow for diagnostic applications. Genome Med 2022; 14:66. [PMID: 35710456 PMCID: PMC9204949 DOI: 10.1186/s13073-022-01069-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 06/07/2022] [Indexed: 11/10/2022] Open
Abstract
Background Approximately two third of patients with a rare genetic disease remain undiagnosed after exome sequencing (ES). As part of our post-test counseling procedures, patients without a conclusive diagnosis are advised to recontact their referring clinician to discuss new diagnostic opportunities in due time. We performed a systematic study of genetically undiagnosed patients 5 years after their initial negative ES report to determine the efficiency of diverse reanalysis strategies. Methods We revisited a cohort of 150 pediatric neurology patients originally enrolled at Radboud University Medical Center, of whom 103 initially remained genetically undiagnosed. We monitored uptake of physician-initiated routine clinical and/or genetic re-evaluation (ad hoc re-evaluation) and performed systematic reanalysis, including ES-based resequencing, of all genetically undiagnosed patients (systematic re-evaluation). Results Ad hoc re-evaluation was initiated for 45 of 103 patients and yielded 18 diagnoses (including 1 non-genetic). Subsequent systematic re-evaluation identified another 14 diagnoses, increasing the diagnostic yield in our cohort from 31% (47/150) to 53% (79/150). New genetic diagnoses were established by reclassification of previously identified variants (10%, 3/31), reanalysis with enhanced bioinformatic pipelines (19%, 6/31), improved coverage after resequencing (29%, 9/31), and new disease-gene associations (42%, 13/31). Crucially, our systematic study also showed that 11 of the 14 further conclusive genetic diagnoses were made in patients without a genetic diagnosis that did not recontact their referring clinician. Conclusions We find that upon re-evaluation of undiagnosed patients, both reanalysis of existing ES data as well as resequencing strategies are needed to identify additional genetic diagnoses. Importantly, not all patients are routinely re-evaluated in clinical care, prolonging their diagnostic trajectory, unless systematic reanalysis is facilitated. We have translated our observations into considerations for systematic and ad hoc reanalysis in routine genetic care. Supplementary Information The online version contains supplementary material available at 10.1186/s13073-022-01069-z.
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Affiliation(s)
- Gaby Schobers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Jolanda H Schieving
- Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Pediatric Neurology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Helger G Yntema
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Maartje Pennings
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rolph Pfundt
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ronny Derks
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Tom Hofste
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ilse de Wijs
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Nienke Wieskamp
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Simone van den Heuvel
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jordi Corominas Galbany
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Christian Gilissen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Marcel Nelen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Han G Brunner
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Clinical Genetics, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Tjitske Kleefstra
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
| | - Erik-Jan Kamsteeg
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Michèl A A P Willemsen
- Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.,Department of Pediatric Neurology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Lisenka E L M Vissers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands. .,Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.
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10
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Isaković J, Šimunić I, Jagečić D, Hribljan V, Mitrečić D. Overview of Neural Tube Defects: Gene–Environment Interactions, Preventative Approaches and Future Perspectives. Biomedicines 2022; 10:biomedicines10050965. [PMID: 35625701 PMCID: PMC9138472 DOI: 10.3390/biomedicines10050965] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 04/13/2022] [Accepted: 04/19/2022] [Indexed: 11/16/2022] Open
Abstract
Neural tube defects (NTDs) are the second most common congenital malformations of humans, characterized by impaired development of the central nervous system. Even though the etiology of most birth defects remains undetermined, genetic and environmental risk factors in the background of NTDs have been identified and extensively reported. On top of genetic and nutritional risks which include mutations in both coding and non-coding regions and maternal folate status, respectively, recent years have seen a rise in the identification of a variety of teratogens that could be implicated in NTD development. These include polycyclic aromatic hydrocarbons, arsenic, pesticides, maternal hyperthermia and antibiotics as well as pain and seizure medication. With an increase in understanding of teratogens leading to NTD formation, preventative and treatment approaches have witnessed great advances throughout the years. While the most common preventative approach includes folic acid food fortification as well as suggested inositol supplementation, treatment and management approaches differ greatly depending on the developmental stage and the site of the lesion and include prenatal surgery, stem cell transplantation and postnatal surgery. Because NTDs still represent a large health and financial burden for the patient and society as a whole, it is crucial to investigate potential risk factors and develop novel approaches in order to fully prevent this category of disorders.
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Affiliation(s)
- Jasmina Isaković
- Omnion Research International Ltd., Heinzelova 4, 10000 Zagreb, Croatia
- Department of Histology and Embryology, University of Zagreb School of Medicine, 10000 Zagreb, Croatia; (D.J.); (V.H.); (D.M.)
- Correspondence:
| | - Iva Šimunić
- Laboratory for Stem Cells, Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10000 Zagreb, Croatia;
| | - Denis Jagečić
- Department of Histology and Embryology, University of Zagreb School of Medicine, 10000 Zagreb, Croatia; (D.J.); (V.H.); (D.M.)
- Laboratory for Stem Cells, Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10000 Zagreb, Croatia;
| | - Valentina Hribljan
- Department of Histology and Embryology, University of Zagreb School of Medicine, 10000 Zagreb, Croatia; (D.J.); (V.H.); (D.M.)
- Laboratory for Stem Cells, Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10000 Zagreb, Croatia;
| | - Dinko Mitrečić
- Department of Histology and Embryology, University of Zagreb School of Medicine, 10000 Zagreb, Croatia; (D.J.); (V.H.); (D.M.)
- Laboratory for Stem Cells, Croatian Institute for Brain Research, University of Zagreb School of Medicine, 10000 Zagreb, Croatia;
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11
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Tsai YY, Su CH, Tarn WY. p53 Activation in Genetic Disorders: Different Routes to the Same Destination. Int J Mol Sci 2021; 22:9307. [PMID: 34502215 PMCID: PMC8430931 DOI: 10.3390/ijms22179307] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 12/18/2022] Open
Abstract
The tumor suppressor p53 is critical for preventing neoplastic transformation and tumor progression. Inappropriate activation of p53, however, has been observed in a number of human inherited disorders that most often affect development of the brain, craniofacial region, limb skeleton, and hematopoietic system. Genes related to these developmental disorders are essentially involved in transcriptional regulation/chromatin remodeling, rRNA metabolism, DNA damage-repair pathways, telomere maintenance, and centrosome biogenesis. Perturbation of these activities or cellular processes may result in p53 accumulation in cell cultures, animal models, and perhaps humans as well. Mouse models of several p53 activation-associated disorders essentially recapitulate human traits, and inactivation of p53 in these models can alleviate disorder-related phenotypes. In the present review, we focus on how dysfunction of the aforementioned biological processes causes developmental defects via excessive p53 activation. Notably, several disease-related genes exert a pleiotropic effect on those cellular processes, which may modulate the magnitude of p53 activation and establish or disrupt regulatory loops. Finally, we discuss potential therapeutic strategies for genetic disorders associated with p53 misactivation.
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12
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Muroi A, Enokizono T, Tsurubuchi T, Tsukada K, Ohto T, Ishikawa E. Association of Kabuki syndrome and tethered cord syndrome: a report of three cases and literature review. Childs Nerv Syst 2021; 37:1339-1343. [PMID: 32691197 DOI: 10.1007/s00381-020-04813-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 07/13/2020] [Indexed: 10/23/2022]
Abstract
Kabuki syndrome (KS) is a congenital disorder characterized by distinctive facial features, skeletal and dermatoglyphic abnormalities, mild-to-moderate intellectual disability, and postnatal growth deficiency. Recently, mutations in the KMT2D and KDM6A genes have been identified as the causative factors in most KS cases. In this study, we present three cases of KS associated with tethered cord syndrome. All cases had a sacral dimple, which is a skin stigmata, and radiological abnormalities, including fatty or thickened filum terminale. Untethering surgery was performed and clinical improvement was achieved. Although in the association between KS and closed neural tube defect (NTD) has rarely been discussed, we emphasize that sacral dimples in KS and tethered cord syndrome are not uncommon. The KS patients with sacral dimple must be carefully investigated by radiological examination and urological study if there is abnormality. Further understanding of the genetic mechanism underlying KS might provide a novel insight on the correlation between the genetics and development of closed NTDs.
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Affiliation(s)
- Ai Muroi
- Department of Neurosurgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.
| | - Takashi Enokizono
- Department of Pediatrics, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Takao Tsurubuchi
- Department of Neurosurgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Kazuaki Tsukada
- Department of Neurosurgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
| | - Tatsuyuki Ohto
- Department of Pediatrics, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Eiichi Ishikawa
- Department of Neurosurgery, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8575, Japan
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13
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Hu Q, Ma H, Shen J, Zhuang Z, Li J, Huang X, Li X, Li H. Case Report: A Novel PAX3 Mutation Associated With Waardenburg Syndrome Type 1. Front Genet 2021; 12:609040. [PMID: 33747040 PMCID: PMC7970110 DOI: 10.3389/fgene.2021.609040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 02/12/2021] [Indexed: 12/04/2022] Open
Abstract
Background: Waardenburg Syndrome Type 1 (WS1) is a rare hereditary disease, which is usually caused by the mutations of PAX3 (paired box 3). Here, we reported a pedigree with WS1, which was caused by a novel mutation in PAX3. Case Report: In this present report, a 10-year-old boy and his twin sister from a Han Chinese family presented with iris pigmentary abnormality, synophrys, and broad and high nasal root. Their father presented premature whitening of the hair, but no iris pigmentary abnormality. Their aunts presented the same clinical characteristics with the twins and premature graying of hair. However, none of the patients reported hearing loss. The clinical diagnosis of the four patients from this pedigree was WS1. The whole exome sequencing (WES) revealed a novel mutation (c.959-5T>G) in the PAX3 gene, which could be responsible for the observed pathogenic of WS1 in this pedigree. The genetic test confirmed the diagnosis of WS1 in the four patients from the studied pedigree. Conclusion: This present study demonstrated that genetic test based on WES, an effective alternative to regular clinical examinations, helps diagnose WS1. The newly identified PAX3 gene mutation can expand the understanding of WS1.
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Affiliation(s)
- Qiuming Hu
- Department of Ophthalmology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Huazhong Ma
- Department of Ophthalmology, Pingguo People's Hospital, Baise, China
| | - Jiawei Shen
- Department of Stomatology, The Affiliated Hospital of Medical School, Ningbo University, Ningbo, China
| | - Zongming Zhuang
- Department of Ophthalmology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China.,Department of Retina and Vitreous, Jingliang Eye Hospital, Guangxi Medical University, Nanning, China
| | - Jianqiang Li
- Department of Retina and Vitreous, Jingliang Eye Hospital, Guangxi Medical University, Nanning, China
| | - Xinlan Huang
- Department of Retina and Vitreous, Jingliang Eye Hospital, Guangxi Medical University, Nanning, China
| | - Xian Li
- Division of Pharmacy and Optometry, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Haoyu Li
- Department of Ophthalmology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China.,Department of Retina and Vitreous, Jingliang Eye Hospital, Guangxi Medical University, Nanning, China
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14
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Masood S, Jalil P, Ahmed Jan N, Sadique M. Waardenburg Syndrome Type-II in Twin Siblings: An Unusual Audio-Pigmentary Disorder. Cureus 2020; 12:e10889. [PMID: 33178541 PMCID: PMC7652366 DOI: 10.7759/cureus.10889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Waardenburg syndrome (WS) is an interesting inherited audio-pigmentary disorder. The syndrome shows no gender, racial, or ethnic predilection. This unique disorder is characterized by pigmentary abnormalities, deafness, and neural crest-derived tissue defect. WS can be recognized by some specific clinical features that appear after birth; not all affected individuals possess all the clinical features. It has four clinical sub types based on the mutant gene and characteristic morphology. These morphological features are broad nasal root, white forelock, the difference in the colour of eyes, congenital leukoderma, and sensorineural deafness. We report an interesting case of WS in twin boys who fulfill the criteria of WS-II. Our cases have four major criteria (white forelock, heterochromia, sensorineural hearing loss, first degree relative with WS), and 1 minor criterion to establish the diagnosis of WS-II. Most clinical features of WS-II except sensorineural deafness are benign and do not need any intervention but severe deafness can be a serious problem. The current report is unique and is a rare case of WS in twin infants. We present this case for its rarity, relative paucity of literature, and also to emphasize the clinical presentation of this extremely rare disease in twins.
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15
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Somashekar PH, Upadhyai P, Narayanan DL, Kamath N, Bajaj S, Girisha KM, Shukla A. Phenotypic diversity and genetic complexity of PAX3-related Waardenburg syndrome. Am J Med Genet A 2020; 182:2951-2958. [PMID: 32990402 DOI: 10.1002/ajmg.a.61893] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 09/11/2020] [Accepted: 09/12/2020] [Indexed: 11/09/2022]
Abstract
Waardenburg syndrome subtypes 1 and 3 are caused by pathogenic variants in PAX3. We investigated 12 individuals from four unrelated families clinically diagnosed with Waardenburg syndrome type 1/3. Novel pathogenic variants identified in PAX3 included single nucleotide variants (c.166C>T, c.829C>T), a 2-base pair deletion (c.366_367delAA) and a multi-exonic deletion. Two novel variants, c.166C>T and c.829C>T and a previously reported variant, c.256A>T in PAX3 were evaluated for their nuclear localization and ability to activate MITF promoter. The coexistence of two subtypes of Waardenburg syndrome with pathogenic variants in PAX3 and EDNRB was seen in one of the affected individuals. Multiple genetic diagnoses of Waardenburg syndrome type 3 and autosomal recessive deafness 1A was identified in an individual. We also review the phenotypic and genomic spectrum of individuals with PAX3-related Waardenburg syndrome reported in the literature.
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Affiliation(s)
- Puneeth H Somashekar
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Priyanka Upadhyai
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Dhanya L Narayanan
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Nutan Kamath
- Department of Pediatrics, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, India
| | | | - Katta M Girisha
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Anju Shukla
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
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16
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Closing in on Mechanisms of Open Neural Tube Defects. Trends Neurosci 2020; 43:519-532. [PMID: 32423763 DOI: 10.1016/j.tins.2020.04.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 04/02/2020] [Accepted: 04/22/2020] [Indexed: 11/24/2022]
Abstract
Neural tube defects (NTDs) represent a failure of the neural plate to complete the developmental transition to a neural tube. NTDs are the most common birth anomaly of the CNS. Following mandatory folic acid fortification of dietary grains, a dramatic reduction in the incidence of NTDs was observed in areas where the policy was implemented, yet the genetic drivers of NTDs in humans, and the mechanisms by which folic acid prevents disease, remain disputed. Here, we discuss current understanding of human NTD genetics, recent advances regarding potential mechanisms by which folic acid might modify risk through effects on the epigenome and transcriptome, and new approaches to study refined phenotypes for a greater appreciation of the developmental and genetic causes of NTDs.
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17
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Abstract
During embryonic development, the central nervous system forms as the neural plate and then rolls into a tube in a complex morphogenetic process known as neurulation. Neural tube defects (NTDs) occur when neurulation fails and are among the most common structural birth defects in humans. The frequency of NTDs varies greatly anywhere from 0.5 to 10 in 1000 live births, depending on the genetic background of the population, as well as a variety of environmental factors. The prognosis varies depending on the size and placement of the lesion and ranges from death to severe or moderate disability, and some NTDs are asymptomatic. This chapter reviews how mouse models have contributed to the elucidation of the genetic, molecular, and cellular basis of neural tube closure, as well as to our understanding of the causes and prevention of this devastating birth defect.
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Affiliation(s)
- Irene E Zohn
- Center for Genetic Medicine, Children's Research Institute, Children's National Medical Center, Washington, DC, USA.
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18
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Sudiwala S, Palmer A, Massa V, Burns AJ, Dunlevy LPE, de Castro SCP, Savery D, Leung KY, Copp AJ, Greene NDE. Cellular mechanisms underlying Pax3-related neural tube defects and their prevention by folic acid. Dis Model Mech 2019; 12:dmm042234. [PMID: 31636139 PMCID: PMC6899032 DOI: 10.1242/dmm.042234] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 10/16/2019] [Indexed: 01/03/2023] Open
Abstract
Neural tube defects (NTDs), including spina bifida and anencephaly, are among the most common birth defects worldwide, but their underlying genetic and cellular causes are not well understood. Some NTDs are preventable by supplemental folic acid. However, despite widespread use of folic acid supplements and implementation of food fortification in many countries, the protective mechanism is unclear. Pax3 mutant (splotch; Sp2H ) mice provide a model in which NTDs are preventable by folic acid and exacerbated by maternal folate deficiency. Here, we found that cell proliferation was diminished in the dorsal neuroepithelium of mutant embryos, corresponding to the region of abolished Pax3 function. This was accompanied by premature neuronal differentiation in the prospective midbrain. Contrary to previous reports, we did not find evidence that increased apoptosis could underlie failed neural tube closure in Pax3 mutant embryos, nor that inhibition of apoptosis could prevent NTDs. These findings suggest that Pax3 functions to maintain the neuroepithelium in a proliferative, undifferentiated state, allowing neurulation to proceed. NTDs in Pax3 mutants were not associated with abnormal abundance of specific folates and were not prevented by formate, a one-carbon donor to folate metabolism. Supplemental folic acid restored proliferation in the cranial neuroepithelium. This effect was mediated by enhanced progression of the cell cycle from S to G2 phase, specifically in the Pax3 mutant dorsal neuroepithelium. We propose that the cell-cycle-promoting effect of folic acid compensates for the loss of Pax3 and thereby prevents cranial NTDs.
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Affiliation(s)
- Sonia Sudiwala
- Developmental Biology and Cancer Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Alexandra Palmer
- Developmental Biology and Cancer Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Valentina Massa
- Developmental Biology and Cancer Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Alan J Burns
- Developmental Biology and Cancer Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Louisa P E Dunlevy
- Developmental Biology and Cancer Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Sandra C P de Castro
- Developmental Biology and Cancer Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Dawn Savery
- Developmental Biology and Cancer Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Kit-Yi Leung
- Developmental Biology and Cancer Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Andrew J Copp
- Developmental Biology and Cancer Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Nicholas D E Greene
- Developmental Biology and Cancer Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
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19
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Bowen ME, Attardi LD. The role of p53 in developmental syndromes. J Mol Cell Biol 2019; 11:200-211. [PMID: 30624728 PMCID: PMC6478128 DOI: 10.1093/jmcb/mjy087] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 11/22/2018] [Accepted: 01/06/2019] [Indexed: 12/17/2022] Open
Abstract
While it is well appreciated that loss of the p53 tumor suppressor protein promotes cancer, growing evidence indicates that increased p53 activity underlies the developmental defects in a wide range of genetic syndromes. The inherited or de novo mutations that cause these syndromes affect diverse cellular processes, such as ribosome biogenesis, DNA repair, and centriole duplication, and analysis of human patient samples and mouse models demonstrates that disrupting these cellular processes can activate the p53 pathway. Importantly, many of the developmental defects in mouse models of these syndromes can be rescued by loss of p53, indicating that inappropriate p53 activation directly contributes to their pathogenesis. A role for p53 in driving developmental defects is further supported by the observation that mouse strains with broad p53 hyperactivation, due to mutations affecting p53 pathway components, display a host of tissue-specific developmental defects, including hematopoietic, neuronal, craniofacial, cardiovascular, and pigmentation defects. Furthermore, germline activating mutations in TP53 were recently identified in two human patients exhibiting bone marrow failure and other developmental defects. Studies in mice suggest that p53 drives developmental defects by inducing apoptosis, restraining proliferation, or modulating other developmental programs in a cell type-dependent manner. Here, we review the growing body of evidence from mouse models that implicates p53 as a driver of tissue-specific developmental defects in diverse genetic syndromes.
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Affiliation(s)
- Margot E Bowen
- Division of Radiation and Cancer Biology in the Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
| | - Laura D Attardi
- Division of Radiation and Cancer Biology in the Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
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20
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Abstract
Melanocyte development is orchestrated by a complex interconnecting regulatory network of genes and synergistic interactions. Piebaldism and Waardenburg syndrome are neurocristopathies that arise from mutations in genes involved in this complex network. Our understanding of melanocyte development, Piebaldism, and Waardenburg syndrome has improved dramatically over the past decade. The diagnosis and classification of Waardenburg syndrome, first proposed in 1992 and based on phenotype, have expanded over the past three decades to include genotype. This review focuses on the current understanding of human melanocyte development and the evaluation and management of Piebaldism and Waardenburg syndrome. Management is often challenging and requires a multidisciplinary approach.
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21
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Barros FS, Marussi VHR, Amaral LLF, da Rocha AJ, Campos CMS, Freitas LF, Huisman TAGM, Soares BP. The Rare Neurocutaneous Disorders: Update on Clinical, Molecular, and Neuroimaging Features. Top Magn Reson Imaging 2018; 27:433-462. [PMID: 30516694 DOI: 10.1097/rmr.0000000000000185] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Phakomatoses, also known as neurocutaneous disorders, comprise a vast number of entities that predominantly affect structures originated from the ectoderm such as the central nervous system and the skin, but also the mesoderm, particularly the vascular system. Extensive literature exists about the most common phakomatoses, namely neurofibromatosis, tuberous sclerosis, von Hippel-Lindau and Sturge-Weber syndrome. However, recent developments in the understanding of the molecular underpinnings of less common phakomatoses have sparked interest in these disorders. In this article, we review the clinical features, current pathogenesis, and modern neuroimaging findings of melanophakomatoses, vascular phakomatoses, and other rare neurocutaneous syndromes that may also include tissue overgrowth or neoplastic predisposition.
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Affiliation(s)
- Felipe S Barros
- Division of Neuroradiology, BP Medicina Diagnóstica, Hospital da Beneficência Portuguesa de São Paulo
| | - Victor Hugo R Marussi
- Division of Neuroradiology, BP Medicina Diagnóstica, Hospital da Beneficência Portuguesa de São Paulo
| | - Lázaro L F Amaral
- Division of Neuroradiology, BP Medicina Diagnóstica, Hospital da Beneficência Portuguesa de São Paulo
| | - Antônio José da Rocha
- Division of Neuroradiology, Department of Radiology, Santa Casa de São Paulo School of Medical Sciences, São Paulo, Brazil
| | - Christiane M S Campos
- Division of Neuroradiology, BP Medicina Diagnóstica, Hospital da Beneficência Portuguesa de São Paulo
| | - Leonardo F Freitas
- Division of Neuroradiology, BP Medicina Diagnóstica, Hospital da Beneficência Portuguesa de São Paulo
| | - Thierry A G M Huisman
- Division of Pediatric Radiology and Pediatric Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Bruno P Soares
- Division of Pediatric Radiology and Pediatric Neuroradiology, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD
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