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Wang YL, Lin HC, Liang T, Lin JY, Simmer J, Hu JC, Wang SK. ENAM Mutations Can Cause Hypomaturation Amelogenesis Imperfecta. J Dent Res 2024; 103:662-671. [PMID: 38716742 PMCID: PMC11122092 DOI: 10.1177/00220345241236695] [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] [Indexed: 05/12/2024] Open
Abstract
Amelogenesis imperfecta (AI) is a diverse group of inherited diseases featured by various presentations of enamel malformations that are caused by disturbances at different stages of enamel formation. While hypoplastic AI suggests a thickness defect of enamel resulting from aberrations during the secretory stage of amelogenesis, hypomaturation AI indicates a deficiency of enamel mineralization and hardness established at the maturation stage. Mutations in ENAM, which encodes the largest enamel matrix protein, enamelin, have been demonstrated to cause generalized or local hypoplastic AI. Here, we characterized 2 AI families with disparate hypoplastic and hypomaturation enamel defects and identified 2 distinct indel mutations at the same location of ENAM, c588+1del and c.588+1dup. Minigene splicing assays demonstrated that they caused frameshifts and truncation of ENAM proteins, p.Asn197Ilefs*81 and p.Asn197Glufs*25, respectively. In situ hybridization of Enam on mouse mandibular incisors confirmed its restricted expression in secretory stage ameloblasts and suggested an indirect pathogenic mechanism underlying hypomaturation AI. In silico analyses indicated that these 2 truncated ENAMs might form amyloid structures and cause protein aggregation with themselves and with wild-type protein through the added aberrant region at their C-termini. Consistently, protein secretion assays demonstrated that the truncated proteins cannot be properly secreted and impede secretion of wild-type ENAM. Moreover, compared to the wild-type, overexpression of the mutant proteins significantly increased endoplasmic reticulum stress and upregulated the expression of unfolded protein response (UPR)-related genes and TNFRSF10B, a UPR-controlled proapoptotic gene. Caspase, terminal deoxynucleotidyl transferase UTP nick-end labeling (TUNEL), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays further revealed that both truncated proteins, especially p.Asn197Ilefs*81, induced cell apoptosis and decreased cell survival, suggesting that the 2 ENAM mutations cause AI through ameloblast cell pathology and death rather than through a simple loss of function. This study demonstrates that an ENAM mutation can lead to generalized hypomaturation enamel defects and suggests proteinopathy as a potential pathogenesis for ENAM-associated AI.
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Affiliation(s)
- Y.-L. Wang
- Department of Dentistry, National Taiwan University School of Dentistry, Taipei City, Taiwan
- Department of Pediatric Dentistry, National Taiwan University Children’s Hospital, Taipei City, Taiwan
| | - H.-C. Lin
- Department of Dentistry, National Taiwan University School of Dentistry, Taipei City, Taiwan
| | - T. Liang
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - J.C.-Y. Lin
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, National Defense Medical University, Taipei City, Taiwan
| | - J.P. Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - J.C.-C. Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - S.-K. Wang
- Department of Dentistry, National Taiwan University School of Dentistry, Taipei City, Taiwan
- Department of Pediatric Dentistry, National Taiwan University Children’s Hospital, Taipei City, Taiwan
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Wang SK, Zhang H, Wang YL, Seymen F, Koruyucu M, Simmer JP, Hu JCC. Phenotypic variability in LAMA3-associated amelogenesis imperfecta. Oral Dis 2023; 29:3514-3524. [PMID: 36326426 PMCID: PMC10154430 DOI: 10.1111/odi.14425] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/04/2022] [Accepted: 10/26/2022] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Amelogenesis imperfecta (AI) is defined as inherited enamel malformations. LAMA3 (laminin alpha-3) encodes a critical protein component of the basement membrane (laminin-332). Individuals carrying heterozygous LAMA3 mutations have previously been shown to have localized enamel defects. This study aimed to define clinical phenotypes and to discern the genetic etiology for four AI kindreds. MATERIALS AND METHODS Whole-exome analyses were conducted to search for sequence variants associated with the disorder, and micro-computed tomography (μCT) to characterize the enamel defects. RESULTS The predominant enamel phenotype was generalized thin enamel with defective pits and grooves. Horizonal bands of hypoplastic enamel with chalky-white discoloration and enamel hypomineralization were also observed and demonstrated by μCT analyses of affected teeth. Four disease-causing LAMA3 mutations (NM_198129.4:c.3712dup; c.5891dup; c.7367del; c.9400G > C) were identified. Compound heterozygous MMP20 mutations (NM_004771.4:c.539A > G; c.692C > T) were also found in one proband with more severe enamel defects, suggesting a mutational synergism on disease phenotypes. Further analyses of the AI-causing mutations suggested that both α3A (short) and α3B (long) isoforms of LAMA3 are essential for enamel formation. CONCLUSIONS Heterozygous LAMA3 mutations can cause generalized enamel defects (AI1A) with variable expressivity. Laminin-332 is critical not only for appositional growth but also enamel maturation.
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Affiliation(s)
- Shih-Kai Wang
- Department of Dentistry, National Taiwan University School of Dentistry, No.1, Changde St., Taipei City 100, Taiwan
- Department of Pediatric Dentistry, National Taiwan University Children’s Hospital, No.8, Zhongshan S. Rd., Taipei City 100, Taiwan
| | - Hong Zhang
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1011 North University, Ann Arbor, MI 48108, USA
| | - Yin-Lin Wang
- Department of Dentistry, National Taiwan University School of Dentistry, No.1, Changde St., Taipei City 100, Taiwan
- Department of Pediatric Dentistry, National Taiwan University Children’s Hospital, No.8, Zhongshan S. Rd., Taipei City 100, Taiwan
| | - Figen Seymen
- Department of Pedodontics, Faculty of Dentistry, Altinbas University, Istanbul, 34147, Turkey
| | - Mine Koruyucu
- Department of Pedodontics, Faculty of Dentistry, Istanbul University, Istanbul, 34116, Turkey
| | - James P. Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1011 North University, Ann Arbor, MI 48108, USA
| | - Jan C.-C. Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1011 North University, Ann Arbor, MI 48108, USA
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Dong J, Ruan W, Duan X. Molecular-based phenotype variations in amelogenesis imperfecta. Oral Dis 2023; 29:2334-2365. [PMID: 37154292 DOI: 10.1111/odi.14599] [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: 09/22/2022] [Revised: 04/03/2023] [Accepted: 04/15/2023] [Indexed: 05/10/2023]
Abstract
Amelogenesis imperfecta (AI) is one of the typical dental genetic diseases in human. It can occur isolatedly or as part of a syndrome. Previous reports have mainly clarified the types and mechanisms of nonsyndromic AI. This review aimed to compare the phenotypic differences among the hereditary enamel defects with or without syndromes and their underlying pathogenic genes. We searched the articles in PubMed with different strategies or keywords including but not limited to amelogenesis imperfecta, enamel defects, hypoplastic/hypomaturation/hypocalcified, syndrome, or specific syndrome name. The articles with detailed clinical information about the enamel and other phenotypes and clear genetic background were used for the analysis. We totally summarized and compared enamel phenotypes of 18 nonsyndromic AI with 17 causative genes and 19 syndromic AI with 26 causative genes. According to the clinical features, radiographic or ultrastructural changes in enamel, the enamel defects were basically divided into hypoplastic and hypomineralized (hypomaturated and hypocalcified) and presented a higher heterogeneity which were closely related to the involved pathogenic genes, types of mutation, hereditary pattern, X chromosome inactivation, incomplete penetrance, and other mechanisms.The gene-specific enamel phenotypes could be an important indicator for diagnosing nonsyndromic and syndromic AI.
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Affiliation(s)
- Jing Dong
- State Key Laboratory of Military Stomatology, Shaanxi Key Laboratory of Stomatology, Department of Oral Biology & Clinic of Oral Rare Diseases and Genetic Diseases, School of Stomatology, National Clinical Research Center for Oral Disease, The Fourth Military Medical University, Xi'an, China
- College of Life Sciences, Northwest University, Xi'an, China
| | - Wenyan Ruan
- State Key Laboratory of Military Stomatology, Shaanxi Key Laboratory of Stomatology, Department of Oral Biology & Clinic of Oral Rare Diseases and Genetic Diseases, School of Stomatology, National Clinical Research Center for Oral Disease, The Fourth Military Medical University, Xi'an, China
| | - Xiaohong Duan
- State Key Laboratory of Military Stomatology, Shaanxi Key Laboratory of Stomatology, Department of Oral Biology & Clinic of Oral Rare Diseases and Genetic Diseases, School of Stomatology, National Clinical Research Center for Oral Disease, The Fourth Military Medical University, Xi'an, China
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Nouara F, Amalou G, Bouzidi A, Charif M, Charoute H, Lenaers G, El Arabi S, Bousfiha B, Barakat A. First characterization of LTBP3 variants in two Moroccan families with hypoplastic amelogenesis imperfecta. Arch Oral Biol 2022; 142:105518. [DOI: 10.1016/j.archoralbio.2022.105518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/02/2022] [Accepted: 08/04/2022] [Indexed: 11/02/2022]
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Urzúa B, Ortega-Pinto A, Adorno-Farias D, Morales-Bozo I, Rojas-Flores S, Briones-Marín D, Lepiman-Torres C. Exploring the Pool of Pathogenic Variants of Amelogenesis Imperfecta: An Approach to the Understanding of Its Genetic Architecture. FRONTIERS IN DENTAL MEDICINE 2021. [DOI: 10.3389/fdmed.2021.785382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Objective: To identify which genes are associated with the clinical phenotype of amelogenesis Imperfecta (AI) and to elucidate which of these genes participate in the determination of isolated and syndromic forms.Methods: In this review, all data on mutations described in AI-related genes were obtained from HGMD® Professional. The data in relation to the mutations, inheritance, phenotype, type of AI and country were supplemented with information from the literature. The identity codes and frequency values were obtained from the dbSNP, ClinVar and OMIM databases. The percentage of specificity (PE) was determined for each gene.Results: HGMD® describes 27 genes involved in AI, which we propose to group into 5 categories: (1) genes whose mutations are associated only with isolated AI, (2) genes whose mutations cause only syndromic AI, (3) genes with both mutations that cause isolated AI and mutations responsible for other pathologies, (4) genes with mutations responsible for syndromic AI and mutations that cause other pathologies, and (5) genes with mutations that cause isolated AI and mutations that cause AI associated with syndromes and other pathologies. Using the PE calculation, the genes were ranked into 5 specificity groups. The genes of category 1 are specific for isolated AI, while the genes of categories 2 and 4 are non-specific. Interestingly, we observed that mutations in some genes were associated with different types of cancer.Conclusion: The ACP4, AMTN, MMP20, ODAPH, RELT, SLC24A4 and SP6 genes participate in causing isolated AI, and the CNNM4, DLX3 and FAM20A genes participate in causing syndromic forms of AI.
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Translational Attenuation by an Intron Retention in the 5' UTR of ENAM Causes Amelogenesis Imperfecta. Biomedicines 2021; 9:biomedicines9050456. [PMID: 33922212 PMCID: PMC8145330 DOI: 10.3390/biomedicines9050456] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/17/2021] [Accepted: 04/20/2021] [Indexed: 11/17/2022] Open
Abstract
Amelogenesis imperfecta (AI) is a collection of rare genetic conditions affecting tooth enamel. The affected enamel can be of insufficient quantity and/or altered quality, impacting structural content, surface integrity and coloration. Heterozygous mutations in ENAM result in hypoplastic AI without other syndromic phenotypes, with variable expressivity and reduced penetrance, unlike other AI-associated genes. In this study, we recruited a Caucasian family with hypoplastic AI. Mutational analysis (using whole exome sequencing) revealed a splicing donor site mutation (NM_031889.3: c. -61 + 1G > A). Mutational effects caused by this variant were investigated with a minigene splicing assay and in vitro expression analysis. The mutation resulted in a retention of intron 1 and exon 2 (a normally skipped exon), and this elongated 5' UTR sequence attenuated the translation from the mutant mRNA. Structure and translation predictions raised the possibility that the long complex structures-especially a hairpin structure located right before the translation initiation codon of the mutant mRNA-caused reduced protein expression. However, there could be additional contributing factors, including additional uORFs. For the first time, we determined that a mutation altered the ENAM 5' UTR, but maintained the normal coding amino acid sequence, causing hypoplastic AI.
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Yu S, Zhang C, Zhu C, Quan J, Liu D, Wang X, Zheng S. A novel ENAM mutation causes hypoplastic amelogenesis imperfecta. Oral Dis 2021; 28:1610-1619. [PMID: 33864320 DOI: 10.1111/odi.13877] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 03/14/2021] [Accepted: 03/16/2021] [Indexed: 12/16/2022]
Abstract
OBJECTIVES To identify the genetic cause of one Chinese family with hypoplastic amelogenesis imperfecta (AI) and explore the relationship between genotype and its phenotype. MATERIAL AND METHODS One Chinese family with generalized hypoplastic AI was recruited. One deciduous tooth from the proband was subjected to scanning electron microscopy. Whole-exome sequencing was performed and identified mutation was confirmed by Sanger sequencing. Bioinformatics studies were further conducted to analyze potential deleterious effects of the mutation. RESULTS The proband presented a typical hypoplastic AI phenotype whose teeth in deciduous and permanent dentitions showed thin, yellow, and hard enamel surface. The affected enamel in deciduous tooth showed irregular, broken, and collapsing enamel rods with borders of the enamel prisms undulated and structural shapes of prisms irregular. A novel homozygous nonsense mutation in the last exon of the enamelin (ENAM) gene (NM_031889.3; c.2078C>G) was identified in the proband, which was predicted to produce a highly truncated protein (NP_114095.2; p.(Ser693*)). This mutation was also identified in the proband's parents in heterozygous form. Surprisingly, the clinical phenotype of the heterozygous parents varied from a lack of penetrance to mild enamel defects. Additional bioinformatics studies demonstrated that the detected mutation could change the 3D structure of the ENAM protein and severely damaged the function of ENAM. CONCLUSION The novel homozygous ENAM mutation resulted in hypoplastic AI in the present study. Our results provide new genetic evidence that mutations involved in ENAM contribute to hypoplastic AI.
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Affiliation(s)
- Shunlan Yu
- Department of Preventive Dentistry, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Chenying Zhang
- Department of Preventive Dentistry, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Ce Zhu
- Department of Preventive Dentistry, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Junkang Quan
- Department of Preventive Dentistry, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Dandan Liu
- Department of Preventive Dentistry, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Xiaozhe Wang
- Department of Preventive Dentistry, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Shuguo Zheng
- Department of Preventive Dentistry, National Clinical Research Center for Oral Diseases, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Key Laboratory of Digital Stomatology, Peking University School and Hospital of Stomatology, Beijing, China
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Ji Y, Li C, Tian Y, Gao Y, Dong Z, Xiang L, Xu Z, Gao Y, Zhang L. Maturation stage enamel defects in Odontogenesis-associated phosphoprotein (Odaph) deficient mice. Dev Dyn 2021; 250:1505-1517. [PMID: 33772937 DOI: 10.1002/dvdy.336] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 02/28/2021] [Accepted: 03/22/2021] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Mutation in Odontogenesis-associated phosphoprotein (ODAPH) has been reported to cause recessive hypomineralized amelogenesis imperfecta (AI) in human. However, the exact role of ODAPH in amelogenesis is still unknown. RESULTS ODAPH was identified as a novel constituent of the atypical basal lamina located at the interface between maturation ameloblasts and the enamel by dual immunofluorescence staining of ODAPH and LAMC2. Odaph knockout mice were generated to explore the function of ODAPH in amelogenesis. Odaph-/- mice teeth showed severely attrition and reduced enamel mineralization. Histological analysis showed from transition or early-maturation stage, ameloblasts were rapidly shortened, lost cell polarity, and exhibited cell pathology. Abundant enamel matrix marked by amelogenin was retained. Temporary cyst-like structures were formed between flattened epithelial cells and the enamel from maturation stage to eruption. The integrity of the atypical basal lamina was impaired indicated by the reduced diffuse expression of LAMC2 and AMTN. The expression of maturation stage related genes of Amtn, Klk4, Integrinβ6 and Slc24a4 were significantly decreased. CONCLUSIONS Our results suggested Odaph played vital roles during amelogenesis by maintaining the integrity of the atypical basal lamina in maturation stage, which may contribute to a better understanding of the pathophysiology of human AI.
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Affiliation(s)
- Yikang Ji
- Department of Stomatology, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, Shandong, China
| | - Cong Li
- Department of Pediatrics and Preventive Dentistry, Hospital Affiliated to Binzhou Medical University, Binzhou, Shandong, China
| | - Yuan Tian
- Department of Pediatrics and Preventive Dentistry, Hospital Affiliated to Binzhou Medical University, Binzhou, Shandong, China
| | - Yan Gao
- Department of Pediatrics and Preventive Dentistry, Hospital Affiliated to Binzhou Medical University, Binzhou, Shandong, China
| | - Zhiheng Dong
- Department of Pediatrics and Preventive Dentistry, Hospital Affiliated to Binzhou Medical University, Binzhou, Shandong, China
| | - Lili Xiang
- Department of Pediatrics and Preventive Dentistry, Hospital Affiliated to Binzhou Medical University, Binzhou, Shandong, China
| | - Zhenzhen Xu
- Department of Pediatrics and Preventive Dentistry, Hospital Affiliated to Binzhou Medical University, Binzhou, Shandong, China
| | - Yuguang Gao
- Department of Pediatrics and Preventive Dentistry, Hospital Affiliated to Binzhou Medical University, Binzhou, Shandong, China.,Institute of Stomatology, Binzhou Medical University, Yantai, Shandong, China
| | - Li Zhang
- Department of Stomatology, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, Shandong, China.,Institute of Stomatology, Binzhou Medical University, Yantai, Shandong, China
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Kim YJ, Lee Y, Zhang H, Song JS, Hu JCC, Simmer JP, Kim JW. A Novel De Novo SP6 Mutation Causes Severe Hypoplastic Amelogenesis Imperfecta. Genes (Basel) 2021; 12:346. [PMID: 33652941 PMCID: PMC7996877 DOI: 10.3390/genes12030346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/26/2021] [Accepted: 02/26/2021] [Indexed: 12/15/2022] Open
Abstract
Amelogenesis imperfecta (AI) is a heterogeneous group of rare genetic disorders affecting tooth enamel formation. Here we report an identification of a novel de novo missense mutation [c.817_818delinsAT, p.(Ala273Met)] in the SP6 gene, causing non-syndromic autosomal dominant AI. This is the second paper on amelogenesis imperfecta caused by SP6 mutation. Interestingly the identified mutation in this study is a 2-bp variant at the same nucleotide positions as the first report, but with AT instead of AA insertion. Clinical phenotype was much more severe compared to the previous report, and western blot showed an extremely decreased level of mutant protein compared to the wild-type, even though the mRNA level was similar.
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Affiliation(s)
- Youn Jung Kim
- Department of Molecular Genetics & DRI, School of Dentistry, Seoul National University, Seoul 03080, Korea;
| | - Yejin Lee
- Department of Pediatric Dentistry & DRI, School of Dentistry, Seoul National University, Seoul 03080, Korea; (Y.L.); (J.-S.S.)
| | - Hong Zhang
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48108, USA; (H.Z.); (J.C.-C.H.); (J.P.S.)
| | - Ji-Soo Song
- Department of Pediatric Dentistry & DRI, School of Dentistry, Seoul National University, Seoul 03080, Korea; (Y.L.); (J.-S.S.)
| | - Jan C.-C. Hu
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48108, USA; (H.Z.); (J.C.-C.H.); (J.P.S.)
| | - James P. Simmer
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48108, USA; (H.Z.); (J.C.-C.H.); (J.P.S.)
| | - Jung-Wook Kim
- Department of Molecular Genetics & DRI, School of Dentistry, Seoul National University, Seoul 03080, Korea;
- Department of Pediatric Dentistry & DRI, School of Dentistry, Seoul National University, Seoul 03080, Korea; (Y.L.); (J.-S.S.)
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Ryu YH, Kyun Chae J, Kim JW, Lee S. Lacrimo-auriculo-dento-digital syndrome: A novel mutation in a Korean family and review of literature. Mol Genet Genomic Med 2020; 8:e1412. [PMID: 32715658 PMCID: PMC7549548 DOI: 10.1002/mgg3.1412] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 05/30/2020] [Accepted: 07/02/2020] [Indexed: 11/18/2022] Open
Abstract
Background Lacrimo‐auriculo‐dento‐digital (LADD) syndrome is a rare autosomal dominant disorder caused by mutations in one of the three genes: fibroblast growth factor receptor 2 (FGFR2), FGFR3, or FGF10. Affected patients have hypoplasia/aplasia of lacrimal ducts/glands, hypoplasia/aplasia of salivary glands, dental anomalies, ear anomalies, hearing loss, and digital anomalies. Case Presentation Proband was an 11‐year‐old male with xerostomia, xerophthalmia, and a referring diagnosis of Sjogren syndrome. He presented with microdontia, hypodontia, low‐set/cupped ear auricles, and hearing loss in the left ear. Methods Whole exome sequencing (WES) was performed on proband. Variations and segregation within the family were verified using Sanger sequencing. Results Molecular studies revealed a novel heterozygous missense mutation in exon 11 of FGFR2: c.1547C>T (p.Ala516Val), compatible with LADD syndrome. Conclusion To the best of our knowledge, this is the first report of a family with LADD syndrome in Korea. The combination of xerostomia and xerophthalmia, seen in patients with LADD syndrome, may be misdiagnosed as Sjogren syndrome. WES may be a useful clinical tool in ascertaining the affected gene in patients with suspected genetic disorders. Here, a literature review and summary of 23 case reports/series of LADD syndrome are presented, which may help to identify patients with this condition.
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Affiliation(s)
- Young Hye Ryu
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Jong Kyun Chae
- Department of Pediatric Dentistry, School of Dentistry & Dental Research Institute, Seoul National University, Seoul, Korea
| | - Jung-Wook Kim
- Department of Pediatric Dentistry, School of Dentistry & Dental Research Institute, Seoul National University, Seoul, Korea.,Department of Molecular Genetics, School of Dentistry & Dental Research Institute, Seoul National University, Seoul, Korea
| | - Soyoung Lee
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea
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Kim Y, Kang J, Seymen F, Koruyucu M, Zhang H, Kasimoglu Y, Bayram M, Tuna-Ince E, Bayrak S, Tuloglu N, Hu JC, Simmer J, Kim JW. Alteration of Exon Definition Causes Amelogenesis Imperfecta. J Dent Res 2020; 99:410-418. [PMID: 31999931 PMCID: PMC7088207 DOI: 10.1177/0022034520901708] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Amelogenesis imperfecta (AI) is a collection of genetic disorders affecting the quality and/or quantity of tooth enamel. More than 20 genes are, so far, known to be responsible for this condition. In this study, we recruited 3 Turkish families with hypomaturation AI. Whole-exome sequence analyses identified disease-causing mutations in each proband, and these mutations cosegregated with the AI phenotype in all recruited members of each family. The AI-causing mutations in family 1 were a novel AMELX mutation [NM_182680.1:c.143T>C, p.(Leu48Ser)] in the proband and a novel homozygous MMP20 mutation [NM_004771.3:c.616G>A, p.(Asp206Asn)] in the mother of the proband. Previously reported compound heterozygous MMP20 mutations [NM_004771.3:c.103A>C, p.(Arg35=) and c.389C>T, p.(Thr130Ile)] caused the AI in family 2 and family 3. Minigene splicing analyses revealed that the AMELX missense mutation increased exonic definition of exon 4 and the MMP20 synonymous mutation decreased exonic definition of exon 1. These mutations would trigger an alteration of exon usage during RNA splicing, causing the enamel malformations. These results broaden our understanding of molecular genetic pathology of tooth enamel formation.
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Affiliation(s)
- Y.J. Kim
- Department of Molecular Genetics & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - J. Kang
- Department of Pediatric Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - F. Seymen
- Department of Pedodontics, Faculty of Dentistry, Istanbul University, Istanbul, Turkey
| | - M. Koruyucu
- Department of Pedodontics, Faculty of Dentistry, Istanbul University, Istanbul, Turkey
| | - H. Zhang
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Y. Kasimoglu
- Department of Pedodontics, Faculty of Dentistry, Istanbul University, Istanbul, Turkey
| | - M. Bayram
- Department of Pedodontics, Faculty of Dentistry, Istanbul Medipol University, Istanbul, Turkey
| | - E.B. Tuna-Ince
- Department of Pedodontics, Faculty of Dentistry, Istanbul University, Istanbul, Turkey
| | - S. Bayrak
- Department of Pediatric Dentistry, Faculty of Dentistry, University of Eskisehir Osmangazi, Eskisehir, Turkey
| | - N. Tuloglu
- Department of Pediatric Dentistry, Faculty of Dentistry, University of Eskisehir Osmangazi, Eskisehir, Turkey
| | - J.C.-C. Hu
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - J.P. Simmer
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - J.-W. Kim
- Department of Molecular Genetics & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea
- Department of Pediatric Dentistry & Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea
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