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Li X, Xing X, Liang X, Song C, Yang J, Ren D, Zhou Y. Piebaldism with café-au-lait macules resulting from a novel mutation of KIT gene in a three-generation Chinese family. Skin Res Technol 2023; 29:e13352. [PMID: 37357653 PMCID: PMC10209842 DOI: 10.1111/srt.13352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 05/04/2023] [Indexed: 06/27/2023]
Abstract
BACKGROUND Piebaldism is a rare, autosomal dominant, and congenital pigmentary disorder characterized by stable depigmentation of the skin and white forelock. Mutations in KIT or SLUG genes result in piebaldism. Most individuals with piebaldism have a family history of the disorder. METHODS In this paper, we report a case of piebaldism with café-au-lait macules resulting from a novel mutation of KIT gene c.1982C > T (p.Thr661Ile) in a three-generation Chinese family. The whole-exome sequencing, mitochondrial gene 3000X, and bioinformatics tools were used to identify the mutation in this new-found pedigree. In addition, we searched the databases of "Punmed, Chinese National Knowledge Infrastructure, CMJD, WANFANG MED ONLINE", reviewed 88 cases of piebaldism caused by KIT gene mutation, and summarized the relationship between clinical phenotype and genotype of piebaldism through logistic regression and other statistical methods. RESULTS The proband and her affected mother carried a heterozygous c.1982C > T missense mutation (p.Thr661Ile) on KIT gene. Bioinformatics analysis hinted that it had potential pathogenicity. The data showed that piebaldism patients with cafè-au-lait macules had KIT mutations almost located in the intracellular tyrosine kinase domain and were mostly related to the severe clinical phenotype of piebaldism. CONCLUSION The new heterozygous c.1982C > T missense mutation on KIT caused piebaldism with café-au-lait macules in this Chinese family. This study provides a new reference index for clinicians to judge the severity of clinical phenotypes of piebaldism, broadens the understanding of the correlation between clinical phenotypes and genotypes of piebaldism, and provides reference of genetic counseling and prenatal diagnosis for affected families.
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Affiliation(s)
- Xiaorong Li
- Department of DermatologyThe First Medical Center of Chinese PLA General HospitalBeijingChina
| | - Xiaojing Xing
- Department of DermatologyBeijing Shijitan HospitalCapital Medical UniversityBeijingChina
| | - Xiaoqiang Liang
- Department of DermatologyThe First Medical Center of Chinese PLA General HospitalBeijingChina
| | - Cuihao Song
- Department of DermatologyThe First Medical Center of Chinese PLA General HospitalBeijingChina
| | - Jie Yang
- Department of DermatologyAffiliated Hospital of North China University of Science and TechnologyTangshanChina
| | - Dan Ren
- Department of DermatologyThe First Medical Center of Chinese PLA General HospitalBeijingChina
| | - Yong Zhou
- Department of DermatologyThe First Medical Center of Chinese PLA General HospitalBeijingChina
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Saravanaperumal SA, Pallotti S, Pediconi D, Renieri C, La Terza A. Exon-1 skipping and intron-1 retaining by alternative splicing of the c-KIT gene encodes a novel splice variant in the skin of Merino sheep (Ovis aries). Mol Biol Rep 2021; 48:4987-4994. [PMID: 34148208 DOI: 10.1007/s11033-021-06486-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 06/08/2021] [Indexed: 12/01/2022]
Abstract
c-KIT, a type III receptor protein tyrosine kinase, plays an essential role in melanocyte development, migration, and survival. Mutations within the c-KIT gene are previously shown to cause the white coat color phenotypes in pigs, mice, goats, and humans. However, up so far, the splicing isoform(s), genomic architecture of c-KIT have not been characterized well in merino sheep. Reverse transcriptase (RT)-PCR analysis with molecular prediction identified two basic splice variants: Transcript Variant-1, 2 for 12 bp insertion coding sequences (CDS) corresponding to the four amino acids 'GNSK', respectively. Using 5' RACE, here we report for the first time a novel c-KIT 'Transcript Variant-3' from the skin of merino sheep by comparative genome analyses at exon(1)-intron(1)-exon(2) boundaries. In contrast, a single product of 795 bp was characterized by 3' RACE. We also demonstrated that the c-KIT gene expression at the transcript level is not mediated via an intron-9 splicing event. Overall, beyond what was observed in other mammals, our data provide novel insights into the molecular structure of the c-KIT gene in sheep.
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Affiliation(s)
- Siva Arumugam Saravanaperumal
- Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street SW Guggenheim 10-21C, Rochester, MN, 55905, USA.
| | - Stefano Pallotti
- School of Pharmacy, University of Camerino, Via Gentile III da Varano, 62032, Camerino, Italy.
| | - Dario Pediconi
- School of Pharmacy, University of Camerino, Via Gentile III da Varano, 62032, Camerino, Italy
| | - Carlo Renieri
- School of Pharmacy, University of Camerino, Via Gentile III da Varano, 62032, Camerino, Italy
| | - Antonietta La Terza
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III da Varano, 62032, Camerino, Italy.
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3
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Tóth B, Kiss N, Hársing J, Kárpáti S, Csomor J, Bödör C, Tímár J, Rásó E. Frequent KIT mutations in skin lesions of patients with BRAF wild-type Langerhans cell histiocytosis. Virchows Arch 2020; 477:749-753. [PMID: 32372223 PMCID: PMC7581584 DOI: 10.1007/s00428-020-02820-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 03/30/2020] [Accepted: 04/19/2020] [Indexed: 12/15/2022]
Abstract
Langerhans cell histiocytosis (LCH) is characterized by mutations of the RAS-RAF-MAPK signaling pathway. We analyzed MAP2K1, NRAS and KIT mutation incidence in skin lesions of BRAF wild-type (wt) LCH patients. We evaluated the occurrence of MAP2K1, NRAS and KIT mutations in seven LCH and one indeterminate cell histiocytosis (ICH) patients. MAP2K1 mutation frequency was found to be 3/7 (42.9%) in LCH and also found in ICH. Similarly, the KIT mutation frequency was found to be equally prevalent (4/7, 57.1%) in LCH and also occurred in ICH. Involvement of KIT exons in LCH-ICH indicated that exon 9/11/18 were equally prevalent followed by exon 13. This exploratory analysis on BRAF-wt LCH revealed a KIT mutation rate comparable to MAP2K1. Although the detected KIT mutations are different from activating mutations found in other KIT-dependent neoplasms, our data suggest that KIT-inhibitors might have a role in treating BRAF-wt LCH patients.
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Affiliation(s)
- Béla Tóth
- Department of Dermatology, Venereology and Dermatooncology, Semmelweis University, 41 Mária utca, Budapest, H-1085, Hungary.
| | - Norbert Kiss
- Department of Dermatology, Venereology and Dermatooncology, Semmelweis University, 41 Mária utca, Budapest, H-1085, Hungary
| | - Judit Hársing
- Department of Dermatology, Venereology and Dermatooncology, Semmelweis University, 41 Mária utca, Budapest, H-1085, Hungary
| | - Sarolta Kárpáti
- Department of Dermatology, Venereology and Dermatooncology, Semmelweis University, 41 Mária utca, Budapest, H-1085, Hungary
| | - Judit Csomor
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
| | - Csaba Bödör
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
| | - József Tímár
- 2nd Department of Pathology, Semmelweis University, Budapest, Hungary
| | - Erzsébet Rásó
- 2nd Department of Pathology, Semmelweis University, Budapest, Hungary
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Hamadah I, Chisti M, Haider M, Al Dosssari H, Alhumaidan R, Meyer BF, Wakil SM. A novel KIT mutation in a family with expanded syndrome of piebaldism. JAAD Case Rep 2019; 5:627-631. [PMID: 31341943 PMCID: PMC6630042 DOI: 10.1016/j.jdcr.2019.01.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Issam Hamadah
- Department of Dermatology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Muzamil Chisti
- Department of Dermatology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Mansoor Haider
- Department of Dermatology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Haya Al Dosssari
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Rawan Alhumaidan
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Brian F Meyer
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Salma M Wakil
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
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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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Hattori M, Ishikawa O, Oikawa D, Amano H, Yasuda M, Kaira K, Ishida-Yamamoto A, Nakano H, Sawamura D, Terawaki SI, Wakamatsu K, Tokunaga F, Shimizu A. In-frame Val 216-Ser 217 deletion of KIT in mild piebaldism causes aberrant secretion and SCF response. J Dermatol Sci 2018; 91:35-42. [PMID: 29631773 DOI: 10.1016/j.jdermsci.2018.03.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 03/14/2018] [Accepted: 03/18/2018] [Indexed: 11/16/2022]
Abstract
BACKGROUND Piebaldism is a pigmentary disorder characterized by a white forelock and depigmented patches. Although the loss-of-function mutations in the KIT gene underlie the disease, the intracellular dynamics of the mutant KIT are largely unknown. We herein report a Japanese family with piebaldism in which the affected members showed a mild phenotype. OBJECTIVE The objective of this study is to investigate the functions and intracellular dynamics of the mutant KIT protein. METHODS We performed genetic analyses of the KIT gene using peripheral blood cells. We analyzed the intracellular localization of the mutant KIT protein in HEK293T cells transfected with wild-type (Wt) and/or mutant KIT genes. Immunoprecipitation analyses, immunoblotting and immunofluorescence studies were performed using antibodies against KIT and downstream signaling proteins. Glycosidase digestion analysis was performed to clarify the intracellular localization of KIT protein. RESULTS A genetic analysis revealed a novel heterozygous mutation c.645_650delTGTGTC which results in the in-frame deletion of Val216 and Ser217 in the extracellular domain of KIT. Immunoprecipitation analyses confirmed that the wild and mutant KIT formed a heterodimer after treatment with stem cell factor (SCF); however, the phosphorylation of the downstream signaling factors was decreased. In an immunofluorescence study, the mutant KIT accumulated predominantly in the endoplasmic reticulum (ER) and was sparsely expressed on the cell surface. A glycosidase digestion study revealed that the mutant KIT is predominantly localized in the ER. CONCLUSION These data reveal an aberrant function and intracellular localization of mutant KIT protein in piebaldism.
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Affiliation(s)
- Mai Hattori
- Department of Dermatology, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan; Department of Dermatology, Japan Red Cross Maebashi Hospital, Maebashi, Japan
| | - Osamu Ishikawa
- Department of Dermatology, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Daisuke Oikawa
- Department of Pathobiochemistry, Graduate School of Medicine, Osaka City University, Osaka, Japan
| | - Hiroo Amano
- Department of Dermatology, Iwate Medical University, Morioka, Iwate, Japan
| | - Masahito Yasuda
- Department of Dermatology, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | - Kyoichi Kaira
- Department of Oncology Clinical Development, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan
| | | | - Hajime Nakano
- Department of Dermatology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Daisuke Sawamura
- Department of Dermatology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
| | - Shin-Ichi Terawaki
- Graduate School of Science and Technology, Gunma University, Kiryu, Gunma, Japan
| | - Kaori Wakamatsu
- Graduate School of Science and Technology, Gunma University, Kiryu, Gunma, Japan
| | - Fuminori Tokunaga
- Department of Pathobiochemistry, Graduate School of Medicine, Osaka City University, Osaka, Japan
| | - Akira Shimizu
- Department of Dermatology, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
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Kerkeni E, Boubaker S, Sfar S, Bizid M, Besbes H, Bouaziz S, Ghedira N, Amara A, Manoubi W, Gribaa M, Monastiri K. Molecular characterization of piebaldism in a Tunisian family. ACTA ACUST UNITED AC 2015; 63:113-6. [PMID: 25910686 DOI: 10.1016/j.patbio.2015.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 03/23/2015] [Indexed: 12/19/2022]
Abstract
OBJECTIVE The present study is aimed at performing the molecular characterization of a Tunisian family with piebaldism. METHODS As the proband and her mother showed a severe phenotype, we first chose to screen exons 10, 11, 12, 13, 16, 17 and 18 of the KIT proto-oncogene by direct sequencing. RESULTS Direct sequencing analysis showed a C to T substitution at 1939 in exon 13 (c.1939C>T) in heterozygous state in the patient and her mother. The mutation was not found in their unaffected family members or normal controls. CONCLUSION Our results provide additional support that mutations in the tyrosine kinase domain of the KIT gene are responsible for the severe form of piebaldism.
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Affiliation(s)
- E Kerkeni
- Research Unit 01/UR/08-14, Faculty of Medicine of Monastir, University of Monastir, Monastir, Tunisia.
| | - S Boubaker
- Research Unit 01/UR/08-14, Faculty of Medicine of Monastir, University of Monastir, Monastir, Tunisia
| | - S Sfar
- Research Unit 01/UR/08-14, Faculty of Medicine of Monastir, University of Monastir, Monastir, Tunisia
| | - M Bizid
- Research Unit 01/UR/08-14, Faculty of Medicine of Monastir, University of Monastir, Monastir, Tunisia; Department of Intensive care and Neonatal Medicine, CHU Fattouma Bourguiba, Monastir, Tunisia
| | - H Besbes
- Research Unit 01/UR/08-14, Faculty of Medicine of Monastir, University of Monastir, Monastir, Tunisia; Department of Intensive care and Neonatal Medicine, CHU Fattouma Bourguiba, Monastir, Tunisia
| | - S Bouaziz
- Research Unit 01/UR/08-14, Faculty of Medicine of Monastir, University of Monastir, Monastir, Tunisia
| | - N Ghedira
- Research Unit 01/UR/08-14, Faculty of Medicine of Monastir, University of Monastir, Monastir, Tunisia
| | - A Amara
- Laboratory of Human Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Sousse, Tunisia
| | - W Manoubi
- Laboratory of Human Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Sousse, Tunisia
| | - M Gribaa
- Laboratory of Human Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Sousse, Tunisia
| | - K Monastiri
- Research Unit 01/UR/08-14, Faculty of Medicine of Monastir, University of Monastir, Monastir, Tunisia; Department of Intensive care and Neonatal Medicine, CHU Fattouma Bourguiba, Monastir, Tunisia
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8
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Frances L, Betlloch I, Leiva-Salinas M, Silvestre JF. Spontaneous repigmentation in an infant with piebaldism. Int J Dermatol 2015; 54:e244-6. [DOI: 10.1111/ijd.12776] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 03/01/2014] [Accepted: 06/01/2014] [Indexed: 11/27/2022]
Affiliation(s)
- Laura Frances
- Section of Dermatology; Hospital General Universitario; Alicante Spain
| | - Isabel Betlloch
- Section of Dermatology; Hospital General Universitario; Alicante Spain
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Abstract
Piebaldism is an uncommon autosomal dominantly inherited pigment anomaly characterized by a congenital white forelock and leukoderma on the frontal scalp, forehead, ventral trunk and extremities. It is caused by a loss-of-function mutation in the KIT gene. Genetic analyses reveal a consistent genotype-phenotype relationship in piebaldism. However, recently reported cases of piebaldism that are milder or severer than genetically expected indicate that other factors, such as a modifier gene of MC1R, influence skin and hair color. The KIT ligand/KIT that triggers the Ras/mitogen-activated protein kinase signaling pathway play essential functions in the migration, proliferation, survival, melanogenesis and melanosome transfer of the melanocytes. We summarize current research progress in piebaldism and related disorders.
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Affiliation(s)
- Naoki Oiso
- Department of Dermatology, Kinki University Faculty of Medicine, Osakasayama, Japan.
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10
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Baxter LL, Pavan WJ. The etiology and molecular genetics of human pigmentation disorders. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2012; 2:379-92. [PMID: 23799582 DOI: 10.1002/wdev.72] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Pigmentation, defined as the placement of pigment in skin, hair, and eyes for coloration, is distinctive because the location, amount, and type of pigmentation provides a visual manifestation of genetic heterogeneity in pathways regulating the pigment-producing cells, melanocytes. The scope of this genetic heterogeneity in humans ranges from normal to pathological pigmentation phenotypes. Clinically, normal human pigmentation encompasses a variety of skin and hair color as well as punctate pigmentation such as melanocytic nevi (moles) or ephelides (freckles), while abnormal human pigmentation exhibits markedly reduced or increased pigment levels, known as hypopigmentation and hyperpigmentation, respectively. Elucidation of the molecular genetics underlying pigmentation has revealed genes important for melanocyte development and function. Furthermore, many pigmentation disorders show additional defects in cells other than melanocytes, and identification of the genetic insults in these disorders has revealed pleiotropic genes, where a single gene is required for various functions in different cell types. Thus, unravelling the genetics of easily visualized pigmentation disorders has identified molecular similarities between melanocytes and less visible cell types/tissues, arising from a common developmental origin and/or shared genetic regulatory pathways. Herein we discuss notable human pigmentation disorders and their associated genetic alterations, focusing on the fact that the developmental genetics of pigmentation abnormalities are instructive for understanding normal pathways governing development and function of melanocytes.
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Affiliation(s)
- Laura L Baxter
- Mouse Embryology Section, Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
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11
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Chong KL, Common JE, Lane EB, Goh BK. A novel mutation in the kinase domain of KIT in an Indian family with a mild piebaldism phenotype. J Dermatol Sci 2010; 59:206-9. [DOI: 10.1016/j.jdermsci.2010.06.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 06/08/2010] [Accepted: 06/25/2010] [Indexed: 11/25/2022]
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12
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A novel KIT missense mutation in one Chinese family with piebaldism. Arch Dermatol Res 2009; 301:387-9. [PMID: 19430803 DOI: 10.1007/s00403-009-0955-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 04/05/2009] [Accepted: 04/19/2009] [Indexed: 10/20/2022]
Abstract
Piebaldism is an autosomal dominant disorder characterized by congenital leukoderma, mostly affecting forehead, abdomen and knee. Previous studies have revealed that piebaldism is caused by mutations of the KIT gene, which encodes the cell surface transmembrane tyrosine kinase receptor for KIT ligand. We reported here a Chinese Han family with piebaldism, and performed mutation detection of KIT gene by direct sequencing. A novel missense mutation C58G was identified in the patients, but not in the healthy individuals from the family and 100 unrelated controls. This study contributes to the database on KIT in piebaldism and enriches the knowledge about the genotype/phenotype correlation.
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Oiso N, Kishida K, Fukai K, Motokawa T, Hosomi N, Suzuki T, Mitsuhashi Y, Tsuboi R, Kawada A. A Japanese piebald patient with auburn hair colour associated with a novel mutation p.P832L in the KIT gene and a homozygous variant p.I120T in the MC1R gene. Br J Dermatol 2009; 161:468-9. [PMID: 19416250 DOI: 10.1111/j.1365-2133.2009.09138.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- N Oiso
- Department of Dermatology, Kinki University School of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, Japan.
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14
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Robinson KC, Fisher DE. Specification and loss of melanocyte stem cells. Semin Cell Dev Biol 2009; 20:111-6. [DOI: 10.1016/j.semcdb.2008.11.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 10/21/2008] [Accepted: 11/19/2008] [Indexed: 10/21/2022]
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15
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Congenital disease SNPs target lineage specific structural elements in protein kinases. Proc Natl Acad Sci U S A 2008; 105:9011-6. [PMID: 18579784 DOI: 10.1073/pnas.0802403105] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The catalytic domain of protein kinases harbors a large number of disease-causing single nucleotide polymorphisms (SNPs) and common or neutral SNPs that are not known or hypothesized to be associated with any disease. Distinguishing these two types of polymorphisms is critical in accurately predicting the causative role of SNPs in both candidate gene and genome-wide association studies. In this study, we have analyzed the structural location of common and disease-associated SNPs in the catalytic domain of protein kinases and find that, although common SNPs are randomly distributed within the catalytic core, known disease SNPs consistently map to regulatory and substrate binding regions. In particular, a buried side-chain network that anchors the flexible activation loop to the catalytic core is frequently mutated in disease patients. This network was recently shown to be absent in distantly related eukaryotic-like kinases, which lack an exaggerated activation loop and, presumably, are not regulated by phosphorylation.
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16
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Yuzawa S, Opatowsky Y, Zhang Z, Mandiyan V, Lax I, Schlessinger J. Structural basis for activation of the receptor tyrosine kinase KIT by stem cell factor. Cell 2007; 130:323-34. [PMID: 17662946 DOI: 10.1016/j.cell.2007.05.055] [Citation(s) in RCA: 239] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 04/25/2007] [Accepted: 05/22/2007] [Indexed: 01/15/2023]
Abstract
Stem Cell Factor (SCF) initiates its multiple cellular responses by binding to the ectodomain of KIT, resulting in tyrosine kinase activation. We describe the crystal structure of the entire ectodomain of KIT before and after SCF stimulation. The structures show that KIT dimerization is driven by SCF binding whose sole role is to bring two KIT molecules together. Receptor dimerization is followed by conformational changes that enable lateral interactions between membrane proximal Ig-like domains D4 and D5 of two KIT molecules. Experiments with cultured cells show that KIT activation is compromised by point mutations in amino acids critical for D4-D4 interaction. Moreover, a variety of oncogenic mutations are mapped to the D5-D5 interface. Since key hallmarks of KIT structures, ligand-induced receptor dimerization, and the critical residues in the D4-D4 interface, are conserved in other receptors, the mechanism of KIT stimulation unveiled in this report may apply for other receptor activation.
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Affiliation(s)
- Satoru Yuzawa
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
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Bondanza S, Bellini M, Roversi G, Raskovic D, Maurelli R, Paionni E, Paterna P, Dellambra E, Larizza L, Guerra L. Piebald Trait: Implication of kit Mutation on In Vitro Melanocyte Survival and on the Clinical Application of Cultured Epidermal Autografts. J Invest Dermatol 2007; 127:676-86. [PMID: 17124503 DOI: 10.1038/sj.jid.5700639] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Piebald trait leukoderma results from "loss-of-function" mutations in the kit gene. Correlations between mutation type and clinical phenotype have been reported. However, mutation classification has been mainly based on the clinical features of patients. The aim of this study was to get a better understanding of the pathogenesis of human piebaldism by establishing whether the kit mutation type may affect the in vitro survival/proliferation of patient melanocytes. Overall, the research was finalized to implement the clinical application of the autologous cultured epidermis in the treatment of piebald patients. Seven patients, who were transplanted with autologous in vitro reconstituted epidermis, showed an average percentage of repigmentation of 90.7. Six novel and one previously reported mutations were found and their postulated effects discussed in relation to the clinical phenotype and in vitro behavior of epidermal cells. Although mutation type did not impair repigmentation given by autotransplantation, it was shown to influence the survival/proliferation of co-cultured melanocytes and keratinocytes. In particular, tyrosine kinase domain mutations were found with melanocyte loss and keratinocyte senescence during expansion of epidermal cultures. Results indicate that the clinical application of cultured epidermis in piebald patients may be optimized by investigating mutation functional effects before planning surgical operations.
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Affiliation(s)
- Sergio Bondanza
- Laboratory of Tissue Engineering and Cutaneous Physiopathology, Istituto Dermopatico dell'Immacolata, IRCCS, Via dei Monti di Creta 104, Rome, Italy
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