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Li C, Chen P, Sun S, Zeng K, Liang J, Wang Q, Zhang S, Xu M, Li Z, Zhang X. Exome sequencing identifies a KRT9 pathogenic variant in a Chinese pedigree with epidermolytic palmoplantar keratoderma. Mol Genet Genomic Med 2019; 7:e00703. [PMID: 31074163 PMCID: PMC6625362 DOI: 10.1002/mgg3.703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 03/16/2019] [Accepted: 04/08/2019] [Indexed: 12/15/2022] Open
Abstract
Background Epidermolytic palmoplantar keratoderma (EPPK) is a rare skin disorder and its pathogenesis and inheritability are unknown. Objective To investigate the inheritance and pathogenesis of EPPK. Methods Two EPPK cases occurred in a three‐generation Chinese family. Patient–parents trio EPPK was carried out and the identified candidate variants were confirmed by Sanger sequencing. Results A heterozygous missense pathogenic variant, c.488G > A (p.Arg163Gln), in the keratin (KRT) 9 gene was detected in the proband and his son via targeted exome sequencing, and then validated by Sanger sequencing. This pathogenic variant cosegregated with the EPPK in extended family members, and was predicted to be pathogenic by SIFT, PolyPhen2, PROVEAN, and Mutation Taster. This heterozygous variation was not evident in 100 healthy controls. Conclusion This report describes a KRT9 c.488G > A (p.Arg163Gln) variant causing a diffuse phenotype of Chinese EPPK. The current results broaden the spectrum of KRT9 pathogenic variants responsible for EPPK and have important implications for molecular diagnosis, treatment, and genetic counseling for this family.
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Affiliation(s)
- Changxing Li
- Department of Dermatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Pingjiao Chen
- Department of Dermatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Silong Sun
- BGI Genomics, BGI-Shenzhen, Shenzhen, China
| | - Kang Zeng
- Department of Dermatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jingyao Liang
- Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou, China
| | - Qi Wang
- Department of Dermatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Sanquan Zhang
- Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou, China
| | - Meinian Xu
- Department of Dermatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zhijia Li
- Department of Dermatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xibao Zhang
- Department of Dermatology, Guangzhou Institute of Dermatology, Guangzhou, China
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Li Y, Tang L, Han Y, Zheng L, Zhen Q, Yang S, Gao M. Genetic Analysis of KRT9 Gene Revealed Previously Known Mutations and Genotype-Phenotype Correlations in Epidermolytic Palmoplantar Keratoderma. Front Genet 2019; 9:645. [PMID: 30666268 PMCID: PMC6330350 DOI: 10.3389/fgene.2018.00645] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 11/29/2018] [Indexed: 11/13/2022] Open
Abstract
Epidermolytic palmoplantar keratoderma (EPPK, OMIM 144200) is an autosomal dominant inherited disease, clinically characterized by diffuse yellowish thickening of the skin on the palms and soles, usually with erythematous borders developing during the first weeks or months after birth. Pathogenesis of EPPK is determined by mutations in the keratin gene (KRT9). Thirty three mutations in the KRT9 gene from 100 EPPK families have been identified. Among these, 23 mutations are located in the 1A region (a mutation hot spot region), 7 are located in the 2B region, and the remaining 3 are synonymous mutations. In this study, three heterozygous mutations (p.N161S, p.R163W, and p.R163Q), located in regions of the gene encoding the conserved central a-helix rod domain, were detected in the KRT9 gene of the three large Chinese families. This study confirms that codon 163 (48 of 100 cases) is a hot spot mutation site for KRT9. Additional findings identified p.N161S (4%) and p.R163W (4%) as potential hot spot mutations for EPPK associated with knuckle pads, and p.R163Q (15 of 100 cases) as the hot spot mutation of EPPK not occurring in combination with knuckle pads. In conjunction with future studies, this research may help lay the foundation for genetics counseling, prenatal diagnosis and clinical treatment of EPPK.
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Affiliation(s)
- Yuwei Li
- Institute of Dermatology and Department of Dermatology of First Affiliated Hospital, Hefei, China.,Key Laboratory of Dermatology, Ministry of Education, Anhui Medical University, Hefei, China
| | - Lili Tang
- Institute of Dermatology and Department of Dermatology of First Affiliated Hospital, Hefei, China.,Key Laboratory of Dermatology, Ministry of Education, Anhui Medical University, Hefei, China
| | - Yang Han
- Institute of Dermatology and Department of Dermatology of First Affiliated Hospital, Hefei, China.,Key Laboratory of Dermatology, Ministry of Education, Anhui Medical University, Hefei, China
| | - Liyun Zheng
- Institute of Dermatology and Department of Dermatology of First Affiliated Hospital, Hefei, China.,Key Laboratory of Dermatology, Ministry of Education, Anhui Medical University, Hefei, China
| | - Qi Zhen
- Institute of Dermatology and Department of Dermatology of First Affiliated Hospital, Hefei, China.,Key Laboratory of Dermatology, Ministry of Education, Anhui Medical University, Hefei, China
| | - Sen Yang
- Institute of Dermatology and Department of Dermatology of First Affiliated Hospital, Hefei, China
| | - Min Gao
- Institute of Dermatology and Department of Dermatology of First Affiliated Hospital, Hefei, China
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3
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Liang YH, Liu QX, Huang L, Zeng K. A recurrent p.M157R mutation of keratin 9 gene in a Chinese family with epidermolytic palmoplantar keratoderma and literature review. Int J Dermatol 2014; 53:e375-9. [PMID: 24899405 DOI: 10.1111/ijd.12352] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Yanhua H Liang
- Department of Dermatology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, 510515, China.
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4
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Shimazu K, Tsunemi Y, Hattori N, Adachi M, Imakado S, Saeki H, Komine M, Tamaki K. Diagnosis of epidermolytic palmoplantar keratoderma in a very early stage by gene analysis. J Dermatol 2005; 32:859-61. [PMID: 16361744 DOI: 10.1111/j.1346-8138.2005.tb00861.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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5
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Li R, Johnson AB, Salomons G, Goldman JE, Naidu S, Quinlan R, Cree B, Ruyle SZ, Banwell B, D'Hooghe M, Siebert JR, Rolf CM, Cox H, Reddy A, Gutiérrez-Solana LG, Collins A, Weller RO, Messing A, van der Knaap MS, Brenner M. Glial fibrillary acidic protein mutations in infantile, juvenile, and adult forms of Alexander disease. Ann Neurol 2005; 57:310-26. [PMID: 15732097 DOI: 10.1002/ana.20406] [Citation(s) in RCA: 175] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Alexander disease is a progressive, usually fatal neurological disorder defined by the widespread and abundant presence in astrocytes of protein aggregates called Rosenthal fibers. The disease most often occurs in infants younger than 2 years and has been labeled a leukodystrophy because of an accompanying severe myelin deficit in the frontal lobes. Later onset forms have also been recognized based on the presence of abundant Rosenthal fibers. In these cases, clinical signs and pathology can be quite different from the infantile form, raising the question whether they share the same underlying cause. Recently, we and others have found pathogenic, de novo missense mutations in the glial fibrillary acidic protein gene in most infantile patients examined and in a few later onset patients. To obtain further information about the role of glial fibrillary acidic protein mutations in Alexander disease, we analyzed 41 new patients and another 3 previously described clinically, including 18 later onset patients. Our results show that dominant missense glial fibrillary acidic protein mutations account for nearly all forms of this disorder. They also significantly expand the catalog of responsible mutations, verify the value of magnetic resonance imaging diagnosis, indicate an unexpected male predominance for the juvenile form, and provide insights into phenotype-genotype relations.
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Affiliation(s)
- Rong Li
- Department of Neurobiology and Civitan International Research Center, University of Alabama-Birmingham, Birmingham, AL, USA
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6
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Kon A, Itagaki K, Yoneda K, Takagaki K. A novel mutation of keratin 9 gene (R162P) in a Japanese family with epidermolytic palmoplantar keratoderma. Arch Dermatol Res 2004; 296:375-8. [PMID: 15605275 DOI: 10.1007/s00403-004-0534-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2004] [Accepted: 11/22/2004] [Indexed: 11/29/2022]
Abstract
Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant inherited skin disorder characterized by hyperkeratosis of the skin over the palms and soles. Mutations in keratin 9 gene (KRT9) have been demonstrated in EPPK. In this study, we screened a Japanese family with EPPK for KRT9 mutation by polymerase chain reaction amplification of genomic sequences, followed by heteroduplex analysis and direct nucleotide sequencing. The mutation consisted of a G-to-C transversion at codon 162 in exon 1, which was located in the hot spot of the mutations that have been reported previously (R162Q and R162W). However, the amino acid substitution was proline for arginine (R162P) in the 1A rod domain, the highly conserved helix initiation motif of keratin 9. Our result illustrates the repertoire of KRT9 mutation underlying the occurrence of EPPK in a Japanese family and is an important contribution to the investigation of the genotype/phenotype correlation.
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Affiliation(s)
- Atsushi Kon
- Department of Biochemistry, Hirosaki University School of Medicine, 5 Zaifu-cho, Hirosaki, Aomori, 036-8562, Japan.
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7
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He XH, Zhang XN, Mao W, Chen HP, Xu LR, Chen H, He XL, Le YP. A novel mutation of keratin 9 in a large Chinese family with epidermolytic palmoplantar keratoderma. Br J Dermatol 2004; 150:647-51. [PMID: 15099359 DOI: 10.1111/j.0007-0963.2004.05865.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant inherited skin disorder characterized by diffuse yellow thickening of the skin of the palms and soles, sharply bordered with erythematous margins. Histologically and ultrastructurally, EPPK presents cytolysis of keratinocytes and abnormal aggregation of tonofilaments in the suprabasal layers of the epidermis. To date, 15 different mutations of the keratin 9 gene (KRT9) have been demonstrated to cause most cases of EPPK. OBJECTIVES To identify the KRT9 mutation in a large Chinese family with EPPK. METHODS Denaturing high-performance liquid chromatography (DHPLC), DNA sequencing and allele-specific polymerase chain reaction (AS-PCR) were used to screen exon 1 of the KRT9 gene for sequence variations. RESULTS The DHPLC elution profiles of the DNA fragments amplified from the affected samples differed from those obtained from unaffected individuals, indicating that a sequence variation existed within the analysed fragment of KRT9. DNA sequencing revealed a novel insertion-deletion mutation in the exon 1 of KRT9, 497delAinsGGCT, resulting in the change of tyrosine(166) to tryptophan and leucine (Y166delinsWL). AS-PCR confirmed the mutation was not a common polymorphism. CONCLUSIONS The results suggest the molecular basis of EPPK in this Chinese family and provide further evidence that mutations in the helix initiation motif of keratin 9 underlie Chinese EPPK.
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Affiliation(s)
- X-H He
- Department of Genetics, School of Medicine, Ningbo University, Ningbo, Zhejiang Province, 315211, China
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8
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Lee JH, Ahn KS, Lee CH, Youn SJ, Kim JW, Lee DY, Lee ES, Steinert PM, Yang JM. Keratin 9 gene mutations in five Korean families with epidermolytic palmoplantar keratoderma. Exp Dermatol 2003; 12:876-81. [PMID: 14675368 DOI: 10.1111/j.0906-6705.2003.00012.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant disease characterized clinically by localized palmoplantar thickening and histopathologically by granular degeneration of the epidermis. Recent molecular biological studies have revealed that EPPK is caused by mutations of the keratin 9 gene in sequences mainly encoding the highly conserved 1 A rod domain. Here we demonstrate a novel mutation of N160H (position 8 of the 1 A domain) and two other previously reported mutations, R162W and N160S, in five unrelated Korean families with EPPK. The three-dimensional structure of the 1 A domain of the related vimentin intermediate filament protein chain is now known. Based on its likely similarity to the keratin 9 chain, we predict that inappropriate amino acid substitutions in position 10 of 1 A will likely interfere with coiled-coil dimer stability, and those in position 8 will interfere with tetramer stability. Accordingly, these mutations compromise the structural integrity of the keratin intermediate filaments leading to the pathology of EPPK.
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Affiliation(s)
- Joo-Heung Lee
- Department of Dermatology, Sungkyunkwan University School of Medicine, Samsung Medical Center, Seoul, Korea
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9
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Lu Y, Guo C, Liu Q, Zhang X, Cheng L, Li J, Chen B, Gao G, Zhou H, Guo Y, Li Y, Gong Y. A novel mutation of keratin 9 in epidermolytic palmoplantar keratoderma combined with knuckle pads. Am J Med Genet A 2003; 120A:345-9. [PMID: 12838553 DOI: 10.1002/ajmg.a.20090] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominantly inherited disease. We studied a family from Shandong, China, having patients suffering from EPPK with a unique symptom-knuckle pads. We noticed that both the hyperkeratosis and knuckle pads in the Chinese family were friction-related. Candidate gene analysis was carried out using linkage analysis and direct sequencing. A novel L160F mutation in keratin 9 was found, and its effects on the secondary structure of keratin 9 were studied. We predict that the L160F mutation is also responsible for the knuckle pads in the family. Our study provides a new clue for the study of the function of keratin 9.
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Affiliation(s)
- Yong Lu
- Research Institute of Medical Genetics, School of Medicine, Shandong University, Jinan Shandong, People's Republic of China
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10
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Tsunemi Y, Hattori N, Saeki H, Adachi M, Komine M, Nakagawa H, Tamaki K. A keratin 9 Gene mutation (Asn160Ser) in a Japanese patient with epidermolytic palmoplantar keratoderma. J Dermatol 2002; 29:768-72. [PMID: 12532041 DOI: 10.1111/j.1346-8138.2002.tb00220.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2002] [Accepted: 10/24/2002] [Indexed: 11/29/2022]
Abstract
We described a 5-year-old Japanese girl with epidermolytic palmoplantar keratoderma and examined her for a keratin 9 gene mutation. Physical examination disclosed diffuse yellowish hyperkeratosis with an erythematous border limited strictly to the palms and soles. Histological examination revealed hyperkeratosis with vacuolar degeneration in the spinous and granular layers of the epidermis. Sequence analysis demonstrated an A to G transition at the middle position of codon 160 in the 1A domain of the keratin 9 gene. The amino acid at codon 160 was deduced to have changed from asparagine (Asn) to serine (Ser). This is the first case with an Asn160Ser mutation in a Japanese. The substitution of Ser for Asn at codon 160 of the keratin 9 gene is assumed to be fatal for keratin filament assembly regardless of race or ethnicity.
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Affiliation(s)
- Yuichiro Tsunemi
- Department of Dermatology, Faculty of Medicine, University of Tokyo, Tokyo, Japan
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11
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Kimyai-Asadi A, Kotcher LB, Jih MH. The molecular basis of hereditary palmoplantar keratodermas. J Am Acad Dermatol 2002; 47:327-43; quiz 344-6. [PMID: 12196741 DOI: 10.1067/mjd.2002.124814] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In recent years, the gene defects causing many types of hereditary palmoplantar keratoderma have been discovered. These genes encode a variety of proteins involved in the terminal differentiation of keratinocytes and the formation of the cornified cell envelope. In this article, we review the molecular defects underlying various palmoplantar keratodermas with particular attention to the role of these molecules in the terminal differentiation of palmoplantar epidermis. Of the proteins involved in keratodermas, loricrin, keratins, and desmosomal proteins provide the protein structure of the cornified cell envelope. Connexins form intercellular gap junctions, which regulate ionic calcium signals necessary for the expression of the proteins that form the cornified cell envelope. Cathepsins likely mediate enzymatic processes necessary for the formation and dissolution of the cornified cell envelope. The clinical phenotypes produced by various mutations affecting these proteins are discussed vis-à-vis data from genetic, cellular, and molecular experiments.
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Affiliation(s)
- Arash Kimyai-Asadi
- Ronald O. Perelman Department of Dermatology, The New York University School of Medicine, New York, USA
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12
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Abstract
Alexander disease is a rare but often fatal disease of the central nervous system. Infantile, juvenile and adult forms have been described that present with different clinical signs, but are unified by the characteristic presence in astrocytes of Rosenthal fibers-protein aggregates that contain glial fibrillary acidic protein (GFAP) and small stress proteins. The chance discovery that mice expressing a human GFAP transgene formed abundant Rosenthal fibers suggested that mutations in the GFAP gene are a cause of Alexander disease. Sequencing results from several laboratories have indeed now identified GFAP coding mutations in most cases of the disease, including both the infantile and juvenile forms. These mutations have been found in the 1A, 2A and 2B segments of the conserved central rod domain of GFAP, and also in the variable tail region. All changes detected are heterozygous missense mutations, and none has been found in any parent of a patient that has been tested. This indicates that most cases of Alexander disease arise through de novo, dominant, GFAP mutations. Many of these mutations are homologous to ones described in other intermediate filament diseases. These other diseases have been attributed to a dominant loss of function, as the intermediate filament network is usually disrupted and a similar phenotype is observed in mice in which the corresponding intermediate filament gene has been inactivated. However, astrocytes of Alexander disease patients have normal appearing intermediate filaments, and GFAP null mice do not display the symptoms or pathology of Alexander disease. Thus, Alexander disease likely results from a dominant gain of function. Drawing upon the homology of many of the Alexander disease mutations to those found in other intermediate filament diseases, it is suggested that the gain of function is due to a partial block of filament assembly that leads to accumulation of an intermediate that participates in toxic interactions.
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Affiliation(s)
- Rong Li
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294-0021, USA
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13
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Rugg EL, Common JEA, Wilgoss A, Stevens HP, Buchan J, Leigh IM, Kelsell DP. Diagnosis and confirmation of epidermolytic palmoplantar keratoderma by the identification of mutations in keratin 9 using denaturing high-performance liquid chromatography. Br J Dermatol 2002; 146:952-7. [PMID: 12072061 DOI: 10.1046/j.1365-2133.2002.04764.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Epidermolytic palmoplantar keratoderma (EPPK) is one of a number of disorders characterized by diffuse thickening of palm and sole skin. Although EPPK is not a life-threatening condition, palmoplantar keratoderma can be associated with cancer and heart disease and therefore differential diagnosis is important so that adequate surveillance can be provided for the more serious conditions. Most cases of EPPK are caused by mutations in the gene encoding the palm- and sole-specific keratin 9 (K9), and this provides an option for molecular diagnosis of this condition. OBJECTIVES To identify the molecular basis of diffuse palmoplantar keratoderma in four British families. METHODS Denaturing high-performance liquid chromatography (dHPLC) and DNA sequencing were used to screen exon 1 of the k9 gene for sequence variations. RESULTS The dHPLC profiles obtained from individuals with EPPK differed from control samples, indicating sequence variations within the fragment analysed. The profiles varied between families, suggesting that underlying mutations were different for each family; this was confirmed by DNA sequencing. In three cases previously reported mutations were found that resulted in the change of methionine156 to valine and arginine162 to either tryptophan or glutamine. A novel mutation was identified in a fourth family that changed valine170 to methionine. dHPLC was used to screen control samples for this sequence variation and confirmed that it was not a common polymorphism. CONCLUSIONS These results confirm the diagnosis of EPPK in these families and underline the usefulness of dHPLC as a method of screening samples for heterozygous mutations.
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Affiliation(s)
- E L Rugg
- Centre for Cutaneous Research, Barts and The London, Queen Mary's School of Medicine and Dentistry, University of London, 2 Newark Street, London E1 2AT, UK.
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14
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Amichai B, Karpati M, Goldman B, Peleg L. Keratin-9 gene mutation in a family with epidermolytic palmoplantar keratoderma. J Eur Acad Dermatol Venereol 2002; 16:134-6. [PMID: 12046815 DOI: 10.1046/j.1468-3083.2002.00426.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Epidermolytic palmoplantar keratoderma is an autosomal dominant inherited disorder of keratinization. METHODS We studied five members of a Jewish family with epidermolytic palmoplantar keratoderma. Genomic DNA was extracted from leucocytes, and exon 1 of the keratin 9 gene was amplified using polymerase chain reaction techniques. RESULTS The mutation was found in exon 1 of the keratin 9 gene in codon 160. CONCLUSIONS Like most of the other families with clinical features of epidermolytic palmoplantar keratoderma the mutation is found in exon 1 of the keratin 9 gene.
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Affiliation(s)
- B Amichai
- Department of Dermatology, Huzot Clinic of Kupat Holim, Ashkelon, Israel
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15
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Rodriguez D, Gauthier F, Bertini E, Bugiani M, Brenner M, N'guyen S, Goizet C, Gelot A, Surtees R, Pedespan JM, Hernandorena X, Troncoso M, Uziel G, Messing A, Ponsot G, Pham-Dinh D, Dautigny A, Boespflug-Tanguy O. Infantile Alexander disease: spectrum of GFAP mutations and genotype-phenotype correlation. Am J Hum Genet 2001; 69:1134-40. [PMID: 11567214 PMCID: PMC1274357 DOI: 10.1086/323799] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2001] [Accepted: 08/14/2001] [Indexed: 11/03/2022] Open
Abstract
Heterozygous, de novo mutations in the glial fibrillary acidic protein (GFAP) gene have recently been reported in 12 patients affected by neuropathologically proved Alexander disease. We searched for GFAP mutations in a series of patients who had heterogeneous clinical symptoms but were candidates for Alexander disease on the basis of suggestive neuroimaging abnormalities. Missense, heterozygous, de novo GFAP mutations were found in exons 1 or 4 for 14 of the 15 patients analyzed, including patients without macrocephaly. Nine patients carried arginine mutations (four had R79H; four had R239C; and one had R239H) that have been described elsewhere, whereas the other five had one of four novel mutations, of which two affect arginine (2R88C and 1R88S) and two affect nonarginine residues (1L76F and 1N77Y). All mutations were located in the rod domain of GFAP, and there is a correlation between clinical severity and the affected amino acid. These results confirm that GFAP mutations are a reliable molecular marker for the diagnosis of infantile Alexander disease, and they also form a basis for the recommendation of GFAP analysis for prenatal diagnosis to detect potential cases of germinal mosaicism.
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Affiliation(s)
- D Rodriguez
- Laboratoire de Neurogénétique Moléculaire, INSERM U546, Université Paris VI, France.
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16
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Warmuth I, Cserhalmi-Friedman PB, Schneiderman P, Grossman ME, Christiano AM. Epidermolytic palmoplantar keratoderma in a Hispanic kindred resulting from a mutation in the keratin 9 gene. Clin Exp Dermatol 2000; 25:244-6. [PMID: 10844507 DOI: 10.1046/j.1365-2230.2000.00626.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Epidermolytic palmoplantar keratoderma (EPPK) is a localized keratinization disorder caused by mutations in the highly conserved coil 1A domain of the keratin 9 gene, KRT9. We present a Hispanic pedigree spanning three generations, with affected individuals in all generations. Using polymerase chain reaction amplification and direct sequencing we demonstrated a previously reported missense mutation in KRT9, which is expressed almost exclusively in the skin of palms and soles. The C-->T missense mutation R162W changes a basic amino acid (arginine) to a neutral amino acid (tryptophan). We describe this mutation in a Hispanic pedigree with EPPK for the first time, extending the finding of this mutation in other genetic backgrounds, and demonstrating the prevalence of this mutation in diverse populations.
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Affiliation(s)
- I Warmuth
- Departments of Dermatology and Genetics & Development, Columbia University, New York 10032, USA
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17
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Hashimoto K, Mizuguchi R, Tanaka K, Dorman M. Palmoplantar keratoderma (Voerner) with composite keratohyalin granules: studies on keratinization parameters and ultrastructures. J Dermatol 2000; 27:1-9. [PMID: 10692816 DOI: 10.1111/j.1346-8138.2000.tb02108.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A case of the Voerner type palmoplantar keratoderma was studied for abnormalities of keratinization parameters. An enzyme and materials used to build the marginal band or cellular envelope of the cornified cell were all abnormally expressed; i.e. transglutaminase I (TGK), loricrin, and involucrin were abnormally immunostained. In the normal controls, their expression was limited to the upper epidermis, mainly in the granular layer. In the lesional skin, they were detected from the suprabasal layer to the lower horny layer. Filaggrin, the protein of the keratohyalin granule, was also expressed more widely than in controls. Ultrastructural abnormalities included a significantly higher frequency of composite keratohyalin granules than controls, early formation of a marginal band in the midepidermis, and, most remarkably, the clumping of tonofilaments causing vacuolization of the cytoplasm of affected keratinocytes.
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Affiliation(s)
- K Hashimoto
- Department of Dermatology and Syphilology, Wayne State University School of Medicine, Detroit, MI 48201, USA
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Szalai S, Szalai C, Becker K, Török E. Keratin 9 mutations in the coil 1A region in epidermolytic palmoplantar keratoderma. Pediatr Dermatol 1999; 16:430-5. [PMID: 10632938 DOI: 10.1046/j.1525-1470.1999.00111.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The palmoplantar keratodermas (PPK) are a heterogeneous group of conditions, most frequently inherited in autosomal dominant fashion. A few are well-documented autosomal recessive disorders; other are acquired in association with certain metabolic disorders and malignancies. Recently different point mutations of the keratin 9 (K9) gene have been identified in unrelated families with epidermolytic palmoplantar keratoderma (EPPK). We investigated two unrelated Hungarian families with EPPK. In one, a mutation consisting of a G-->A transversion at nucleotide position 551, which changes codon arginine to glutamine at codon 162 (R162Q), was found. In the other, we observed a novel mutation at nucleotide position 571, which changes codon 169 lysine (AAG) into the amber stop codon (TAG) (K169X). Each found mutation is present in the highly conserved coil 1A region of the rod domain. In the case of a stop codon type of mutation, it is questionable whether it really results in a clinical phenotype, but segregation analysis revealed cosegregation of the PPK phenotype with the mutant allele.
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Affiliation(s)
- S Szalai
- Department of Dermatology, Heim Pál Children's Hospital, Budapest, Hungary
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Kobayashi S, Kore-eda S, Tanaka T. Demonstration of the pathogenic effect of point mutated keratin 9 in vivo. FEBS Lett 1999; 447:39-43. [PMID: 10218578 DOI: 10.1016/s0014-5793(99)00233-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A wild type keratin 9 (K9) cDNA and a point mutated keratin 9 cDNA were injected subcutaneously into mouse skin. The hemagglutinin tag staining of the wild type K9 cDNA injected specimens mainly showed a homogeneous pattern, whereas the point mutated K9 cDNA injected specimens mainly showed a granular pattern in the suprabasal cells. Double staining of K9 and the endogenous keratin revealed the incorporation of de novo synthesized K9 into the keratin network. These results demonstrate that (1) a naked DNA transfection into mouse skin can detect the pathogenic changes of point mutated keratin in vivo and (2) the keratin 9 mutation disrupts the keratin network formation in the suprabasal cells in vivo.
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Affiliation(s)
- S Kobayashi
- Department of Dermatology, Graduate School of Medicine, Kyoto University, Japan
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Coleman CM, Munro CS, Smith FJ, Uitto J, McLean WH. Epidermolytic palmoplantar keratoderma due to a novel type of keratin mutation, a 3-bp insertion in the keratin 9 helix termination motif. Br J Dermatol 1999; 140:486-90. [PMID: 10233272 DOI: 10.1046/j.1365-2133.1999.02715.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant genodermatosis characterized by diffuse keratoderma, typically with an erythematous border. Histologically, palmoplantar epidermis shows suprabasal cytolysis and ultrastructurally, tonofilament aggregation with overlying epidermolytic hyperkeratosis. Mutations in the KRT9 gene, encoding keratin 9 (K9), a cytoskeletal protein expressed exclusively in suprabasal keratinocytes of palmoplantar epidermis, have been reported to cause EPPK. To date, all KRT9 defects reported in EPPK have been missense mutations in exon 1, which encodes the start of the alpha-helical rod domain. However, based on studies of other keratin disorders, it was postulated that mutations at the other end of the rod domain might also produce the EPPK phenotype. Here, we report the first mutation in the 2B domain of KRT9, 1362ins3, leading to an insertion of histidine in the helix termination motif of the K9 polypeptide. Insertional mutations have not been previously described in keratins. The phenotype of this case is similar to EPPK caused by 1A domain mutations, demonstrating that mutations in either of the helix boundary motif sequences of K9 are detrimental to keratin function and keratinocyte structure.
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Affiliation(s)
- C M Coleman
- Epithelial Genetics Group, Department of Dermatology, Jefferson Medical College, 233 South 10th Street, Philadelphia, PA 19107, USA
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Covello SP, Irvine AD, McKenna KE, Munro CS, Nevin NC, Smith FJ, Uitto J, McLean WH. Mutations in keratin K9 in kindreds with epidermolytic palmoplantar keratoderma and epidemiology in Northern Ireland. J Invest Dermatol 1998; 111:1207-9. [PMID: 9856842 DOI: 10.1046/j.1523-1747.1998.00445.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Epidermolytic palmoplantar keratoderma (EPPK, MIM #144200) is an autosomal dominant disorder in which hyperkeratosis confined to the palms and soles is characterized histologically by cytolysis of suprabasal keratinocytes. Mutations in the keratin 9 gene (KRT9), a type 1 keratin expressed exclusively in the suprabasal keratinocytes of palmoplantar epidermis, have previously been demonstrated in this disorder. Here, we have studied four Northern Irish kindreds presenting with EPPK. By direct sequencing of polymerase chain reaction products, heterozygous missense mutations in exon 1 of KRT9 were detected in all the families. These included a novel mutation M156T; as well as M156V in two kindreds; and R162Q in the remaining family. All mutations were confirmed by reverse strand sequencing and restriction enzyme analysis. The point prevalence of EPPK in Northern Ireland was found to be 4.4 per 100,000. To date, all reported EPPK mutations occur in the helix initiation motif at the start of the central coiled-coil rod domain of K9.
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Affiliation(s)
- S P Covello
- Epithelial Genetics Group, Department of Dermatology and Cutaneous Biology, Jefferson Medical College, Philadelphia, Pennsylvania, USA
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Ammirati CT, Mallory SB. The major inherited disorders of cornification. New advances in pathogenesis. Dermatol Clin 1998; 16:497-508. [PMID: 9704207 DOI: 10.1016/s0733-8635(05)70248-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
This article provides a synopsis of the major (most common) inherited disorders of cornification. It also reviews the recent advances that have been made for each disorder and their practical applications.
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Affiliation(s)
- C T Ammirati
- Department of Internal Medicine, Washington University, St. Louis, Missouri, USA
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