RESUMEN
Congenital skin disorders are a class of complex genetic diseases that are difficult to diagnose and treat. We developed trio whole-exome sequencing-plus (WES-plus) for detecting de novo mutations and evaluated the use of traditional Chinese medicine (TCM) for treating congenital skin disorders. In this study, we successively performed panel-based next-generation sequencing (NGS) and Trio WES-plus in a child with frequent large blisters. Panel-based NGS revealed no pathogenic mutations. Trio WES-plus for resequencing based on cutaneous keratosis of the palms and feet detected a missense mutation (c.1436T>A, p.Ile479Asn) in the coding region of KRT1 in the child but not in his parents. Following prenatal diagnosis, a healthy second baby without the mutation was born. The disease symptoms of epidermolytic palmoplantar keratoderma (EPPK) application were improved by TCM and Western medicine. Our study revealed the pathogenicity of a de novo mutation in human KRT1, which expands the mutation spectrum of EPPK. Trio WES-plus is useful for diagnosing genetic diseases and providing genetic guidance from prenatal diagnosis to treatment.
Asunto(s)
Queratodermia Palmoplantar Epidermolítica , Niño , Lactante , Embarazo , Femenino , Humanos , Queratodermia Palmoplantar Epidermolítica/diagnóstico , Queratodermia Palmoplantar Epidermolítica/genética , Queratodermia Palmoplantar Epidermolítica/patología , Secuenciación del Exoma , Mutación Missense/genética , Mutación , Diagnóstico Prenatal , Linaje , Queratina-1/genéticaAsunto(s)
Queratodermia Palmoplantar Epidermolítica , Queratodermia Palmoplantar , Humanos , Pueblos del Este de Asia , Queratina-9/genética , Queratinas , Queratodermia Palmoplantar/diagnóstico , Queratodermia Palmoplantar/genética , Queratodermia Palmoplantar Epidermolítica/diagnóstico , Queratodermia Palmoplantar Epidermolítica/genética , Mutación , Mutación Missense , Linaje , Eliminación de SecuenciaRESUMEN
Epidermolytic palmoplantar keratoderma (EPPK), a highly penetrant autosomal dominant genodermatosis, is characterized by diffuse keratoses on palmplantar epidermis. The keratin 9 gene (KRT9) is responsible for EPPK. To date, phenotypic therapy is the primary treatment for EPPK. Because KRT9 pairs with a type II keratin-binding partner to function in epidermis, identifying the interaction partner is an essential first step in revealing EPPK pathogenesis and its fundamental treatment. In this study, we proved that keratin 6C (KRT6C) is a probable hereterodimer partner for KRT9. In silico model for KRT6C/KRT9 shows a typical coiled-coil structure in their 2B domains. Proteomics analysis shows that KRT6C/KRT9 pair is in a densely connected protein-protein interaction network, where proteins participate jointly in regulating cytoskeleton organization and keratinization. This study shows that co-immunoprecipitation coupled with mass spectroscopy and proteomics analysis provide a sensitive approach, which compensates for inevitable inadequacies of anti-keratin 6C antibody and helps discover the probable hereterodimer partner KRT6C for KRT9. The acknowledgement of KRT6C/KRT9 pairwise relationship may help re-classify EPPK and PC-K6c (a milder form of pachyonychia congenita, caused by KRT6C) as a group of hereditary defects at a molecular-based level, and lay foundation for deciphering the keratin network contributing to EPPK and PC-K6c. SIGNIFICANCE OF THE STUDY: What is already known about this topic? KRT9 and KRT6C are disease-causing factors for epidermolytic palmoplantar keratoderma (EPPK) and a milder form of pachyonychia congenita (PC-K6c), respectively. EPPK and PC-K6c have some symptom similarities. Keratins are the major structural proteins in epithelial cells. Each of the type I keratin is matched by a particular type II keratin to assemble a coiled-coil heterodimer. The hereterodimer partner for KRT9 is unknown. What does this study add? We discovered and proved that KRT6C is a probable hereterodimer partner for KRT9 in palmplantar epidermis in a native endogenous environment by using co-immunoprecipitation coupled with mass spectroscopy and proteomics analysis, etc. The proteomics analysis shows that KRT6C/KRT9 keratin pair is in a densely connected protein-protein interaction network, where proteins participate jointly in regulating intermediate filament-based cytoskeleton organization and keratinization processes. What are the implications of this work? The new understanding of probable KRT6C/KRT9 pairwise correlation may help re-classify the genetic cutaneous disorders EPPK and PC-K6c as a group of hereditary defects at a molecular-based level, and lay foundation for pathogenic mechanism research in EPPK and PC-K6c. The densely related network components derived from the proteomic data using Metascape in the study and pairwise regulation fashion of specific keratin pairs should attract more attention in the further explorations when investigators concern the physiological functions of keratins and the pathogenesis of related skin diseases.
Asunto(s)
Queratodermia Palmoplantar Epidermolítica , Paquioniquia Congénita , Humanos , Queratodermia Palmoplantar Epidermolítica/genética , Queratodermia Palmoplantar Epidermolítica/patología , Proteómica , Epidermis , Queratinas/genética , Queratinas Tipo II/genética , Mutación , Linaje , Queratina-9/genéticaRESUMEN
BACKGROUND: Epidermolytic palmoplantar keratoderma (EPPK) is characterized by diffuse hyperkeratosis affecting palms and soles with suprabasal epidermolysis or vacuolar degeneration histopathologically. The disorder is caused by heterozygous mutations in KRT9 or KRT1. Dominant-negative mutations in KRT1 could also result in epidermolytic ichthyosis with EPPK, a more severe entity affecting the entire body. OBJECTIVE: To investigate the genetic basis and pathogenesis of two unrelated patients with EPPK and knuckle pads, both of whom were born to consanguineous parents of Chinese origin. METHODS: Next-generation sequencing was applied to the two patients using genomic DNA extracted from peripheral blood. Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR), immunofluorescence (IF) staining and Western blot (WB) were employed to evaluate mRNA and protein expression level. Ultrastructural changes of skin lesion were analysed using transmission electron microscopy. RESULTS: Two novel homozygous mutations, c.457C>T (p.Gln153*) and c.33C>G (p.Tyr11*) in KRT1, were identified in patients 1 and 2 respectively. The nonsense mutations were predicted to result in nonsense-mediated mRNA decay and absence of keratin 1, which was confirmed in the skin lesions from patient 1. Upregulated keratin 2 was detected both in the affected and unaffected skin samples from patient 1, while the protein abundance and distribution pattern of keratin 10 remained unchanged. An aberrant and clumped staining pattern of keratin 9 was noted in the palmar skin of patient 1. CONCLUSIONS: Homozygous 'knockout' mutations in KRT1 resulted in EPPK with knuckle pads rather than epidermolytic ichthyosis. We speculated that sparing of non-acral skin might be due to compensatory effect of keratin 2 upregulation by forming heterodimer with keratin 10.
Asunto(s)
Hiperqueratosis Epidermolítica , Queratina-1 , Queratodermia Palmoplantar Epidermolítica , Queratodermia Palmoplantar , Paniculitis , Codón sin Sentido , Humanos , Hiperqueratosis Epidermolítica/genética , Queratina-1/genética , Queratina-10/genética , Queratina-2/genética , Queratinas/genética , Queratodermia Palmoplantar/genética , Queratodermia Palmoplantar Epidermolítica/genética , Queratodermia Palmoplantar Epidermolítica/patología , Mutación , LinajeRESUMEN
Keratin intermediate filaments constitute the primary cytoskeletal component of epithelial cells. Numerous human disease phenotypes related to keratin mutation remain mechanistically elusive. Our recent crystal structures of the helix 1B heterotetramer from keratin 1/10 enabled further investigation of the effect of pathologic 1B domain mutations on keratin structure. We used our highest resolution keratin 1B structure as a template for homology-modeling the 1B heterotetramers of keratin 5/14 (associated with blistering skin disorders), keratin 8/18 (associated with liver disease), and keratin 74/28 (associated with hair disorder). Each structure was examined for the molecular alterations caused by incorporating pathogenic 1B keratin mutations. Structural modeling indicated keratin 1B mutations can harm the heterodimer interface (R265PK5, L311RK5, R211PK14, I150VK18), the tetramer interface (F231LK1, F274SK74), or higher-order interactions needed for mature filament formation (S233LK1, L311RK5, Q169EK8, H128LK18). The biochemical changes included altered hydrophobic and electrostatic interactions, and altered surface charge, hydrophobicity or contour. Together, these findings advance the genotype-structurotype-phenotype correlation for keratin-based human diseases.
Asunto(s)
Queratina-1/química , Modelos Moleculares , Humanos , Queratina-1/genética , Queratodermia Palmoplantar Epidermolítica/genética , Hepatopatías/genética , Mutación Missense , Estructura Cuaternaria de ProteínaRESUMEN
We report a 6-year-old girl showing epidermolytic ichthyosis/epidermolytic hyperkeratosis (EI/EH). Targeted Next Generation Sequencing revealed a de novo, previously unidentified KRT1 mutation. The findings of this study expands the clinical and spectrum and genotype-phenotype correlation associated with EI/EH.
Asunto(s)
Hiperqueratosis Epidermolítica/genética , Queratina-1/genética , Queratodermia Palmoplantar Epidermolítica/genética , Mutación , Niño , Femenino , Pie/patología , Mano/patología , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Hiperqueratosis Epidermolítica/patología , Queratodermia Palmoplantar Epidermolítica/patologíaRESUMEN
BACKGROUND: Annular epidermolytic ichthyosis (AEI) is a rare autosomal dominant ichthyosis that was recently described in 10 separate families in the English literature. There are no reports on the phenotypic heterogeneity of AEI. OBJECTIVES: We investigated, for the first time, a large Chinese AEI pedigree exhibiting interfamilial phenotypic heterogeneity. MATERIALS AND METHODS: We collected clinical data and DNA from the members of the family, and skin lesions were obtained from two patients with different phenotypes. Skin imaging examinations were performed. Whole-exome sequencing (WES) and Sanger sequencing were used to detect gene mutations. RESULTS: The characteristic features of granular layer degeneration in the two biopsies were verified via histological methods. The missense mutation c.1436T > C in KRT1 was detected in all nine patients. CONCLUSION: This study demonstrates that AEI may present with different clinical phenotypes and that mutation analysis for suspected cases is necessary to obtain a precise diagnosis.
Asunto(s)
Hiperqueratosis Epidermolítica/diagnóstico por imagen , Hiperqueratosis Epidermolítica/genética , Queratina-1/genética , Queratodermia Palmoplantar Epidermolítica/genética , Fenotipo , Adulto , Biopsia , Preescolar , Análisis Mutacional de ADN , Dermoscopía , Femenino , Humanos , Hiperqueratosis Epidermolítica/complicaciones , Hiperqueratosis Epidermolítica/patología , Queratina-1/metabolismo , Queratodermia Palmoplantar Epidermolítica/complicaciones , Masculino , Microscopía Confocal , Mutación Missense , Linaje , Piel/patología , Secuenciación del ExomaRESUMEN
Inherited monogenic palmoplantar keratodermas are a heterogeneous group of conditions characterised by persistent epidermal thickening of the palmoplantar skin. Palmoplantar keratodermas are grouped depending on the morphology of the keratoderma into diffuse, focal/striate or papular/punctate. Some palmoplantar keratodermas just affect the skin of the palms and soles and others have associated syndromic features which include changes in hair, teeth, nails, hearing loss or cardiomyopathy. Next generation sequencing has helped discover genes involved in many of these conditions and has led to reclassification of some palmoplantar keratodermas. In this review, we discuss the diagnostic features of palmoplantar keratodermas and management options.
Asunto(s)
Queratodermia Palmoplantar/diagnóstico , Queratodermia Palmoplantar/genética , Humanos , Queratodermia Palmoplantar/terapia , Queratodermia Palmoplantar Epidermolítica/diagnóstico , Queratodermia Palmoplantar Epidermolítica/genética , Queratodermia Palmoplantar Epidermolítica/terapia , Mutación , FenotipoRESUMEN
BACKGROUND: Epidermolytic palmoplantar keratoderma (EPPK) is characterized by hyperkeratotic lesions on palms and soles. The disorder is caused by mutations of keratin 9 (KRT9) or KRT1 gene. METHODS: Epidermolytic palmoplantar keratoderma was diagnosed by physical examination and histopathological analysis in a five-generation Chinese family. Mutation was screened by Sanger sequencing. The palmar expression of multiple cytokeratins were analyzed by tape-stripping and Real-time PCR. Literatures of EPPK with additional symptoms were reviewed. RESULTS: Affected family members showed diffuse palmoplantar keratosis, with knuckle pads, friction-related lesions and a novel additional symptom of palmar constriction. A heterozygous mutation of c.T491C (p.L164P) of KRT9 was found within the helix initiation motif. The hydrophobic effect was decreased and the initiation of coiled-coil conformation was delayed. The KRT16/KRT6 expression were significantly increased in the patients, especially on the right, indicating activation of stress-response and wound-healing cytokeratins. There were also increased KRT9/KRT2, unchanged KRT10/KRT1, and undetectable KRT14/KRT5 expression. The genetic and phenotypic heterogeneity of EPPK with additional symptoms were summarized by literature review. CONCLUSION: The p.L164P mutation of KRT9 caused EPPK with a novel symptom of palmar constriction. The expression of multiple cytokeratins was altered in EPPK patients.
Asunto(s)
Pueblo Asiatico/genética , Queratina-9/genética , Queratodermia Palmoplantar Epidermolítica/genética , Queratodermia Palmoplantar Epidermolítica/patología , Mutación , Estudios de Casos y Controles , Femenino , Estudios de Seguimiento , Heterocigoto , Humanos , Lactante , Masculino , LinajeRESUMEN
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.
Asunto(s)
Pueblo Asiatico/genética , Queratina-9/genética , Queratodermia Palmoplantar Epidermolítica/genética , Adulto , China , Análisis Mutacional de ADN , Heterocigoto , Humanos , Queratodermia Palmoplantar Epidermolítica/patología , Masculino , Mutación Missense , Linaje , Fenotipo , Piel/patologíaRESUMEN
No disponible
Asunto(s)
Humanos , Masculino , Preescolar , Queratodermia Palmoplantar Epidermolítica/diagnóstico , Eritema/diagnóstico , Queratodermia Palmoplantar Epidermolítica/patología , ATPasas de Translocación de Protón Vacuolares , Queratinocitos , Retinoides/administración & dosificaciónRESUMEN
BACKGROUND/AIMS: Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant genodermatosis. It is characterized by diffuse yellow keratoses on the palmoplantar epidermis, with an erythematous border. The keratin 9 gene (KRT9) and less frequently the keratin 1 gene (KRT1) are responsible for EPPK. This study aims to identify and analyse genetic defects responsible for EPPK in a Han Chinese pedigree. METHODS: A four-generation Han Chinese pedigree containing five individuals affected with EPPK was recruited. Exome sequencing, Sanger sequencing, and bioinformatics tools were conducted to identify the mutation in this pedigree. HaCaT cells were transfected with either wild-type or mutated KRT9. Confocal laser immunofluorescence assay, imaging processing, and statistical analysis were performed to evaluate wild-type and mutant KRT9 groups. RESULTS: A novel heterozygous c.1369C>T transition (p.Leu457Phe) in exon 6 of the KRT9 gene was identified in four patients. It co-segregated with the disorder in the family. Functional analysis showed that withdrawal of the filament network from the cell periphery and particle formation were present in about 10% of Leu457Phe-transfected HaCaT cells, while approximately 3% of cells transfected with wild-type KRT9 showed this phenotype. The particles in mutant group were larger than that in wild-type group (P-value < 0.05). CONCLUSION: The variant may be the disease-causing missense mutation and produce dominant negative effects by interrupting keratin network formation. This study indicates the pathogenic role of the KRT9 gene mutation in this pedigree with EPPK, and may be helpful in genetic counseling, prenatal diagnosis and gene-targeted therapies of EPPK.
Asunto(s)
Queratina-9/genética , Queratodermia Palmoplantar Epidermolítica/genética , Mutación Missense , Adulto , Anciano , Secuencia de Aminoácidos , Animales , Pueblo Asiatico/genética , Línea Celular , Femenino , Humanos , Queratina-9/química , Masculino , Persona de Mediana Edad , Linaje , Análisis de SecuenciaRESUMEN
BACKGROUND: Mutations of keratin 9 (KRT9) gene is a hot research area of epidermolytic palmoplantar keratoderma (EPPK). AIMS: To identify the genes caused the EPPK of a Chinese family. PATIENTS/METHODS: Three cases of lesions were collected for pathological examination. Genomic DNA was extracted from peripheral blood samples of six patients and five healthy individuals and 100 unrelated individuals. Polymerase chain reaction (PCR) was used to amplify exons 1 of KRT9 gene. PCR products were sequenced to identify potential mutations. RESULTS: The lesion pathology of the proband and two ill relatives diagnosed EPPK. A new heterozygous missense mutation (488G>T) was identified in the 488 site of exon 1 of KRT9 gene in all six patients, which resulted in substitution of thymine for guanine, and substitution of leucine acid for arginine acid at position 163 of the KRT9 protein. The same mutation was not found in the five healthy individuals of the family and 100 unrelated individuals. CONCLUSIONS: The new heterozygous missense mutation (488G>T) of KRT9 gene is probably the cause of EPPK in this Chinese family.