[show abstract][hide abstract] ABSTRACT: Dystrophic epidermolysis bullosa (DEB) is a group of heritable bullous skin disorders caused by mutations in the COL7A1 gene. One of the most severe forms of DEB is the severe generalized [recessive dystrophic epidermolysis bullosa (RDEB-SG)] subtype, which is inherited in an autosomal recessive manner. This subtype is most often due to COL7A1 mutations resulting in a premature termination codon on both alleles. We report here, the molecular investigation of 15 patients belonging to 14 nuclear families from the city of Sfax in Southern Tunisia, with clinical features of RDEB-SG complicated by squamous cell carcinoma in 3 patients. We identified two novel mutations, p.Val769LeufsX1 and p.Ala2297SerfsX91, in addition to one previously reported mutation (p.Arg2063Trp). The p.Val769LeufsX1 mutation was shared by 11 families and haplotype analysis indicated that it is a founder mutation. The p.Ala2297SerfsX91 mutation was a private mutation found in only one family. Together with the previously described recurrent mutations in Tunisia, screening for the founder p.Val769LeufsX1 mutation should provide a rapid molecular diagnosis tool for mutation screening in RDEB patients from Southern Tunisia and possibly from other Mediterranean populations sharing the same genetic background.
Archives for Dermatological Research 10/2013; · 2.71 Impact Factor
[show abstract][hide abstract] ABSTRACT: Epidermolysis bullosa simplex with migratory circinate erythema (EBS-MCE) is a rare EBS subtype characterised by migratory blistering lesions that resolve with brownish pigmentation. It is caused by a recurrent readthrough mutation, c.1649delG, in the tail of keratin 5. Here, we report a child with EBS-MCE and investigated the immunologic mechanisms underlying the migratory lesions in this patient. A skin biopsy from the patient from an active border of an erythematous lesion was used for the immunohistochemical characterisation of the inflammatory infiltrate and for TUNEL assay to detect apoptotic cells. We found abundant CD4+ and CD8+ T lymphocytes infiltrating the papillary dermis and lining the dermal-epidermal junction. A number of these cells expressed the activation marker CD69. CD83+ dendritic cells were present both in the epidermis and papillary dermis. Finally, TUNEL staining showed apop-tosis of basal and suprabasal keratinocytes. These findings suggest a critical role of the cellular immunity in determining the EBS-MCE phenotype.
[show abstract][hide abstract] ABSTRACT: Here we report a lethal case of Netherton syndrome presenting with neurologic complications, hypernatremic dehydration, failure to thrive, and episodes of sepsis. Molecular analysis of the serine protease inhibitor Kazal-type 5 gene identified a homozygous mutation (c.1111C>T, p.Arg371X). This case highlights the importance of early diagnosis to start appropriate care in a timely fashion and prevent disease complications.
[show abstract][hide abstract] ABSTRACT: Background: Individuals with Kindler syndrome (KS) have loss-of-function mutations in the FERMT1 gene that encodes the focal adhesion component kindlin-1. The major clinical manifestation of KS patients is the epidermal atrophy (premature skin aging). This phenotypic feature is thought to be related to the decreased proliferation rate of KS keratinocytes, nevertheless molecular mediators of such abnormal behaviour have not been fully elucidated. Methods: We serially cultivated nine primary KS keratinocyte strains until senescence and determined their lifespan and colony forming efficiency (CFE) at each serial passage. The expression of molecular markers of stemness and cellular senescence were investigated by immunoblotting using cell extracts of primary keratinocyte cultures from KS and healthy donors. In another set of experiments, kindlin-1 downregulation in normal keratinocytes was obtained by siRNA technology. Results: We found that KS keratinocytes exhibited a precocious senescence and strongly reduced clonogenic potential. Moreover, KS cultures showed a strikingly increased percentage of aborted colonies (paraclones) already at early passages indicating an early depletion of stem cells. Immunoblotting analysis of KS keratinocyte extracts showed reduced levels of the stemness markers p63 and Bmi-1, upregulation of p16 and scant amounts of hypophosphorylated Rb protein, which indicated cell cycle-arrested status. Treatment of normal human primary keratinocytes with siRNA targeting kindlin-1 proved that its deficiency was directly responsible for p63, Bmi-1 and pRb downregulation and p16 induction. Conclusions: Our data directly imply kindlin-1 in preventing premature senescence of keratinocytes.
British Journal of Dermatology 12/2012; · 3.76 Impact Factor
[show abstract][hide abstract] ABSTRACT: Background Severe skin diseases, such as epidermolysis bullosa (EB), may have a strong impact not only on patients but also on caregivers. A specific questionnaire evaluating the family impact of dermatological conditions has been created, the Family Dermatology Life Quality Index (FDLQI), but it has not yet been translated in Italian and validated. Objective To evaluate the burden of recessive dystrophic EB on family caregivers, using for the first time the Italian version of the FDLQI, and to validate the instrument. Methods Patients with recessive dystrophic EB participated in a postal survey enquiring about the burden of EB on family caregivers. They completed the Family Strain Questionnaire and the FDLQI and they marked on a silhouette of the human body the skin lesion distribution. Results Data on 62 family caregivers were collected. The overall mean FDLQI score was 9.8. The most frequently reported problems were the time spent on looking after the patient, emotional distress, physical well-being, and increased household expenditure. FDLQI scores were higher in family caregivers of patients between 10 and 20 years. The Italian FDLQI showed high internal consistency, construct and convergent validity. Factor analysis revealed the presence of one factor structure underlying the items of the FDLQI, which explained 51.5% of the total variance, very similar to the original questionnaire (55.8%). Conclusion The Italian version of the FDLQI seems to be a useful tool to evaluate the impact of EB on family caregivers. Further studies are necessary to test this instrument in other dermatological conditions.
Journal of the European Academy of Dermatology and Venereology 08/2012; · 2.69 Impact Factor
[show abstract][hide abstract] ABSTRACT: Netherton syndrome (NS) is a rare, life-threatening ichthyosiform syndrome caused by recessive loss-of-function mutations in SPINK5 gene encoding lymphoepithelial Kazal-type-related inhibitor (LEKTI), a serine protease inhibitor expressed in the most differentiated epidermal layers and crucial for skin barrier function. We report the functional characterization of a previously unrecognized synonymous variant, c.891C>T (p.Cys297Cys), identified in the SPINK5 exon 11 of an NS patient. We demonstrated that the c.891C>T mutation is associated with abnormal pre-mRNA splicing and residual LEKTI expression in the patient's keratinocytes. Subsequent minigene splicing assays and in silico predictions confirmed the direct role of the synonymous mutation in inhibiting exon 11 inclusion by a mechanism that involves the activity of exonic regulatory sequences, namely splicing enhancer and silencer. However, this deleterious effect was not complete and a residual amount of normal mRNA and LEKTI protein could be detected, correlating with the relatively mild patient's phenotype. Our study represents the first identification of a disease-causing SPINK5 mutation that alters splicing without affecting canonical splice sites.
Journal of Human Genetics 03/2012; 57(5):311-5. · 2.37 Impact Factor
[show abstract][hide abstract] ABSTRACT: Mutations in the FERMT1 gene (also known as KIND1), encoding the focal adhesion protein kindlin-1, underlie the Kindler syndrome (KS), an autosomal recessive skin disorder with an intriguing progressive phenotype comprising skin blistering, photosensitivity, progressive poikiloderma with extensive skin atrophy, and propensity to skin cancer. Herein we review the clinical and genetic data of 62 patients, and delineate the natural history of the disorder, for example, age at onset of symptoms, or risk of malignancy. Although most mutations are predicted to lead to premature termination of translation, and to loss of kindlin-1 function, significant clinical variability is observed among patients. There is an association of FERMT1 missense and in-frame deletion mutations with milder disease phenotypes, and later onset of complications. Nevertheless, the clinical variability is not fully explained by genotype-phenotype correlations. Environmental factors and yet unidentified modifiers may play a role. Better understanding of the molecular pathogenesis of KS should enable the development of prevention strategies for disease complications.
Human Mutation 09/2011; 32(11):1204-12. · 5.21 Impact Factor
[show abstract][hide abstract] ABSTRACT: The 14-3-3 protein family controls diverse biochemical processes through interaction with phosphorylated consensus sequences in protein targets. Its epithelial specific member, 14-3-3σ, also known as stratifin, is highly expressed in differentiated keratinocytes, and in vitro evidence indicates that 14-3-3σ downregulation leads to keratinocyte immortalization. To define the role of 14-3-3σ in skin homeostasis in vivo, we generated transgenic mice overexpressing 14-3-3σ in proliferating keratinocytes of the epidermis and hair follicle. Transgenic animals show decreased epidermal thickness and hair follicle density associated with reduced number of proliferating keratinocytes and decreased levels of keratins 14, 5, and 15. Primary keratinocytes isolated from transgenic mice manifest reduced proliferation and migration. Moreover, clonogenicity assessment and label-retaining analysis reveal a reduction in keratinocyte progenitor cell number in transgenic mice. Response to IGF-1 is strongly impaired in cultured transgenic keratinocytes compared with wild-type cells. Consistently, activation of phosphoinositol 3-kinase (PI3K), AKT, and Rac1, all IGF-1 downstream mediators, is reduced. Our results demonstrate that 14-3-3σ controls the in vivo epidermal proliferation-differentiation switch by reducing proliferative potential and forcing keratinocytes to exit the cell cycle, and that this effect associates with inhibition of the IGF-1 pathway.
Journal of Investigative Dermatology 06/2011; 131(9):1821-9. · 6.19 Impact Factor
[show abstract][hide abstract] ABSTRACT: Basal epidermolysis bullosa simplex (EBS) is a group of blistering genodermatoses mostly caused by mutations in the keratin genes, KRT5 and KRT14. Recessive mutations represent about 5% of all EBS mutations, being common and specific in populations with high consanguinity, where affected patients show severe phenotypes.
To accomplish the first mutational analysis in patients of Spanish origin with EBS and to delineate a comprehensive genotype-phenotype correlation.
Twenty-one EBS families were analysed. Immunofluorescence mapping at the dermoepidermal junction level was performed on skin biopsies from patients. Mutation screening of the entire coding sequences of KRT5 and KRT14 in genomic DNA was assessed by polymerase chain reaction and direct sequencing.
KRT5 or KRT14 causative mutations were identified in 18 of the 21 EBS families. A total of 14 different mutations were disclosed, of which 12 were dominant missense mutations and two truncating recessive mutations. Five of the 14 mutations were novel including three dominant in KRT5 (p.V186E, p.T321P and p.A428T) and two recessive in KRT14 (p.K116X and p.K250RfsX8). The two patients with EBS carrying homozygous recessive mutations were affected by severe phenotypes and belonged to consanguineous families. All five families with the EBS Dowling-Meara subtype carried recurrent mutations affecting the highly conserved ends of the α-helical rod domain of K5 and K14. The seven mutations associated with the localized EBS subtype were widely distributed along the KRT5 and KRT14 genes. Two families with mottled pigmentation carried the P25L mutation in KRT5, commonly associated with this subtype.
This study further confirms the genotype-phenotype correlation established for EBS in other ethnic groups, and is the first in a Mediterranean country (excluding Israel). This study adds two novel recessive mutations to the worldwide record to date, which includes a total of 14 mutations. As in previous reports, the recessive mutations resulted in a lack of keratin K14, giving rise to a generalized and severe presentation.
British Journal of Dermatology 05/2011; 165(3):683-92. · 3.76 Impact Factor
[show abstract][hide abstract] ABSTRACT: Dystrophic epidermolysis bullosa pruriginosa (DEB-Pr) (OMIM 604129) represents a distinct variant within the DEB clinical spectrum. It is characterized by intense pruritus and distinctive nodular prurigo-like and/or hypertrophic lichenoid lesions mainly localized on the arms, legs and upper shoulders. DEB-Pr is caused by either dominant (DDEB-Pr) or recessive mutations in the COL7A1 gene encoding type VII collagen (COLVII). The full spectrum of COL7A1 mutations in DEB-Pr remains elusive and the genotype-phenotype correlation is largely incomplete. Here, we report and functionally characterize a previously unrecognized translationally silent exonic COL7A1 mutation that results in skipping of exon 87 and is associated with DDEB-Pr phenotypes in several members of three apparently unrelated Danish families. A haplotype segregation study suggested a common ancestor in these kindred. Functional splicing analysis of the mutant exon by a COL7A1 minigene construct and computational prediction for splicing regulatory cis-sequences prove that the mutation alters the activity of an exonic splicing enhancer (ESE) critical for exon inclusion. These findings substantiate for the first time the involvement of an ESE mutation in the pathogenesis of DEB and have implications for genetic counselling of Danish families with DDEB.
British Journal of Dermatology 05/2011; 165(3):678-82. · 3.76 Impact Factor
[show abstract][hide abstract] ABSTRACT: The SKI protein is a transcriptional coregulator over-expressed in melanoma. Experimentally induced down-regulation of SKI inhibits melanoma cell growth in vitro and in vivo. MicroRNAs (miRNAs) negatively modulate gene expression and have been implicated in oncogenesis. We previously showed that microRNA-155 (miR-155) is down-regulated in melanoma cells as compared with normal melanocytes and that its ectopic expression impairs proliferation and induces apoptosis. Here, we investigated whether miR-155 could mediate melanoma growth inhibition via SKI gene silencing. Luciferase reporter assays demonstrated that miR-155 interacted with SKI 3'UTR and impaired gene expression. Transfection of melanoma cells with miR-155 reduced SKI levels, while inhibition of endogenous miR-155 up-regulated SKI expression. Specifically designed small interfering RNAs reduced SKI expression and inhibited proliferation. However, melanoma cells over-expressing a 3'UTR-deleted SKI were still susceptible to the antiproliferative effect of miR-155. Our data demonstrate for the first time that SKI is a target of miR-155 in melanoma. However, impairment of SKI expression is not the leading mechanism involved in the growth-suppressive effect of miR-155 found in this malignancy.
[show abstract][hide abstract] ABSTRACT: Dystrophic epidermolysis bullosa (DEB) is a rare, clinically heterogeneous, blistering genodermatosis inherited as either autosomal dominant or recessive trait. All DEB forms are caused by mutations in the COL7A1 gene, which encodes for type VII collagen, the major component of the anchoring fibrils ensuring epithelial-mesenchymal adhesion. Major determinants of clinical heterogeneity in DEB are COL7A1 mutation types and their consequences at mRNA and protein levels; nevertheless, siblings with the same genetic alterations can manifest highly variable clinical signs. Here, we report novel compound heterozygous recessive COL7A1 missense mutations in 2 siblings presenting different DEB clinical subtypes. Our findings document the rare occurrence of recessive inheritance for the nails only DEB variant and emphasize the role of acquired phenotype-modifying factors in DEB pruriginosa pathogenesis.
[show abstract][hide abstract] ABSTRACT: Epidermolysis bullosa is a rare, inherited group of disorders characterized by blistering of the skin following friction or mechanical trauma. The aim of this study was to assess the family burden of epidermolysis bullosa in children aged 0-7 years. A postal survey was conducted. The perceived severity of the disease was evaluated by the caregivers, using the Patient Global Assessment 5-point scale. The caregiver received the Family Strain Questionnaire and the 12-item General Health Questionnaire to assess the probable presence of depression/anxiety. A single-item analysis was also performed for questions related to the burden of disease. Forty-two families were invited to participate. Data from 28 young patients and their caregivers were analysed (response rate 66.7%). The family burden increased with increasing caregiver's perceived disease severity, with increasing patient's body surface involved, and if parents had depression/anxiety, reaching statistical significance in several Family Strain Questionnaire scales. The family burden due to epidermolysis bullosa is very high independent of disease type/subtype.
[show abstract][hide abstract] ABSTRACT: The case of a male neonate of 41 weeks' gestation who developed blistering of the skin immediately after birth is described. His parents were consanguineous Tunisians. Electron microscopy of a cutaneous biopsy showed skin cleavage within the lamina lucida and immunoepitope mapping revealed a complete absence of laminin 332 expression. These findings referred to the diagnosis of junctional epidermolysis bullosa (JEB) Herlitz type. The neonate died at 3 months of age due to sepsis. Molecular analysis of laminin 332 chain genes LAMA3, LAMB3 and LAMC2 disclosed a novel homozygous nonsense mutation in LAMA3 (p.Y955X). Clinical and laboratory analyses are essential for the diagnosis of JEB subtypes, and molecular analysis screening is crucial to manage a new pregnancy in families with suspected cases of JEB.
[show abstract][hide abstract] ABSTRACT: The development of DNA technology and improved knowledge of the structure and function of the human genome have led to the identification of the causative genes responsible for the different forms of epidermolysis bullosa (EB) and provided the opportunity to determine the precise location and type of mutations present in EB patients, allowing diagnosis of this disease at the level of the defective gene itself. The large genetic heterogeneity of EB, however, precludes the direct use of molecular testing for EB diagnosis. In addition, only a few diagnostic or research laboratories in the world are equipped to perform mutational screening, which is still labor intensive and associated with considerable costs, because most mutations are unique to one or a few families. This article reviews the most popular methods used in EB molecular analysis.
[show abstract][hide abstract] ABSTRACT: Epidermolysis bullosa (EB) has officially been recognized as a rare disease in Italy. Regional reference centers for EB have been created during the past years. This article discusses the clinical services and coordinated multidisciplinary management of EB in Italy.