Dermoscopy for the pediatric dermatologist, part ii: dermoscopy of genetic syndromes with cutaneous manifestations and pediatric vascular lesions.

Genetic syndromes including basal cell nevus syndrome (BSNS), xeroderma pigmentosum (XP), and epidermodysplasia verruciformis (EV) predispose the individual to skin cancer. Basal cell carcinomas (BCCs) often develop in patients with BCNS and XP. One of the aims of surveillance examination in these patients is to detect BCC while the tumors are still small and easy to manage. Dermoscopy, by allowing the visualization of arborizing vessels, ovoid nests, nonaggregated blue-gray globules, and spoke-wheel and leaf-like structures, can facilitate in the early detection of BCC. Patients with XP are also at risk for developing squamous cell carcinoma (SCC). Dermoscopy can assist in the early detection of these cancers by allowing the observer to visualize focal glomerular vessels, which is a common feature seen in SCC. This feature can also assist in detecting SCC developing in other syndromes such as EV and epidermolysis bullosa (EB). In addition to helping in the detection of BCC and SCC, dermoscopy can also help detect melanoma in individuals with XP and evaluate nevi developing in those with EB. This review will discuss how dermoscopy can be used in the management of patients with BSNS, XP, EV, and EB and will discuss the dermoscopic findings of vascular lesions, including pyogenic granuloma, hemangioma, port-wine stain, and lymphangioma circumscriptum.

Herlitz junctional epidermolysis bullosa.

Junctional epidermolysis bullosa type Herlitz (JEB-H) is the autosomal recessively inherited, more severe variant of "lucidolytic" JEB. Characterized by generalized, extensive mucocutaneous blistering at birth and early lethality, this devastating condition is most often caused by homozygous null mutations in the genes LAMA3, LAMB3, or LAMC2, each encoding for 1 of the 3 chains of the heterotrimer laminin-332. The JEB-H subtype usually presents as a severe and clinically diverse variant of the EB group of mechanobullous genodermatoses. This article outlines the epidemiology, presentation, and diagnosis of JEB-H. Morbidity and mortality are high, necessitating optimized protocols for early (including prenatal) diagnosis and palliative care. Gene therapy remains the most promising perspective.

Epidermolysis bullosa nevi.

Epidermolysis bullosa (EB) nevi are large, eruptive, asymmetrical, often irregularly pigmented melanocytic lesions. Such nevi may give rise to small satellite nevi surrounding the primary nevus, and thus frequently manifest clinical features suggestive of melanoma. They usually arise in sites of previous bullae or erosions. At least twice a year all persisting wounds and EB nevi should be evaluated with a low threshold for histopathologic examination if warranted. Our practice is to punch biopsy EB nevi showing dermoscopic features of concern as well as dermoscopically featureless lesions. Given the skin fragility and potentially impaired wound healing in EB patients, we avoid prophylactic total excision of large EB nevi, but rather use the dermoscope to select appropriate sites for punch biopsies within giant EB nevi.

Dermoscopy of benign and malignant neoplasms in the pediatric population.

Dermoscopy is a noninvasive technique that enables visualization of subsurface colors and structures within the skin that are imperceptible to the naked eye. The dermatoscope allows the physician to examine both the macroscopic and microscopic primary morphology of skin lesions, identify subtle clinical clues, confirm naked-eye clinical diagnoses, and monitor treatment progress while posing little threat to the young patient. Dermoscopic findings have been formulated into diagnostic criteria that assist experienced clinicians in differentiating benign and malignant neoplasms. In this review, clinical morphology of melanocytic nevi and melanoma in the pediatric population is examined and the relevant dermoscopic findings and histopathologic correlates that aid in the diagnosis and management of these lesions are described.

Transient anti-CD40L co-stimulation blockade prevents immune responses against human bullous pemphigoid antigen 2: implications for gene therapy.

Skin grafts from mice expressing human bullous pemphigoid antigen 2 (hBPAG2) in epidermal basement membrane elicit hBPAG2-specific IgG and graft loss in wild-type (Wt) recipients. Graft loss was dependent on CD4+ T cells and correlated with the production and tissue deposition of hBPAG2-specific IgG. To explore the role of CD40/CD40 ligand (CD40L) interaction in this model, Wt mice grafted with transgenic (Tg) skin were treated with hamster anti-CD40L mAb MR1. In contrast to grafted Wt mice treated with equivalent doses of control IgG, 22 of 23 MR1-treated Wt mice did not develop hBPAG2-specific IgG or graft loss for >or=60 days. MR1-treated mice also accepted a second Tg skin graft without durable production of hBPAG2-specific IgG or graft loss. Moreover, splenocytes and enriched CD4+ T cells from MR1-treated graft recipients transferred un- or hyporesponsiveness to hBPAG2 to other mice and demonstrated a dominant tolerant effect over cotransferred naive splenocytes following adoptive transfer to Rag2-/- mice. Successful inhibition of hBPAG2-specific IgG production and Tg graft loss following CD40:CD40L co-stimulatory blockade in this model provides opportunities to study mechanisms of peripheral tolerance and generate antigen-specific regulatory CD4+ cells-issues of relevance to patients with pemphigoid as well as individuals undergoing gene replacement therapy for epidermolyis bullosa.

Cytokeratin-related loss of cellular integrity is not a major driving force of human intrinsic skin aging.

The contribution of extracellular matrix components to intrinsic skin aging has been investigated thoroughly, however, there is little information as to the role of the cytoskeletal proteins in this process. Therefore, we compared the expression of the constituents of the cytoskeleton, keratins 1-23 (K1-K23) as well as junction-plakoglobin (JUP), alpha-tubulin (TUBA), and beta-actin (ACTB) in human foreskins of both young (mean 6.4 years) and aged (mean 54.3 years) individuals. By applying RNA expression analysis to intrinsically aged human skin, we demonstrated that the mRNA levels of the genes for K1, K3, K4, K9, K13, K15, K18, K19 and K20 are downregulated in aged skin, K5 and K14 are unchanged, and K2, K16 and K17 are upregulated in aged skin. The mRNA data were confirmed on the protein level. This diverse picture is in contrast to other cytoskeletal proteins including components of the desmosome (JUP), microtubuli (TUBA) and microfilaments (ACTB) - often regarded as house-keeping genes - that were all reduced in aged skin. These cytoskeletal features of intrinsic aging highlight the importance of the cellular compartment in this process and demonstrate that special attention has to be given to RNA as well as protein normalization in aging studies.

IgG anti-laminin-332 autoantibodies are present in a subset of patients with mucous membrane, but not bullous, pemphigoid.

BACKGROUND: Antiepiligrin cicatricial pemphigoid is a mucosal-predominant subepidermal blistering disease associated with an increased relative risk of cancer. In contrast to prior reports showing that anti-laminin (L)-332 autoantibodies are a reliable marker for patients with antiepiligrin cicatricial pemphigoid, a recent report suggested that as many as 40% of patients with bullous pemphigoid (BP) have IgG reactive with this laminin isoform. OBJECTIVE: We sought to determine whether patients with BP possess circulating IgG anti-L-332 autoantibodies. METHODS: Sera from 100 adults with BP were analyzed by indirect immunofluorescence testing of intact skin, immunoblot studies of human keratinocyte (HK) extracts, and a new L-332 enzyme-linked immunosorbent assay. Sera showing reactivity suggestive of anti-L-332 autoantibodies in these assays were further analyzed in immunoblot studies of HK extracellular matrix and immunoprecipitation studies of biosynthetically radiolabeled HK extracts. RESULTS: IgG from all patients with BP bound intact epidermal basement membrane by indirect immunofluorescence microscopy and immunoblotted bullous pemphigoid antigen-1, -2, or both in HK extracts. None of these sera immunoblotted L-332 in HK extracts, although 13 did score above the cut point of a new IgG(4) L-332 enzyme-linked immunosorbent assay (sensitivity = 0.91, specificity = 0.98, Youden index = 0.89). Further analysis of sera from these 13 patients found: (1) all had IgG that bound the epidermal side of 1 mol/L NaCl split skin by indirect immunofluorescence microscopy; (2) none immunoblotted L-332 purified from HK extracellular matrix; and (3) none immunoprecipitated L-332 from biosynthetically radiolabeled HK extracts. LIMITATIONS: The basis of false-positive enzyme-linked immunosorbent assay determinations for anti-L-332 IgG among patients with BP is unknown. CONCLUSION: Anti-L-332 autoantibodies remain a reliable marker for patients with antiepiligrin cicatricial pemphigoid.

Novel KIND1 gene mutation in Kindler syndrome with severe gastrointestinal tract involvement.

BACKGROUND: Kindler syndrome (online Mendelian Inheritance in Man No. 173650) is an autosomal recessive genodermatosis characterized by acral trauma-induced blistering that improves with age and by progressive poikiloderma in later life. Other clinical features include photosensitivity, webbing of the fingers and toes, nail dystrophy, periodontal disease, and mucosal alterations. Aside from esophageal or anal stenosis, gastrointestinal tract involvement seems to be rare in Kindler syndrome. Recently, mutations in the KIND1 gene that encodes for the membrane-associated protein kindlin-1 have been identified. Kindlin-1 links the actin cytoskeleton to the extracellular matrix and is supposed to have cell-signaling functions owing to different functional domains. In particular, a domain with high homology to 4.1/ezrin/radixin/moesin (FERM) proteins is closely related to the sequences of talin that mediate integrin binding and therefore may play a role in integrin-dependent processes such as cell growth, differentiation, and apoptosis. OBSERVATION: Complete loss of this multifunctional protein in our patient with Kindler syndrome resulted in severe gastrointestinal tract involvement with hemorrhagic colitis. Mucosa of the descending and sigmoid colon and the rectum showed erosions and ulcers with pseudomembranous alterations of an overall highly vulnerable mucosa. Mutation analysis revealed a homozygous status for the novel mutation 20/21delTT in exon 2 of the KIND1 gene resulting in a preterminal stop codon creating a nonfunctional peptide 17 amino acids in length. CONCLUSION: Because of our experience with this and another patient, we propose that gastrointestinal tract involvement should be looked at more frequently in Kindler syndrome.

Haploinsufficiency due to deletion within the 3'-UTR of C1-INH-gene associated with hereditary angioedema.

PURPOSE: Sequences within the non-coding 3'UTR (untranslated region) of genes were reported to be involved in the regulation of gene expression by modifying pathways of (co)transcription, post-transcriptional processing and RNA transport. However, direct biological evidence (i.e., knock-out models) is sparse. This report intends to correlate the first reported alteration within the 3'UTR of the C1 inhibitor (C1-INH) gene with clinical presentation of hereditary angioedema (HAE). METHODS AND RESULTS: Direct sequencing of genomic DNA revealed in all affected members of a family suffering from HAE a heterozygous 155 bp deletion 100 bp downstream of the physiological stop-codon in exon 8. A substantial reduction of both mRNA as well as C1-INH protein expression was revealed by RT-PCR and nephelometry, respectively. CONCLUSION: We suppose that the mutation within the 3'UTR interferes with integral pathways of gene expression leading to pathogenic haploinsufficiency in this family.

Analysis of the LAMB3 gene in a junctional epidermolysis bullosa patient reveals exonic splicing and allele-specific nonsense-mediated mRNA decay.

How splicing, the process of intron removal in pre-messenger RNA (mRNA), is carried out with such fidelity in human cells is still not understood, although some general rules are being proposed mainly by in vitro experiments. These rules are currently being redefined by analysis of splicing mechanisms in patients presenting splicing defects. We analysed material of a patient suffering from junctional epidermolysis bullosa, a heritable blistering skin disease. Absence of laminin-5 protein together with hypoplastic hemidesmosomes at the dermo-epidermal junction in the patient's skin was shown by immunohistochemical analysis and immunoelectron microscopy. Subsequent DNA analysis revealed heterozygosity for the mutations R635X and 3009C-->T in the LAMB3 gene. The latter did not alter codon translation, but introduced an exonic splice site in exon 20. Interestingly, this exonic splice site, which presented a splice score of only 68.6, was preferentially used by the spliceosome over the wild-type splice site at the exon 20-intron 20 border, which showed a splice score of 92.2. LAMB3 mRNA was still detectable in RT-PCR analysis although the aberrantly spliced mRNA leads to a stop codon in exon 21, 5' of the commonly assumed 3' border for nonsense-mediated mRNA decay. These results describe an exception to the proposed rules of pre-mRNA splicing and RNA degradation.

Pathogenic mechanisms in epidermolysis bullosa naevi.

Epidermolysis bullosa naevi are large, eruptive melanocytic naevi which frequently arise in areas of former blisters in patients suffering from inherited epidermolysis bullosa. Morphologically, these naevi are similar to malignant melanoma, although so far no malignant transformation has been observed. To investigate the pathogenesis of these moles we documented their clinical evolution and their histopathological and immunocytological characteristics in three patients with epidermolysis bullosa. Clinically, we observed signs of malignant transformation, such as explosive growth and the occurrence of satellite lesions of epidermolysis bullosa naevi. However, malignant melanoma was excluded by histopathological evaluation. In addition, we evaluated the concentrations of various factors known to stimulate melanocyte growth in blister fluid. Human interleukin 8, basic fibroblast growth factor, human hepatocyte growth factor, GM-CSF, leukotriene B4 and prostaglandin E2 revealed concentrations comparable with the levels in inflammatory blisters. We were able to detect individual melanocytes/naevus cells in blister fluid from a blister over an epidermolysis bullosa naevus. The factors detected in the blister fluid might therefore promote the proliferation, migration and melanogenesis of disconnected melanocytes/naevus cells representing the basis of the highly dynamic appearance of epidermolysis bullosa naevi.