Congenital fascial dystrophy: stiff skin syndrome--a human counterpart of the tight-skin mouse

Classification and rising medication therapy in stiff skin syndrome: A case report and literature review

Stiff skin syndrome (SSS) is a rare disorder characterized by skin induration and limited joint mobility in the absence of visceral, musculoskeletal, vascular, or immunologic abnormalities. Distinctive subsets of SSS could be distinguished by various manifestation and mechanism, which accounts for the high heterogeneity in SSS cases. Although rehabilitation training remains the mainstay of management, rising medications has drawn awareness in recent years, owing to the potential efficacy. Nevertheless, experience was limited, especially in widespread SSS. We report on a 5-year-old girl with widespread SSS, whose lesion stopped progressing after combination therapy by mycophenolic acid (MPA) and losartan (LST) in addition to rehabilitation exercise. Despite limited experience, a combined therapy of MPA and LST seems to be effective in retarding progression of widespread SSS.

Pro-Fibrotic Phenotype in a Patient with Segmental Stiff Skin Syndrome via TGF-β Signaling Overactivation

Transforming growth factor β (TGF-β) superfamily signaling pathways are ubiquitous and essential for several cellular and physiological processes. The overexpression of TGF-β results in excessive fibrosis in multiple human disorders. Among them, stiff skin syndrome (SSS) is an ultrarare and untreatable condition characterized by the progressive thickening and hardening of the dermis, and acquired joint limitations. SSS is distinct in a widespread form, caused by recurrent germline variants of FBN1 encoding a key molecule of the TGF-β signaling, and a segmental form with unknown molecular basis. Here, we report a 12-year-old female with segmental SSS, affecting the right upper limb with acquired thickening of the dermis evident at the magnetic resonance imaging, and progressive limitation of the elbow and shoulder. To better explore the molecular and cellular mechanisms that drive segmental SSS, several functional studies on patient's fibroblasts were employed. We hypothesized an impairment of TGF-β signaling and, consequently, a dysregulation of the associated downstream signaling. Lesional fibroblast studies showed a higher phosphorylation level of extracellular signal-regulated kinase 1/2 (ERK1/2), increased levels of nuclear factor-kB (NFkB), and a nuclear accumulation of phosphorylated Smad2 via Western blot and microscopy analyses. Quantitative PCR expression analysis of genes encoding key extracellular matrix proteins revealed increased levels of COL1A1, COL3A1, AGT, LTBP and ITGB1, while zymography assay reported a reduced metalloproteinase 2 enzymatic activity. In vitro exposure of patient's fibroblasts to losartan led to the partial restoration of normal transforming growth factor β (TGF-β) marker protein levels. Taken together, these data demonstrate that in our patient, segmental SSS is characterized by the overactivation of multiple TGF-β signaling pathways, which likely results in altered extracellular matrix composition and fibroblast homeostasis. Our results for the first time reported that aberrant TGF-β signaling may drive the pathogenesis of segmental SSS and might open the way to novel therapeutic approaches.

Stiff skin syndrome--case report

Stiff skin syndrome is a rare scleroderma-like disorder of unknown etiology characterized by stone-hard indurations of skin, mild hypertrichosis and limited joint mobility. No effective treatment has yet been found. Exercises and rehabilitative therapy are important in maintaining the patient's quality of life. The authors present a case of a two-year-old boy with progressive skin hardening since he was eight-month old and secondary restricted joint mobility, diagnosed as Stiff skin syndrome.

Fibrillin assemblies: extracellular determinants of tissue formation and fibrosis

The extracellular matrix (ECM) plays a key role in tissue formation, homeostasis and repair, mutations in ECM components have catastrophic consequences for organ function and therefore, for the fitness and survival of the organism. Collagen, fibrillin and elastin polymers represent the architectural scaffolds that impart specific mechanic properties to tissues and organs. Fibrillin assemblies (microfibrils) have the additional function of distributing, concentrating and modulating local transforming growth factor (TGF)-β and bone morphogenetic protein (BMP) signals that regulate a plethora of cellular activities, including ECM formation and remodeling. Fibrillins also contain binding sites for integrin receptors, which induce adaptive responses to changes in the extracellular microenvironment by reorganizing the cytoskeleton, controlling gene expression, and releasing and activating matrix-bound latent TGF-β complexes. Genetic evidence has indicated that fibrillin-1 and fibrillin-2 contribute differently to the organization and structural properties of non-collagenous architectural scaffolds, which in turn translate into discrete regulatory outcomes of locally released TGF-β and BMP signals. Additionally, the study of congenital dysfunctions of fibrillin-1 has yielded insights into the pathogenesis of acquired connective tissue disorders of the connective tissue, such as scleroderma. On the one hand, mutations that affect the structure or expression of fibrillin-1 perturb microfibril biogenesis, stimulate improper latent TGF-β activation, and give rise to the pleiotropic manifestations in Marfan syndrome (MFS). On the other hand, mutations located around the integrin-binding site of fibrillin-1 perturb cell matrix interactions, architectural matrix assembly and extracellular distribution of latent TGF-β complexes, and lead to the highly restricted fibrotic phenotype of Stiff Skin syndrome. Understanding the molecular similarities and differences between congenital and acquired forms of skin fibrosis may therefore provide new therapeutic tools to mitigate or even prevent disease progression in scleroderma and perhaps other fibrotic conditions.

Mutations in fibrillin-1 cause congenital scleroderma: stiff skin syndrome

The predisposition for scleroderma, defined as fibrosis and hardening of the skin, is poorly understood. We report that stiff skin syndrome (SSS), an autosomal dominant congenital form of scleroderma, is caused by mutations in the sole Arg-Gly-Asp sequence-encoding domain of fibrillin-1 that mediates integrin binding. Ordered polymers of fibrillin-1 (termed microfibrils) initiate elastic fiber assembly and bind to and regulate the activation of the profibrotic cytokine transforming growth factor-beta (TGFbeta). Altered cell-matrix interactions in SSS accompany excessive microfibrillar deposition, impaired elastogenesis, and increased TGFbeta concentration and signaling in the dermis. The observation of similar findings in systemic sclerosis, a more common acquired form of scleroderma, suggests broad pathogenic relevance.

Stiff skin syndrome: evidence for an inflammation-independent fibrosis?

OBJECTIVES

Stiff skin syndrome (SSS) is a rare scleroderma-like syndrome of unknown aetiology. A 16-year-old boy presented with thoracic and abdominal asymmetry, and 'orange peel' cutaneous lesions, with fibrotic stone-hard indurations at the buttocks, thighs and arms leading to secondary joint contractures of the extremities. Our aim was to analyse the expression of extracellular matrix (ECM) molecules and pro-fibrotic cytokines in the dermis and epidermis of SSS.

METHODS

The diagnosis of SSS was confirmed by clinical and histopathological examination. Collagen type 1 alpha-2 chain (Col1A2), fibronectin-1, thrombospondin-1, TGF-beta, connective tissue growth factor (CTGF), IL-6, -1beta, ET-1, Fibroblast growth factor receptor 3 (FGFR-3) and MCP-1 expression was analysed in SSS and age- and sex-matched healthy control skin by real-time PCR. VEGF expression was also studied.

RESULTS

Histopathological examination showed flattened dermal papillae, a scarce presence of sub-epidermal microvessels and mild dermal fibrosis, but no inflammatory infiltrates. In the SSS dermis, the expression of IL-1beta, -6 and MCP-1 was low, whereas VEGF was intensively expressed. No differences were observed for TGF-beta, CTGF and ET-1. In contrast, col1A2, fibronectin-1 and thrombospondin-1 were overexpressed in the SSS dermis.

CONCLUSION

In our SSS patient, an overexpression of ECM proteins was detected, whereas no inflammatory infiltrates or up-regulation of pro-fibrotic cytokines were found. The data suggest that fibrosis in SSS might be independent from inflammation.

Stiff skin syndrome versus scleroderma: a report of two cases

Stiff skin syndrome is a rare cutaneous disease, scleroderma-like disorder that presents in infancy or early childhood with rock-hard skin, limited joint mobility, and mild hypertrichosis. Normally, it occurs in the absence of visceral or muscle involvement. Patients do not present immunologic abnormalities or vascular hyperactivity. We describe two adults who initially were diagnosed suffering from scleroderma but fit criteria for stiff skin syndrome. A review of the clinical range of this disorder and discussion of the differential diagnosis with scleroderma is presented.

Hammerhead ribozyme-mediated silencing of the mutant fibrillin-1 of tight skin mouse: insight into the functional role of mutant fibrillin-1

The tight skin (Tsk/+) mouse is a model for fibrotic disorders. The genetic defect in the Tsk/+ is an in-frame duplication between exons 17 and 40 of the fibrillin-1 gene which gives rise to a large transcript and protein. Mice homozygous for the mutation die in utero, whereas heterozygotes survive and spontaneously develop connective tissue disease. In this study, we generated hammerhead ribozymes directed against the mutant fibrillin-1 transcript. A partially mispairing ribozyme was the most effective vehicle to cleave the mutant transcript without undesired cleavage of wild type transcripts, as shown by cell-free RNA cleavage and cleavage in cell lines harboring the ribozyme, by RT-PCR, Northern and Western Blotting. Global gene expression profiling using oligonucleotide microarrays showed the expected reduction in fibrillin-1 mRNA, and down-regulation of several gene cohorts in ribozyme harboring TskR1 cells compared to Tsk/+ cells. Two of the functional clusters included genes regulating extracellular matrix such as connective tissue growth factor, serpine-1 (plasminogen activator inhibitor-1) and TIMP-1 and TIMP-3, and those involved in cytoskeletal organization and myofibroblast formation including calponins and transgelin. Ribozyme-mediated inhibition was confirmed by Western Blot and functional analysis using cell-reporter systems and remodeling of three dimensional collagen gels. Our results underline the therapeutic potential of hammerhead ribozymes in dominant negative defects and suggest that changes in microfibril architecture brought about by fibrillin-1 mutation lead to a complex disease phenotype.

Life-threatening cutaneous conditions in neonates

One of the major medical concerns in neonates is their vulnerability to life-threatening complications. Early diagnosis of potentially serious medical conditions is essential in prevention of such complication by prompt administration of appropriate treatments. Recognition of cutaneous manifestations of potentially fatal diseases may assist a clinician in management of newborns. To overview the full spectrum of this category of conditions, Medline search was performed for cases of cutaneous manifestations associated with mortality during the first month of live that were published in the English language literature since 1977. This is a concise review of the clinical aspects of most of the potentially life-threatening disorders in neonates divided by basic morphology of their cutaneous manifestations.

A Role for the Androgen Receptor in Collagen Content of the Skin

Collagen, the major macromolecular component of skin, is responsible for maintaining the structural integrity of the tissue as well as for providing important functional characteristics, such as pliability and thickness. We have been studying the structure and regulation of collagen in mouse mutations affecting the skin. In the course of these studies, we found that there are significant differences in collagen content between the skin of wild-type male and female mice, which become evident at puberty. Furthermore, male mice with an X-linked mutation in the androgen receptor gene (formerly called testicular feminization and abbreviated as Ar(Tfm)) showed decreased levels of collagen, indicating that the androgen receptor pathway contributes to the observed differences. These findings demonstrate that there are striking differences in the collagen content of skin between male and female mice, and provide a biochemical explanation for these differences.

Two cases for diagnosis: asymmetric childhood scleredema or stiff skin syndrome?

Two children with chronic and asymmetric skin indurations are presented. The clinical and pathologic features are suggestive of asymmetric childhood scleredema and stiff skin syndrome. The key features of scleredema and stiff skin syndrome are discussed.

Hypertrichosis

Hypertrichosis is hair growth that is abnormal for the age, sex, or race of an individual, or for a particular area of the body. Recognized forms of hypertrichosis are reviewed. Hirsutism, which is male-pattern hair growth in a female or child, is not included in this review. Hypertrichosis is categorized as congenital or acquired, and regional or generalized. Methods of managing hypertrichosis are also briefly reviewed

Congenital fascial dystrophy: abnormal composition of the fascia

BACKGROUND

A scleroderma-like genetic disease, congenital fascial dystrophy, probably a variant of stiff skin syndrome described by Esterly and McKusick, was found to be related to genetically determined fascial abnormalities. Our previous electronmicroscopic study disclosed as a main pathologic finding presence of giant amianthoid-like collagen fibrils in the affected fascia.

OBJECTIVE

The aim of the present study was to disclose the collagen abnormalities in the affected and control fascias and in the patient's fibroblast cultures derived from the skin and fascia.

METHODS

The study was performed by histologic, immunohistochemical, and electronmicroscopic techniques. Immunohistochemical studies were done with the use of monoclonal antibodies: anti-collagens I, III, IV, and VI, anti-laminin, anti-fibronectin, anti-desmin, anti-spectrin, anti-vimentin, anti-laminin, anti-heparan sulfate, and anti-alpha-actinin. Electronmicroscopic studies were performed on the fascia sections and on cultured fibroblasts.

RESULTS

The main abnormality leading to giant collagen fibril formation was presence of myofibroblasts, absence of collagen III, and overproduction of spectrin and collagen type VI, mainly its filamentous form.

CONCLUSION

Our findings suggest that the abnormal composition of the fascia could depend on modulation of fibroblasts into myofibroblasts capable of producing spectrin and long-spacing collagen.

Scleroderma-like indurations involving fascias: an abortive form of congenital fascial dystrophy (Stiff skin syndrome)

Four patients are described with stone-hard indurations of the skin and subcutaneous tissue, predominantly on the buttocks and thighs, in the areas of the thickest fascia lata and glutealis. All cases were sporadic, started in early infancy, were only slightly or not progressive, and showed no visceral involvement or immunologic abnormalities. In all, the hallmark of the disease was strikingly enlarged fascia. In one patient, typical features developed progressively for 9 years, and in two patients the changes remained abortive, limited to some areas, and not symmetrical. The fourth patient showed some similarity to profound morphea with no cutaneous involvement. Recognition of atypical or abortive cases of congenital fascial dystrophy, which is probably a variant of heterogeneous stiff skin syndrome involving exclusively fascia, is of practical importance, since no therapy is required. However, intensive rehabilitation should start in early infancy and continue throughout life. The genetic defect of molecular organization of collagen in the fascia results in formation of giant amianthoid-like collagen fibrils.

Scleroderma-like disorders

Scleroderma-like disorders are widely disparate conditions mimicking either systemic sclerosis or cutaneous localized scleroderma, not infrequently displaying features of both. Some are exclusively sclerotic, some scleroatrophic with prevailing sclerosis or atrophies. The recognition of scleroderma-like disorders is of practical importance because by establishing the cause of the disease, it is possible to introduce an effective therapy, as in scleredema Buschke or scleredema diabeticorum, sclerodermiform porphyria, Borrelia burgdorferi-induced sclerodermiform acrodermatitis atrophicans, sclerodermiform phenylketonuria, drug-induced conditions, and so on. Scleroderma-like disorders strongly suggest that the pathogenesis of skin sclerosis and internal involvement may be divergent, and of various causes. Some of them, such as atrophoderma Pasini-Pierini or progressive facial hemiatrophy, frequently overlapping with scleroderma, make the differentiation very difficult, if at all possible, and the diagnosis is often arbitrary. Some, as sclerodermiform graft-versus-host reaction, point to the autoimmune origin of scleroderma. The amply-covered congenital sclerodermiform conditions present a large spectrum of still not widely known and extremely heterogeneous syndromes, associated with numerous anomalies and/or malignancies.

A tandem duplication within the fibrillin 1 gene is associated with the mouse tight skin mutation

Mice carrying the Tight skin (Tsk) mutation have thickened skin and visceral fibrosis resulting from an accumulation of extracellular matrix molecules. These and other connective tissue abnormalities have made Tskl + mice models for scleroderma, hereditary emphysema, and myocardial hypertrophy. Previously we localized Tsk to mouse chromosome 2 in a region syntenic with human chromosome 15. The microfibrillar glycoprotein gene, fibrillin 1 (FBN1), on human chromosome 15q, provided a candidate for the Tsk mutation. We now demonstrate that the Tsk chromosome harbors a 30- to 40-kb genomic duplication within the Fbn1 gene that results in a larger than normal in-frame Fbn1 transcript. These findings provide hypotheses to explain some of the phenotypic characteristics of Tskl + mice and the lethality of Tsk/Tsk embryos.