Search

Ullrich congenital muscular dystrophy (UCMD) is caused by mutations in the three genes coding for the alpha chains of collagen VI and characterized by generalized muscle weakness, striking hypermobility of distal joints in conjunction with variable contractures of more proximal joints, and normal intellectual development. The diagnosis is supported by abnormal immunoreactivity for collagen VI on muscle biopsies. As patients with UCMD show clinical characteristics typical of classical disorders of connective tissue such as Ehlers-Danlos syndromes (EDS), we investigated the ultrastructure of skin biopsy samples from patients with UCMD (n=5). Electron microscopy of skin biopsies revealed ultrastructural abnormalities in all cases, including alterations of collagen fibril morphology (variation in size and composite fibers) and increase in ground substance, which resemble those seen in patients with EDS. Our findings suggest that there is a true connective tissue component as part of the phenotypic spectrum of UCMD and that there is considerable clinical as well as morphological overlap between UCMD and classic connective tissue disorders.

Plectin is one of the largest and most versatile cytolinker proteins known. In basal keratinocytes it links the intermediate filament network to cell membrane-associated hemidesmosomes. Several mutations in its gene have been identified that lead to the recessive disease epidermolysis bullosa with muscular dystrophy. We report here a mutation that leads to a dominant form of the disease, epidermolysis bullosa simplex Ogna. We found that the epidermolysis bullosa simplex Ogna phenotype is due to a site-specific missense mutation within plectin's rod domain. Further, we show that epidermolysis bullosa simplex Ogna is not restricted to a single Norwegian kindred as previously believed. A German family with the phenotypic hallmarks of epidermolysis bullosa simplex Ogna was found to carry an identical de novo mutation. These two mutations arose about 200 y apart in time. Consistent with the absence of muscular symptoms in these patients, muscle biopsies from several epidermolysis bullosa simplex Ogna members of the Norwegian kindred showed normal staining patterns using antibodies to plectin. Skin changes in epidermolysis bullosa simplex Ogna patients are documented on the ultrastructural level.

Lysosomal cysteine proteinases of the papain family are involved in lysosomal bulk proteolysis, major histocompatibility complex class II mediated antigen presentation, prohormone processing, and extracellular matrix remodeling. Cathepsin L (CTSL) is a ubiquitously expressed major representative of the papain-like family of cysteine proteinases. To investigate CTSL in vivo functions, the gene was inactivated by gene targeting in embryonic stem cells. CTSL-deficient mice develop periodic hair loss and epidermal hyperplasia, acanthosis, and hyperkeratosis. The hair loss is due to alterations of hair follicle morphogenesis and cycling, dilatation of hair follicle canals, and disturbed club hair formation. Hyperproliferation of hair follicle epithelial cells and basal epidermal keratinocytes-both of ectodermal origin-are the primary characteristics underlying the mutant phenotype. Pathological inflammatory responses have been excluded as a putative cause of the skin and hair disorder. The phenotype of CTSL-deficient mice is reminiscent of the spontaneous mouse mutant furless (fs). Analyses of the ctsl gene of fs mice revealed a G149R mutation inactivating the proteinase activity. CTSL is the first lysosomal proteinase shown to be essential for epidermal homeostasis and regular hair follicle morphogenesis and cycling.

This rare, ubiquitous neurocutaneous disorder is inherited in an autosomal recessive fashion. Its primary clinical manifestations are congenital ichthyosis, spastic diplegia or tetraplegia, and mental retardation. The causative biochemical defect has been identified as a deficiency of the enzyme fatty aldehyde dehydrogenase, a component of fatty alcohol:NAD+ oxidoreductase. We present a case report of an affected 3.5 year old white girl to give an overview of the pre- and postnatal diagnostic procedures as well as of therapeutic options.

The gene encoding the human fatty aldehyde dehydrogenase (FALDH) is located on 17p11.2, causing Sjogren-Larsson syndrome (SLS) when mutated. SLS is an autosomal recessive disorder characterized by a combination of mental retardation, congenital ichthyosis, and spastic di- or tetraplegia. We report here on studies of 16 SLS families from Europe and the Middle East, which resulted in identification of 11 different mutations. The spectrum of mutations characterized in the present study are five nucleotide substitutions resulting in amino acid changes, five frameshift mutations introducing a stop codon, and one in-frame deletion with insertion at the same position. We also observed silent sequence variants in the FALDH gene and a base pair substitution in exon 5 that alters aspartic acid to asparagine, all of which are considered polymorphisms. Hum Mutat 12:377–384, 1998. © 1998 Wiley-Liss, Inc.

We describe a patient with severe generalized dystrophic epidermolysis bullosa (EBD) and a novel combination of compound heterozygous mutations in the COL7A1 gene. The maternal mutation was an A-to-G transition (425-A --> G) at position -2 of the donor splice site within exon 3 that causes aberrant splicing of two abnormal transcripts. One includes intron 3, and one excludes both exon 3 and intron 3. Both splice variants contained a premature termination of the translation. The paternal mutation is a 25-bp deletion in exon 20 (2638de125) that leads to a frameshift and a premature termination codon 133 bp downstream from the site of deletion. This combination of mutations allowed expression of collagen VII mRNA. Immunofluorescence staining of the patient's skin and cultured keratinocytes with domain-specific collagen VII antibodies, however, demonstrated markedly reduced levels of alpha1(VII) polypeptides, and no stable collagen VII protein could be extracted from the patient's cells. Electron microscopy showed severely hypoplastic fibrils below the lamina densa, without evidence of normal anchoring fibrils. The clinically unaffected parents were heterozygous for the mutations, suggesting that both COL7A1 gene defects were recessively inherited disease-causing mutations that are "silent" in heterozygous carriers but in combination can severely interfere with the dermal-epidermal adhesion and lead to severe EBD.

Dystrophic epidermolysis bullosa (EBD) is a clinically heterogeneous skin disorder, characterized by abnormal anchoring fibrils (AF) and loss of dermal-epidermal adherence. EBD has been linked to the COL7A1 gene at chromosome 3p21 which encodes collagen VII, the major component of the AF. Here we investigated two unrelated EBD families with different clinical phenotypes and novel combinations of recessive and dominant COL7A1 mutations. Both families shared the same recessive heterozygous 14 bp deletion at the exon-intron 115 boundary of the COL7A1 gene. The deletion caused in-frame skipping of exon 115 and the elimination of 29 amino acid residues from the pro-alpha1(VII) polypeptide chain. As a result, procollagen VII was not converted to collagen VII and the C-terminal NC-2 propeptide which is normally removed from the procollagen VII prior to formation of the anchoring fibrils was retained in the skin. All affected individuals also carried missense mutations in exon 73 of COL7A1 which lead to different glycine-to-arginine substitutions in the triple-helical domain of collagen VII. Combination of the deletion mutation with a G2009R substitution resulted in a mild phenotype. In contrast, combination of the deletion with a G2043R substitution led to a severe phenotype. The G2043R substitution was a de novo mutation which alone caused a mild phenotype. Thus, different combinations of dominant and recessive COL7A1 mutations can modulate disease activity of EBD and alter the clinical presentation of the patients.

We examined skin biopsy specimens from 17 of 19 newborns or infants with generalized ichthyosiform, exfoliative, seborrheic, or psoriasiform erythroderma. The specimens showed similar characteristic but nonspecific and therefore, at first sight, uninformative histologic features. Morphologically, the skin was affected overall with a persistent outbreak of eczema-like eruptions of subacute or chronic dermatitis. Pronounced dermal inflammatory processes were obvious by their perivascular and interstitial presence as well as exocytosis of lymphocytes, macrophages, and neutrophils. Epidermal barrier function was Impaired by the highly suppressed terminal differentiation, with thin or in part completely absent stratum corneum, decrease of keratin filaments, decrease or lack of keratohyalin granules, and of keratinosomes containing stacks of lipid membranes. As a result, the formation and discharge of epidermal barrier lipids from the keratinosomes that normally provide intercellular lamellar sheets at the granular-horny layer interface contributing to the epidermal barrier, was highly disturbed. The concomitant loss of water, electrolytes, and proteins by fluid exudation caused the patients severe metabolic problems and recurrent infections. The suspicion of Netherton syndrome was eventually confirmed in 18 patients by light microscopic demonstration of bamboo hairs (trichorrhexis invaginata), mostly from the scalp, but also in vellus hairs and eyelashes. Atopy actually belongs to the symptom triad defining Netherton syndrome and is, in our opinion, primarily responsible for the pathologic events within the skin and of the keratinizing parts of the growing hair shafts. Differential expression of the atopic condition determines the appearance of the keratinization disorder of the skin, namely, severe, generalized, exfoliative erythroderma or milder forms of ichthyosis linearis circumflexa Comel. Retinold treatment seems to be contraindicated in these conditions since their biopharmacologic effects involve suppression of terminal differentiation, which is the proper pathognomonic event. In six patients the condition had a fatal course within months because of hypernatremia, recurrent infections, failure to thrive, and sepsis. Our aim is to call attention to and reaffirm that in congenital or early infantile cases of generalized exfoliative erythroderma. Netherton syndrome should be suspected as the underlying disease.

The present article discusses specific, directly gene-dependent ultrastructural markers of dominantly inherited epidermal disorders that serve as clues to their underlying molecular genetic abnormalities. These are epidermolysis bullosa simplex Koebner and Weber-Cockayne with rupture or non-assembly of basal cell keratins and point mutations in keratins 5 and 14. Clumping of basal cell keratins is pathognomonic of EB Dowling-Meara and caused by mutations in hot spots of the rod domain of K 5 and K 14. Clumps and aggregates of basal keratins occur side by side in the same cell and thus do not indicate specific different types of mutations. Similar clumping of suprabasal keratins in bullous CIE Brocq and in palmoplantar keratoderma Voerner have been assigned to identical types of mutations in the same critical position of the rod domain in K 1, K 10, and K 9, respectively. Highly unusual tubular keratins are pathognomonic of another dominant palmoplantar keratoderma type the genetic basis of which still awaits elucidation. Shell formation of (low molecular weight?) keratins in ichthyosis hystrix Curth-Macklin is not linked to the keratin gene clusters on chromosomes 12 and 17 and might be related to regulatory genes of keratin expression. Suprabasal shells in congenital reticular ichthyosiform erythroderma do not consist of keratins but resemble glycoprotein networks. Finally, the keratohyalin abnormality in ichthyosis vulgaris was the clue for the identification of a filaggrin deficiency, at the same time giving evidence to the heterogeneity of keratohyalin proteins.

Since their discovery, the function of intermediate filaments (IFs) has remained obscure. In skin, epidermal cells have extensive cytoskeletal architectures of IFs, composed of type I and type II keratin heterodimers. Clues to possible functions of these proteins have come from recent studies showing that several autosomal-dominant, blistering skin disorders are caused by defects in genes that encode epidermal keratins. These diseases all exhibit cell degeneration and keratin network perturbations in cells that express the particular mutant keratin gene. However, it is not clear from these studies whether cytolysis arises from the presence of large insoluble keratin aggregates that compromise cellular physiology or from the absence of an extensive keratin filament network, which jeopardizes mechanical integrity. We report here the analysis of an extremely rare case of severe recessive epidermolysis bullosa simplex (EBS), where the patient lacks a discernible keratin filament network in basal epidermal cells. Genetic analyses revealed a homozygous point mutation that yielded a premature termination codon in the major basal type I keratin gene and caused complete ablation of K14. The consanguineous parents were normal, each harboring one copy of the null K14 mutation. Analysis of cultured keratinocytes enabled us to document that the loss of K14 is not compensated for by the up-regulation of any other type I keratin. When taken together with the in vivo studies showing the presence of cell fragility generated from the lack of an extensive basal keratin network, these findings provide the first clear demonstration of loss of function associated with the absence of an IF protein in vivo.

Erythrokeratolysis hiemalis, keratolytic winter erythema or Oudtshoorn skin has been reported from the South African district of Oudtshoorn as a dominantly inherited dermatosis beginning in early childhood, in some cases with circinar scaling erythemas. Seasonal manifestation in winter-time and a characteristic multi-form histology distinguish this dermatosis from other childhood scaling erythemas. We present clinical, histological and preliminary immunohistological data of a 4-year-old girl with the attributes of erythrokeratolysis hiemalis. No ancestors from the endemic region were traced. The lack of further cases in the family is interpreted as indicative of a spontaneous dominant new mutation.

We report on a 7-year-old boy suffering from two rare genetic diseases, namely hyalinosis cutis et mucosae and Ehlers-Danlos syndrome. The diagnosis was finally established after 7 years, by means of light and electron microscopy and immunohistology. Therefore, this report deals with the typical clinical and morphological features of both genetic disorders.

Junctional epidermolysis bullosa inversa is an autosomal recessive blistering skin disease with an ultrastructural hemidesmosome defect similar to that of the Herlitz disease, yet with a non-lethal and different course of the disease. Its delineation is based on five geographically associated Norwegian families where all parents are likely to carry a mutant EBR2A allele identical in descent. Three informative families show a lod score of +1.65 at zero recombination to a trinucleotide repeat marker in intron 20 of the laminin gamma 1 (LAMC1, previously LAMB2) locus on 1q31. The four patients of these families are all homozygous for the 146 bp LAMC1 allele present only on 5% of random Norwegian chromosomes. The daughter of a deceased patient in a fourth family carries the same 146 bp allele. This extreme association confirms that the disease locus, EBR2A, is at or closely linked to LAMC1. Localized and generalized Mitis types as well as the majority of tested families with the Herlitz type of junctional epidermolysis bullosa appeared not to be similarly linked or associated to LAMC1. The MspI and AluI RFLPs of LAMC1 showed absolute allelic association. Each of the two RFLP haplotypes showed association to either 'long' or 'short' intron 20 STR alleles.

In random pattern skin flaps of mice, tissue fluorescence measured by means of videodensitometry at 24 h after flap elevation significantly correlates with intravital microscopically measured functional vessel density and viability of skin tissue as assessed by transmission light and electron microscopy. The correlation was found reproducible in non-ischaemic flaps (r = 0.86) and flaps being rendered ischaemic for 6 h after elevation (r = 0.98), indicating that increased microvascular permeability as a result of ischaemia/reperfusion does neither affect tissue fluorescence nor the accuracy of the fluorescein dye test. In addition, tissue fluorescence at 24 h after flap elevation accurately predicts ultimate flap survival on the 7th postoperative day with a sensitivity of 0.89 and a specificity of 0.85. These results suggest that in non-ischaemic as well as in ischaemic random pattern skin flaps tissue fluorescence can be used for assessment of nutritive blood flow, viability of skin tissue and ultimate tissue survival in these flaps.

Recent biochemical and morphological investigations have provided evidence for a heterogeneous composition of keratohyalin in human skin. A major component is filaggrin. In interfollicular epidermis the heterogeneity of keratohyalin is not directly visible, whereas in normal ridged skin bicomponent keratohyalin is revealed by electron microscopy. Skin biopsies of ridged and non-ridged skin of normal individuals and patients with autosomal dominant ichthyosis vulgaris (ADI) — characterized by defective keratohyalin synthesis and lack of filaggrin — were investigated by routine transmission electron microscopy and immunogold postembedding techniques using a commercial monoclonal anti-filaggrin antibody. In normal interfollicular epidermis filaggrin labelling was demonstrated on keratohyalin granules and in the lowermost cornified cells, whereas in ADI patients crumbly keratohyalin granules were present that did not show specific labelling for filaggrin. In normal ridged skin only the major (more electron-dense) component reacted with anti-filaggrin, whereas the attached (less electron-dense) component did not react. Ridged skin of ADI patients contained globular keratohyalin that did not react with anti-filaggrin, thus corresponding to the attached keratohyalin component in normal ridged skin. Our results provide a visible counter-part to the recent biochemical investigations of keratohyalin protein heterogeneity and contribute to the understanding of terminal differentiation in human skin and of the defective keratohyalin synthesis in ADI.

Epidermolysis bullosa simplex (EBS) is caused by defective assembly of keratin intermediate filaments in basal keratinocytes and recent studies indicated causal mutations in the keratin KRT5 and KRT14 genes. In this study, we describe a novel KRT5 mutation in a German sporadic case of EBS Dowling–Meara. Transition of G to T (nucleotide position 2334) leads to a premature stop codon (E477stop, residue 93 of the 2B helix) in the last residue of the highly conserved helix-termination peptide K/LLEGE of the 2B rod domain of keratin K5. This represents the first premature stop codon mutation identified within the K/LLEGE motif of any disorder reported so far that is caused by keratin mutations.

Recently a monoclonal antibody (19-DEJ-1) was produced with binding specificity for the mid-lamina lucida of the skin dermo-epidermal junction, in very close association with overlying hemidesmosomes. Since skin cleavage occurs within the lamina lucida in the inherited blistering disorder, junctional epidermolysis bullosa (EB), and is associated with aberrations in the morphology and/or number of hemidesmosomes in such tissue, we have sought to determine whether this monoclonal antibody could be used for prenatal diagnosis. Fetoscopy-directed skin biopsies were obtained from two fetuses at risk for junctional EB and post-mortem samples from two other fetuses with the Herlitz type of junctional EB, the latter after prenatal diagnosis by electron microscopy and termination of each pregnancy. Specimens were examined in part by light and electron microscopy for evidence of skin cleavage or other alterations in morphology, and in part by indirect immunofluorescence for altered basement membrane antigenicity. Three of four fetuses were shown to have intra-lamina lucida blister formation indicative of, and hemidesmosome hypoplasia proving, junctional EB. Each was also shown to lack expression of GB3 and 19-DEJ-1 antigens, consistent with findings noted postnatally in junctional EB; diagnosis was confirmed in each at the time of therapeutic abortion. A fourth fetus had no abnormalities detected; lack of disease involvement was confirmed at the time of delivery, and subsequently over 8 months of careful serial evaluation. We conclude that 19-DEJ-1 monoclonal antibody is an accurate and sensitive immunohistochemical probe for junctional EB, and may be employed in the prenatal diagnostic evaluation of fetuses at risk for this disorder.

Background: Autosomal recessive congenital ichthyosis (ARCI) is a heterogeneous group of skin disorders. Several mutant genes have been identified in ARCI, but the association between genotype and phenotype is poorly understood. Methods: To investigate genotype-phenotype correlations in ARCI, we selected 27 patients from 18 families with specific ultrastructural features of the epidermis. The characteristic findings using electron microscopy (EM) were abnormal lamellar bodies and elongated membranes in the stratum granulosum, classified as ARCI EM type III. DNA samples from a subset of affected individuals were screened for homozygous genomic regions, and a candidate gene region was identified on chromosome 5q33. The region coincides with the ichthyin gene, previously reported as mutated in ARCI. Results: Mutation screening of ichthyin revealed missense or splice-site mutations in affected members from 16 of 18 (89%) families with characteristics of ARCI EM type III. In a control group of 18 patients with ARCI without EM findings consistent with type III, we identified one patient homozygous for a missense mutation in ichthyin. Discussion: Our findings indicate a strong association between ultrastructural abnormalities in the granular layer of epidermis and ichthyin mutations. The results also suggest that EM provides a tool for specific diagnosis in a genetically homogenous subgroup of patients with ARCI.

Ullrich congenital muscular dystrophy (UCMD) is caused by mutations in the three genes coding for the alpha chains of collagen VI and characterized by generalized muscle weakness, striking hypermobility of distal joints in conjunction with variable contractures of more proximal joints, and normal intellectual development. The diagnosis is supported by abnormal immunoreactivity for collagen VI on muscle biopsies. As patients with UCMD show clinical characteristics typical of classical disorders of connective tissue such as Ehlers-Danlos syndromes (EDS), we investigated the ultrastructure of skin biopsy samples from patients with UCMD (n=5). Electron microscopy of skin biopsies revealed ultrastructural abnormalities in all cases, including alterations of collagen fibril morphology (variation in size and composite fibers) and increase in ground substance, which resemble those seen in patients with EDS. Our findings suggest that there is a true connective tissue component as part of the phenotypic spectrum of UCMD and that there is considerable clinical as well as morphological overlap between UCMD and classic connective tissue disorders.

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.

Restrictive dermopathy is a rare autosomal recessive lethal skin dysplasia. It has been assumed that the characteristic morphologic abnormalities should allow a reliable prenatal diagnosis on fetal skin biopsies at about 20 weeks pregnancy. We report on a false-negative prenatal diagnosis.

Autosomal recessive congenital ichthyosis (ARCI) is a clinically heterogeneous disorder of keratinisation. It was recently shown that mutations in the transglutaminase 1 (TGM1) gene may be associated with the clinical subtypes lamellar ichthyosis (LI) and non-bullous congenital ichthyosiform erythroderma (CIE). Thirty-six Norwegian families with LI and seven with non-bullous CIE were studied with microsatellite markers linked to the TGMI gene. One common haplotype for two markers was found on 74% of disease associated chromosomes. Three individuals homozygous for the common haplotype, two affected by LI and one affected by CIE, were analysed for mutations in the TGM1 gene. All three patients were found homozygous for a single A to G transition located in the canonical splice acceptor site of intron 5. Probands from the remaining 40 families with LI and CIE were screened for this mutation and the A to G transition was found on 61 out of 72 alleles associated with LI and on 9 out of 15 alleles associated with CIE. These findings suggest a single founder mutation for the majority of patients with LI and CIE in Norway. The 2526A-->G mutation results in the insertion of a guanosine at position 877 (876insG) in the mature cDNA and the frame shift creates a premature termination at codon 293. The mutation was previously observed in one family with a resulting cDNA that included the entire intron 5. These results suggest that the mutation can result in variant transcripts in different individuals.

Epidermolysis bullosa simplex (EBS) is a group of autosomal dominant inherited skin diseases caused by mutations in either the keratin 5 (K5) or the keratin 14 (K14) genes and characterized by development of intraepidermal skin blisters. The three major subtypes of EBS are Weber-Cockayne, Koebner, and Dowling-Meara, of which the Dowling-Meara form is the most severe. We have investigated five large Danish families with EBS and two sporadic patients with the Dowling-Meara form of EBS. In the sporadic Dowling-Meara EBS patients, a novel K14 mutation (N123S) and a previously published K5 mutation (N176S) were identified, respectively. A novel K14 mutation (K116N) was found in three seemingly unrelated families, whereas another family harbored a different novel K14 mutation (L143P). The last family harbored a novel K5 mutation (L325P). The identified mutations were not present in more than 100 normal chromosomes. Six polymorphisms were identified in the K14 gene and their frequencies were determined in normal controls. These polymorphisms were used to show that the K14 K116N mutation was located in chromosomes with the same haplotype in all three families, suggesting a common ancestor. We observed a strict genotype-phenotype correlation in the investigated patients as the same mutation always resulted in a similar phenotype in all individuals with the mutation, but our results also show that it is not possible to predict the EBS phenotype merely by the location (i.e., head, rod, or linker domains) of a mutation. The nature of the amino acid substitution must also be taken into account.

The cause of spontaneous cervicocerebral artery dissection is unknown. An underlying arteriopathy due to a connective tissue disorder has often been presumed. We studied 25 patients with proven nontraumatic dissections. The ultrastructural morphology of dermal connective tissue components was assessed by transmission electron microscopy of skin biopsies. Ultrastructural abnormalities were seen in 17 (68%) patients, resembling in some cases the aberrations found in Ehlers-Danlos syndrome type II or III. These observations indicate a correlation of cervical artery dissections with connective tissue abnormalities. A structural abnormality in the extracellular matrix potentially caused by basic molecular defects is suggested and warrants further exploration.

We report a 21-month-old girl with symptoms consistent with the Zunich neuroectodermal syndrome, an apparently rare condition first described in 1983. Common features of all previously reported patients as well as in this child are characteristic craniofacial dysmorphism, bilateral colobomas of the retina, sparse and fine hair, hearing loss, ichthyosiform erythroderma, mental retardation, ear anomalies, brachydactyly, and broad second toes. Light microscopic and ultrastructural investigations of the affected skin showed characteristic but nonspecific changes. The structural hair shaft abnormalities as well as the dysplastic nails in our patient have not been described before and are consistent with the previous assumption of an ectodermal dysplasia syndrome.

Among the different subtypes of Ehlers-Danlos syndrome (EDS), the dominant types I-III have, so far, been uninformative biochemically and molecular genetically, and diagnostic problems with subgroup boundaries often arise. We have investigated the ultrastructural pattern of connective tissue macromolecules in skin biopsy specimens of some 85 patients aged 4 months-54 years who exhibit clinical symptoms or the suspicion of EDS I-IV. Based on the differential features of collagen fibrils and ground substance material, four distinct groups could be established. Group I (clinically EDS type I) showed disorganized collagen bundles and dense aggregations of collagen fibrils with bizarre shapes. Group II (clinically varying from EDS types I-III) revealed collagen bundles that regularly contained numerous "composite collagen fibrils" with enlarged "flower-like" cross-sections and rope-like longitudinal sections, often associated with increased amounts of matrix substances in the form of electron-dense irregular strands and filaments in a branched network. Group III (clinically EDS types II-III) presented smaller isolated collagen flowers and ropes associated with excessive filamentous ground substance material and flocculent material. Group IV (with clinical symptoms of EDS type IV) had a dermis thinned to one third of the normal and a reduced number of collagen bundles with small diameter fibrils. In 13 patients, the abnormal ultrastructural dermal architecture did not coincide with any of these four groups or with the pattern of any other inherited connective tissue disorder. In 16 additional patients with mostly mild clinical symptoms, such as muscle weakness and small joint hyperlaxity, no ultrastructural aberrations could be found. Even though the primary defects underlying the respective aberration of the collagen fibrils are still unknown, the differential ultrastructural changes of the collagen fibrils together with clinical symptoms should, as in other heterogeneous genetic disorders, facilitate the (provisional?) classification of EDS and permit the diagnosis of individual cases.

Epidermolytic hyperkeratosis (EHK), (bullous congenital ichthyosiform erythroderma), is an autosomal dominant human skin disorder. Recently, we and others have described mutations in keratins 1 and 10 (K1 and K10) in patients with this disease. Structure-function models predict that these mutations would impair normal filament assembly and function. We have extended our earlier studies to include 8 more incidences of EHK. In half of these families, we were unable to locate a mutation within the rod domains of either K1 or K10. However, polymorphic restriction site and sequence analysis of the other families revealed a mutational hot spot within the 1A alpha-helical segment of K10. These involve Arginine to Histidine, Arginine to Cysteine and Arginine to Leucine substitutions at residue 10 of the rod domain. Interestingly, mutations in the corresponding Arginine residue in keratin K14 have been identified in patients with epidermolysis bullosa simplex. The large number of mutations found at this position in both keratins K10 and K14 suggests that other epithelia cell disorders will be discovered that are caused by the corresponding mutation in related type I keratin genes.

Filaggrin, a basic protein of the stratum corneum, was named as such because of its capability to aggregate keratin intermediate filaments in vitro. To investigate its filament-aggregating capability in vivo, we performed immunoelectron microscopy in three autosomal dominant genodermatoses serving as in vivo models of abnormalities of keratin filament aggregation. In bullous congenital ichthyosiform erythroderma Brocq and epidermolytic palmoplantar keratoderma Voerner suprabasal clumping of keratin filaments prevents the normal spreading of keratohyalin between keratin filaments. Keratohyalin granules, either isolated or attached to clumped keratins, were specifically labelled by the anti-filaggrin antibody, whereas tonofilament clumps did not show any reaction. In epidermolysis bullosa herpetiformis Dowling-Meara the abnormal filament aggregation occurred in basal cell keratins where no reaction of the anti-filaggrin antibody was detected. In high level keratinocytes with normal distribution of tonofilaments, normal stellate keratohyalin reacted specifically. In all instances keratin filament clumping occurred independently of, and spatially separated from, the first signs of profilaggrin synthesis and keratohyalin granule formation. Thus, in these disorders, filaggrin is not involved in filament aggregation.

A male patient presented with a congenital ichthyosis clinically characterized by generalized erythroderma, fine scaling on the trunk and palmoplantar hyperkeratoses with severely affected nails. The acanthotic epidermis was characterized by hyperproliferation with a large quantity of mitoses and extremely suppressed keratinization without a normal granular layer. The horny layer was parakeratotic and contained remnants of cell debris and lipid droplets. Ultrastructurally the prickle cell layer was characterized by binuclear cells, oedematization of the keratinocytes and isolated dyskeratotic cells. Some suprabasal cells showed unusual morphological features, containing nuclei with cytoplasmic pseudoinclusions, sometimes leading to a complete disintegration of the nuclear structure, and bowl- and lens-shaped accumulations of a filamentous material. Instead of normal tonofibrils, the aggregated material consisted of fine interlacing filaments. The latter are compared with the filamentous shells in ichthyosis hystrix Curth-Macklin and congenital reticular ichthyosiform erythroderma. The clinical symptomatology — congenital ichthyosis, growth retardation, secondary hypogonadism, hepatomegaly — and the ultrastructural characteristics of the keratinization disorder indicate that the present case cannot be considered as a subtype of the recessively inherited ichthyosis congenita group, but suggest a new syndrome as a separate nosologic entity.

The preferred description for the Gronblad-Strandberg syndrome, pseudoxanthoma elasticum (PXE), refers only to the cutaneous aspect of the disease, although the skin is the least severely involved organ. The potential catastrophic manifestation of this heterogeneous heritable disorder is described in a dominant pedigree where mother and grandmother died because of major vascular problems. The family requested predictive testing of the three children. Diagnosis of PXE is usually performed by morphological examination of skin lesions, which reveal incrustations formed by inorganic ions (mainly calcium) and various organic (degraded?) materials in the elastin moiety of the elastic fibers. The ubiquitous elastic fibers in other organs and arteries may be similarly involved. Moreover, there is co-involvement of collagen fibrils at the electron microscopical level. The three adolescent siblings did not show any clinical PXE symptoms. However, ultrastructural investigation of overtly normal skin in predilection sites gave a positive diagnosis for this dominant PXE type. Dermal connective tissue showed a specific aberrant pattern: elastin of elastic fibers regularly contained small foci of calcification resembling those in perilesional skin of the mother and other PXE patients; in collagen bundles adjacent to altered elastic fibers, collagen fibrils occurred with thickened diameters and flower-like contours; ground substance material was increased. The possible pathogenetic mechanism and problems posed by predictive testing of adult-onset diseases are discussed.

We report the first use of amnion epithelium for prenatal diagnosis. Prenatal diagnosis of recessive epidermolysis bullosa atrophicans generalisata gravis Herlitz type can at present be achieved with safety by detailed ultrastructural analysis of fetal skin. Because of the close developmental origin of amnion and skin, which has been elucidated by the recent development of anti-amnion antibodies against dermo-epidermal junction antigens and by their abnormal binding in epidermolysis bullosa skin, there is presumably some morphological relationship between amnion epithelium and skin. In a comparative study of extra-embryonic tissues, we found ultrastructurally complete hemidesmosomes in all 24 investigated normal amnion samples from gestational weeks 15-27, but not in 7 reflected chorion samples from weeks 16-22. The results of placental chorion samples were not reliable. Amnion of 5 fetuses affected with epidermolysis bullosa atrophicans generalisata gravis revealed only hypoplastic hemidesmosomes, the same defect as in the respective skin. In a recent case where unfortunately only non-skin material was available, a positive prenatal diagnosis of epidermolysis bullosa atrophicans gravis Herlitz was performed from the amnion material. The diagnosis was confirmed by investigation of the fetal skin after termination. Investigation of amnion membranes is therefore an alternative for prenatal diagnosis of epidermolysis bullosa atrophicans gravis Herlitz in certain cases. The possibility and limitations of the general use of amnion for prenatal diagnosis are discussed.

Prenatal diagnosis of X-linked hypohidrotic ectodermal dysplasia was previously performed by the direct histological analysis of fetal skin obtained by late second trimester fetoscopy. The recent gene mapping of the locus for the disorder to the region of Xq11-21.1 now permits the indirect prenatal diagnosis of the disorder by the method of linkage analysis, based on closely linked marker loci, during the first trimester of pregnancy. We report the prenatal diagnosis of a male fetus with a high probability of the disorder by a linkage analysis utilizing restriction fragment length polymorphisms at the DXS159, PGK1, and DXS72 loci, from a DNA sample obtained by a chorionic villus biopsy at 9 weeks gestation. After further counseling, the pregnancy was terminated but the diagnosis could not be confirmed by histological analysis, even though analysis of skin samples by light and electron microscopy showed lack of hair germs, primary dermal ridges, and sweat gland primordia, due to the early developmental stage of the fetus. The use of DNA-based linkage analysis now offers the opportunity for an earlier diagnosis of X-linked hypohidrotic ectodermal dysplasia by a method other than fetal skin sampling. However, families must also fully understand the present limitations of the method prior to undertaking the procedure.

Up to now, bicomponent keratohyalin has only been described for rat epithelium and human intraepidermal sweat ducts and fetal nail organ cells. In normal human interductal epidermis, the keratohyalin appears homogeneous, osmiophilic and stellate in shape. Under pathological conditions, bicomponent keratohyalin has been observed in different palmoplantar keratoses and has therefore been thought to be associated with abnormal keratosis. We studied the keratinization process in normal human plantar epidermis, in which keratohyalin was found to exhibit several morphological differences as compared to that seen in non-ridged skin. The most striking feature was seen in upper granular cells, where the keratohyalin granules consisted of two components of differing electron density. The electron-dense component formed the main part of the composite granule and was found in the cytoplasm of lower and upper granular cells. The less-electron-dense component was attached to the main component and appeared in the cytoplasm of upper granular cells, forming the convex contact zone. No intranuclear osmiophilic inclusions were present. The respective electron densities of the two keratohyalin components of ridged skin were obviously different to that of the bicomponent keratohyalin granules seen in the epidermal sweat-duct cells of the same specimen. These findings indicate the presence of at least two different types of keratohyalin proteins in normal human ridged skin. They can be distinguished at the electron-microscope level and differ from the keratohyalin of human non-ridged skin as well as from bicomponent keratohyalin granules derived from human epidermal sweat-duct cells or from rat epithelium.

A new kind of diffuse palmoplantar keratoderma with autosomal recessive inheritance and without associated symptoms was described in Norrbotten, Sweden by Gamborg Nielsen in 1985. Clinically, it ranges between the less severe dominant Unna-Thost type and the more severe recessive Meleda type, as it is milder than the latter. Skin biopsies of five patients from three different families with this new palmoplantar keratoderma, as well as five obligatory heterozygotes from one family, were investigated ultrastructurally in order to characterize this new entity and to differentiate it from the Meleda type. Several features are common to both autosomal recessive palmoplantar keratoses. They show a broadened granular layer, a transit region consisting of cells with a marginal envelope, and considerable hyperkeratosis. Morphologically, this transformation delay is less pronounced in the Gamborg Nielsen type than in the classical Meleda type. As is typical for ridged skin, both types of palmoplantar keratoses possess composite keratohyaline granules. In contrast to the normal appearance of keratohyaline granules in the Meleda type, the Gamborg Nielsen type also shows qualitative deviations of keratohyaline granules with different degrees of spongiosity and electron density and sometimes with a granular border. It seems that abnormal keratohyaline proteins are synthesized that behave differently. The sudden transformation of a granular into a horny cell is physiologically regulated by different enzymes. A delay in this process may be caused by a mutation that reduces or alters the enzymes concerned. We assume the palmoplantar keratoderma of the Gamborg Nielsen type to be a variant of the heterogeneous group of the Meleda type of palmoplantar keratoderma with autosomal recessive inheritance.

• Background.— The homogeneous material found in the skin is commonly identified as amyloid. We describe a previously unknown disease that is caused by proteinaceous deposits and that does not fulfill the criteria of the earlier recognized amyloid diseases. Observations.— The unusual deposits, which were initially found in the dermis, were ultrastructurally composed of fibrillar material with a tubular substructure. Immunohistologically, the material was tested using a large panel of antibodies, and the results revealed that it was unlike any commonly known proteinaceous material. The deposits later spread to other organs and disturbed the vital functions of the body. Conclusions.— We describe a unique syndrome characterized by fibrillar extracellular deposits that was recognized and differentiated from other similar clinical syndromes by ultrastructural examination. Further biochemical analysis is necessary to identify the origin of the material. ( Arch Dermatol. 1993;129:757-762)

• Background.— Restrictive dermopathy is an autosomal recessive phenotype characterized by universal tautness of skin resulting in fetal akinesia and death during the neonatal period. The clinical signs and symptoms of this uncommon disease are described in two brothers, and evidence is provided that fetal biopsy specimens obtained during the 20th week of gestational age are nondiagnostic. Observations.— The first patient was a growth-retarded preterm boy suffering from generalized desquamation, marked joint contractures, and facial hypoplasia. Prominent light microscopic findings were hyperorthokeratosis intermingled with parakeratosis and absence of the elastic fibers in a thinned dermis. Electron microscopic examination of the epidermis revealed a lack of keratin filaments and an abnormal globular shape of the keratohyalin granules. The child died 4 days after birth. A following pregnancy resulted in birth of a preterm boy who died of the same disease within 2 hours. In the 20th week of gestational age, fetal biopsy specimens were obtained, but light and electron microscopy failed to reveal any abnormalities. Conclusions.— Restrictive dermopathy is a genuine skin disease resulting in fetal akinesia that precludes a normal intrauterine development. The clinical features of this disorder are so distinctive that an on-the-spot diagnosis can be established. In view of the data obtained in this case, the feasiblity of prenatal diagnosis should be regarded with great caution. ( Arch Dermatol. 1992;128:232-235)

Ultrastructural examination was performed in 42 biopsy specimens from 22 patients with the Hallopeau-Siemens types or with the inverse type of epidermolysis bullosa dystrophica recessiva. The patient group consists of 8 cases of the localized Hallopeau-Siemens type, 9 of the generalized Hallopeau-Siemens type and 5 of the inverse type. The origins of the biopsy specimens are involved, intact and experimentally frictioned skin from blister-predilected sites, as well as clinically normal skin from nonpredilection sites. It is confirmed that all the blisters initiate below the basal lamina. Anchoring fibrils are moderately to markedly decreased in most cases, but normal in 3 cases. The collagen fibrils are more or less changed in the majority of cases, while they are normal in 3 other cases. It is thought that secondary degradation of anchoring fibrils and/or collagen fibrils plays an important role in blistering mechanism in the Hallopeau-Siemens and inverse types of recessive dystrophic epidermolysis bullosa, whereas a primary aplasia of anchoring fibrils as causative defect has been out ruled.

The late onset of normal keratinization after week 24 menstrual age (MA) of fetal life is the cause of considerable problems with the prenatal diagnosis of congenital ichthyosis. This paper summarizes the experiences with prenatal diagnosis in nine pregnancies at risk of congenital ichthyosis and one at risk of chondrodysplasia punctata, rhizomelic type. An important prerequisite--and the main problem--is the manifestation of the mutant genes early enough in fetal life to allow a safe exclusion. Continuous precocious keratinization of the interfollicular epidermis, hyperkeratosis, and/or specific markers of congenital ichthyosis such as various types of lipid inclusions had been expected. With a normal ultrastructure and development of fetal epidermis no evidence of ichthyosis was present in eight cases; all eight children were born healthy. Regional variations of the onset of keratinization of the interfollicular epidermis, observed in one of these eight fetuses as well as in one fetus at risk (but normal for) recessive dystrophic epidermolysis bullosa, posed considerable problems and might lead to a false-positive diagnosis. Examination after birth allowed one to localize these regions to areas close to the mamillae. Regional variations in addition to the well-known cranio-caudal gradient thus are normal findings: both children have normal skin. One fetus at risk of non-bullous congenital ichthyosiform erythroderma (type II) was involved without prenatal manifestation of interfollicular keratinization, specific markers, or increased numbers of cornified cells in the pilosebaceous follicles at 20 weeks MA. A slightly more irregular pattern of the horn cell contents was not regarded as sufficient evidence alone to indicate congenital ichthyosis. A severely affected boy was born in week 34 MA. Similarly the fetus at risk of chondrodysplasia punctata showed no skin abnormalities, neither at fetoscopy (week 22 MA) nor after abortion (week 24 MA) although based on other clinical features it was clearly affected. Thus, this genodermatosis cannot be diagnosed prenatally by its keratinization disturbances. In future cases, precocious keratinization and hyperkeratosis cannot be expected to be expressed before week 24 MA, and minor signs, such as irregularities of horn cell contents, have to be taken as an indication of involvement. Multiple biopsies are required, and a safe exclusion may be impossible before week 22 MA.

We report the case of a 15-year-old girl with an uneventful family history. Her skin condition was clinically, histologically and ultrastructurally compatible with the diagnosis of ichthyosis congenita. She suffered from neurosensory deafness and oligophrenia. Further findings included dental aplasia, brachydactyly, clinodactyly and accessory cervical ribs. At the age of 14, a thyroid carcinoma was diagnosed. Therapy with a retinoid derivative (Ro 10–9359) resulted in a marked improvement of the ichthyosis. We assume a genetic syndrome with autosomal-recessive inheritance.

The ultrastructure of epidermolysis bullosa simplex type Weber-Cockayne has as yet not been studied systematically. Therefore biopsies of blisters freshly produced by friction after a hot bath were investigated by electron microscopy in 8 subjects of 6 families. Blister formation was found always to start in the basal layer of the epidermis. At first the cytoplasm with the cell organelles appears to become diluted, then holes develop in the cytoplasm which merge and finally form cytolytic blisters between the dermo-epidermal junction and the nucleus. The cell organelles remain remarkably intact. The cause of blister formation is still unknown, however, no structural abnormality was observed.

Hopes are held out for chorion villus sampling, a technique which is gaining more and more importance for the first trimester prenatal diagnosis of chromosomal aberrations and metabolic abnormalities. A variety of inherited skin diseases can be diagnosed postnatally and prenatally (in the second trimester) by ultrastructural diagnostic markers. For evaluation of prenatal diagnosis in the first trimester, we investigated chorionic villi derived from the trophoblast layer of the early pregnancy by light microscopy and conventional electron microscopy. The ultrastructure of the cellular layers covering the villi, i.e., the inner cytotrophoblast and the outer syncytiotrophoblast, as well as that of the connective tissue of the inner extraembryonic mesoderm, are thoroughly described in relation to the ultra-structural changes in certain genodermatoses including epidermolyses and keratinization disorders. We found that chorionic villi have only a few of the characteristics differentiated in skin, and none of the structures which are relevant to the diagnosis of genodermatoses. In our view, the ultrastructural approach is not suitable for first trimester prenatal diagnosis of genodermatoses in chorionic villi.

Ultrastructural examination was performed in 8 biopsies from 4 patients with the Pasini type of epidermolysis bullosa dystrophica dominans. The biopsies were taken from: 1. clinically normal skin from nonpredilection areas, 2. intact skin from predilection areas, 3. involved skin and 4. experimentally frictioned skin. The main ultrastructural alterations detected are as follows: hypoplasia of anchoring fibrils, split or blister formation between basal lamina and dermis, hernia-like protrusion of basal cells, sub- and intraepidermal deposition of fibrillar bodies, and duplications of basal lamina. Among them, the constantly observed finding in all of the four biopsy groups is the structural defect of anchoring fibrils, namely, that the anchoring fibrils are rudimentary and reduced in number. Presence of the structural defect of anchoring fibrils in clinically normal skin fromnonpredilection areas in patients with the Pasini type of epidermolysis bullosa dystrophica dominans indicates that this defect is not a secondary change following repeated mechanical trauma, but a primary, genetically determined event.

Clinical, histopathological, and ultrastructural features of a new clinical variant of porokeratosis Mibelli (PM) are presented. We report a solitary case of a patient, male aged 62, who developed disseminated verrucous nodules on the buttocks and the lower extremities 3 years before diagnosis. Histopathologically, all specific signs of the keratinization disorder of PM were demonstrable; in addition, however, multiple cornoid lamellae were found at the margin as well as in the center of the lesions, which only in part showed relationships to the epidermal appendages. In the papillary dermis, numerous ectatic capillaries were conspicuous. Using electron microscopy the same specific abnormalities of the keratinization process as known from classical cases of PM could be demonstrated: autophagocytic cells that revealed perinuclear edematization and vacuolization, accumulation of autophagic vacuoles and heterolysosomes, and dyskeratotic corps ronds-like cells that become transformed to fibrillar or Civatte bodies. Problems of the classification, differential diagnosis, and pathomorphogenesis are discussed.

Comparative ultrastructural investigations on the pathomorphogenesis of inherited ichthyoses and epidermolyses have shown that such heterogeneous skin disorders may serve as model systems for genetic interactions with developmental processes, such as keratinization, or functional systems, such as dermal-epidermal junctional integrity. Most interesting from the morphologic point of view are dominantly inherited skin disorders in the ichthyosis and epidermolysis bullosa groups in which primary structural defects of structural proteins have been demonstrated that seem to be under the direct control of the mutant gene. Such structural abnormalities concern keratohyalin in autosomal-dominant ichthyosis vulgaris, the tonofilament system in hystrix-like ichthyoses, and the anchoring fibrils in dominant dystrophic epidermolyses. Taking bullous congenital ichthyosiform erythroderma (epidermolytic hyperkeratosis) as a central example, we discuss the stability of such structural defects, the heterogeneity in the ultrastructural abnormalities of clinically closely similar entities (ichthyosis hystrix Curth-Macklin, congenital reticulate ichthyosiform erythroderma), and, in the latter keratinization disorder, the presence of an unusual filament system of unknown biochemical composition in the abnormal keratinocytes. Expression of mutant genes during fetal life and fetal manifestation of such abnormalities are a precondition for the prenatal diagnosis of genetic skin disorders (bullous ichthyosiform erythroderma, epidermolysis bullosa dystrophica Hallopeau-Siemens, Herlitz syndrome). Finally, problems related to the differentiation of mutant keratinocytes and of amniotic fluid cells of fetuses at risk of genetic skin disorders under the in vitro conditions of primary cell cultures are briefly discussed.

Total replacement of the esophagus by colonic interposition has been recommended as the treatment of esophageal obstruction in recessive dystrophic epidermolysis bullosa. We report our experience in the conservative management of esophageal blisters, strictures, and complete occlusion in 5 patients (aged 2-61 yr). Our therapy consists of a combination of the following principles: (a) inhibition of collagenase formation by oral phenytoin to reduce epithelial detachment; (b) pureed or semiliquid food because minor trauma by hard food particles may induce blistering and result in scarring of the upper esophagus, and larger food particles may obstruct an esophageal stricture; (c) avoidance of tangential shearing forces induced by bougienage and endoscopy and instead use of inflatable dilatator balloons which produce vertical pressure that seems to be less harmful; and (d) long-term nasogastric tube feeding, which may relieve even tight strictures. Our observations suggest that successful long-term conservative management of esophageal stenoses in dystrophic epidermolysis bullosa is possible.

Ultrastructural studies on a familiar case of Epidermolysis bullosa dystrophica dominans have demonstrated that normal anchoring fibrils are missing in the junctional area beneath the basal lamina; some rudimentary fibrils without typical banding patterns may be found occasionally. All other junctional structures, i.e. half desmosomes, plasmamembrane, anchoring filaments, and basal lamina, are of normal ultra-structure. The bulla is formed subepidermally, the basal lamina remaining at the top of the bulla.

Ultrastructural evidence is presented for significant distinction of autosomal dominant ichthyosis vulgaris (ADI) and x-linked recessive ichthyosis (XRI). In the case of ADI a severe disturbance of keratohyalin synthesis reults in a largely reduced deposition of minute abnormal keratohyalin granules of crumbly appearance; on the contrary, keratohyalin in XRI is synthesized in normal or increased amounts. The mode of inheritance has been confirmed by genetic analysis of the patient’s families.