1/62. A premature stop codon mutation in the 2B helix termination peptide of keratin 5 in a German epidermolysis bullosa simplex Dowling-Meara case.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.- - - - - - - - - - ranking = 1keywords = simplex (Clic here for more details about this article) |
2/62. Myopathy, myasthenic syndrome, and epidermolysis bullosa simplex due to plectin deficiency.plectin, an intermediate filament linking protein, is normally associated with the sarcolemma, nuclear membrane, and intermyofibrillar network in muscle, and with hemisdesmosomes in skin. A 20-year-old female with epidermolysis bullosa simplex since birth had progressive ocular, facial, limb, and trunkal weakness and fatigability since age 9, fivefold CK elevation, a 25% decrement with myopathic motor unit potentials and increased electrical irritability on electromyography, and no anti-acetylcholine receptor (AChR) antibodies. plectin expression was absent in muscle and severe plectin deficiency was noted in skin. Morphologic studies revealed necrotic and regenerating fibers and a wide spectrum of ultrastructural abnormalities: large accumulations of heterochromatic and lobulated nuclei, rare apoptotic nuclei, numerous cytoplasmic and few intranuclear nemaline rods, disarrayed myofibrils, thick-filament loss, vacuolar change, and pathologic alterations in membranous organelles. Many endplates (EPs) had an abnormal configuration with chains of small regions over the fiber surface and a few displayed focal degeneration of the junctional folds. The EP AChR content was normal. in vitro electrophysiologic studies showed normal quantal release by nerve impulse, small miniature EP potentials, and fetal as well as adult AChR channels at the EP. Our findings support the notion that plectin is essential for the structural integrity of muscle and skin, and for normal neuromuscular transmission.- - - - - - - - - - ranking = 1keywords = simplex (Clic here for more details about this article) |
3/62. epidermolysis bullosa simplex with mottled pigmentation: clinical aspects and confirmation of the P24L mutation in the KRT5 gene in further patients.epidermolysis bullosa simplex with mottled pigmentation (EBS-MP) is a rare dermatologic disorder of autosomal dominant inheritance with intraepidermal blistering after minor trauma, reticular hyperpigmentation unrelated to the blistering, nail dystrophy, and mild palmoplantar keratosis. Keratin 5 and keratin 14 are known to be essential for the basal keratinocyte cytoskeleton and are defective in several forms of epidermolysis bullosa simplex. Recently, a 71C-->T transition in the keratin 5 gene (KRT5) causing a P24L substitution was identified in some patients with EBS-MP. We present a family with three affected members and a sporadic patient with EBS-MP. They exemplify clinically mild expression with intrafamilial variability and the possibility of improvement with time. In all of them, mutation analysis of the KRT5 gene showed the P24L mutation. So far, other mutations in the same or in other genes have not been reported in patients with EBS-MP.- - - - - - - - - - ranking = 1.2keywords = simplex (Clic here for more details about this article) |
4/62. epidermolysis bullosa simplex associated with muscular dystrophy: phenotype-genotype correlations and review of the literature.BACKGROUND: epidermolysis bullosa simplex associated with muscular dystrophy (EBS-MD; OMIM# 226670) is an autosomal recessive disorder caused by genetic defects in the plectin gene. Because EBS-MD is relatively rare, and gene defects have been elucidated only in a limited number of patients, the precise phenotype-genotype correlations have not yet been fully elucidated. OBJECTIVE: The purpose of this study was to define clinical features of EBS-MD and to clarify its phenotype-genotype correlations. methods: Clinical, ultrastructural, immunohistochemical, and molecular features of 4 unrelated Japanese patients with EBS-MD were recorded. In addition, 6 cases with defined plectin gene mutations reported in the literature were reviewed. RESULTS: In skin of the EBS-MD patients, the blister formation always occurs just above the hemidesmosomes, and expression of plectin is absent or markedly reduced in all cases examined. All 10 patients, including 6 cases in the literature, showed generalized blistering at birth or soon thereafter, and experienced nail deformities. In addition, decayed teeth (5 cases), urethral strictures (3), mild palmoplantar hyperkeratosis (2), infantile respiratory complications (2), alopecia (1), and laryngeal webs (1) were present. All 8 patients who were older than 9 years demonstrated considerable muscle weakness, and the majority of them ended up being wheelchair bound. Among the 10 patients, 7 were products of consanguineous marriage, 9 have premature termination codon (PTC) mutations in both alleles of the plectin gene, and 7 cases were homozygous for the mutation. One patient who is homozygous for a 2719del9 in-frame deletion mutation that resulted in elimination of 3 amino acids, QEA, could still walk at the age of 46 and showed milder clinical severity. CONCLUSION: EBS-MD reveals clinical features not only characteristic of EBS and MD, but also other manifestations including urethral, dental, and respiratory complications. The majority of patients are products of consanguineous marriage and have homozygous plectin gene mutations. Whereas patients with PTC mutations in both alleles typically showed severe clinical features of EBS-MD and ended up being wheelchair bound, a homozygous patient for an in-frame deletion mutation showed positive, yet attenuated, plectin expression and milder clinical phenotype. Thus plectin immunofluorescence, combined with identification of the underlying plectin mutations, is of value in predicting the severity of the muscle involvement that occurs later in life of patients with EBS-MD.- - - - - - - - - - ranking = 1keywords = simplex (Clic here for more details about this article) |
5/62. Laryngeal involvement in the Dowling-Meara variant of epidermolysis bullosa simplex with keratin mutations of severely disruptive potential.The clinical features of the Dowling-Meara variant of epidermolysis bullosa simplex (EBS-DM) can, in an infant, be indistinguishable from other severe forms of epidermolysis bullosa (EB). Two unrelated infants with no family history of skin disease are described who, within hours of birth, developed extensive blistering of skin and oral mucosae and who both subsequently developed hoarse cries. Despite this superficial resemblance to other forms of EB, electron microscopy revealed a basal cell rupture and keratin aggregates characteristic of EBS-DM in the skin of both infants and in the vocal cord epithelium of one. Molecular analysis confirmed the diagnosis by identification of mis-sense point mutations in basal cell keratin genes in both cases. One patient carries a point mutation in keratin 14 (converting arginine at position 125 to histidine) and the other has a novel point mutation in keratin 5 (converting serine at position 181 to proline). hoarseness is not a well documented feature of EBS-DM and is usually associated with junctional EB. These two patients demonstrate that the presence of a hoarse cry in an infant affected by severe EB does not necessarily indicate a poor prognosis.- - - - - - - - - - ranking = 1keywords = simplex (Clic here for more details about this article) |
6/62. Leukocytoclastic vasculitis in a child with epidermolysis bullosa simplex.A 10-year-old boy with epidermolysis bullosa simplex (Weber-Cockayne variant) together with leukocytoclastic vasculitis is presented. He was admitted to the hospital with the provisional diagnoses of infected epidermolysis bullosa simplex or drug eruption. On the sixth day of hospitalization he developed palpable purpura, abdominal pain and bloody diarrhea, together with hematuria and proteinuria. A generalized tonic-clonic convulsion, changes in mental status, fluctuations in arterial blood pressure and intractable pain in his extremities occurred during the course of hospitalization. Systemic pulse steroid therapy, antibiotics, and antihypertensive and anticonvulsive drugs were given. On the 30th day of hospitalization, a skin graft was performed to replace a large tissue defect on his left hand. Despite high dose steroid therapy, his hematuria, proteinuria and hypertension continued after his discharge, suggesting a steroid-resistant renal pathology, such as focal glomerulosclerosis, that occurred secondary to leukocytoclastic vasculitis.- - - - - - - - - - ranking = 1.2keywords = simplex (Clic here for more details about this article) |
7/62. dna based prenatal testing for the skin blistering disorder epidermolysis bullosa simplex.epidermolysis bullosa simplex (EBS) is a skin fragility disorder in which mild physical trauma leads to blistering. The phenotype of the disorder is variable, from relatively mild affecting only the hands and/or feet, to very severe with widespread blistering. For the severest forms of EBS there is a demand for prenatal diagnosis which until now has involved a fetal skin biopsy in the second trimester. The identification of mutations in the genes encoding keratins K5 and K14 as the cause of EBS opens up the possibility of much earlier diagnosis of the disease. We report here four cases in which prenatal testing was performed. In three of the cases the genetic lesions were unknown at the start of the pregnancy, requiring the identification of the causative mutation prior to testing fetal dna. In two of the four cases novel mutations were identified in K14 and in the two remaining families, a previously identified type of mutation was found. Fetal dna, obtained by chorionic villus sampling or amniocentesis, was analysed for the identified mutations. Three of the dna samples were found to be normal; a mutant K14 allele was identified in the fourth case and the pregnancy was terminated. These results demonstrate the feasibility of dna-based prenatal testing for EBS in families where causative mutations can be found.- - - - - - - - - - ranking = 1keywords = simplex (Clic here for more details about this article) |
8/62. epidermolysis bullosa simplex (Dowling-Meara type) associated with pyloric atresia and congenital urologic abnormalities.We report a case of epidermolysis bullosa simplex, Dowling-Meara type (EBS-DM), which was associated with congenital pyloric atresia (PA) and various urologic abnormalities, a diagnosis confirmed by immunofluorescence mapping and electron microscopic findings. Immunofluorescent mapping showed the serum from a patient with bullous pemphigoid faintly binding to the floor of the blister, and monoclonal antibodies against type IV and VII collagens were also stained on the floor of the blister. Electron microscopy showed epidermolytic cleavage and prominent clumping of tonofilaments in the basal and suprabasal keratinocytes. An abdominal radiograph and barium swallow showed a complete obstruction at the pyloric channel level. The widespread bullae healed without any scar formation and the bullae formation was localized on the extremities after 3 months of age without any specific treatment. Multiple urologic abnormalities such as bilateral hydronephrosis, hydroureter and a distended bladder with trabeculation were observed at 12 months of age. Currently, with the patient at 4 years of age, bullae still appear on the hands and feet and nail shedding can be observed. The patient's father, a paternal uncle and a paternal aunt had had similar bullous eruptions in infancy, all of which had improved spontaneously by the age of one.- - - - - - - - - - ranking = 1keywords = simplex (Clic here for more details about this article) |
9/62. A keratin 14 'knockout' mutation in recessive epidermolysis bullosa simplex resulting in less severe disease.epidermolysis bullosa simplex (EBS) is a blistering skin disease caused in most cases by mis-sense mutations in genes encoding the basal epidermal keratin (K) 5 and K14. The inheritance is usually autosomal dominant and the mutant keratin proteins appear to exert a dominant negative effect on the keratin intermediate filament cytoskeleton in basal keratinocytes. We report a child with a homozygous K14 mutation resulting in the complete absence of K14 protein in the epidermis; remarkably, he only had mild to moderate disease. Electron microscopy of a skin biopsy showed a marked reduction in numbers of keratin intermediate filaments in the basal keratinocytes. Immunofluorescence microscopy using monoclonal antibody LL001 against K14 showed no staining, suggesting a functional knockout of K14. sequence analysis of genomic dna revealed a homozygous mutation in codon 31 of K14 that resulted in a premature stop codon further downstream in exon 1. The child's mother, who is unaffected by the disease, is heterozygous for the mutation. The consanguineous father was unaffected and unavailable for testing. The resulting mRNA is predicted to encode a protein of 116 amino acids, of which the first 30 are identical to the normal K14 sequence, and the remaining 86 residues are mis-sense sequence. Four previously reported cases of autosomal recessive EBS with functional knockout of K14 were severely affected by blistering, in contrast to our patient in whom the predicted protein has only the first 30 amino acids of K14 and is therefore the closest to a true knockout of K14 protein yet identified.- - - - - - - - - - ranking = 1keywords = simplex (Clic here for more details about this article) |
10/62. Cultured keratinocytes from plectin/HD1-deficient epidermolysis bullosa simplex showed altered ability of adhesion to the matrix.epidermolysis bullosa simplex associated with late onset of muscular dystrophy has been found to show defective expression of plectin, an intracytoplasmic protein in hemidesmosomes. In this report, we examined ability of cell-to-matrix attachment of cultured keratinocytes derived from a case with this disease by various cell biological methods, and compared it to that of normal keratinocytes. In cell adhesion assay, the patient keratinocytes showed more prominent short-time cell adhesion than normal keratinocytes. In contrast, the patient keratinocytes could be detached much easier than normal keratinocytes in cell detachment assay by treatment with dispase. In phagokinetic track assay, no apparent difference of cell migration was observed between the patient and normal keratinocytes. These results indicate that plectin-deficiency may up-regulate short-term cell contact and reduce stable cell-matrix adhesion at the epidermal basement membrane zone.- - - - - - - - - - ranking = 1keywords = simplex (Clic here for more details about this article) |
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