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Recently, the molecular bases of the most frequent ectodermal dysplasias have been identified; they involve genes responsible for the epithelial morphogenesis, and the regulation of cell survival and proliferation. Teeth alterations with characteristic features are often observed in X-linked anhidrotic ectodermic dysplasia and in autosomic recessive anhidrotic ectoderma, rarely in hidrotic ectodermal dysplasia.
Hereditary ectodermal dysplasia is an inherited disorder characterized by aplasia or dysplasia of ectodermal tissues, such as hair, nails, teeth, and skin, that occurs in approximately 1 in every 100,000 live births. Dental abnormalities and abnormal facial appearance are of major concern in childhood and adolescence, since they can restrict the individual socially and affect his or her self-confidence. Oral rehabilitation in the early stages of the patient's life may provide functional and esthetic restoration as well as safeguard psychologic health. This report presents the clinical procedures involved in the rehabilitation of a 10-year-old female patient with complete bilateral cleft lip and palate and ectodermal dysplasia.
The ectodermal dysplasia, ectrodactyly, cleft lip/palate syndrome (EEC syndrome) is an autosomal dominant dysplasia syndrome, whose pleiotropic effects involve mainly ectodermal structures. The most common clinical manifestations are ectodermal dysplasia, ectrodactyly , cleft lip/palate, and tear-duct anomalies. Very rarely the ectrodactyly may be absent, and skeletal abnormalities may be subtle. We present a 44-month-old girl who had features of EEC syndrome but without the classic ectrodactyly.
The hereditary condition known as ectodermal dysplasia is characterized by the absence or defect of 2 or more ectodermally derived structures. A case of a 6-year-old child with hypohidrotic ectodermal dysplasia with complete anodontia is presented. Common dental, oral, and physical conditions were taken into consideration. Clinical management consisted of removable complete dentures to improve psychologic development and to promote better functioning of the stomatognathic system.
The most characteristic oral feature in ectodermal dysplasia is hypodontia. Children and adolescents suffering from ectodermal dysplasia often need extensive and complicated prosthetic treatment. The development of techniques for osseointegrated implants offers new possibilities for the oral habilitation of these children. This paper describes the oral habilitation of a boy with severe ectodermal dysplasia and where Brånemark osseointegrated implants have been used as part of the treatment. The patient was seen at the dental department at the age of 1.5 years. Two conically-shaped upper incisors were at that time the only teeth that had erupted. The treatment was planned in a multidisciplinary odontological group involving paediatric dentistry, orthodontics, prosthodontics, oral surgery and maxillofacial radiology. At the age of 3 years it was verified that the boy had four primary teeth (53, 51, 61, 63) and four permanent teeth (16, 11, 21, 26). There were no teeth in the lower jaw. The alveolar ridges in the edentulous areas were low or missing. During the period 3-6 years of age the boy used an upper partial denture adapted to allow the mesial drift of the 16 and 26 teeth. At the age of 6 years, two Brånemark implants were inserted in the lower front-cuspid region. A specially designed overdenture for the lower jaw was constructed. The overdenture was retained in contact with the male attachments by two cuffs of heat-polymerized resilient silicone. Over the next 4 years the dentures were modified due to the eruption of permanent teeth and growth. However, only minor corrections were necessary concerning the retention system of the lower denture. The implants are well osseointegrated and stable and allow the boy to use a lower denture without any complications.
The anhydrotic ectodermal dysplasia are malformative syndromes involving the ectodermal components of the organism. They may be associated with very varied ocular manifestations. We described one sporadic case of anhydrotic ectodermal dysplasia in a twenty-four year-old man, involving the following ocular manifestations: severe and bilateral keratopathy corneal hypoesthesia involvement of the lacrymal system horizontal nystagmus and a high rate of antilens antibodies not yet reported a far as we know in the literature.
In the present work, we have analysed the possible involvement of ectodermal tissue in the control of interdigital mesenchymal cell death. Two types of experiments were performed in the stages previous to the onset of interdigital cell death: removal of the AER of the interdigit; removal of the dorsal ectoderm of the interdigit. After the operation embryos were sacrificed at 10-12 h intervals and the leg buds were studied by whole-mount cartilage staining, vital staining with neutral red and scanning electron microscopy. Between stages 27 and 30, ridge removal caused a local inhibition of the growth of the interdigit. In a high percentage of the cases, ridge removal at these stages was followed 30-40 h later by the formation of ectopic nodules of cartilage in the interdigit. The incidence of ectopic cartilage formation was maximum at stage 29 (60%). In all cases, cell death took place on schedule although the intensity and extent of necrosis appeared diminished in relation to the intensity of inhibition of interdigital growth and to the presence of interdigital cartilages. Ridge removal at stage 31 did not cause inhibition of the growth of the interdigit and ectopic chondrogenesis was only detected in 3 out of 35 operated embryos. Dorsal ectoderm removal from the proximal zone of the interdigit at stage 29 caused the chondrogenesis of the proximal interdigital mesenchyme in 6 out of 18 operated embryos. The pattern of neutral red vital staining was consistent with these results revealing a partial inhibition of interdigital cell death in the proximal zone of the interdigit. It is proposed that under the present experimental conditions the mesenchymal cells are diverted from the death programme by a primary transformation into cartilage.
The congenital ectodermal dysplasias are a rare group of hereditary disorders manifesting with variable defects in structures of ectodermal origin. This report describes a patient with the hypohidrotic form of ectodermal dysplasia who presented with dysphagia and pneumonia. He was shown to have laryngeal incompetence and it is postulated that this may be a mechanism for the recurrent chest infections reported in patients with this condition.
The obliteration of the lens stalk lumen and the separation of the lens vesic from the surface ectoderm were studied by means of light microscop transmission electron microscopy, scanning electron microscopy and three-dimensional reconstruction. Our observations suggest that the obliteration of the lens stalk lumen is effected by means of cellular protrusions which grown from the apical cell surface, intertwine, meet, form interconnecting junctions and finally fuse. Junctions, and also microfilaments, which probably contract, seem to be temporary structures which assist in drawing the cell projections together and forming a firm tissue complex. Separation of the lens vesicle from the surface ectoderm takes place when the obliteration of the lens stalk lumen is completed. Cell death in a circumscribed area of the lens stalk and absence of the basal lamina of the lens stalk accompany the separation of the vesicle. Necrotic cells are phagocytosed by neighbouring epithelial cells or are expelled into the lens stalk lumen or into the interspace between lens vesicle and surface ectoderm.
The ectoderm of oral regions from the chick embryos at the stage of 10 to 19 somites was cultivated in vitro and on chorioallantois in the complex with underlying tissues. In all the explants which, besides ectoderm, contained head gut and mesenchyme, lentoids and lenses formed within 6 days of in vitro cultivation. All specific antigens of chicken lens (alpha, beta- and delta-crystallins) were found in them by means of immunofluorescence. In the explants which contained diencephalon, besides single lentoids or lenses, adenohypophyses were found. The possibility of direct lens-inducing effect of the head gut endoderm on the ectoderm of oral region and the participation of diencephalon in this process are discussed.
The purpose of this continuing education feature is to introduce nurses to a group of disorders called ectodermal dysplasias. The ectodermal dysplasias are genetic disorders that affect individuals from all ethnic groups. Most of the features of ectodermal dysplasias can be evaluated easily and useful information can be given to affected individuals and their families about the disorder and readily available treatment.
Undissociated mesoderm placed onto collagen gels forms three subpopulations of mesenchyme which differentiate along myogenic, chondrogenic and fibrogenic phenotypes. Co-culture with ectoderm appears to inhibit the formation of distinct cartilage elements and myotubes by interfering with the differentiation of chondrogenic and fibrogenic progenitors. Addition of CCM enriched in ES antigens enhances the effects of the ectoderm on chondrogenesis. Culture in the presence of CCM alone retards chondrogenesis and almost completely inhibits myogenesis. These results suggest that the primary effect of ectoderm or CCM in our culture system is on myogenic and chondrogenic differentiation, and ES antigens, if responsible for these effects, appear to have no role in pattern formation.
Ectodermal dysplasia is a rare group of inherited disorders, transmitted as an X-linked recessive. Patients with ectodermal dysplasia usually exhibit a fine smooth dry skin, with partial or complete absence of sweat glands. The main dental manifestation is hypodontia, which is of variable severity. Peg shaped teeth and reduced vertical dimension are also frequently present. In this report a case of ectodermal dysplasia which presented at the Cork University Dental School and Hospital is discussed.
We have investigated a fragment of the regulatory region of the EDA gene in a patient with clinical symptoms of anhidrotic ectodermal dysplasia (EDA), whose DNA sequence of exon 1 was normal. The single-strand conformation polymorphism (SSCP) analysis of PCR-amplified fragments of the regulatory region of the EDA gene suggested a mutation localized within the fragment extending from nucleotide -571 to -182 upstream of the 5' end of the cDNA. Sequence analysis of this fragment documented an additional adenine in position -452, located 32 nucleotides upstream from the response element HK-1, a target for transcription factor LEF-1, involved in the differentiation of tissues of ectodermal and mesodermal origin. We postulate that this mutation might interfere with the transcription process of the EDA gene and might be responsible, at least in part, for the clinical symptoms of anhidrotic ectodermal dysplasia.
During gastrulation in vertebrates the cells of the embryonic ectoderm give rise to epidermal progenitors in the ventral side and neural progenitors in the dorsal side. Despite many years of scrutiny, the molecular basis of these important embryonic cell fate decisions have not been solved. Only recently have we witnessed swift progress in the quest for factors involved in neural and epidermal induction. Several of what seem to be bona fide in vivo neural and epidermal inducers have been cloned, and the mechanism of their functions in embryos is also beginning to be understood. These new molecular results have revolutionized our view on the patterning of embryonic ectoderm and suggest that while the induction of epidermis requires instructive inductive signals, the establishment of neural fate occurs by default when epidermal inducers are inhibited. In this review, we discuss recent advances of our knowledge on epidermal and neural induction in the context of the "default model". We will then address the process of neurogenesis as well as recent findings on neural patterning. Emphasis is placed on, but not limited to, discoveries made in Xenopus, as most of our progress in understanding the ectodermal patterning is obtained from studies using this organism.
Msx2, a member of the highly conserved and widely distributed msh homeobox gene family, is expressed in a variety of sites in the vertebrate embryo, including craniofacial structures, heart, limb buds and otic and optic vesicles. In many of these sites, its expression is regulated by tissue interactions. Here we address the cis-trans regulatory interactions that direct Msx2 expression to specific regions of the embryo and enable it to respond to tissue interactions. We created a series of Msx2-lacZ fusion constructs with varying amounts of Msx2 genomic sequences. These were introduced into mouse embryos and their expression monitored by staining for beta-galactosidase activity. A construct bearing 5.2 kb of 5' flanking sequence, the intron, both exons and 3 kb of 3' flanking sequence was expressed in a pattern that closely resembled that of the endogenous Msx2 gene. In the E12.5 embryo, sites of expression included craniofacial mesenchyme, portions of the neural ectoderm, mesoderm in the distal limb bud and the overlying apical ectodermal ridge (AER). Removal of intronic and 3' UTR sequences slightly altered the pattern of Msx2 expression in the neural ectoderm of the E12 embryo. Deletion of 5' flanking sequences to -0.5 kb eliminated Msx2 expression in all sites except the AER. The proximal Msx2 promoter, including sequences required for the AER-specific expression of the -0.5 lacZ transgene, is highly conserved between mouse and human, one stretch exhibiting 100% identity over 72 bp. This conservation suggests that the AER element is under remarkably tight evolutionary constraint.
Among Ewing's sarcoma (ES) of bone and related entities are tumours with neuro-ectodermal features that could represent a biologically distinct type. In order to assess the prognostic significance of the various forms of ES, a retrospective joint study involving three cancer centres in Europe and the U.S.A. was initiated. The material from 315 primary ES was reviewed by a panel of five pathologists and classified as typical ES (220 cases), atypical ES (48 cases) or ES with neuro-ectodermal features (47 cases). Prognostic factor analysis on treatment failure-free survival was performed using the Cox model. It included histopathological classification, initial patient characteristics, clinical presentation and treatment type. After multivariate analysis, in addition to treatment type (P < 0.001), metastases (P = 0.003) and proximal tumour location (P = 0.006), two histopathological parameters correlated with poor treatment failure-free survival, the presence of filigree pattern (P = 0.044) and dark cells (P = 0.043). We conclude that ES with neuro-ectodermal features does not appear to have a different outcome to the other subtypes.
PURPOSE: To report a case of bilateral cataracts in a child that led to diagnosis of autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy. DESIGN: Observational case report. METHODS: A 12-year-old boy was being investigated for weakness, lethargy, short stature, and blurred vision. He developed bilateral, dense cataracts over a 2-week period. He was found to be hypocalcemic and diagnosed with hypoparathyroidism and autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy. RESULTS: Because of hypoparathyroidism, adrenocortical failure, and insulin-dependent diabetes, it was 9 months before the patient's metabolic imbalance was brought under sufficient control to allow cataract surgery. CONCLUSIONS: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy should be considered with diagnoses of hypocalcemic cataract.