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PubMed1995

Induction of visceral and cardiac mesoderm by ectodermal Dpp in the early Drosophila embryo.

After gastrulation, progenitor cells of the cardiac, visceral and body wall musculature arise at defined positions within the mesodermal layer of the Drosophila embryo. The regulatory mechanisms underlying this process of pattern formation are largely unknown, although ablation experiments carried out in other insects indicate that inductive influences from ectodermal cells have major roles in embryonic mesoderm differentiation. An early and important event in the regional subdivision of the mesoderm is the restriction of tinman expression to dorsal mesodermal cells. Genetic analysis has shown that this homeobox gene controls the formation of the visceral musculature and the heart from dorsal portions of the mesoderm. We now show that an inductive signal from dorsal ectodermal cells is required for activation of tinman in the underlying mesoderm and present evidence that Decapentaplegic (Dpp), a member of the transforming growth factor-beta superfamily, serves as a signalling molecule in this process. This demonstrates that the spatial expression of dpp in the ectoderm determines which cells of the mesoderm become competent to develop into visceral mesoderm and the heart.

Animals↗
PubMed2002

Beta-catenin-dependent Wnt signaling in apical ectodermal ridge induction and FGF8 expression in normal and limbless mutant chick limbs.

The fibroblast growth factor (FGF) and beta-catenin-dependent Wnt signaling pathways are key regulators of vertebrate limb development. FGF10 induces expression of Wnt3a, which regulates the formation and FGF8 expression of the apical ectodermal ridge (AER). In amelic limbless limbs, an AER fails to form and FGF8 is not expressed, despite expression of FGF10. It has been found that Wnt3a is initially expressed in limbless ectoderm, although subsequently is drastically reduced. In addition, changes in the expression pattern or level of several Frizzled receptors, Axin, Lef1/Tcf1 and beta-catenin have been found in limbless limbs. Notably, while normal wing buds respond to LiCl-stimulated activation of beta-catenin-dependent signaling by forming ectopic, FGF8-expressing AER, LiCl was unable to induce an AER in limbless wing buds. The results of this study suggest that the limbless gene is required for beta-catenin-dependent Wnt signaling in limb ectoderm leading to FGF8 expression and AER formation.

Animals↗
PubMed1990

Localization of the sea urchin Spec3 protein to cilia and Golgi complexes of embryonic ectoderm cells.

Expression of the Spec3 gene of Strongylocentrotus purpuratus is associated with ectodermal ciliogenesis. An antiserum was raised against the amino terminus of the deduced Spec3 amino acid sequence and used for immunofluorescent staining. Cilia and an apical structure at the base of the stained cilium of each ectodermal cell stained intensely in gastrula and later stage embryos. Microtubule-depolymerizing agents dispersed the concentrated spot of apical staining, suggesting a localization of Spec3 antigen to the Golgi complex. Immunogold electron microscopy confirmed the localization of Spec3 antigen on cilia and in the Golgi complex. Spec3 antigen showed a diffuse punctate staining pattern in the ectodermal cytoplasm of hatching blastula when Spec3 transcripts are most prevalent, suggesting that after synthesis, Spec3 is sequestered in the Golgi complex before appearing on cilia. Whereas the predicted Mr of the Spec3 protein is 21,600, immunoblotting with S. purpuratus proteins indicated that a Spec3 antigen was concentrated in cilia and migrated as an SDS-resistant aggregate of Mr approximately 350,000. Spec3 is also concentrated in cilia of Lytechinus pictus but the protein migrated with an Mr approximately 23,000 in this species. The S. purpuratus Spec3 antigen remains associated with the ciliary axoneme after extraction of membrane proteins.

Amino Acid Sequence↗
PubMed2005

Regulation of Slug transcription in embryonic ectoderm by beta-catenin-Lef/Tcf and BMP-Smad signaling.

Neural crest is formed at the boundary of epidermal and neural ectoderm. To understand the molecular mechanism of neural crest formation, we focused on the transcriptional regulation of the Slug gene. In the upstream sequence of the chicken Slug gene, we have identified potential binding sites for transcription factors, such as Lef/Tcf and Smad1. Transgenic mouse embryos carrying the chicken Slug promoter-reporter gene showed a crest-specific activation of the reporter, suggesting the isolated sequence included the cis-regulatory elements to receive Slug-inducing signals in the mouse neural crest. While these potential cis-regulatory elements could be recognized and activated by corresponding transcription factors, such as Lef1 and Smad1, Wnt-Lef-beta-catenin signal failed to induce endogenous Slug expression in quail neural plate tissue prepared from forebrain and midbrain levels. In contrast, Slug expression and subsequent epithelial-mesenchymal transition were effectively induced by BMP4. Consistently, while we could detect phosphorylation of Smad1 in the ectoderm including the neural plate and the neural fold region, the activation of a reporter gene for a detection of canonical Wnt signal activation was below the level of detection at the forebrain and midbrain levels. These observations indicated that in the anterior ectoderm BMP signal has a predominant role for Slug expression.

Animals↗
PubMed1993

Experimental evidence for an early commitment of gonadotropin-releasing hormone neurons, with special regard to their origin from the ectoderm of nasal cavity presumptive territory.

The origin and the migration of gonadotropin-releasing hormone (GnRH)-producing neurons were studied using the indirect immunoperoxidase method in normal and surgically operated chick embryos. In normal embryos, during early embryonic development, GnRH neurons were located only in the respiratory and the olfactory epithelia. Then, these neurons followed the nearest nerve bundle and occupied, thereafter, the dorsal, medial or ventral part of the olfactory nerve according to the time and area of the olfactory epithelium they emerged from. At the junction with the forebrain, the majority of GnRH neurons passed ventromedially round the olfactory bulb. Therefore, they penetrated through the interhemispheric space and coursed obliquely toward caudal and dorsal telencephalon from where they will be later distributed to reach their adult-like position. In view of the large distribution of these neurons in the nasal region, unilateral surgical ablation either of the whole or of each presumptive territory of nasal structures was performed from 2 to 4 somite stages. As expected, when both olfactory placode and ectoderm of nasal cavity presumptive territories were unilaterally removed, olfactory nerve, nasal structures and GnRH neurons failed to develop in the operated side. After the unilateral removal of the olfactory placode anlage, the distribution pattern of GnRH neurons was not disturbed in the operated as well as in the control side although ipsilateral olfactory structures were greatly reduced. In contrast, when the presumptive ectoderm of nasal cavity was unilaterally removed, GnRH neurons were detected only in the control side where this territory was left intact. Therefore, from early neurogenesis, GnRH neurons seem to be already committed, and they originate from the ectoderm of nasal cavity presumptive territory.

Animals↗
PubMed1964

CALCIFIED ECTODERMAL COLLAGENS OF SHARK TOOTH ENAMEL AND TELEOST SCALE.

Amino acid analysis of protein from the enamel of shark teeth and from teleost scales shows the presence of collagens which can be classified chemically as ectodermal. This finding, together with results from a histological examination of the development of these tissues, constitutes strong evidence that both proteins are derived from the ectoderm, like the enamel of higher vertebrates. Since both are calcified, calcification cannot be a specific property of collagens of mesodermal origin alone.

Amino Acids↗
PubMed2006

Hypohidrotic ectodermal dysplasia (HED).

Hypohidrotic Ectodermal Dysplasia (HED) is a hereditary congenital disorder of ectodermal origin. It is characterized by lack of sweat glands (hypohidrosis), nail dystrophy(onychodysplasia), alopecia (hypotrichosis), defective palms and soles (palmoplantar hyperkeratosis) and the oral presentations of partial absence of teeth (hypodontia) or complete absence of teeth (anodontia). Hypodontia of primary and permanent dentition is one of the most frequently occurring oral symptoms in HED patients. These features of poor aesthetic affect the social and the psychological well-being of the patient. This case report describes the prosthetic rehabilitation of a HED patient.

Adolescent↗
PubMed2004

Otologic manifestations of ectodermal dysplasia.

OBJECTIVES: To determine the range and prevalence of otologic disorders in patients with ectodermal dysplasia (ED) and provide a general review of its multiple otolaryngological manifestations. DESIGN: Case series. SETTING: Ectodermal dysplasia family conference. PATIENTS: Sixty-nine individuals with ED were evaluated. The average age was 11 years (range, 1-56 years). Most were male patients (44 [64%]), and most had Christ-Siemens-Touraine syndrome/hypohidrotic ED (42 [61%]), with the remaining having Hay-Wells, Clouston, and ectrodactyly ED clefting syndromes and unclassified types of ED. INTERVENTIONS: Questionnaire including a quality-of-life assessment modeled after the Otitis Media 6 instrument, physical examination, screening audiogram, and tympanometry. RESULTS: Of the 69 patients, 15 (22%) had a known history of hearing loss, and over half reported some level of difficulty processing verbal information (30 patients [43%] reported speech problems and 4 patients [6%] required hearing aids). A history of otitis media was common, with 15 patients (21%) presenting with tympanostomy tubes in place. The mean +/- SD quality-of-life rating was 2.0 +/- 1.1 (range 1-7), with lower scores suggesting less of a problem. On physical examination, 18 patients (26%) had pinna anomalies. One case of advanced cholesteatoma and 2 cases of external auditory canal stenosis were identified. Of the 24 patients who received 4-tone screening audiogram, 2 (8%) had a highest pure-tone average threshold of 50 to 65 dB, whereas 5 patients (21%) had a 30- to 45-dB threshold, with the remaining having a 0- to 25-dB threshold. CONCLUSION: In our study, which is, to our knowledge, the largest reported collection of ED patients evaluated for otologic disease, most patients were found to have 1 or more otologic abnormalities, ranging from auricular anomaly to complications of otitis media to profound hearing loss.

Adolescent↗
PubMed1997

Brain anomalies, retardation of mentality and growth, ectodermal dysplasia, skeletal malformations, Hirschsprung disease, ear deformity and deafness, eye hypoplasia, cleft palate, cryptorchidism, and kidney dysplasia/hypoplasia (BRESEK/BRESHECK): new X-linked syndrome?

Two half brothers (maternally related) had a similar syndrome of microhydrocephaly in both brothers and dilatation of the spinal canal with fusion of thalami in one brother. Primordial growth delay was noted in both brothers, with severe mental retardation in the surviving brother. Both had ectodermal dysplasia with scaling, hyperkeratosis, and generalized alopecia, but normal sweat and sebaceous glands. Skeletal anomalies included hemivertebrae with abnormal segmentation in one and scoliosis with polydactyly in the other. Ears were apparently low set, large, and protruding, with mixed hearing loss in the brother who survived. Eye anomalies included maldevelopment of one eye in Patient 1 and small optic nerves more noticeable on one side in Patient 2. Both had cryptorchidism and dysplastic/hypoplastic kidneys of varying severity that resulted in the early postnatal death of one sib. Manifestations present in only one or the other sib included submucous cleft palate, aganglionosis of the rectum and colon, agenesis of one testicle, and single umbilical artery. This syndrome has not been described previously and may be due to an X-linked mutation. The acronym BRESEK reflects the common findings, whereas BRESHECK denotes all manifestations of both patients: brain, retardation, ectodermal dysplasia, skeletal deformities, Hirschsprung disease, ear/eye anomalies, cleft palate/cryptorchidism, and kidney dysplasia/hypoplasia. In addition to an X-linked mutation, a contiguous gene deletion or maternal mosaicism of an autosomal dominant gene must be considered.

Abnormalities, Multiple↗
PubMed1997

Trichorrhexis nodosa and lip pits in autosomal dominant ectodermal dysplasia--central nervous system malformation syndrome.

A Dandy-Walker-like malformation was observed in a retarded girl who had signs of hidrotic ectodermal dysplasia. This is the third report of the rare triad ectodermal dysplasia-CNS malformation-mental retardation. We observed additional findings, such as submucous cleft palate with lip pits and trichorrhexis nodosa. The proposita's mother had similar hair and facial changes. Two maternal relatives had cleft palate. Autosomal dominant inheritance is suggested.

Abnormalities, Multiple↗
PubMed1997

Autosomal dominant hypohidrotic ectodermal dysplasia in a large family.

We have studied an autosomal dominant hypohidrotic ectodermal dysplasia in 38 individuals over six generations in one family. Thirty-two affected individuals in four generations are still living. Questionnaire responses were received from 21 of the affected relatives and some of the individuals were examined by one of the authors. Smooth, dry, thin skin is seen in most affected individuals. Nearly all have fine, slow-growing scalp and body hair and all have sparse eyebrows and short eyelashes. Nearly all show a decrease in sweating, with some only sweating under the arms and/or on the palms and soles. All affected individuals lacked some deciduous teeth and some permanent teeth. Some teeth are abnormally shaped. Nail abnormalities are more variable and may occur more frequently with increasing age. No other abnormalities are seen in affected individuals in this family. We reviewed 40 autosomal dominant ectodermal dysplasia syndromes. This family bears some resemblance to a family described by Jorgensen et al. [1987]; however, it appears to represent a disorder that has not been described previously.

Abnormalities, Multiple↗
PubMed1993

Expression of Xenopus snail in mesoderm and prospective neural fold ectoderm.

Expression of the Xsna gene during Xenopus laevis embryogenesis has been analysed by in situ hybridisation. Like its homologue snail in Drosophila, Xsna is expressed zygotically in all early mesoderm. Expression starts during stage 9 in the dorsal marginal zone and spreads to the ventral side by stage 10. During gastrulation, each cell begins to express as it involutes so that cells newly expressing Xsna are added to the forming mesoderm mantle in an anterior-to-posterior progression. Xsna expression is then down-regulated in a tissue-specific fashion that reveals the subdivision of the mesoderm before its derivatives are overtly differentiated; e.g., the appearance of the notochord, myotomes, and pronephroi are preceded by the disappearance of Xsna mRNA, while undifferentiated mesoderm remains labelled, even into tadpole stages. Xsna is expressed in the suprablastoporal endoderm during gastrulation and in its derivatives, the prechordal and sub-notochordal endoderm, during neurulation. Relationships between Xbra, Xtwi, and Xsna expression are examined. Xsna is also expressed in the prospective neural fold ectoderm from stage 11 in a low arc above the dorsal marginal zone, precisely identifying a distinct band of cells that surrounds the prospective neural plate that we designate the neural plate border. The anterior transverse neural fold, which becomes forebrain, ceases Xsna expression during neurulation. In the longitudinal neural folds, the deep and superficial ectoderm compartments labelled by Xsna expression are the prospective neural crest and prospective roof of the neural tube, respectively. Xsna expression persists in the neural crest during migration and in some derivatives at least until metamorphosis but ceases in the roof of the neural tube soon after neurulation.

Animals↗
PubMed2002

Analysis of craniofacial development in children with hypohidrotic ectodermal dysplasia.

Ectodermal dysplasias (ED) are a heterogeneous group of inheritable disorders characterized by abnormal development of embryologic ectoderm derivatives. The purposes of this study were to: 1) create baseline cephalometric norms for male children with ED; 2) assess craniofacial growth and development in hypohidrotic ED male children with severe hypodontia, compared with non-ED children with class I dental relationships; 3) compare the craniofacial morphology of titanium dental implant-treated ED males with non-implant-treated ED males; and 4) correlate the severity of hypodontia to craniofacial dysmorphology. Cephalometric radiographs of class I individuals and implant-treated and nontreated ED groups were used to evaluate craniofacial morphology. Traditional cephalometric landmarks and measurements were used to compare groups using the generalized estimate equation analysis. Age, gender, and the number of permanent maxillary teeth present had a significant (P =.01) explanatory relationship with the craniofacial measures when comparing untreated ED children to norms. Mean craniofacial differences between ED and non-ED children still existed when the explanatory effects of these variables were controlled, indicating dysmorphology in several craniofacial structures (e.g., cranial base, mandibular length). The number of missing maxillary permanent teeth was significantly related with craniofacial dysmorphology in the ED population. Craniofacial morphology did not differ significantly between implant-treated and nontreated ED children, suggesting that treatment with intraosseous dental implants, as applied in this population, did not rescue normal craniofacial growth and development.

Adolescent↗
PubMed1989

Cataracts, alopecia, and sclerodactyly: a previously apparently undescribed ectodermal dysplasia syndrome on the island of Rodrigues.

An unique autosomal recessive ectodermal dysplasia is present in 5 sibs from the Indian Ocean island of Rodrigues. The main manifestations are total congenital alopecia, bilateral congenital cataracts, and skin changes of the hands and feet including sclerodactyly, hyperkeratosis, contractures, and pseudoainhum formation. The phenotype differs from that of other genetic ectodermal dysplasias and independent syndromic status is probable.

Abnormalities, Multiple↗
PubMed1990

Prenatal diagnosis of X-linked hypohidrotic ectodermal dysplasia by linkage analysis.

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.

Adult↗
PubMed1993

Congenital contractures, ectodermal dysplasia, cleft lip/palate, and developmental impairment: a distinct syndrome.

Brothers were affected with severe congenital contractures, multiple cutaneous manifestations of ectodermal dysplasia, cleft lip/palate, and psychomotor and growth impairment. High resolution prometaphase chromosomes were normal. Molecular studies of DNA markers, closely flanking the X-linked hypohidrotic ectodermal dysplasia locus, did not show evidence of a submicroscopic deletion from the Xq12-q13 region. The parents and a normal sister exhibited none of these findings. This constellation of anomalies appears to represent a unique AR or XLR syndrome.

Abnormalities, Multiple↗
PubMed1995

"New" ectodermal dysplasia with mental retardation and syndactyly.

We describe a girl with an unusual form of ectodermal dysplasia. She was mildly mentally retarded, had normal height, weight, and head circumference, a large scalp defect, a peculiar face with large palpebral fissures, a broad nasal bridge and constantly open mouth, abnormally-modeled ears, syndactyly of fingers/toes, mild hypohidrosis, and severe onychogryposis. Her hair was short, abundant, and stiff, her eyebrows were sparse, and her skin was dry. Analysis of the literature showed that this type of association of ectodermal dysplasia and other defects has not been previously described.

Abnormalities, Multiple↗