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PubMed1986

Otolaryngologic manifestations of the ectodermal dysplasias--clinical note.

The recent formation of a national organization for ectodermal dysplasias has focused attention on this unusual congenital problem. In any rare condition, information dissemination is essential in order to appropriately educate the patients' families and the physicians caring for them. The otolaryngologist is a vital component of the health care team managing these patients. An overview of the disease process is presented with special emphasis placed on the role of the pediatric otolaryngologist in the care of children with ectodermal dysplasias.

Child↗
PubMed1985

AEC syndrome: ankyloblepharon, ectodermal defects, and cleft lip and palate. Report of two cases.

An unusual syndrome of ectodermal dysplasia was seen in a young woman and her son. The constellation of findings included hair, nail, and teeth dystrophies, as well as hypohidrosis. The patients appear to exhibit the previously described syndrome of ankyloblepharon, ectodermal defects, and clefting of the lip and palate. Their cases are the eighth and ninth cases reported in the literature.

Adult↗
PubMed1986

Ectodermal defects and chronic mucocutaneous candidiasis in idiopathic hypoparathyroidism.

Idiopathic hypoparathyroidism is a rare disorder produced by parathyroid hormone deficiency of unknown cause. It is often associated with other endocrine abnormalities. Patients with idiopathic hypoparathyroidism frequently develop ectodermal disease, including dry, rough skin: coarse, brittle hair; and lusterless, distally split nails. All of these complaints are relatively common in a dermatologic practice. Chronic mucocutaneous candidiasis is also a manifestation of idiopathic hypoparathyroidism. A patient is presented with a prominent ectodermal dysplasia and a chronic mucocutaneous candidiasis that were due to the underlying idiopathic hypoparathyroidism. A brief review of idiopathic hypoparathyroidism is included, as well as the implications of this diagnosis in terms of differential diagnosis, associated endocrine disorders, and therapy.

Candidiasis↗
PubMed2002

Dorsalization of the neural tube by Xenopus tiarin, a novel patterning factor secreted by the flanking nonneural head ectoderm.

We have isolated a novel secreted dorsalizing factor of the neural tube, Xenopus Tiarin, which belongs to the olfactomedin-related family. Tiarin expression starts at the late gastrula stage in the nonneural ectoderm adjacent to the anterior neural plate. Overexpression of Tiarin in the embryo causes expansion of dorsal neural markers and suppression of ventral markers. In the eye-forming field, Tiarin overexpression induces the retinal markers and represses optic stalk markers. Tiarin directly dorsalizes neural tissues in the absence of mesodermal tissues and antagonizes the ventralizing activity of Sonic hedghog (Shh). Unlike BMP4, another dorsalizing factor, Tiarin does not display antineuralizing activity on the ectoderm or mesoderm-ventralizing activity. These findings show that Tiarin is a novel patterning signal candidate acting in the specification of the dorsal neural tube.

Animals↗
PubMed1989

Hypoplastic-hypocalcified enamel of teeth and dysplastic nails: an undescribed ectodermal dysplasia syndrome.

Hypoplastic-hypocalcified enamel of all permanent teeth and dysplasia of finger- and toe-nails were found in a 17-year-old Japanese male. Physical examination revealed no remarkable changes in skin, hair, sweat glands, bones, etc. Family history revealed the same abnormalities of teeth and nails in his mother's brother. A review of the literature concerning ectodermal dysplasia syndromes failed to reveal a combination of hypoplastic-hypocalcified enamel and dysplastic nails without changes in any other ectodermal tissues.

Adolescent↗
PubMed2000

Indian hedgehog signaling in extraembryonic endoderm and ectoderm differentiation in ES embryoid bodies.

We previously demonstrated that a member of the Hedgehog gene family, Indian hedgehog (Ihh), is expressed in the visceral endoderm of EC and ES cell embryoid bodies and mouse embryos. Overexpression studies suggested that Ihh was involved in visceral endoderm differentiation. We now provide evidence for a Hh response in the embryoid body core and in the mesothelial layer of the visceral yolk sac. We also demonstrate that treatment of ES embryoid bodies with the Hh antagonists cAMP and forskolin results in downregulation of the Hh response and altered embryoid body differentiation. The outer endoderm layer undergoes a transition to parietal endoderm while formation of an embryonic ectoderm layer surrounding a cavity is inhibited. These treatments also result in a decrease in the expression of markers for the mesoderm derivatives, blood and endothelial cells. We present a model to explain how Ihh and BMP signaling may regulate extraembryonic endoderm and embryonic ectoderm differentiation.

Animals↗
PubMed2000

A serum response factor homologue is expressed in ectodermal tissues during development of the crustacean Artemia franciscana.

Complementary DNA clones have been isolated from the crustacean Artemia franciscana coding for a serum response factor (SRF)-homologue that is more than 96% identical to human and Drosophila melanogaster SRFs in their MADS boxes. The SRF homologue is expressed in ectodermal tissues, as determined by in situ hybridization experiments. A SRF-binding site has been identified in the promoter region of the Actin403 gene that is also expressed in ectodermal tissues, in accordance with its transcriptional regulation by the SRF homologue. The mRNA coding for A. franciscana SRF is present at similar levels in cryptobiotic encysted embryos and in developing nauplii. However, there is a significant increase in CArG-binding activity at the later developmental stage, indicating a postranscriptional regulation of SRF during A. franciscana embryonic development.

Amino Acid Sequence↗
PubMed2001

Xenopus p63 expression in early ectoderm and neurectoderm.

The tumor-suppressor protein p53 belongs to a small gene family that includes p63 and p73. While p53 and p73 regulate cell cycle progression and apoptosis, the major role of p63 appears to be in promoting ectodermal proliferation and differentiation. In this report we describe the cloning of a Xenopus orthologue of mammalian p63 that is extraordinarily conserved in sequence. The major sites of expression of Xenopus p63 mRNA are the epidermis and some neural crest and crest derivatives such as the branchial arches and tail fin. Expression is also observed in the neural plate and in the stomodeal-hypophyseal anlage. Antibodies against p63 detect a nuclear protein that is distributed in a manner similar to that of Xp63 mRNA. Both mRNA and protein are conspicuously absent from regions of the epidermal sensorial layer that are induced to form a number of (but not all) ectodermal placodes and Xp63 protein levels are particularly dynamic in the epidermis of the eye as the lens forms.

Amino Acid Sequence↗
PubMed1997

Graded amounts of Xenopus dishevelled specify discrete anteroposterior cell fates in prospective ectoderm.

Signals emitted from the prospective dorsal marginal zone (the organizer) are thought to specify neuroectodermal cell fates along the anteroposterior (AP) axis, but the mechanisms underlying this signaling event remain to be elucidated. To assess the effect of Xenopus Dishevelled (Xdsh), a proposed component of the Wnt, Notch and Frizzled signal transduction pathways, on AP axis determination, it was supplied in varying doses to presumptive ectodermal cells. Two-fold increments in levels of microinjected Xdsh mRNA revealed a gradual shift in cell fates along the AP axis. Lower doses of Xdsh mRNA activated anterior neuroectodermal markers, XAG1 and Xotx2, whereas the higher doses induced more posterior neural tissue markers such as En2, Krox20 and HoxB9. At the highest dose of Xdsh mRNA, explants contained maximal amount of HoxB9 transcripts and developed notochord and somites. When compared with Xdsh, Xwnt8 mRNA also activated anterior neuroectodermal markers, but failed to elicit mesoderm formation. Analysis of explants overexpressing Xdsh at the gastrula stage revealed activation of several organizer-specific genes which have been implicated in determination of neural tissue (Xotx2, noggin, chordin and follistatin). Whereas Goosecoid, Xlim1 and Xwnt8 were not induced in these explants, another early marginal zone marker, Xbra, was activated at the highest level of Xdsh mRNA. These observations suggest that the effects of Xdsh on AP axis specification may be mediated by combinatorial action of several early patterning genes. Increasing levels of Xdsh mRNA activate posterior markers, whereas increasing amounts of the organizer stimulate the extent of anterior development (Stewart, R.M. and Gerhart, J.C. (1990) Development 109, 363-372). These findings argue against induction of the entire organizer by Xdsh in ectodermal cells and implicate signal transduction pathways involving Xdsh in AP axis determination. Thus, different levels of a single molecule, Xdsh, can specify distinct cell states along the AP axis.

Actins↗
PubMed1997

JAGGED2: a putative Notch ligand expressed in the apical ectodermal ridge and in sites of epithelial-mesenchymal interactions.

The Drosophila Notch gene and its ligands, Delta and Serrate, are involved in cell fate determination in a variety of developing tissues. Recently, several Notch, Delta and Serrate homologues have been identified in vertebrates. We report here the cloning of the human and murine JAGGED2 (JAG2), a Serrate-like gene, and the analysis of its expression pattern during embryogenesis. Jag2 was found to be expressed as early as E9 in the surface ectoderm of the branchial arches and in the apical ectodermal ridge (AER) of the developing limb. At E12.5, Jag2 expression is upregulated in differentiated neurons of the central and peripheral nervous system and in the inner neuroblastic layer of the developing retina. Outside the nervous system, Jag2 is expressed in the developing vibrissae follicles, tooth buds, thymus, submandibular gland and stomach. Our findings suggest the involvement of Jagged2 in the development of the mammalian limb, branchial arches, central and peripheral nervous systems and several tissues whose development depends upon epithelial-mesenchymal interactions.

Animals↗
PubMed2002

Genotype-phenotype correlation in skin fragility-ectodermal dysplasia syndrome resulting from mutations in plakophilin 1.

We report a 42-year-old Japanese man with an unusual autosomal recessive genodermatosis. The clinical features comprised normal skin at birth, loss of scalp hair at 3-months of age after a febrile illness, progressive nail dystrophy during infancy, palmoplantar keratoderma starting around the age of 18 years and trauma-induced skin fragility and blisters noted from the age of 20 years. Skin biopsy of rubbed non-lesional skin revealed widening of spaces between adjacent keratinocytes from the suprabasal layer upwards. Electron microscopy demonstrated a reduced number of hypoplastic desmosomes. Immunohistochemical labeling showed a reduction in intercellular staining for the desmosome component plakophilin 1. Mutation analysis revealed a homozygous intron 11 donor splice site mutation in the plakophilin 1 gene, 2021+1 G>A (GenBank no. Z34974). RT-PCR, using RNA extracted from the skin biopsy, provided evidence for residual low levels of the full-length wild-type transcript (approximately 8%) as well as multiple other near full-length transcripts, one of which was in frame leading to deletion of 17 amino acids from the 9th arm-repeat unit of the plakophilin 1 tail domain. Thus, the molecular findings help explain the clinical features in the patient, who has a similar but milder phenotype to previously reported patients with skin fragility-ectodermal dysplasia syndrome associated with complete ablation of plakophilin 1 (OMIM 604536). This new 'mitis' phenotype provides further clinicopathological evidence for the role of plakophilin 1 in keratinocyte cell-cell adhesion and ectodermal development.

Adult↗
PubMed1990

Induction of sweat glands by epidermal growth factor in murine X-linked anhidrotic ectodermal dysplasia.

Tabby (Ta), a murine X-linked mutant gene, produces a syndrome of ectodermal dysplasia including anhidrosis (absence of sweat glands). Development of sweat glands is related to that of dermal ridges (dermatoglyphics) and abnormal ridges may be associated with absence of sweat glands in the human syndrome of hypohidrotic ectodermal dysplasia (HED). We have found that dermal ridges occur in normal mice but are lacking in Ta mutants. Previously we showed that epidermal growth factor (EGF) reverses delayed eyelid opening and incisor eruption in Ta mice. We now report that EGF induces development of dermal ridges and functional sweat glands in Ta/Y hemizygotes, indicating a role in mammalian morphogenesis. Ta seems to be genetically homologous to human X-linked HED, as Ta maps close to loci homologous to linkage markers of HED and the two syndromes share many traits, including absence of all or most sweat glands. Absence of these glands causes hyperpyrexia, a clinical emergency in infants with HED; reversal of the trait in the mouse homologue of the disease indicates that an important genetically determined congenital defect in humans may become treatable.

Animals↗
PubMed1996

X-linked anhidrotic (hypohidrotic) ectodermal dysplasia is caused by mutation in a novel transmembrane protein.

Ectodermal dysplasias comprise over 150 syndromes of unknown pathogenesis. X-linked anhidrotic ectodermal dysplasia (EDA) is characterized by abnormal hair, teeth and sweat glands. We now describe the positional cloning of the gene mutated in EDA. Two exons, separated by a 200-kilobase intron, encode a predicted 135-residue transmembrane protein. The gene is disrupted in six patients with X;autosome translocations or submicroscopic deletions; nine patients had point mutations. The gene is expressed in keratinocytes, hair follicles, and sweat glands, and in other adult and fetal tissues. The predicted EDA protein may belong to a novel class with a role in epithelial-mesenchymal signalling.

Adult↗
PubMed2001

Mutational spectrum of the ED1 gene in X-linked hypohidrotic ectodermal dysplasia.

X-linked hypohidrotic ectodermal dysplasia (XLHED) is the most common form of the ectodermal dysplasias characterised by an abnormal development of eccrine sweat glands, hair and teeth. The ED1 gene responsible for the disorder undergoes extensive alternative splicing and to date few studies have concerned the full length transcript. We screened 52 unrelated families or sporadic cases for mutation in the full coding sequence of this gene. SSCA analysis or direct sequencing allowed identification of mutations in 34 families: one initiation defect, twenty-two missenses, two nonsense, eight insertions or deletions, and a large deletion encompassing all the ED1 gene. Fourteen of these mutations have not been previously described, including five missenses. One third of identified mutations were localised in codons 155 and 156, affecting CpG dinucleotides and nine of them correspond to the R156H missense. Hypothesis of a founder effect has been ruled out by haplotype analysis of flanking microsatellites. These recurrent mutations indicate the functional importance of the positively charged domain of the protein. Including our data, there are now 56 different mutations reported in 85 independent patients, that we have tabulated. Review of clinical features in the present series of affected males and female carriers showed no obvious correlation between the type of mutations, the phenotype and its severity. The X-chromosome pattern of inactivation in leucocytes showed little correlation with expressivity of the disease in female carriers. Finally this study is useful for functional studies of the protein and to define a diagnostic strategy for mutation screening of the ED1 gene.

Dosage Compensation, Genetic↗
PubMed2005

Induction and specification of the vertebrate ectodermal placodes: precursors of the cranial sensory organs.

The sensory organs of the vertebrate head derive from two embryological structures, the neural crest and the ectodermal placodes. Although quite a lot is known about the secreted and transcription factors that regulate neural crest development, until recently little was known about the molecular pathways that regulate placode development. Herein we review recent findings on the induction and specification of the pre-placodal ectoderm, and the transcription factors that are involved in regulating placode fate and initial differentiation.

Animals↗
PubMed2002

EEC (Ectrodactyly, Ectodermal dysplasia, Clefting) syndrome: heterozygous mutation in the p63 gene (R279H) and DNA-based prenatal diagnosis.

BACKGROUND: Germline mis-sense mutations in the DNA-binding domain of the p63 gene have recently been established as the molecular basis for the autosomal dominant EEC (Ectrodactyly, Ectodermal dysplasia, Clefting) syndrome. OBJECTIVES: To examine genomic DNA from a 36-year-old woman, her 58-year-old father and her 11-year-old son, all with the EEC syndrome, to determine the inherent p63 mutation and, after genetic counselling, to use knowledge of the mutation to undertake a first-trimester DNA-based prenatal diagnosis in a subsequent pregnancy. METHODS: Fetal DNA was extracted from chorionic villi and used to amplify exon 7 of p63 containing the potential mutation. Direct sequencing and restriction endonuclease digestion (loss of AciI site on mutant allele) were used for DNA-based prenatal diagnosis. RESULTS: We identified a heterozygous arginine to histidine p63 mutation, R279H, in all three affected individuals. Prenatal diagnosis demonstrated a homozygous wild-type sequence predicting an unaffected child: a healthy boy was subsequently born at full-term. CONCLUSIONS: These data expand the p63 gene mutation database and provide the first example of a DNA-based prenatal test in this ectodermal dysplasia syndrome.

Abnormalities, Multiple↗
PubMed2003

A novel p63 sterile alpha motif (SAM) domain mutation in a Japanese patient with ankyloblepharon, ectodermal defects and cleft lip and palate (AEC) syndrome without ankyloblepharon.

We present a sporadic case of a Japanese female infant with ectodermal dysplasia, complete cleft lip and palate, severe skin erosions at birth and recurrent scalp infection. She had typical clinical features of ankyloblepharon, ectodermal defects and cleft lip and palate (AEC) syndrome without ankyloblepharon. Histological and immunohistochemical analyses showed reduced granular cell layers and aberrant expression of the p63 protein in the suprabasal keratinocytes. Mutation analysis of the exon 13 of p63 gene revealed a heterozygous in-frame 3-bp insert (c. 538-539 ins TTC) encoding additional amino acid residues (F). This is the first report of sterile alpha motif domain mutation except for single nucleotide transitions.

Abnormalities, Multiple↗