PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “ECTODERMAL DEFECT”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed1987

Variable expression in ankyloblepharon-ectodermal defects-cleft lip and palate syndrome.

The ankyloblepharon-ectodermal defects-cleft lip and palate (Hay-Wells) syndrome is a rare autosomal dominant form of congenital ectodermal dysplasia. It is characterized by coarse, wiry, sparse hair; dystrophic nails; slight hypohidrosis; scalp infections; ankyloblepharon filiforme adnatum; hypodontia; maxillary hypoplasia; and cleft lip and palate. To date, 12 patients have been reported; however, the diagnosis has been questioned in 3 of these patients. We report 2 additional patients, one of whom has nasal speech but not cleft palate, in contrast to all other reported patients. This entity must be distinguished from numerous other forms of ectodermal dysplasia, especially those forms that can be associated with oral clefts and/or ankyloblepharon.

Child↗
PubMed1993

Taurodontism and length of teeth in patients with oligodontia.

Taurodontism and a reduced tooth length are reported to occur in patients with oligondontia. The aim of this study was to evaluate the occurrence of these factors in Dutch patients with oligodontia. Panoramic radiographs of 117 patients with oligodontia and 91 controls were collected. Taurodontism of the mandibular first molars was recorded and the length of cuspids, bicuspids and first molars of the mandible were measured. In patients with oligodontia 28.9% showed taurodontism of one or two mandibular first molars. The prevalence of taurodontism in normal Dutch subjects was 9.9%. No significant differences were found between the two sexes in both groups. Neither was there a significant difference in the unilateral and bilateral occurrence of taurodontism. The present findings supported the hypothesis that taurodontism may be the result of an ectodermal defect and a manifestation of developmental instability in patients with oligodontia. The length of mandibular cuspids and first molars in females were significantly reduced. In males only the lower right first molar was significantly reduced. The reduced length of the teeth may also be the result of a defect in ectodermal cells. Both taurodontism and a reduced length are of importance considering dental therapy.

Adolescent↗
PubMed1990

Nude mice are not hairless. A morphological study.

In the present study, the morphological aspect of the skin and the hairs of athymic, macroscopically nude mice (NMRI, nu/nu) was investigated by descriptive light- and electron-microscopical methods and compared with the appearance of the skin and the hairs in normally haired mice (NMRI). These morphological studies revealed that athymic, macroscopically nude mice are not at all hairless, but have about the same number of hair bulbs, embedded in the hypodermis, as normally haired animals. However, within the hair follicles of athymic mice, the keratinization processes are obviously deeply impaired, resulting in the formation of short, crippled and bent hair shafts which only seldom emerge from the hair follicles. The cuticles of the inner root sheath and the hair are not built up, the cortex of the hair being composed by abnormal globular aggregates. The epidermis shows similar disturbances of keratinization, which are reflected by the presence of only few and thin bundles of tonofilaments in the basal, spinous and granular layers of the epidermis and, in the stratum corneum, by bizarrely formed and irregularly arranged lamellae of corneocytes, separated from one another. These results demonstrate that athymic, nude mice are not hairless but that the development and differentiation of hairs are severely injured in this mouse mutant. Analogously, the keratinization of the epidermis is also impaired. In view of the previously shown ectodermal defect as primary cause for the dysgenesis of the thymus, it seems to be probable that defects of the ectoderm are actually the common reason for both the thymus dysgenesis and the severe disturbances of hair development in 'athymic, nude' mice.

Animals↗
PubMed1996

The Drosophila embryonic midline is the site of Spitz processing, and induces activation of the EGF receptor in the ventral ectoderm.

The Drosophila EGF receptor (DER) is activated by secreted Spitz to induce different cell fates in the ventral ectoderm. Processing of the precursor transmembrane Spitz to generate the secreted form was shown to be the limiting event, but the cells in which processing takes place and the mechanism that may generate a gradient of secreted Spitz in the ectoderm were not known. The ectodermal defects in single minded (sim) mutant embryos, in which the midline fails to develop, suggested that the midline cells contribute to patterning of the ventral ectoderm. This work shows that the midline provides the site for Spitz expression and processing. The Rhomboid and Star proteins are also expressed and required in the midline. The ectodermal defects of spitz, rho or Star mutant embryos could be rescued by inducing the expression of the respective normal genes only in the midline cells. Rho and Star thus function non-autonomously, and may be required for the production or processing of the Spitz precursor. Secreted Spitz is the only sim-dependent contribution of the midline to patterning the ectoderm, since the ventral defects observed in sim mutant embryos can be overcome by expression of secreted Spitz in the ectoderm. While ectopic expression of secreted Spitz in the ectoderm or mesoderm gave rise to ventralization of the embryo, increased expression of secreted Spitz in the midline did not lead to alterations in ectoderm patterning. A mechanism for adjustment to variable levels of secreted Spitz emanating from the midline may be provided by Argos, which forms an inhibitory feedback loop for DER activation. The production of secreted Spitz in the midline, may provide a stable source for graded DER activation in the ventral ectoderm.

Animals↗
PubMed2002

Bilateral nephroblastoma in familial Hay-Wells syndrome associated with familial reticulate pigmentation of the skin.

We report on a girl with maxillary hypoplasia, prominent ears, dry sparse hair, palmar and plantar keratoderma, dystrophic nails, patchy pigmented skin lesions in hands and feet and bilateral Wilms tumor. She was born with bilateral ankyloblepharon. The mother and maternal grandmother presented similar ectodermal defects. Skin biopsies of the patient and her mother proved to contain cells overexpressing p63 by immunohistochemistry. Karyotypes of the patient and her mother, and FISH studies on lymphocytes and tumor cells of the girl demonstrated a mosaic 11p15.5 deletion. These findings suggest a relationship between familial ankyloblepharon, ectodermal defects and cleft lip and palate (AEC) syndrome (Hay-Wells syndrome) and familial reticulate pigmentation of the skin. In addition the development of Wilms tumor and 11p15.5 region involvement expand the genetic relationship between these conditions and the enlarging group of genetic entities related to nephroblastoma.

Abnormalities, Multiple↗
PubMedDate not supplied

Gene defect in ectodermal dysplasia implicates a death domain adapter in development.

Members of the tumour-necrosis factor receptor (TNFR) family that contain an intracellular death domain initiate signalling by recruiting cytoplasmic death domain adapter proteins. Edar is a death domain protein of the TNFR family that is required for the development of hair, teeth and other ectodermal derivatives. Mutations in Edar-or its ligand, Eda-cause hypohidrotic ectodermal dysplasia in humans and mice. This disorder is characterized by sparse hair, a lack of sweat glands and malformation of teeth. Here we report the identification of a death domain adapter encoded by the mouse crinkled locus. The crinkled mutant has an hypohidrotic ectodermal dysplasia phenotype identical to that of the edar (downless) and eda (Tabby) mutants. This adapter, which we have called Edaradd (for Edar-associated death domain), interacts with the death domain of Edar and links the receptor to downstream signalling pathways. We also identify a missense mutation in its human orthologue, EDARADD, that is present in a family affected with hypohidrotic ectodermal dysplasia. Our findings show that the death receptor/adapter signalling mechanism is conserved in developmental, as well as apoptotic, signalling.

Amino Acid Sequence↗
PubMed1998

Björnstad syndrome in a patient with mental retardation.

Björnstad syndrome in a patient with mental retardation: Pili torti or twisted hair can appear as an isolated defect, in association with other ectodermal defects, in association with other clinical features or can be acquired. Björnstad syndrome is a rare condition with apparent autosomal recessive inheritance, characterized by hearing loss and twisted hairs (pili torti). All patients with Björnstad syndrome reported thusfar have normal intelligence. We report on a patient with severe mental retardation and review the literature.

Hair↗
PubMed2003

The cytoplasmic domain of Xenopus NF-protocadherin interacts with TAF1/set.

Protocadherins are members of the cadherin superfamily of cell adhesion molecules proposed to play important roles in early development, but whose mechanisms of action are largely unknown. We examined the function of NF-protocadherin (NFPC), a novel cell adhesion molecule essential for the histogenesis of the embryonic ectoderm in Xenopus, and demonstrate that the cellular protein TAF1, previously identified as a histone-associated protein, binds the NFPC cytoplasmic domain. NFPC and TAF1 coprecipitate from embryo extracts when ectopically expressed, and TAF1 can rescue the ectodermal disruptions caused by a dominant-negative NFPC construct lacking the extracellular domain. Furthermore, disruptions in either NFPC or TAF1 expression, using NFPC- or TAF1-specific antisense morpholinos, result in essentially identical ectodermal defects. These results indicate a role for TAF1 in the differentiation of the embryonic ectoderm, as a cytosolic cofactor of NFPC.

Amino Acid Sequence↗
PubMed1988

Familial occurrence of eccrine tumours in a family with ectodermal dysplasia.

In two brothers and their sister, ectodermal defects including hypodontia, onychodystrophia, trichodysplasia and palmoplantar keratosis were observed. In addition to the ectodermal dysplasia a diffuse palmoplantar eccrine hyperplasia was noted as well as tumours and cysts of eccrine origin. This seems to be the first report of familial occurrence of eccrine tumours.

Adenocarcinoma↗
PubMed2003

Penetrating keratoplasty and keratolimbal allograft transplantation for corneal perforations associated with the ectodermal dysplasia syndrome.

PURPOSE: To report two patients with ectodermal dysplasia-associated keratopathy treated with keratolimbal allograft transplantation and penetrating keratoplasty. METHODS: Two patients with ectodermal dysplasia suffered multiple corneal perforations. In both patients, keratolimbal allograft transplantation was performed along with penetrating keratoplasty. Histopathology of the corneal buttons was obtained. RESULTS: Histopathologic examination showed chronic inflammation with thin, irregular epithelium, loss of stromal tissue, and thin or absent Bowman's membrane. Both patients had multiple contributing factors predisposing them to corneal perforations including an inherent ectodermal defect, trichiasis, poor tear film, and limbal stem cell deficiency. CONCLUSIONS: Patients with keratopathy and corneal perforations associated with the ectodermal dysplasia syndrome has a poor prognosis. Keratolimbal allograft transplantation may have a role in the treatment of this disease. Longer follow-up and additional case reports will determine whether this technique confers a better prognosis than keratoplasty alone.

Adult↗
PubMed2001

Hedgehog signaling patterns the tracheal branches.

The elaborate branching pattern of the Drosophila tracheal system originates from ten tracheal placodes on both sides of the embryo, each consisting of about 80 cells. Simultaneous cell migration from each tracheal pit in six different directions gives rise to the stereotyped branching pattern. Each branch contains a fixed number of cells. Previous work has shown that in the dorsoventral axis, localized activation of the Dpp, Wnt and EGF receptor (DER) pathways, subdivides the tracheal pit into distinct domains. We present the role of the Hedgehog (Hh) signaling system in patterning the tracheal branches. Hh is expressed in segmental stripes abutting the anterior border of the tracheal placodes. Induction of patched expression, which results from activation by Hh, demonstrates that cells in the anterior half of the tracheal pit are activated. In hh-mutant embryos migration of all tracheal branches is absent or stalled. These defects arise from a direct effect of Hh on tracheal cells, rather than by indirect effects on patterning of the ectoderm. Tracheal cell migration could be rescued by expressing Hh only in the tracheal cells, without rescuing the ectodermal defects. Signaling by several pathways, including the Hh pathway, thus serves to subdivide the uniform population of tracheal cells into distinct cell types that will subsequently be recruited into the different branches.

Animals↗
PubMed1982

The conditions manifesting taurodontism.

Taurodontism is a trait that has captured the interests of evolutionists and clinical geneticists. This paper reviews the reported cases of taurodontism as an isolated trait and as a component of malformation syndromes. Because of the nature of the syndromes with which it is associated and its frequency in the general population, it is concluded that taurodontism is the result of an ectodermal defect and may be useful as an indicator of development instability.

Abnormalities, Multiple↗
PubMed1990

Developmentally regulated lectin in dark versus white axolotl embryos.

The white mutant of the Mexican axolotl, A. mexicanum, involves an ectodermal defect which prevents melanophore colonization. Endogenous lectins have been suggested to function in neural crest-derived melanophore adhesion in other animals. To determine if differences in endogenous lectins exist in dark and white axolotls during melanophore colonization, white and dark ectoderm and carcass tissues have been assayed for lectin activity at premigratory, early migratory, and late migratory neural crest stages. Lectin content (specific for D-glucosamine, N-acetyl-D-glucosamine and D-mannose) increases significantly during early migration only in dark ectoderm and white carcass tissues, whereas white ectoderm and dark carcass lectin activities remain close to premigration levels. Neural crest cells in these embryos are associated with regions of high lectin activity suggesting that the differences in endogenous lectins may be involved in establishment of the dark/white phenotype.

Ambystoma↗
PubMed2000

Control of neurulation by the nucleosome assembly protein-1-like 2.

Neurulation is a complex process of histogenesis involving the precise temporal and spatial organization of gene expression. Genes influencing neurulation include proneural genes determining primary cell fate, neurogenic genes involved in lateral inhibition pathways and genes controlling the frequency of mitotic events. This is reflected in the aetiology and genetics of human and mouse neural tube defects, which are of both multifactorial and multigenic origin. The X-linked gene Nap1l2, specifically expressed in neurons, encodes a protein that is highly similar to the nucleosome assembly (NAP) and SET proteins. We inactivated Nap1l2 in mice by gene targeting, leading to embryonic lethality from mid-gestation onwards. Surviving mutant chimaeric embryos showed extensive surface ectoderm defects as well as the presence of open neural tubes and exposed brains similar to those observed in human spina bifida and anencephaly. These defects correlated with an overproduction of neuronal precursor cells. Protein expression studies showed that the Nap1l2 protein binds to condensing chromatin during S phase and in apoptotic cells, but remained cytoplasmic during G1 phase. Nap1l2 therefore likely represents a class of tissue-specific factors interacting with chromatin to regulate neuronal cell proliferation.

Animals↗
PubMed1986

Hay-Wells syndrome.

Hay-Wells syndrome is an autosomal dominant constellation of facial clefting, ankyloblepharon filiforme adnatum (fused eyelids), and ectodermal defects. Our patient, a child who had these unusual features at birth, led us to consider possible differential diagnoses based on clinical features and review of the literature.

Cleft Lip↗
PubMed1994

Selective disruption of E-cadherin function in early Xenopus embryos by a dominant negative mutant.

E-cadherin function was disrupted in vivo in developing Xenopus laevis embryos through the expression of a mutant E-cadherin protein lacking its cytoplasmic tail. This truncated form of E-cadherin was designed to act as a dominant negative mutant by competing with the extracellular interactions of wild-type endogenous E-cadherin. Expression of truncated E-cadherin in the early embryo causes lesions to develop in the ectoderm during gastrulation. In contrast, expression of a similarly truncated N-cadherin protein failed to cause the lesions. The ectodermal defect caused by the truncated E-cadherin is rescued by overexpression of wild-type E-cadherin, by co-injection of full-length E-cadherin RNA along with the RNA for the truncated form. Overexpression of full-length C-cadherin, however, is unable to compensate for the disruption of E-cadherin function and can actually cause similar ectodermal lesions when injected alone, suggesting that there is a specific requirement for E-cadherin. Therefore, E-cadherin seems to be specifically required for maintaining the integrity of the ectoderm during epiboly in the gastrulating Xenopus embryo. Differential cadherin expression reflects, therefore, the requirement for distinct adhesive properties during different morphogenetic cell behaviors.

Amino Acid Sequence↗