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PubMed1993

Skeletal histopathology in fetuses with chondroectodermal dysplasia (Ellis-van Creveld syndrome).

Chondroectodermal dysplasia (CED) is an uncommon autosomal recessive disorder and one of the short rib polydactyly syndromes (SRPS). It is characterized by acromelic and mesomelic shortness of limbs, postaxial polydactyly, small chest, ectodermal dysplasia, and in many cases, congenital heart defects. Controversy exists over possible changes in the growth plate. With the advent of ultrasonographic examination, increasing numbers of fetuses with osteochondrodysplasias are examined by pathologists. Since histopathologic examination of the skeletal system is useful in defining various osteochondrodysplasias and it has not been described in the fetus with CED, we herein describe 3 cases of fetal CED with emphasis on skeletal histopathology. All 3 pregnancies were terminated at 22-23 weeks because of ultrasonographic demonstration of short limbs and growth retardation. Radiologically, each fetus had acromelic and mesomelic shortness of long bones with smooth round metaphyses, vertically short iliac bones, short ribs and normal vertebrae. These findings are similar to those described in the larger newborn infant with CED. Histopathologically, the cartilage of the long bones showed chondrocytic disorganization in the physeal growth zone. The findings are dissimilar to those of larger infants and older children in whom chondrocytic columnization has been seen in the central physis and disorganization in peripheral physis. Furthermore, a variable degree of chondrocytic disorganization was also seen in the central physeal growth zone of vertebrae in these fetuses. Other findings noted at fetopsy were: polydactyly in all 3 cases, congenital heart defect in 2 and an abnormal frenulum in one case. The foregoing phenotypic and radiographic manifestations and skeletal histopathology help separate CED from other SRPS.

Bone and Bones↗
PubMed2004

Tooth patterning and enamel formation can be manipulated by misexpression of TNF receptor Edar.

Signaling by Edar, a tumor necrosis factor receptor, is required for the development of ectodermal organs. Mutations in Edar or other molecules of the same signaling pathway cause ectodermal dysplasias in humans and mice. In these diseases, teeth are missing or malformed, and the development of hairs and several glands is hypoplastic. During tooth and hair development, Edar expression becomes patterned to ectodermal placodes and signaling centers. This localization has been suggested to be required for organogenesis. We have expressed Edar throughout the ectoderm using the keratin 14 promoter and show that this misexpression disrupts tooth patterning and differentiation. Tooth shape and cusp number are differentially affected, depending on the amount of transgene expression. In addition, tooth enamel formation is defective in a dose-dependent manner. We speculate that the tooth patterning defects are caused by ectopic Edar activity outside the signaling centers.

Amelogenesis↗
PubMed1999

Limb mammary syndrome: a new genetic disorder with mammary hypoplasia, ectrodactyly, and other Hand/Foot anomalies maps to human chromosome 3q27.

We report on a large Dutch family with a syndrome characterized by severe hand and/or foot anomalies, and hypoplasia/aplasia of the mammary gland and nipple. Less frequent findings include lacrimal-duct atresia, nail dysplasia, hypohydrosis, hypodontia, and cleft palate with or without bifid uvula. This combination of symptoms has not been reported previously, although there is overlap with the ulnar mammary syndrome (UMS) and with ectrodactyly, ectodermal dysplasia, and clefting syndrome. Allelism with UMS and other related syndromes was excluded by linkage studies with markers from the relevant chromosomal regions. A genomewide screening with polymorphic markers allowed the localization of the genetic defect to the subtelomeric region of chromosome 3q. Haplotype analysis reduced the critical region to a 3-cM interval of chromosome 3q27. This chromosomal segment has not been implicated previously in disorders with defective development of limbs and/or mammary tissue. Therefore, we propose to call this apparently new disorder "limb mammary syndrome" (LMS). The SOX2 gene at 3q27 might be considered an excellent candidate gene for LMS because the corresponding protein stimulates expression of FGF4, an important signaling molecule during limb outgrowth and development. However, no mutations were found in the SOX2 open reading frame, thus excluding its involvement in LMS.

Abnormalities, Multiple↗
PubMedDate not supplied

Spectrum of phenotypic manifestations from a single point mutation of the p63 gene, including new cutaneous and immunologic findings.

Mutations in the p63 gene have been identified in five human disorders characterized by varying degrees of limb anomalies, ectodermal dysplasia, and facial clefts. We report a new point mutation in the p63 gene in a family in which the mother was initially diagnosed with Rapp-Hodgkin syndrome and her two offspring manifested ankyloblepharon, ectodermal defects, cleft lip and palate, syndrome. These three patients are the first to be reported with this particular mutation, which consists of a change from glycine to aspartic acid at position 506 on exon 14. The clinical spectrum observed in the three family members highlights the wide range of phenotypic variations that result from a single point mutation in the p63 gene. The mother lacks certain features classically associated with AEC, dermatitis of the scalp in particular. Severe erosive dermatitis of the scalp developed in both offspring, along with previously undescribed poikilodermatous skin changes and a deficiency of CD4 T lymphocytes. The new and varied phenotypic features noted in these patients emphasize the spectrum of disease caused by mutations in the p63 gene and raise the possibility of a role for it in maintaining immunocompetence.

Abnormalities, Multiple↗
PubMedDate not supplied

Uncombable hair syndrome with angel-shaped phalango-epiphyseal dysplasia.

Uncombable hair syndrome or "cheveux incoiffables" is due to a characteristic longitudinal grooving of the hair shaft resulting in a triangular cross section (pili trianguli et canaliculi). In the majority of cases the abnormality is an isolated finding, although uncombable hair-type changes have been observed in conjunction with other features of ectodermal dysplasia. Ultrastructural studies in the latter have revealed more complex changes of the hair shaft, such as longitudinal grooving in combination with torsion, suggesting classification as a different entity. We describe a 6-year-old girl with typical "cheveux incoiffables," as confirmed by scanning electron microscopy, in combination with angel-shaped phalango-epiphyseal dysplasia. The relationship to a previously described syndrome of uncombable hair in combination with retinal dystrophy, juvenile cataract, and brachydactyly, in which both hair and skeletal abnormalities are common, remains to be further elucidated.

Abnormalities, Multiple↗
PubMed2001

Hay-Wells syndrome is caused by heterozygous missense mutations in the SAM domain of p63.

Hay-Wells syndrome, also known as ankyloblepharon-ectodermal dysplasia-clefting (AEC) syndrome (OMIM 106260), is a rare autosomal dominant disorder characterized by congenital ectodermal dysplasia, including alopecia, scalp infections, dystrophic nails, hypodontia, ankyloblepharon and cleft lip and/or cleft palate. This constellation of clinical signs is unique, but some overlap can be recognized with other ectodermal dysplasia syndromes, for example ectrodactyly--ectodermal dysplasia--cleft lip/palate (EEC; OMIM 604292), limb--mammary syndrome (LMS; OMIM 603543), acro-dermato-ungual-lacrimal-tooth syndrome (ADULT; OMIM 103285) and recessive cleft lip/palate--ectodermal dysplasia (CLPED1; OMIM 225060). We have recently demonstrated that heterozygous mutations in the p63 gene are the major cause of EEC syndrome. Linkage studies suggest that the related LMS and ADULT syndromes are also caused by mutations in the p63 gene. Thus, it appears that p63 gene mutations have highly pleiotropic effects. We have analysed p63 in AEC syndrome patients and identified missense mutations in eight families. All mutations give rise to amino acid substitutions in the sterile alpha motif (SAM) domain, and are predicted to affect protein--protein interactions. In contrast, the vast majority of the mutations found in EEC syndrome are amino acid substitutions in the DNA-binding domain. Thus, a clear genotype--phenotype correlation can be recognized for EEC and AEC syndromes.

Abnormalities, Multiple↗
PubMedDate not supplied

Ectodysplasin signaling in development.

Ectodysplasin (Eda), a signaling molecule belonging to the tumor necrosis factor family, is required for normal development of several ectodermally derived organs in humans and mice. Two closely related isoforms of ectodysplasin, Eda-A1 and Eda-A2, have been described which bind to and activate two different receptors, Edar and X-linked Eda-A2 receptor (Xedar), respectively. Mutations in Eda, Edar or other molecules of this signaling pathway cause ectodermal dysplasias characterized by defective development of teeth, hairs, and several exocrine glands such as sweat glands presumably due to impaired NF-kappaB response. Studies with mice either lacking the functional proteins of Edar pathway or overexpressing the ligand or receptor suggest that Eda-A1-Edar signaling has multiple roles in ectodermal organ development regulating their initiation, morphogenesis, and differentiation.

Animals↗
PubMed2002

Death receptor signaling giving life to ectodermal organs.

A new tumor necrosis factor (TNF) pathway has been identified that has an important function in the regulation of embryonic development. Three key components of this pathway are previously unknown proteins: the TNF ligand ectodysplasin (also known as EDA), its death domain-containing receptor EDAR, and the death domain adapter molecule EDARADD. This pathway was discovered and delineated through the cloning of genes that cause human hypohidrotic ectodermal dysplasia (HED) syndromes and by analysis of the corresponding mouse mutants (Tabby, downless, and crinkled) showing defects in hair, teeth, and several exocrine glands. EDAR signaling is mediated by the activation of nuclear factor kappa B, but other downstream targets are not known. Ectodysplasin-EDAR signaling mediates cell interactions within the ectoderm and regulates the initiation and morphogenesis of hair and teeth. It is also necessary for the development of fish scales, indicating that this pathway and its function have been conserved during the evolution of ectodermal organs.

Animals↗
PubMed2002

Mutations in the p53 homolog p63: allele-specific developmental syndromes in humans.

p63 is the most recently discovered but most ancient member of the p53 family. In marked contrast to p53, p63 is highly expressed in embryonic ectoderm and in the basal, regenerative layers of many epithelial tissues in the adult. The p63-knockout mouse dies at birth and lacks limbs, epidermis, prostate, breast and urothelial tissues, apparently owing to the loss of stem cells required for these tissues. Significantly, several dominant human syndromes involving limb development and/or ectodermal dysplasia have been mapped to chromosome 3q27 and ultimately the gene encoding p63. The heterozygous p63mutations are distinct for each of the syndromes and are thought to act through both dominant-negative and gain-of-function mechanisms rather than a loss-of-function haploinsufficiency. The allele specificity of these syndromes offers unique molecular insights into the poorly understood actions of p63 in limb development, ectodermal-mesodermal interactions and stem cell maintenance.

Abnormalities, Multiple↗
PubMed2000

The p53/p63/p73 family of transcription factors: overlapping and distinct functions.

The p53 gene is the most frequently mutated gene in human cancer. The identification of two homologues, p63 and p73, revealed that p53 is a member of a family of related transcription factors. Given that they share amino acid sequence identity reaching 63% in the DNA-binding domain, p53, p63 and p73 should have redundant functions in the regulation of gene expression. Indeed, p73 can activate p53-regulated genes and suppress growth or induce apoptosis. Moreover, p53 and p73 are both induced by DNA damage - albeit through distinct mechanisms. Other evidence, however, suggests that p63 and p73 are important for regulation of normal development. An extended C-terminal region, not found in p53, is alternatively spliced in p63 and p73. Within this C-terminal extension is a sterile &agr; motif (SAM) previously found in other proteins that regulate development. The p63-deficient mice showed developmental abnormalities. Interestingly, the human p63 gene is mutated in children who have the disease Ectrodactyly, Ectodermal dysplasia and facial Clefts (EEC) syndrome, and the disease phenotype is similar to the one of p63-deficient mice. The p63 and p73 genes are rarely mutated in human cancer, although p73 loss is observed in neuroblastoma and a subtype of T-cell lymphoma. p53, p63 and p73 appear to have overlapping and distinct functions: p53 regulates the stress response to suppress tumors; p63 is essential for ectoderm development; and p73 might regulate both the stress response and development. Because p53 and p73 are linked to different upstream pathways, this family of transcription factors might regulate a common set of genes in response to different extracellular signals and developmental cues.

Animals↗
PubMed1996

Mental retardation, distinct craniofacial dysmorphism, and central nervous system malformation: confirmation of a syndrome.

We present a child with severe mental retardation, a central nervous system malformation, signs of ectodermal dysplasia, and a distinct craniofacial dysmorphism. Similar but less pronounced craniofacial features were present in the mildly mentally retarded mother. This observation confirms a previous report of a boy with the same MCA-MR syndrome and suggests X linked or autosomal dominant inheritance.

Adult↗
PubMed2001

TNF signaling via the ligand-receptor pair ectodysplasin and edar controls the function of epithelial signaling centers and is regulated by Wnt and activin during tooth organogenesis.

Ectodermal dysplasia syndromes affect the development of several organs, including hair, teeth, and glands. The recent cloning of two genes responsible for these syndromes has led to the identification of a novel TNF family ligand, ectodysplasin, and TNF receptor, edar. This has indicated a developmental regulatory role for TNFs for the first time. Our in situ hybridization analysis of the expression of ectodysplasin (encoded by the Tabby gene) and edar (encoded by the downless gene) during mouse tooth morphogenesis showed that they are expressed in complementary patterns exclusively in ectodermal tissue layer. Edar was expressed reiteratively in signaling centers regulating key steps in morphogenesis. The analysis of the effects of eight signaling molecules in the TGFbeta, FGF, Hh, Wnt, and EGF families in tooth explant cultures revealed that the expression of edar was induced by activinbetaA, whereas Wnt6 induced ectodysplasin expression. Moreover, ectodysplasin expression was downregulated in branchial arch epithelium and in tooth germs of Lef1 mutant mice, suggesting that signaling by ectodysplasin is regulated by LEF-1-mediated Wnt signals. The analysis of the signaling centers in tooth germs of Tabby mice (ectodysplasin null mutants) indicated that in the absence of ectodysplasin the signaling centers were small. However, no downstream targets of ectodysplasin signaling were identified among several genes expressed in the signaling centers. We conclude that ectodysplasin functions as a planar signal between ectodermal compartments and regulates the function, but not the induction, of epithelial signaling centers. This TNF signaling is tightly associated with epithelial-mesenchymal interactions and with other signaling pathways regulating organogenesis. We suggest that activin signaling from mesenchyme induces the expression of the TNF receptor edar in the epithelial signaling centers, thus making them responsive to Wnt-induced ectodysplasin from the nearby ectoderm. This is the first demonstration of integration of the Wnt, activin, and TNF signaling pathways.

Activins↗
PubMed1992

Association of autosomal dominant cleft lip and palate and translocation 6p23;9q22.3.

Orofacial clefting (OFC) is genetically complex in that no single gene defect is responsible for all forms. We have identified a family who exhibit autosomal dominant orofacial clefting together with some features of ectodermal dysplasia. In this family there is concordance between these features and an apparently balanced translocation t(6;9)(p23;q22.3) which raises the possibility that a locus for one form of orofacial clefting may be located at one of the translocation breakpoints. Fluorescent in situ hybridization has shown that a candidate gene for OFC, which maps to distal 6p, is located on the derived chromosome 9 in affected individuals from this family. Further characterization of the translocation breakpoints and of their relationship with the candidate gene will determine whether a gene important for normal facial and/or ectodermal development is disrupted in this family.

Adult↗
PubMed1993

Dolichonychia in a patient with the Marfan syndrome.

Dolichonychia is a descriptive term for elongated, slender nails. Although published observations of this finding are uncommon, dolichonychia has previously been seen in patients with connective tissue disorders, with hypohidrotic ectoderma dysplasia, or with abnormal hormonal states. Dolichonychia is a clinical feature which may be observed in patients with the Marfan syndrome. A woman with the Marfan syndrome and dolichonychia is described. Measurements of the patient's arm span, height, lower segment, hand length, and middle finger length were performed. In addition, the length-to-width ratio of each of her finger nails was determined. The mean of finger nail length-to-width quotients in the patient with the Marfan syndrome was 1.54. In conclusion, the detection of dolichonychia should prompt the physician to rule out associated systemic conditions: after eunuchoidism, hypohidrotic ectodermal dysplasia, and hypopituitarism have been excluded, an evaluation for Ehlers-Danlos syndrome and the Marfan syndrome should be considered.

Adult↗
PubMed2001

Altered skin development and impaired proliferative and inflammatory responses in transgenic mice overexpressing the glucocorticoid receptor.

Glucocorticoids (GCs) are potent inhibitors of epidermal proliferation and effective anti-inflammatory compounds, which make them the drug of choice for a wide range of inflammatory and hyperproliferative skin disorders. GC action is mediated via the glucocorticoid receptor (GR). To study the role of GR in skin development and the molecular mechanisms underlying its action, we generated transgenic mice overexpressing GR in epidermis and other stratified epithelia, under the control of the keratin K5 promoter. Newborn mice show altered skin development, manifested as variable-sized skin lesions that range from epidermal hypoplasia and underdeveloped dysplastic hair follicles to a complete absence of this tissue. In the most affected individuals, skin was absent at the cranial and umbilical regions, and the vibrissae and eyebrows appear scarce, short, and curly. In addition, as a consequence of transgene expression in other ectodermally derived epithelia, K5-GR mice exhibited further abnormalities that strikingly resemble the clinical findings in patients with ectodermal dysplasia, which includes aplasia cutis congenita. In adult transgenic skin, topical application of the tumor promoter TPA did not elicit hyperplasia or transcriptional induction of several proinflammatory cytokines. This anti-inflammatory role of GR was due at least in part to interference with NF-kB, leading to a strong reduction in the kB-binding activity without altering the transcriptional levels of the inhibitor IkBa.

Animals↗
PubMed2004

Myodegeneration in EDA-A2 transgenic mice is prevented by XEDAR deficiency.

EDA-A1 and EDA-A2 are members of the tumor necrosis factor family of ligands. The products of alternative splicing of the ectodysplasin (EDA) gene, EDA-A1 and EDA-A2 differ by an insertion of two amino acids and bind to distinct receptors. The longer isoform, EDA-A1, binds to EDAR and plays an important role in sweat gland, hair, and tooth development; mutations in EDA, EDAR, or the downstream adaptor EDARADD cause hypohidrotic ectodermal dysplasia. EDA-A2 engages the receptor XEDAR, but its role in the whole organism is less clear. We have generated XEDAR-deficient mice by gene targeting and transgenic mice expressing secreted forms of EDA-A1 or EDA-A2 downstream of the skeletal muscle-specific myosin light-chain 2 or skin-specific keratin 5 promoter. Mice lacking XEDAR were indistinguishable from their wild-type littermates, but EDA-A2 transgenic mice exhibited multifocal myodegeneration. This phenotype was not observed in the absence of XEDAR. Skeletal muscle in EDA-A1 transgenic mice was unaffected, but their sebaceous glands were hypertrophied and hyperplastic, consistent with a role for EDA-A1 in the development of these structures. These data indicate that XEDAR-transduced signals are dispensable for development of ectoderm-derived organs but might play a role in skeletal muscle homeostasis.

Animals↗
PubMed1976

Hereditary congenital alacrima.

We describe a family with markedly deficient lacrimation from infancy and punctate corneal epithelial erosions. An autosomal dominant inheritance pattern is suggested. A hypoplasia of the lacrimal gland in this family was suggested by pharmacologic testing and by histopathologic examination of the lacrimal gland of the proposita. The family investigated in this report represents the first instance of hereditary congenital alacrima without associated ocular or adnexal abnormalities and apart from systemic disorders such as the Riley-Day syndrome and anhidrotic ectodermal dysplasia.

Adolescent↗