Ectodermal dysplasias: not only 'skin' deep

Canine noninflammatory alopecia: An approach to its classification and a diagnostic aid

Noninflammatory alopecia is common in dogs and is a frequent cause to consult a veterinarian. It is also a common reason to take biopsies. Noninflammatory alopecia can be attributed to a decreased formation or cytodifferentiation of the hair follicle or the hair shaft in utero, resulting in congenital alopecia. Congenital alopecia often has a hereditary cause, and examples of such disorders are ectodermal dysplasias associated with gene variants of the ectodysplasin A gene. Noninflammatory alopecia may also be caused by impaired postnatal regeneration of hair follicles or shafts. Such disorders may have a clear breed predilection, and alopecia starts early in life. A hereditary background is suspected in those cases but has not been proven. They are referred to as follicular dysplasia although some of these disorders present histologically like a hair cycle disturbance. Late-onset alopecia is usually acquired and may be associated with endocrinopathies. Other possible causes are impaired vascular perfusion or stress. As the hair follicle has limited possible responses to altered regulation, and histopathology may change during the course of a disease, a detailed clinical history, thorough clinical examination including blood work, appropriate biopsy site selection, and detailed histological findings need to be combined to achieve a final diagnosis. This review aims to provide an overview about the known noninflammatory alopecic disorders in dogs. As the pathogenesis of most disorders is unknown, some statements are based on comparative aspects or reflect the authors' opinion.

Dental Phenotype with Minor Ectodermal Symptoms Suggestive of WNT10A Deficiency

Ectodermal dysplasias (EDs) represent a heterogeneous group of genetic disorders characterized by the abnormal development of ectodermal-derived tissues. They include the involvement of the hair, nails, skin, sweat glands, and teeth. Pathogenic variants in EDA1 (Xq12-13.1; OMIM*300451), EDAR (2q11-q13; OMIM*604095), EDARADD (1q42-q43, OMIM*606603), and WNT10A (2q35; OMIM*606268) genes are responsible for most EDs. Bi-allelic pathogenic variants of WNT10A have been associated with autosomal recessive forms of ED, as well as non-syndromic tooth agenesis (NSTA). The potential phenotypic impact of associated modifier mutations in other ectodysplasin pathway genes has also been pointed out. We present on an 11-year-old Chinese boy with oligodontia, with conical-shaped teeth as the main phenotype, and other very mild ED signs. The genetic study identified the pathogenic variants WNT10A (NM_025216.3): c.310C > T; p. (Arg104Cys) and c.742C > T; p. (Arg248Ter) in compound heterozygosis, confirmed by parental segregation. In addition, the patient had the polymorphism EDAR (NM_022336.4): c.1109T > C, p. (Val370Ala) in homozygosis, named EDAR370. A prominent dental phenotype with minor ectodermal symptoms is very suggestive of WNT10A mutations. In this case, the EDAR370A allele might also attenuate the severity of other ED signs.

Confirmation of a Phenotypic Entity for TSPEAR Variants in Egyptian Ectodermal Dysplasia Patients and Role of Ethnicity

Ectodermal dysplasia (ED) are hereditary disorders characterized by the disturbance of the ectodermal development of at least two of four ectodermal tissues: teeth, hair, nails and sweat glands. Clinical classification of ED is challenged by overlapping features, variable expressivity, and low number of patients, hindering full phenotypic spectrum identification. Disease-causing variants in elements of major developmental pathways, e.g., Ectodysplasin/NFκB, Wnt, and Tp63 pathways, have been identified in fewer than half of ED phenotypes. Whole-exome sequencing (WES) was performed for ten Egyptian ED patients presenting with tooth agenesis, normal sweating, scalp hypotrichosis, and sharing characteristic facial features. WES was followed by in silico analysis of the effects of novel detected genetic variants on mRNA and protein structure. The study identified four novel rare pathogenic and likely pathogenic TSPEAR variants, a gene which was recently found to be involved in ectodermal organogenesis. A novel in-frame deletion recurred in eight patients from six unrelated families. Comparing our cohort to previously reported TSPEAR cohorts highlighted the influence of ethnicity on TSPEAR phenotypic affection. Our study expands the clinical and mutational spectrum of the growing TSPEAR associated phenotypes, and pinpoints the influence of WES and in silico tools on identification of rare disease-causing variants.

Central nervous system variations and abnormalities in anhidrotic ectodermal dysplasia (AED): neuroimaging findings

BACKGROUND

Anhidrotic ectodermal dysplasia (AED) is a rare, mostly X-linked recessive genodermatosis, characterized by congenital defects of ectodermal derivative structures as the central nervous system (CNS) is primarily ectodermal in origin.

PURPOSE

To evaluate CNS variations and abnormalities in AED.

MATERIAL AND METHODS

A retrospective analysis was made of the neurological and neuroimaging findings of 17 children (12 boys, 5 girls; median age = 8 years; age range = 2-14 years) diagnosed with AED in our pediatric clinics during 2008-2016. The pattern of CNS variation and abnormalities were evaluated by comparing of these findings with an age- and gender-matched healthy control group with no family history.

RESULTS

Of the 17 AED cases identified on the basis of neuroimaging findings, 6 (35.3%) were seen to be normal. Associated CNS variation and abnormalities including cavum septum pellucidum (35.3%), callosal dysgenesis (11.8%), prominent Virchow-Robin spaces (64.7%), cortical sulcal dilation (41.1%), mega cisterna magna (35.3%), focal cortical dysplasia (11.8%), and delayed myelination (58.8%) were observed in 11 (64.7%) children with AED.

CONCLUSION

AED suggests a spectrum of CNS variation and abnormalities, presenting with neurological and neuroimaging findings, demonstrated in the embryonic surface- and neuro-ectoderm derived structures. The results of this study suggest that CNS variation and abnormalities might be associated with AED.

Soft Tissue Facial Angles in Individuals with Ectodermal Dysplasia: A Three-Dimensional Noninvasive Study

Objective

To supply quantitative information about the facial soft tissues of patients with hypohidrotic ectodermal dysplasia.

Design

Prospective assessment.

Setting

National meetings of hypohidrotic ectodermal dysplasia patients and families.

Patients and Main Outcome Measures

Facial and mandibular corpus convexities in the horizontal plane; facial convexity in the sagittal plane; interlabial, naso-labial, nasal convexity, and left and right soft tissue gonial angles were calculated from the three-dimensional coordinates of 11 soft tissue facial landmarks obtained in 18 male and 17 female hypohidrotic ectodermal dysplasia patients aged 3 to 41 years and in 504 reference healthy individuals. In addition, z-scores were computed and the patients were grouped by cluster analysis.

Results

Male and female z-scores did not differ. In the pooled group, facial convexities in the horizontal and sagittal planes were significantly (Student's t, p < .01) increased (flatter) in hypohidrotic ectodermal dysplasia patients, compared with normal controls. The naso-labial angle was significantly reduced (more acute). Upper and lower facial convexity and mandibular corpus convexity in the horizontal plane deviated less from the norm with increasing age. Facial convexity in the horizontal and sagittal planes, soft tissue gonial angles, and naso-labial and interlabial angles deviated less from the norm with increasing number of teeth present in the mouth. Cluster analysis identified three homogeneous groups, all characterized by a peculiar facial phenotype. Modifications in facial convexity and gonial and interlabial angles differentiated each cluster.

Conclusions

Patients with hypohidrotic ectodermal dysplasia had flatter faces in the horizontal and sagittal planes than normal controls had. Cluster analysis revealed patterned differences in facial phenotype.

Cavernous angioma after chemotherapy for desmoplastic/nodular medulloblastoma associated with anhidrotic ectodermal dysplasia

PURPOSE

While cavernous angioma (CVA) after cranial irradiation has been documented, its development after high-dose chemotherapy with autologous peripheral blood stem cell transplantation (PBSCT) has not. We present a patient with desmoplastic/nodular medulloblastoma (DNMB) associated with anhidrotic ectodermal dysplasia (AED) who developed CVA 2 years after high-dose chemotherapy and PBSCT.

METHODS

A 1-year-old boy with ingravescent vomiting was admitted to our institute. He presented with a large head, a depressed nasal bridge, low-set ears, thick lips with peg-shaped teeth, hypohidrosis, sparse hair, thin atrophic skin, scaly dermatitis with frontal bossing, and a bulging anterior fontanel. Neuroradiological examination revealed multiple cerebellar masses with heterogeneous enhancement and speckled calcifications and severe obstructive hydrocephalus. The histological diagnosis of surgical specimens was DNMB, and he underwent postoperative multiple-drug chemotherapy with autologous PBSCT. The outcome was favorable and he did not undergo radiotherapy.

RESULTS

After 2 years, intracranial hemorrhage was detected at his regular radiological check-up and he again underwent surgery. The histological diagnosis was CVA.

CONCLUSIONS

To our knowledge, this is the first report of AED-associated DNMB and CVA.

Unraveling the Link Between Ectodermal Disorders and Primary Immunodeficiencies

Primary immunodeficiencies (PIDs) include a heterogeneous group of mostly monogenic diseases characterized by functional/developmental alterations of the immune system. Skin and skin annexa abnormalities may be a warning sign of immunodeficiency, since both epidermal and thymic epithelium have ectodermal origin. In this review, we will focus on the most common immune disorders associated with ectodermal alterations. Elevated IgE levels represent the immunological hallmark of hyper-IgE syndrome, characterized by severe eczema and susceptibility to infections. Ectodermal dysplasia (ED) is a group of rare disorders that affect tissues of ectodermal origin. Hypoidrotic ED (HED), the most common form, is inherited as autosomal dominant, autosomal recessive or X-linked trait (XLHED). HED and XLHED are caused by mutations in NEMO and EDA-1 genes, respectively, and show similarities in the cutaneous involvement but differences in the susceptibility to infections and immunological phenotype. Alterations in the transcription factor FOXN1 gene, expressed in the mature thymic and skin epithelia, are responsible for human and murine athymia and prevent the development of the T-cell compartment associated to ectodermal abnormalities such as alopecia and nail dystrophy. The association between developmental abnormalities of the skin and immunodeficiencies suggest a role of the skin as a primary lymphoid organ. Recently, it has been demonstrated that a co-culture of human skin-derived keratinocytes and fibroblasts, in the absence of thymic components, can support the survival of human haematopoietic stem cells and their differentiation into T-lineage committed cells.

Second International Conference on a classification of ectodermal dysplasias: development of a multiaxis model

Ectodermal dysplasias (EDs) comprise a large clinically and etiologically heterogeneous group of genetic disorders characterized by abnormalities in tissues derived from the embryonic ectoderm. Controversy exists over which syndromes should be classified as EDs and which should be excluded from the classification. The challenge will be to balance comprehensiveness within the classification with usability and accessibility so that the benefits truly serve the needs of researchers, health-care providers, and ultimately the individuals and families directly affected by EDs. The overarching goal of the Second International Conference was to develop a consensus on EDs classifications, with the ultimate goal of creating a system that integrates clinical and molecular knowledge, using an interactive Internet-based database that clinicians, researchers, and laymen can use. The Conference, brought together a group of experts from around the world, including a diverse health-care providers, researchers, patient advocate representatives, and administrators. The Conference was modeled after the 2008 conference, with plenary sessions, scientific updates, and small group discussions. Based on the present clinical knowledge, new molecular advances and both coupled with new bioinformatics developments, the participants agree to develop a multi-axis system approach for the classification of EDs. The multi-axis approach will include a clinical/phenotype axis, a gene-based axis, and a functional/pathways axis. The significance of the conference outcomes includes, a new classification approach that will foster a better understanding of EDs, open new fields of research and develop a nosologic approach that may have broad implications for classifying other hereditary conditions.

Retinal tear presenting in a patient with ectrodactyly ectodermal dysplasia

PURPOSE

This article aims to report a case of known ectrodactyly ectodermal dysplasia in a young male patient who subsequently was found to have a retinal tear and localized retinal detachment.

CASE REPORT

This is a case report of a 22-year-old white male patient with a history of ectrodactyly ectodermal dysplasia. Our patient initially presented with an acute exacerbation of bilateral, red, irritated eyes. No recent changes in vision were reported. The patient's ocular surface disease was consistent with ectrodermal dysplasia syndrome. However, a dilated fundus examination revealed an asymptomatic retinal tear with a surrounding localized retinal detachment.

CONCLUSIONS

In this case, the patient presented with longstanding ocular surface disease known to be associated with this patient's inherited ectoderm disorder. In addition, this patient revealed a retinal tear, raising the possibility that patients with inherited congenital ectodermal dysplasia could be at risk for damaged structures originating from the neural ectoderm. In this heterogeneous disease, we are contributing to the existing literature a case of ectodermal dysplasia syndrome with obvious ectodermal complications that also had retinal findings leading us to speculate question if neural ectoderm could also be involved in this inherited disease.

Hypohidrotic ectodermal dysplasia: a multidisciplinary approach

Hypohidrotic ectodermal dysplasia (HED; Christ-Siemens-Touraine syndrome) is a genetic disorder characterized by sparse hair, oligodontia with peg-shaped teeth, reduced sweating, and defects in a number of other ectodermal organs. A partial or complete absence of eccrine glands can lead to recurrent severe overheating that may cause seizures and neurological deficits. This clinical report presents a 14-year-old male patient with hypohidrotic ectodermal dysplasia, including the clinical and radiographic findings, and multidisciplinary treatment. The Schedule for Affective Disorders and Schizophrenia for School Aged Children-Present and Lifetime Version (K-SADS-PL) was administered to patient along with mother to assess for any psychiatric disorders. The screening and rating scales completed by mother and two teachers to evaluate the severity of attention deficit hyperactivity disorder (ADHD) symptoms, and other behavioral problems. Patient's academic performance, adaptive functioning, and problem behavior was evaluated using. The Teacher Report Form. Mental capacity was assessed with the Wechsler Intelligence Scale for Children (WISC-R). Illness Perception Questionnaire Revised was used to systematically assess illness representation attributes and emotional representations of illness. On the psychiatric diagnosis assessment using K-SADS-PL sub-threshold attention deficits and anxiety symptoms were determined. In this case we established a multidisciplinary approach in his treatment with pediatric, dermatological, and dental examinations, beside his psychiatric evaluation. The prosthetic rehabilitation included restoring upper teeth with copings and fabrication of upper and lower complete dentures. Metal framework was not incorporated in the partial denture design allowing modifications as the oral and maxillofacial development continued. Removable complete or partial dentures without metal framework is a treatment of choice until the completion of facial growth at which definitive treatment is considered.

Ectodermal dysplasias: a clinical and molecular review

The ectodermal dysplasias are a large group of hereditary disorders characterized by alterations of structures of ectodermal origin. Although some syndromes can have specific features, many of them share common clinical characteristics. Two main groups of ectodermal dysplasias can be distinguished. One group is characterized by aplasia or hypoplasia of ectodermal tissues, which fail to develop and differentiate because of a lack of reciprocal signaling between ectoderm and mesoderm, the other has palmoplantar keratoderma as its most striking feature, with additional manifestations when other highly specialized epithelia are also involved. In recent decades, the genes responsible for at least 30 different types of ectodermal dysplasia have been identified, throwing light on the pathogenic mechanisms involved and their correlation with clinical findings.

Ectodermal dysplasia: otolaryngologic evaluation of 23 cases

The aim of this prospective study was to improve the quality of life of and reduce morbidity for patients with ectodermal dysplasia by assessing their actual and potential ENT pathologies, and offering methods of prevention and treatment. The study was conducted between 2006 and 2008 and included 23 patients diagnosed with ectodermal dysplasia. The major symptoms of ectodermal dysplasia were evaluated. Patient histories were obtained in all cases, and a complete head and neck examination was carried out. Of the 23 patients (11 males and 12 females, aged 5 to 45 years) diagnosed with ectodermal dysplasia, 22 had hypohidrotic ectodermal dysplasia and 1 had ectrodactyly-ectodermal dysplasia-clefting syndrome. In all patients diagnosed with hypohidrotic ectodermal dysplasia, the salivary glands were examined by ultrasonography and, when necessary, by scintigraphy. Hearing defects in patients with otologic problems were determined by audiometric examination: 39.1% of the patients had hearing loss, 43.5% had otitis media, and 39.1% had impacted cerumen. The most common rhinologic findings were saddle nose deformity in 56.5%, nasal obstruction and nasal dryness (52.2% each), and chronic rhinitis/rhinosinusitis (34.8%). The most common oral and oropharyngeal findings were difficulty chewing in 82.6% and dry mouth in 78.3%. All 23 patients had required dental work. Because this disorder affects several aspects of the body, its treatment requires a multidisciplinary approach, with the otolaryngologist being a vital part of the management team.

Quality of life of cutaneous disease in the ectodermal dysplasias

The ectodermal dysplasias are a complex, heritable group of syndromes that affect derivatives of ectoderm. The dermatologist plays an important role in ectodermal dysplasias as the visible defects of skin, hair, and nails are often recognized first. Our objective was to examine how quality of life relates to the degree of skin involvement in ectodermal dysplasias. Subjects (n = 42) with ectodermal dysplasias were surveyed at national and regional conferences hosted by National Foundation for Ectodermal Dysplasias on July 26 to 28, 2007 and November 17, 2007. Severity of hypohidrosis, alopecia, and fingernail involvement were measured using validated Likert scales. The quality of life was measured using the Children's Dermatology Life Quality Index in children, and the Skindex-29 and RAND Short Form-36 in adults. The severity for all subjects (n = 42) was greatest for hypohidrosis, which clinically translated into "little ability to sweat." We found that the greatest impact on quality of life was related to the actual symptoms of ectodermal dysplasias, which is not surprising as almost all participants reported skin involvement (93%), most likely related to hypohidrosis, atopic dermatitis, skin erosions and infections. The symptoms of ectodermal dysplasias may also be related to the nail involvement, as manifested by dystrophic or fragmented nails. Alopecia did not play a significant role in the quality of life burden. The challenge of providing proper skin care emphasizes the benefit of dermatologic involvement, and the need for increased recognition and enhanced awareness of the cutaneous burden in ectodermal dysplasias.

Congenital subcostal hernia with unusual contents

Congenital hernias arising in the subcostal region are rare. We describe a case of a former preterm infant, born with congenitally fused right 11th and 12th ribs and a protuberant mass in the right subcostal region. This mass was associated with a small fascial defect and herniation of abdominal contents. At operation, the mass was determined to be a hernia with an incarcerated ovarian remnant and fallopian tube.

Ectodermal dysplasias: an overview and update of clinical and molecular-functional mechanisms

The ectodermal dysplasias (EDs) are a large and complex group of disorders. In various combinations, they all share anomalies in hair, teeth, nails, and sweat gland function. The anomalies affecting the epidermis and epidermal appendages are extremely variable. Many are associated with malformations in other organs and systems. Clinical overlap is present among EDs. Few causative genes have been identified, to date. Most of the EDs present multisystem involvement with abnormal development of structures also derived from mesoderm. In the last few years, it has become evident that gene expression in the EDs is not limited to the ectoderm and that there is a concomitant effect on developing mesenchymal structures, with modification or abolition of ectodermal-mesenchymal signaling. It is possible to approach this group of diseases basing on functional and molecular findings and to begin to explain the complex clinical consequences of mutations affecting specific developmental pathways. We have reviewed the molecular basis of ectodermal dysplasias applying this new clinical-functional classification. For each subset of the identified ED, we will now describe the genes and related proteins involved in terms of: (1) structure of the genes and their role in differentiation of the epidermis and the ectodermal derivatives; (2) genotype-phenotype correlation.

2008 International Conference on Ectodermal Dysplasias Classification: conference report

There are many ways to classify ectodermal dysplasia syndromes. Clinicians in practice use a list of syndromes from which to choose a potential diagnosis, paging through a volume, such as Freire-Maia and Pinheiro's corpus, matching their patient's findings to listed syndromes. Medical researchers may want a list of syndromes that share one (monothetic system) or several (polythetic system) traits in order to focus research on a narrowly defined group. Special interest groups may want a list from which they can choose constituencies, and insurance companies and government agencies may want a list to determine for whom to provide (or deny) health-care coverage. Furthermore, various molecular biologists are now promoting classification systems based on gene mutation (e.g., TP63-associated syndromes) or common molecular pathways. The challenge will be to balance comprehensiveness within the classification with usability and accessibility so that the benefits truly serve the needs of researchers, health-care providers, and ultimately the individuals and families directly affected by ectodermal dysplasias. It is also recognized that a new classification approach is an ongoing process and will require periodical reviews or updates. Whatever scheme is developed, however, will have far-reaching application for other groups of disorders for which classification is complicated by the number of interested parties and advances in diagnostic acumen. Consensus among interested parties is necessary for optimizing communication among the diverse groups whether it be for equitable distribution of funds, correctness of diagnosis and treatment, or focusing research efforts.

DeltaNp63 knockdown mice: A mouse model for AEC syndrome

Dominant mutations in TP63 cause ankyloblepharon ectodermal dysplasia and clefting (AEC), an ectodermal dysplasia characterized by skin fragility. Since DeltaNp63alpha is the predominantly expressed TP63 isoform in postnatal skin, we hypothesized that mutant DeltaNp63alpha proteins are primarily responsible for skin fragility in AEC patients. We found that mutant DeltaNp63alpha proteins expressed in AEC patients function as dominant-negative molecules, suggesting that the human AEC skin phenotype could be mimicked in mouse skin by downregulating DeltaNp63alpha. Indeed, downregulating DeltaNp63 expression in mouse epidermis caused severe skin erosions, which resembled lesions that develop in AEC patients. In both cases, lesions were characterized by suprabasal epidermal proliferation, delayed terminal differentiation, and basement membrane abnormalities. By failing to provide structural stability to the epidermis, these defects likely contribute to the observed skin fragility. The development of a mouse model for AEC will allow us to further unravel the genetic pathways that are normally regulated by DeltaNp63 and that may be perturbed in AEC patients. Ultimately, these studies will not only contribute to our understanding of the molecular mechanisms that cause skin fragility in AEC patients, but may also result in the identification of targets for novel therapeutic approaches aimed at treating skin erosions. (c) 2009 Wiley-Liss, Inc.

Candidate EDA targets revealed by expression profiling of primary keratinocytes from Tabby mutant mice

EDA, the gene mutated in anhidrotic ectodermal dysplasia, encodes ectodysplasin, a TNF superfamily member that activates NF-kB mediated transcription. To identify EDA target genes, we have earlier used expression profiling to infer genes differentially expressed at various developmental time points in Tabby (Eda-deficient) compared to wild-type mouse skin. To increase the resolution to find genes whose expression may be restricted to epidermal cells, we have now extended studies to primary keratinocyte cultures established from E19 wild-type and Tabby skin. Using microarrays bearing 44,000 gene probes, we found 385 preliminary candidate genes whose expression was significantly affected by Eda loss. By comparing expression profiles to those from Eda-A1 transgenic skin, we restricted the list to 38 "candidate EDA targets", 14 of which were already known to be expressed in hair follicles or epidermis. We confirmed expression changes for 3 selected genes, Tbx1, Bmp7, and Jag1, both in keratinocytes and in whole skin, by Q-PCR and Western blotting analyses. Thus, by the analysis of keratinocytes, novel candidate pathways downstream of EDA were detected.

Implications for tooth development on ENU-induced ectodermal dysplasia mice

BACKGROUND

In this study, the mutated phenotypes were produced by treatment of chemical mutagen, N-ethyl-N-nitrosourea (ENU). We analyzed the mutated mice showing the specific phenotype of ectodermal dysplasia (ED) and examined the affected gene.

METHODS

Phenotypes, including size, bone formation, and craniofacial morphology of ENU-induced ED mice, were focused. Tooth development and expression of several molecules were analyzed by histologic observations and immunohistochemistry. We carried out genome-wide screening and quantitative real-time PCR to define the affected and related genes.

RESULTS

As examined previously in human ectodermal dysplasia, ENU-induced ED mice showed the specific morphologic deformities in tooth, hair, and craniofacial growth. Tooth development in the ENU-induced ED mice ceased at early cap stage. In addition, skeletal staining showed retardation in craniofacial development. Finally, the affected gene, which would be involved in the mechanism of ED, was located between the marker D3Mit14 and D3Mit319 on chromosome 3.

CONCLUSIONS

The affected gene in ENU-induced ED mice showed several defects in ectodermal organogenesis and these results indicate that this gene plays an important role in mouse embryogenesis.

Aplasia cutis congenita, congenital heart lesions, and frontonasal cysts in four successive generations

We report a family with four known generations of individuals in the maternal family tree with aplasia cutis congenita (ACC) of the scalp, congenital heart lesions, brachydactyly, and frontonasal cysts. This is the first reported finding of craniofacial, digital, and cardiac abnormalities associated with ACC, likely representing a new variant of the autosomal dominant hidrotic ectodermal dysplasia subtype. These rare disorders are characterized by common anomalies of at least two elements of the ectoderm and its appendages, namely the skin, teeth, hair, nails, and sweat glands. These patients also frequently have chronic dental problems with early loss of teeth, and recurrent lung, ear, and nose infections secondary to a defect in mucous membrane function. The clinical findings in these patients are delineated and compared to patients with other forms of ectodermal dysplasia in the literature.

Mechanisms regulating epithelial stratification

The epidermis is a stratified epithelium that functions as a barrier protecting the organism from dehydration, mechanical trauma, and microbial insults. This barrier function is established during embryogenesis through a complex and tightly controlled stratification program. Whereas the morphological changes that occur during epidermal development have been extensively studied, the molecular mechanisms that govern this process remain poorly understood. In this review we summarize the current advances that have been made in understanding the molecular mechanisms that regulate epidermal morphogenesis.

Implants in children with ectodermal dysplasia: a case report and literature review

The replacement of teeth by implants is usually restricted to patients with completed craniofacial growth. Implant insertions in children or adolescents are circumvented due to several unfavorable potential effects including trauma to tooth germs, tooth eruption disorders and multidimensional restrictions of skeletal craniofacial growth. Moreover, the functional and esthetic results of the oral rehabilitation are only temporary acceptable. However, to a small number of pediatric patients suffering congenitally from severe hypodontia caused by syndromes such as ectodermal dysplasia, conventional prosthodontic rehabilitations are insufficient. We report the case of a boy with ectodermal dysplasia who exhibited a severe hypodontia and who was treated with implants inserted into the anterior mandible at the age of 8 years. The implants were functionally loaded and resulted in a high patient satisfaction. We recommend the early insertion of dental implants in children with severe hypodontia. Reviewing the current literature, several aspects of syndromic hypodontia, patient selection and implant planning are discussed.

Ectodermal Dysplasia: Retrospective Study of Fifteen Cases

The aim of this article is to review possible cranio-maxillofacial deformative consequences associated with hypohidrotic ectodermal dysplasia and embryonic malformations, which include dental ageneses, and describe the oral habilitation. Hypohidrotic ectodermal dysplasia patients had a clinical examination and underwent radiographic and Steiner's analyses and a respiratory capability test before assessment and treatment. Fifteen patients (eight males and seven females, aged 5-45 years) had tooth ageneses (from hypodontia to anodontia) associated with cutaneous dyshydrosis and hair and nail dystrophy. Most patients had sparse or absent hair, a short face with an unusual facial concavity, a maxillary retrusion and a relative mandibular protrusion. Dentists must conduct a comprehensive and multidisciplinary approach to these patients in order to improve their dental, masticatory, growth and orthognathic conditions.

Evaluation of Ectodermal Dysplasia

This case series report outlines possible cranio-maxillofacial deformation consequences associated with ectodermal dysplasia (ED) and embryonic malformations, including dental agenesis. Also described are the oral aspects and rehabilitation. A total of 14 ED patients (7 males and 7 females, aged 5-45 years) underwent clinical examination before assessment and treatment. Lateral cephalometric radiography, Steiner's analysis, and respiratory capacity tests were performed. Most of the patients had sparse or absent hair, a short face with an unusual facial concavity, a maxillary retrusion, and a relative mandible protrusion. Depending on age and orthopedic abnormalities, patients were treated with prosthodontic and orthodontic approaches or implant treatment. Therapists should take a comprehensive and multidisciplinary approach with these patients to improve their dental, masticatory, growth, and orthognathic conditions, as well as esthetic appearance.

Dlx genes, p63, and ectodermal dysplasias

Many events in vertebrate morphogenesis and organogenesis develop from epithelial/mesenchymal interactions. These processes involve a series of sequential and reciprocal interactions between the thickened epithelial sheets and underlying mesenchymal cells. Much has been learned from in vitro assays and knockout experiments in mice on the early signaling molecules that regulate the initial stages of the epithelial/mesenchymal interactions. In this review, we discuss effectors of these initial signals, specifically the p63 and Dlx families of transcription factors, that play central roles in embryonic patterning and regulation of different developmental processes, and provide a review of some of the mutations in these genes that have been associated with ectodermal dysplasias (EDs).

X-linked anhidrotic ectodermal dysplasia disruption yields a mouse model for ocular surface disease and resultant blindness

X-linked anhidrotic/hypohidrotic ectodermal dysplasia (EDA) is caused by mutations in the (EDA) gene, which is required for the morphogenesis of ectoderm-derived tissues. Although EDA function in skin appendage development has been studied in Eda mutant "Tabby" mice, we have recently identified characteristic abnormalities in the ocular surface, an ectoderm-derived tissue. Histology of eyes of Tabby males revealed that 1) as previously reported, mice lacked meibomian glands; 2) >80% developed corneal lesions such as neovascularization, keratitis, ulceration, and keratinization identifiable from 9 weeks of age; and 3) > 80% showed ocular surface inflammation (blepharitis and conjunctivitis) when housed in a standard environment. Strikingly, both corneal defects and inflammation were prevented in Tabby mice bearing a transgene for the Eda-A1 isoform, but meibomian glands were restored little if at all. These findings suggest that intact ocular surface health is EDA dependent and that Tabby corneal abnormalities are not solely dependent on meibomian gland lipid secretion. Alternatively, susceptibility to inflammation and other phenotypes could result from failure of the usual EDA receptor to activate nuclear factor-kappaB transcription factors. This can be further tested in Tabby and Tabby-EDA transgenic mice, which provide unique models of severe ocular surface disease.

Anhydrotic ectodermal dysplasia (Christ-Siemens-Touraine syndrome). A case report

The ectodermal dysplasias (EDs) are a complex group of diseases clinically characterised by congenital absence of ectodermally derived structures. The present report details the features of a 13 year old schoolboy with the rare anhydrotic ectodermal dysplasia (Christ-Siemens-Touraine syndrome).

p63 and epithelial appendage development

Abstract Epithelial appendages share a common developmental program that relies on extensive interactions between epithelia and adjacent mesenchyme. The transcription factor p63 has a critical role in epithelial appendage development in both vertebrates and non-vertebrates. Both mice and zebrafish lacking p63 expression fail to develop epithelial appendages and other structures that develop as a result of epithelial-mesenchymal interactions. Furthermore, dominantly inherited mutations in p63 are the cause of a subset of human ectodermal dysplasias, which are characterized by developmental abnormalities in epithelia and epithelial appendages. While the importance of p63 for epithelial appendage development is evident, the molecular mechanisms by which p63 functions are largely unknown. In this review, we will discuss the current knowledge of the developmental role of p63 and the implications for epithelial appendage development.

Differential diagnosis of hair loss in children. Differentialdiagnose des Haarausfalls bei Kindern

Hair loss in childhood covers a broad differential diagnosis and often presents the involved dermatologist and pediatrician with a diagnostic and therapeutic challenge. Correct classification of the hair disease, especially in the case of underlying genetic syndromes, metabolic defects or endocrine disorders, is often an important prerequisite for continued normal physical and mental development of the young patients. Dealing with hair loss in childhood, one should differentiate between congenital and acquired diseases. The clinical manifestation profile, the age of the patient when the initial manifestation occurred, and the presence of associated symptoms are important for the classification of the hair disease. In the present paper, a classification of hair loss in childhood based on clinical appearance, age of onset and associated symptoms is proposed as a guide for the evaluation of hair loss and alopecia in childhood.

Hypertelorism, ptosis, and myopia associated with drug-resistant epilepsy, mental delay, growth deficiency, ectodermal defects, and osteopenia

We report a 30-year-old woman with hypertelorism, ptosis, and myopia associated with drug-resistant epilepsy (DRE, Lennox-Gastaut syndrome), mental delay, growth deficiency, ectodermal defects, and osteopenia. To the best of our knowledge, this patient has an unusual combination of symptoms not previously described, associated with severe central nervous system dysfunction. The ectodermal defects were present in a very intriguing form, were difficult to diagnose, and did not conform to any classification or previous description.

Ectodermal dysplasia with tetramelic deficiencies and no mutation in p63: odontotrichomelic syndrome or a new entity?

The ectodermal dysplasias (ED) are a large and complex group of diseases characterized by anomalies of the ectoderm and its derivates, often associated with malformations in other organs. We report a patient with an ectodermal dysplasia affecting hair, teeth, and nails and malformations of all four extremities including absence of several rays in the hands and feet. This patient shares many similarities with odontotrichomelic syndrome, a rare ectodermal dysplasia syndrome that has so far only been described in three individuals. However, some differences exist and this patient might also represent a separate ectodermal dysplasia syndrome. p63, a gene that is mutated in a number of syndromes associated with ectodermal dysplasia and limb malformations, was considered a possible candidate gene. However, no mutation in p63 was identified.

Towards a new classification of ectodermal dysplasias

Ectodermal dysplasias (EDs) constitute a large and complex group of diseases characterized by various defects in hair, nails, teeth and sweat glands. Of the 170 EDs described so far, fewer than 30 have been explained at the molecular level with identification of the causative gene. This review proposes a new classification of EDs based on the function of the protein encoded by the mutated gene. The EDs are reviewed in light of the recent molecular and biochemical findings and an attempt is made to classify ED causative genes into four major functional subgroups: cell-cell communication and signalling; adhesion; transcription regulation; and development.

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.

Child with De Novo t(1;6)(p22.1;p22.1) translocation and features of ectodermal dysplasia with hypodontia and developmental delay

We report on a 6.5-year-old girl with a balanced translocation between the short arms of chromosomes 1 and 6. She was referred for genetics evaluation because of developmental speech delay and congenital absence of several deciduous and permanent teeth. She was very sensitive to noise (hyperacusis), had poor hair and nail growth, decreased sweating, and turned very red with high fever. She had microcephaly (head circumference at the second centile; weight and height were at 25th centile), short palpebral fissures, epicanthal folds, sparse eyelashes, large ears, partial anodontia, short finger and toenails, and dry skin. She had mild developmental delay. Family history was significant for learning problems in two paternal uncles, one paternal aunt, and several paternal cousins. Thyroid studies, calcium, phosphorus, and alkaline phosphatase levels were normal. Her karyotype was 46,XX,t(1;6)(p22.1;p22.2), and parental karyotypes were normal. This apparently balanced translocation may have resulted in either a submicroscopic loss or disruption of a gene or genes involved in ectodermal dysplasia. There are no reported cases of ectodermal dysplasia associated with this chromosome rearrangement.