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Background: Ectodermal dysplasias (EDs) are a heterogeneous group of genetic conditions affecting the development and/or homeostasis of two or more ectodermal derivatives, including hair, teeth, nails, and certain glands. There are currently 49 recognized EDs with molecularly confirmed etiology. The EDs are very rare disorders, individually and in aggregate. Very little is published regarding the prevalence of these rare disorders. As a result of the genomics revolution, rare diseases have emerged as a global health priority. The various disabilities arising from rare disorders, as well as diagnostic and treatment uncertainty, have been demonstrated to have detrimental effects on the health, psychosocial, and economic aspects of families affected by rare disorders. Contemporary research methodologies and databases can address what have been historic challenges encountered when conducting research on rare diseases. Objective: In this study, we aim to ascertain period prevalence rates for several of the more common ectodermal dysplasia syndromes, by querying a large multicenter database of electronic health records, Oracle Real‐World Data. Methods: For each of the included ectodermal dysplasia syndromes a clinical definition was developed by a committee of international experts with interests in EDs. The clinical definitions were based upon a combination of clinical features and designated by ICD‐9 and ICD‐10 codes. The January 2023 version of the Oracle Real‐World Data database was queried for medical records that coincided with the clinical definitions. For our study, there were 64,523,460 individual medical records queried. Results: Period prevalence rates were calculated for the following ED disorders: hypohidrotic ectodermal dysplasia, found to be 2.99 per 100,000; ectodermal dysplasia and immunodeficiency 1, 0.23 per 100,000; Clouston syndrome, 0.15 per 100,000; ectrodactyly ectodermal dysplasia and cleft lip/palate syndrome, 0.61 per 100,000; ankyloblepharon‐ectodermal defects‐cleft lip/palate syndrome, 0.36 per 100,000; focal dermal hypoplasia, 0.10 per 100,000; and incontinentia pigmenti, 0.88 per 100,000. Conclusion: This study established estimated period prevalence rates for several of the ectodermal dysplasia syndromes, and it demonstrated the feasibility of utilizing large multicenter databases of electronic health records, such as Oracle Real World Data. [ABSTRACT FROM AUTHOR]

Objective: Tooth agenesis is a common craniofacial malformation, which is often associated with gene mutations. The purpose of this research was to investigate and uncover ectodysplasin A (EDA) gene variants in eight Chinese families affected with tooth agenesis. Methods: Genomic DNA was extracted from tooth agenesis families and sequenced using whole‐exome sequencing. The expression of ectodysplasin A1 (EDA1) protein was studied by western blot, binding activity with receptor was tested by pull‐down and the NF‐κB transcriptional activity was analyzed by Dual luciferase assay. Results: Eight EDA missense variants were discovered, of which two (c.T812C, c.A1073G) were novel. The bioinformatics analysis indicated that these variants might be pathogenic. The tertiary structure analysis revealed that these eight variants could cause structural damage to EDA proteins. In vitro functional studies demonstrated that the variants greatly affect protein stability or impair the EDA‐EDAR interaction; thereby significantly affecting the downstream NF‐κb transcriptional activity. In addition, we summarized the genotype–phenotype correlation caused by EDA variants and found that EDA mutations leading to NSTA are mostly missense mutations located in the TNF domain. Conclusion: Our results broaden the variant spectrum of the EDA gene associated with tooth agenesis and provide valuable information for future genetic counseling. [ABSTRACT FROM AUTHOR]

Ectodermal dysplasia is a rare disease that belongs to a diverse group of inherited monogenic disorders involving defects in one or more ectodermally or mesodermally derived tissues. Hypohidrotic ectodermal dysplasia, also known as Christ-Siemens-Touraine syndrome is a type of ectodermal dysplasia characterized by a triad of anhidrosis, dysodontia, and hypotrichiasis. The most prevalent method of transmission is X-linked recessive, manifesting fully in men and only partially in female carrier heterozygotes. Atrophic rhinitis and nasal myiasis are rare characteristics of this condition. We hereby report a case of a 52-year-old female with atrophic rhinitis and nasal myiasis who was managed conservatively.

Abstract Background The aim of this study was to analyse the differences in the phenotypes of missing teeth between a pair of brothers with hypohidrotic ectodermal dysplasia (HED) and to investigate the underlying mechanism by comparing the mutated gene loci between the brothers with whole-exome sequencing. Methods The clinical data of the patients and their mother were collected, and genomic DNA was extracted from peripheral blood samples. By Whole-exome sequencing filtered for a minor allele frequency (MAF) ≤0.05 non-synonymous single-nucleotide variations and insertions/deletions variations in genes previously associated with tooth agenesis, and variations considered as potentially pathogenic were assessed by SIFT, Polyphen-2, CADD and ACMG. Sanger sequencing was performed to detect gene variations. The secondary and tertiary structures of the mutated proteins were predicted by PsiPred 4.0 and AlphaFold 2. Results Both brothers were clinically diagnosed with HED, but the younger brother had more teeth than the elder brother. An EDA variation (c.878 T > G) was identified in both brothers. Additionally, compound heterozygous variations of WNT10A (c.511C > T and c.637G > A) were identified in the elder brother. Digenic variations in EDA (c.878 T > G) and WNT10A (c.511C > T and c.637G > A) in the same patient have not been reported previously. The secondary structure of the variant WNT10A protein showed changes in the number and position of α-helices and β-folds compared to the wild-type protein. The tertiary structure of the WNT10A variant and molecular simulation docking showed that the site and direction where WNT10A binds to FZD5 was changed. Conclusions Compound heterozygous WNT10A missense variations may exacerbate the number of missing teeth in HED caused by EDA variation.

Objectives: To analyse the pathogenic genes in a patient with hypohidrotic ectodermal dysplasia (HED) and explore the relationship between pathogenic genes and the oligodontia phenotype. Methods: Clinical data and peripheral blood were collected from a patient with HED. Pathogenic genes were analysed by whole-exon sequencing (WES) and verified by Singer sequencing. The secondary and tertiary structures of the variant proteins were predicted to analyse their toxicity. Results: The patient exhibited a severe oligodontia phenotype, wherein only two deciduous canines were left in the upper jaw. WES revealed a hemizygous EDA variant c.466C > T p.(Arg156Cys) and a novel heterozygous EVC2 variant c.1772T > C p.(Leu591Ser). Prediction of the secondary and tertiary structures of the EDA variant p.(Arg156Cys) and EVC2 variant p.(Leu591Ser) indicated impaired function of both molecules. Conclusion: The patient demonstrated a more severe oligodontia phenotype when compared with the other patients caused by the EDA variant c.466C > T. Since Evc2 is a positive regulator of the Sonic Hedgehog (Shh) signal pathway, we speculated that the EVC2 variant p.(Leu591Ser) may play a synergistic role in the oligodontia phenotype of HED, thereby exacerbating the oligodontia phenotype. Knowledge of oligodontia caused by multiple gene variants is of great significance for understanding individual differences in oligodontia phenotypes.

The article focuses on identifying a novel splicing mutation in the Ectodysplasin A (EDA) gene within a hypohidrotic ectodermal dysplasia (HED) pedigree, exploring the molecular pathogenesis of HED through genetic testing technologies. Topics covered include the characterization of HED, involvement of specific genes like EDA, and the identification of various mutation types leading to HED, emphasizing the significance of this novel splicing mutation in the EDA gene within a Chinese family.

Background and Aim: Ectodermal dysplasia is a genetic condition that affects ectodermal derivatives such as skin, hair, nails, teeth and sweat glands. The disease is diagnosed at birth or in early childhood. Tooth developmental disorders are observed in different forms in these children. These disorders expose children to ridicule, which can lead to psychological problems; Therefore, the physical treatment of these children is very important, especially in the oral area. This report describes the appearance and dental treatments performed on a 6-year-old girl with ectodermal dysplasia. Case Report: A 6-year-old girl with no systemic disease complained of a history of being ridiculed by her peers. Lack of deciduous and permanent teeth and conical teeth were visible in this child. The child had reduced, thin hair, hypotonic lips, and a dry mouth. The bridge of the nose also seemed concaved. The baby's teeth had no caries or periodontal disease. The treatment plan for this child included a composite build-up of the conical anterior teeth and then the design of a removable partial denture to preserve the space of the missing teeth as well as their replacement. Conclusion: Removable prostheses are a suitable treatment option for children with ectodermal dysplasia. After the age of 18, surgical treatments for implant placement and then placement of implant-based prostheses can be considered. [ABSTRACT FROM AUTHOR]

Abstract Objective The objective of this systematic review was to determine the orthodontic and dentofacial orthopedic treatments carried out in patients with ectodermal dysplasia to facilitate functional and aesthetic rehabilitation. Methods The systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis statement. We systematically searched PubMed, Web of Science, Scopus, Scielo, LILACS, EBSCOhost and Embase databases up to 6 January 2022. We included articles describing patients with any type of ectodermal dysplasia who received orthodontic or dentofacial orthopedic treatment to facilitate functional and aesthetic oral rehabilitation. The search was not restricted by language or year of publication. The quality of the studies was assessed using the Joanna Briggs Institute Quality Assessment Scale of the University of Adelaide for case series and case reports. The review was registered at the University of York Centre for reviews (CRD42021288030). Results Of the initial 403 studies found, 29 met the inclusion criteria. After applying the quality scale, 23 were left for review—21 case reports and 2 case series. The initial age of patients ranged from 34 months to 24 years. Thirteen studies were on hypohidrotic and/or anhidrotic ectodermal dysplasia, of which two were X-chromosome linked. In one study, the patient had Wiktop syndrome, and in nine the type of ectodermal dysplasia was not specified. The duration of treatment was 7 weeks to 10 years. The treatments described were: fixed orthodontic appliances or simple acrylic plates designed for tooth movement, including leveling and aligning, closing of diastemata, retraction of impacted teeth in the dental arch; clear aligners; fixed and/or removable appliances for the correction of skeletal and/or dentoalveolar relationships; palatal expanders in combination with face masks for orthopedic traction of the maxilla; and orthognathic surgery. Only three studies provided cephalometric data. Conclusion The level of evidence of the articles reviewed was low and most orthopedic and dentofacial orthodontic treatments described were focused on correcting dental malpositioning and jaw asymmetries and not on stimulating growth from an early age. Studies with greater scientific evidence are needed to determine the best treatment for these patients.

Background: Hypohidrotic ectodermal dysplasia (HED) mainly results from gene mutations in the EDA/EDAR/NF‐κB pathway. Function analysis of the mutations in the collagen domain of ectodysplasin A (EDA)result in HED has been rarely studied. This study aimed at determining the mechanism by which the novel collagen domain mutation of EDA results in HED. Methods: We analyzed the DNAs from a Chinese family with HED and performed bioinformatics analysis. A new three‐dimensional structure model of the EDA trimer was built and used to predict the effect of the mutations on EDA. We performed a western blot to detect EDA1 proteins in cell lysates and supernatants. We then performed coimmunoprecipitation to determine whether the mutation would affect the interaction of EDA1 with the EDA receptor (EDAR). Dual luciferase reporter assay and immunofluorescence were performed to detect the effect of the mutant EDA1 protein on nuclear factor kappa B (NF‐κB) activation. Results: A novel missense mutation (c.593G > A, p. Gly198Glu) in the collagen domain of EDA was detected. The mutation was predicted to be disease‐causing. A three‐dimensional structure model of the EDA trimer was first built in this study, in which the mutation site is located around the receptor binding domain. Functional studies showed that there was no difference in the secretion activity between the mutant EDA1 and the wild‐type EDA1. However, the receptor‐binding activity and the transcription activation of NF‐κB were impaired by the mutation. Conclusion: We identified a novel mutation (c.593G > A, p. Gly198Glu) in the collagen domain of EDA. Bioinformatics analysis and functional studies showed this mutation was damaging, indicating that mutations in the collagen domain of EDA could result in HED by affecting the receptor‐binding activity of EDA and the transcriptional activity of NF‐κB. [ABSTRACT FROM AUTHOR]

Abstract Background Hypohidrotic ectodermal dysplasia (HED) mainly results from gene mutations in the EDA/EDAR/NF‐κB pathway. Function analysis of the mutations in the collagen domain of ectodysplasin A (EDA)result in HED has been rarely studied. This study aimed at determining the mechanism by which the novel collagen domain mutation of EDA results in HED. Methods We analyzed the DNAs from a Chinese family with HED and performed bioinformatics analysis. A new three‐dimensional structure model of the EDA trimer was built and used to predict the effect of the mutations on EDA. We performed a western blot to detect EDA1 proteins in cell lysates and supernatants. We then performed coimmunoprecipitation to determine whether the mutation would affect the interaction of EDA1 with the EDA receptor (EDAR). Dual luciferase reporter assay and immunofluorescence were performed to detect the effect of the mutant EDA1 protein on nuclear factor kappa B (NF‐κB) activation. Results A novel missense mutation (c.593G > A, p. Gly198Glu) in the collagen domain of EDA was detected. The mutation was predicted to be disease‐causing. A three‐dimensional structure model of the EDA trimer was first built in this study, in which the mutation site is located around the receptor binding domain. Functional studies showed that there was no difference in the secretion activity between the mutant EDA1 and the wild‐type EDA1. However, the receptor‐binding activity and the transcription activation of NF‐κB were impaired by the mutation. Conclusion We identified a novel mutation (c.593G > A, p. Gly198Glu) in the collagen domain of EDA. Bioinformatics analysis and functional studies showed this mutation was damaging, indicating that mutations in the collagen domain of EDA could result in HED by affecting the receptor‐binding activity of EDA and the transcriptional activity of NF‐κB.

Hypohidrotic ectodermal dysplasia is a rare condition characterized by hypohidrosis, hypodontia, and hypotrichosis. The disease can show X‐linked recessive, autosomal dominant or autosomal recessive inheritance trait. Of these, the autosomal forms are caused by mutations in either EDAR or EDARADD. To date, the underlying pathomechanisms or genotype–phenotype correlations for autosomal forms have not completely been disclosed. In this study, we performed a series of in vitro studies for four missense mutations in the death domain of EDAR protein: p.R358Q, p.G382S, p.I388T, and p.T403M. The results revealed that p.R358Q‐ and p.T403M‐mutant EDAR showed different expression patterns from wild‐type EDAR in both western blots and immunostainings. NF‐κB reporter assays demonstrated that all the mutant EDAR showed reduced activation of NF‐κB, but the reduction by p.G382S‐ and p.I388T‐mutant EDAR was moderate. Co‐immunoprecipitation assays showed that p.R358Q‐ and p.T403M‐mutant EDAR did not bind with EDARADD at all, whereas p.G382S‐ and p.I388T‐mutant EDAR maintained the affinity to some extent. Furthermore, we demonstrated that all the mutant EDAR proteins analyzed aberrantly bound with TRAF6. Sum of the data suggest that the degree of loss‐of‐function is different among the mutant EDAR proteins, which may be associated with the severity of the disease. [ABSTRACT FROM AUTHOR]

Hypohidrotic ectodermal dysplasia (HED) is a rare hereditary disease characterized by hypoplasia of tissues derived from the ectoderm, such as hair, teeth, and sweat glands. There have been no reports of oral cancer in HED patients. Here, we report a case of multiple oral cancers in a patient with HED. A 24-year-old woman with HED visited our hospital for oligodontia-associated dental treatment. During follow-up, metachronous squamous cell carcinoma occurred in the left maxillary gingiva and right mandibular gingiva. Although surgery and chemoradiation were performed, the cancer progressed to unresectable cervical lymph node metastasis. Cetuximab-based therapy was selected as the subsequent anticancer therapy, and administered for 11 months. Because the patient developed sick sinus syndrome, which is an unlikely side effect of cetuximab, anticancer therapy could not be continued. The patient eventually died at 36 years old. We concluded that careful follow-up focusing on possibility of early onset of oral cancer is required, and cetuximab can be a treatment option for cancers in patients with HED. [ABSTRACT FROM AUTHOR]

Objective: The objective of this systematic review was to determine the orthodontic and dentofacial orthopedic treatments carried out in patients with ectodermal dysplasia to facilitate functional and aesthetic rehabilitation.Methods: The systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis statement. We systematically searched PubMed, Web of Science, Scopus, Scielo, LILACS, EBSCOhost and Embase databases up to 6 January 2022. We included articles describing patients with any type of ectodermal dysplasia who received orthodontic or dentofacial orthopedic treatment to facilitate functional and aesthetic oral rehabilitation. The search was not restricted by language or year of publication. The quality of the studies was assessed using the Joanna Briggs Institute Quality Assessment Scale of the University of Adelaide for case series and case reports. The review was registered at the University of York Centre for reviews (CRD42021288030).Results: Of the initial 403 studies found, 29 met the inclusion criteria. After applying the quality scale, 23 were left for review-21 case reports and 2 case series. The initial age of patients ranged from 34 months to 24 years. Thirteen studies were on hypohidrotic and/or anhidrotic ectodermal dysplasia, of which two were X-chromosome linked. In one study, the patient had Wiktop syndrome, and in nine the type of ectodermal dysplasia was not specified. The duration of treatment was 7 weeks to 10 years. The treatments described were: fixed orthodontic appliances or simple acrylic plates designed for tooth movement, including leveling and aligning, closing of diastemata, retraction of impacted teeth in the dental arch; clear aligners; fixed and/or removable appliances for the correction of skeletal and/or dentoalveolar relationships; palatal expanders in combination with face masks for orthopedic traction of the maxilla; and orthognathic surgery. Only three studies provided cephalometric data.Conclusion: The level of evidence of the articles reviewed was low and most orthopedic and dentofacial orthodontic treatments described were focused on correcting dental malpositioning and jaw asymmetries and not on stimulating growth from an early age. Studies with greater scientific evidence are needed to determine the best treatment for these patients. [ABSTRACT FROM AUTHOR]

We report a case of a patient with genetic sequencing-confirmed X-linked hypohidrotic ectodermal dysplasia without the typical characteristic hair growth abnormalities with the disorder. While this patient had already received guidance from a genetic counselor about his condition, many cases of ectodermal dysplasia go underdiagnosed or misdiagnosed due to mild or atypical presentations. With gene therapies emerging, the authors hope to highlight the importance of recognizing the disorder in patients who have not yet received a diagnosis to better manage their clinical course and guide future life decisions., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Nardone et al.)

The term ectodermal dysplasias (EDs) describes a heterogeneous group of inherited developmental disorders that affect several tissues of ectodermal origin. The most common form of EDs is hypohidrotic ectodermal dysplasia (HED), which is characterized by hypodontia, hypotrichosis, and partial or total eccrine sweat gland deficiency. HED is estimated to affect at least 1 in 17,000 people worldwide. Patients with HED have characteristic facies with periorbital hyperpigmentation, depressed nasal bridge, malar hypoplasia, and absent or sparse eyebrows and eyelashes. The common ocular features of HED include madarosis, trichiasis, and ocular chronic surface disease due to dry eye syndrome, which manifests clinically with discomfort, photophobia, and redness. Dry eye is common in HED and results from a combination of ocular surface defects: mucus abnormalities (abnormal conjunctival mucinous glands), aqueous tear deficiency (abnormalities in the lacrimal gland) and lipid deficiency (due to the partial or total absence of the meibomian glands; modified sebaceous glands with the tarsal plate). Sight-threatening complications result from ocular surface disease, including corneal ulceration and perforation with subsequent corneal scarring and neovascularization. Rare ocular features have been reported and include bilateral or unilateral congenital cataracts, bilateral glaucoma, chorioretinal atrophy and atresia of the nasolacrimal duct. Recognition of the ocular manifestations of HED is required to perform clinical surveillance, instigate supportive and preventative treatment, and manage ocular complications. [ABSTRACT FROM AUTHOR]

Background: Ectodysplasin A (EDA) variations are major pathogenic factors for hypohidrotic ectodermal dysplasia (HED), the most common form of ectodermal dysplasia (ED), characterized by hypotrichosis, hypohidrosis, hypodontia, and other oral features. Methods: Molecular genetic defects in three HED families were detected by whole-exome sequencing and confirmed by Sanger sequencing or multiplex ligation-dependent probe amplification. The effect of splicing variant was further verified by EDA minigene in vitro analysis. De novo deletion was confirmed by chromosomal microarray analysis. Results: Three variants (c.396 + 1 G > C, c.171-173 del GTT, and exon 1 deletion) were identified, all affecting exon 1 of the EDA gene. Variants c.396 + 1 G > Cand c.171-173 del GTT were first identified. Minigene analysis of the splicing variant (c.396 + 1 G > C) displayed a prolonged EDA-A1 transcript containing extra 699 bp at the start of intron 1, representing a functional cryptic splice site formation in vitro. Combining the results of chromosomal microarray analysis and whole-exome sequencing, the deletion variant was over 87 kb. Three variants were predicted to affect protein function to differing degrees, and were responsible for X-linked HED with varying phenotype. Conclusion: Investigating the clinical and molecular characteristics of these variations broadens our understanding of EDA gene variants, supporting clinical diagnosis, genetic counseling, and prenatal diagnosis of HED. [ABSTRACT FROM AUTHOR]

Anhidrotic/hypohidrotic ectodermal dysplasia (A/HED) is a congenital disorder characterized by anhidrosis/hypohidrosis and inadequate hair and dental dysplasia. Large‐scale case studies of patients with A/HED have already been conducted overseas, while there has been no large‐scale study, but only a few case reports in Japan. Furthermore, an epidemiological study of this disease has not been conducted in Japan to date. The purpose of this study was to investigate the clinical characteristics of A/HED patients, the status of genetic aberrations and complications of A/HED in Japan. Initially, we conducted a physician‐initiated questionnaire survey of A/HED patients who visited medical institutions across Japan to investigate their backgrounds, clinical symptoms, genotypes, diagnostic methods and complications of A/HED. We also investigated the presence or absence of various allergic diseases (atopic dermatitis‐like skin manifestations, bronchial asthma and food allergies). Questionnaires were also obtained from 26 patients with ectodermal dysplasia (ED) who visited four medical institutions. We compared the incidence of allergic diseases in healthy controls in a similar study to that of patients. Twenty‐four of those patients were considered to have A/HED, of which 18 had a confirmed genetic diagnosis and were genotyped. All patients had anhidrosis or hypohidrosis, hair and dental dysplasia, and unique facial appearance; 23 patients had several cutaneous manifestations and seven patients had periorbital pigmentation. In addition, there was a significantly higher incidence of atopic dermatitis‐like cutaneous manifestations, bronchial asthma and food allergies in the A/HED patients than in healthy controls. We report the results from a questionnaire survey of 24 patients with A/HED. This is the first report of a large number of A/HED patients in Japan. This study clarifies the status of clinical diagnosis and genetic testing of A/HED patients in Japan, as well as the characteristics of their skin symptoms and allergic complications. [ABSTRACT FROM AUTHOR]

In mice, rats, dogs and humans, the growth and function of sebaceous glands and eyelid Meibomian glands depend on the ectodysplasin signalling pathway. Mutation of genes encoding the ligand EDA, its transmembrane receptor EDAR and the intracellular signal transducer EDARADD leads to hypohidrotic ectodermal dysplasia, characterised by impaired development of teeth and hair, as well as cutaneous glands. The rodent ear canal has a large auditory sebaceous gland, the Zymbal’s gland, the function of which in the health of the ear canal has not been determined. We report that EDA-deficient mice, EDAR-deficient mice and EDARADD-deficient rats have Zymbal’s gland hypoplasia. EdaTa mice have 25% prevalence of otitis externa at postnatal day 21 and treatment with agonist anti-EDAR antibodies rescues Zymbal’s glands. The aetiopathogenesis of otitis externa involves infection with Gram-positive cocci, and dosing pregnant and lactating EdaTa females and pups with enrofloxacin reduces the prevalence of otitis externa. We infer that the deficit of sebum is the principal factor in predisposition to bacterial infection, and the EdaTa mouse is a potentially useful microbial challenge model for human acute otitis externa.

Background: Hypohidrotic ectodermal dysplasia (HED) is a hereditary disorder with agenesis of ectodermal derivatives, causing oligodontia or anodontia. Dentures are needed to improve the patients' mastication., Aim: This study aimed at preliminarily evaluating the masticatory function changes in Chinese individuals with HED after prosthetic rehabilitation from childhood to adolescence., Design: This longitudinal study enrolled 10 HED patients. Data were collected during childhood and adolescence, respectively. The healthy children and adolescents were recruited as the control group. The surface electromyography (EMG) of masseter (MM) and anterior temporalis (TA) muscles during clenching and chewing were recorded. The EMG activity, asymmetry index (As), activity index (Ac), and chewing cycle were analyzed. The masticatory efficiency was measured by spectrophotometry with subjective masticatory ability assessed by a questionnaire., Results: The EMG activities and masticatory efficiency of HED patients during childhood and adolescence were mostly lower with a higher As (p < .05). The chewing process enhanced the TA activity and balanced the As of HED adolescents (p > .05). The HED adolescents showed a more prevalent TA activity (p < .05)., Conclusion: The masticatory function of the growing HED patients was functionally inferior to the dentate individuals with a narrowed gap from childhood to adolescence., (© 2024 BSPD, IAPD and John Wiley & Sons Ltd.)

The term ectodermal dysplasias (EDs) describes a heterogeneous group of inherited developmental disorders that affect several tissues of ectodermal origin. The most common form of EDs is hypohidrotic ectodermal dysplasia (HED), which is characterized by hypodontia, hypotrichosis, and partial or total eccrine sweat gland deficiency. HED is estimated to affect at least 1 in 17,000 people worldwide. Patients with HED have characteristic facies with periorbital hyperpigmentation, depressed nasal bridge, malar hypoplasia, and absent or sparse eyebrows and eyelashes. The common ocular features of HED include madarosis, trichiasis, and ocular chronic surface disease due to dry eye syndrome, which manifests clinically with discomfort, photophobia, and redness. Dry eye is common in HED and results from a combination of ocular surface defects: mucus abnormalities (abnormal conjunctival mucinous glands), aqueous tear deficiency (abnormalities in the lacrimal gland) and lipid deficiency (due to the partial or total absence of the meibomian glands; modified sebaceous glands with the tarsal plate). Sight-threatening complications result from ocular surface disease, including corneal ulceration and perforation with subsequent corneal scarring and neovascularization. Rare ocular features have been reported and include bilateral or unilateral congenital cataracts, bilateral glaucoma, chorioretinal atrophy and atresia of the nasolacrimal duct. Recognition of the ocular manifestations of HED is required to perform clinical surveillance, instigate supportive and preventative treatment, and manage ocular complications.

Objectives: To analyse the pathogenic genes in a patient with hypohidrotic ectodermal dysplasia (HED) and explore the relationship between pathogenic genes and the oligodontia phenotype., Methods: Clinical data and peripheral blood were collected from a patient with HED. Pathogenic genes were analysed by whole-exon sequencing (WES) and verified by Singer sequencing. The secondary and tertiary structures of the variant proteins were predicted to analyse their toxicity., Results: The patient exhibited a severe oligodontia phenotype, wherein only two deciduous canines were left in the upper jaw. WES revealed a hemizygous EDA variant c.466C > T p.(Arg156Cys) and a novel heterozygous EVC2 variant c.1772T > C p.(Leu591Ser). Prediction of the secondary and tertiary structures of the EDA variant p.(Arg156Cys) and EVC2 variant p.(Leu591Ser) indicated impaired function of both molecules., Conclusion: The patient demonstrated a more severe oligodontia phenotype when compared with the other patients caused by the EDA variant c.466C > T. Since Evc2 is a positive regulator of the Sonic Hedgehog (Shh) signal pathway, we speculated that the EVC2 variant p.(Leu591Ser) may play a synergistic role in the oligodontia phenotype of HED, thereby exacerbating the oligodontia phenotype. Knowledge of oligodontia caused by multiple gene variants is of great significance for understanding individual differences in oligodontia phenotypes., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors. Published by Elsevier Ltd.)

Background: Ectodysplasin A (EDA) variations are major pathogenic factors for hypohidrotic ectodermal dysplasia (HED), the most common form of ectodermal dysplasia (ED), characterized by hypotrichosis, hypohidrosis, hypodontia, and other oral features. Methods: Molecular genetic defects in three HED families were detected by whole-exome sequencing and confirmed by Sanger sequencing or multiplex ligation-dependent probe amplification. The effect of splicing variant was further verified by EDA minigene in vitro analysis. De novo deletion was confirmed by chromosomal microarray analysis. Results: Three variants (c.396 + 1 G > C, c.171-173 del GTT, and exon 1 deletion) were identified, all affecting exon 1 of the EDA gene. Variants c.396 + 1 G > C and c.171-173 del GTT were first identified. Minigene analysis of the splicing variant (c.396 + 1 G > C) displayed a prolonged EDA-A1 transcript containing extra 699 bp at the start of intron 1, representing a functional cryptic splice site formation in vitro . Combining the results of chromosomal microarray analysis and whole-exome sequencing, the deletion variant was over 87 kb. Three variants were predicted to affect protein function to differing degrees, and were responsible for X-linked HED with varying phenotype. Conclusion: Investigating the clinical and molecular characteristics of these variations broadens our understanding of EDA gene variants, supporting clinical diagnosis, genetic counseling, and prenatal diagnosis of HED., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Wang, Zhang, Zhou, Hui, Zheng, Chen, Wang, Yang, Hao and Zhang.)

In mice, rats, dogs and humans, the growth and function of sebaceous glands and eyelid Meibomian glands depend on the ectodysplasin signalling pathway. Mutation of genes encoding the ligand EDA, its transmembrane receptor EDAR and the intracellular signal transducer EDARADD leads to hypohidrotic ectodermal dysplasia, characterised by impaired development of teeth and hair, as well as cutaneous glands. The rodent ear canal has a large auditory sebaceous gland, the Zymbal's gland, the function of which in the health of the ear canal has not been determined. We report that EDA-deficient mice, EDAR-deficient mice and EDARADD-deficient rats have Zymbal's gland hypoplasia. EdaTa mice have 25% prevalence of otitis externa at postnatal day 21 and treatment with agonist anti-EDAR antibodies rescues Zymbal's glands. The aetiopathogenesis of otitis externa involves infection with Gram-positive cocci, and dosing pregnant and lactating EdaTa females and pups with enrofloxacin reduces the prevalence of otitis externa. We infer that the deficit of sebum is the principal factor in predisposition to bacterial infection, and the EdaTa mouse is a potentially useful microbial challenge model for human acute otitis externa., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2022. Published by The Company of Biologists Ltd.)