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Background: Ectodermal dysplasia (ED) is a rare genetic disorder that affects structures derived from the ectodermal germ layer., Results: In this study, we analyzed the genetic profiles of 27 Korean patients with ED. Whole exome sequencing (WES) was performed on 23 patients, and targeted panel sequencing was conducted on the remaining 4 patients. Among the patients in the cohort, 74.1% (20/27) tested positive for ED. Of these positive cases, EDA and EDAR mutations were found in 80% (16/20). Notably, 23.1% (3/13) of EDA-positive cases exhibited copy number variations. Among the 23 patients who underwent WES, we conducted a virtual panel analysis of eight well-known genes, resulting in diagnoses for 56.5% (13/23) of the cases. Additionally, further analysis of approximately 5,000 OMIM genes identified four more cases, increasing the overall positivity rate by approximately 17%. These findings underscore the potential of WES for improving the diagnostic yield of ED. Remarkably, 94.1% of the patients manifesting the complete triad of ED symptoms (hair/skin/dental) displayed detectable EDA/EDAR mutations. In contrast, none of the 7 patients without these three symptoms exhibited EDA/EDAR mutations., Conclusions: When conducting molecular diagnostics for ED, opting for targeted sequencing of EDA/EDAR mutations is advisable for cases with classical symptoms, while WES is deemed an effective strategy for cases in which these symptoms are absent., (© 2024. The Author(s).)

Background: Non-syndromic tooth agenesis (NSTA) is a type of ectodermal dysplasia (ED) in which patients with non-syndromic oligodontia may only affect teeth. No pathological findings were found in other tissues of the ectodermal. Herein, we report a case of a NSTA patient with severe dental anxiety and poor oral health., Case Presentation: A 5-year-old boy without systemic diseases presented as a patient with oligodontia, extensive caries, and periapical periodontitis. Molecular genetic analysis found a mutation in the Ectodysplasin A (EDA) gene, confirming the diagnosis of NSTA., Conclusion: Tooth agenesis (TA) is the most common ectodermal developmental abnormality in humans. Non-syndromic oligodontia patients often seek treatment in the department of stomatology. Because of their complex oral conditions, these patients should be provided with a systematic and personalized treatment plan., (© 2024. The Author(s).)

Hypohidrotic ectodermal dysplasia is a developmental defect characterized by sparse or absent hair, missing or malformed teeth and defects in eccrine glands. Loss-of-function variants in the X-chromosomal EDA gene have been reported to cause hypohidrotic ectodermal dysplasia in humans, mice, dogs and cattle. We investigated a male cat exhibiting diffuse truncal alopecia with a completely absent undercoat. The cat lacked several teeth, and the remaining teeth had an abnormal conical shape. Whole-genome sequencing revealed a hemizygous missense variant in the EDA gene, XM_011291781.3:c.1042G>A or XP_011290083.1:p.(Ala348Thr). The predicted amino acid exchange is located in the C-terminal TNF signaling domain of the encoded ectodysplasin. The corresponding missense variant in the human EDA gene, p.Ala349Thr, has been reported as a recurring pathogenic variant in several human patients with X-linked hypohidrotic ectodermal dysplasia. The identified feline variant therefore represents the likely cause of the hypohidrotic ectodermal dysplasia in the investigated cat, and the genetic investigation confirmed the suspected clinical diagnosis. This is the first report of an EDA -related hypohidrotic ectodermal dysplasia in cats., Competing Interests: The authors declare no conflicts of interest.

Ectodysplasin A related hypohidrotic ectodermal dysplasia (XLHED) is a well-studied fetal developmental disorder in mammals that mainly affects ectodermal structures. It has been identified in a variety of species, including mice, rats, dogs, cattle, and humans. Here, we report the clinical, histological, and molecular biological analyses of a case of XLHED in Limousin cattle. An affected Limousin calf showed pathognomonic signs of ectodermal dysplasia, i.e. sparse hair and characteristic dental aplasia. Histopathologic comparison of hairy and glabrous skin and computed tomography of the mandible confirmed the phenotypic diagnosis. In addition, a keratoconjunctivitis sicca was noted in one eye, which was also confirmed histopathologically. To identify the causative variant, we resequenced the bovine X-chromosomal ectodysplasin A gene (EDA) of the affected calf and compared the sequences to the bovine reference genome. A single missense variant (rs439722471) at position X:g.80411716T>C (ARS-UCD1.3) was identified. The variant resulted in an amino acid substitution from glutamic acid to glycine within the highly conserved TNF-like domain. To rule out the possibility that the variant was relatively common in the cattle population we genotyped 2,016 individuals including 40% Limousin cattle by fluorescence resonance energy transfer analysis. We also tested 5,116 multibreed samples from Run9 of the 1000 Bull Genomes Project for the said variant. The variant was not detected in any of the cattle tested, confirming the assumption that it was the causative variant. This is the first report of Ectodysplasin A related hypohidrotic ectodermal dysplasia in Limousin cattle and the description of a novel causal variant in cattle., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Krull et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Salivary gland myoepithelial cells regulate saliva secretion and have been implicated in the histological diversity of salivary gland tumors. However, detailed functional analysis of myoepithelial cells has not been determined owing to the few of the specific marker to isolate them. We isolated myoepithelial cells from the submandibular glands of adult mice using the epithelial marker EpCAM and the cell adhesion molecule CD49f as indicators and found predominant expression of the transcription factor FoxO1 in these cells. RNA-sequence analysis revealed that the expression of cell cycle regulators was negatively regulated in FoxO1-overexpressing cells. Chromatin immunoprecipitation analysis showed that FoxO1 bound to the p21/p27 promoter DNA, indicating that FoxO1 suppresses cell proliferation through these factors. In addition, FoxO1 induced the expression of ectodysplasin A (Eda) and its receptor Eda2r, which are known to be associated with X-linked hypohidrotic ectodermal dysplasia and are involved in salivary gland development in myoepithelial cells. FoxO1 inhibitors suppressed Eda/Eda2r expression and salivary gland development in primordial organ cultures after mesenchymal removal. Although mesenchymal cells are considered a source of Eda, myoepithelial cells might be one of the resources of Eda. These results suggest that FoxO1 regulates myoepithelial cell proliferation and Eda secretion during salivary gland development in myoepithelial cells., (© 2024. The Author(s).)

Competing Interests: Conflicts of interest The authors declare no conflicts of interest.

XEDAR is a member of the TNF receptor subfamily and a mediator of the ectodysplasin (EDA) pathway. EDA signaling plays evolutionarily conserved roles in the development of the ectodermal appendage organ class, which includes hair, eccrine sweat glands, and mammary glands. Loss-of-function sequence variants of EDA, which encodes the two major ligand isoforms, EDA-A1 and EDA-A2, result in X-linked hypohidrotic ectodermal dysplasia characterized by defects in two or more types of ectodermal appendages. EDA-A1 and EDA-A2 signal through the receptors EDAR and XEDAR, respectively. Although the contributions of the EDA-A1/EDAR signaling pathway to EDA-dependent ectodermal appendage phenotypes have been extensively characterized, the significance of the EDA-A2/XEDAR branch of the pathway has remained obscure. In this study, we report the phenotypic consequences of disrupting the EDA-A2/XEDAR pathway on mammary gland differentiation and growth. Using a mouse Xedar knockout model, we show that Xedar has a specific and temporally restricted role in promoting late pubertal growth and branching of the mammary epithelium that can be influenced by genetic background. Our findings implicate Xedar in ectodermal appendage development and suggest that the EDA-A2/XEDAR signaling axis contributes to the etiology of EDA-dependent mammary phenotypes., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: Identify the disease-causing mutation in a patient with features of X-linked hypohidrotic ectodermal dysplasia, which is a genetic disorder characterized by hypodontia, hypohidrosis and hypotrichosis. It is caused by mutations in Ectodysplasin A gene, which encodes ectodysplasin A, a member of the tumor necrosis factor superfamily., Design: Genetic analysis, was performed using chromosomal microarray analysis, whole exome sequencing and multiplex ligation-dependent probe amplification analysis in a 4-year-old boy with hypohidrotic ectodermal dysplasia features. Moreover, the boy's parents were tested for clinically significant findings identified in order to elucidate the pattern of inheritance of the finding detected in the proband., Results: A novel deletion of entire exon 4 in Ectodysplasin A gene identified in the 4-year-old patient. This deletion was found in heterozygous state in the mother of the proband and was not detected in his father. RNA analysis revealed an in-frame deletion r.527_706del, p.(176_236del) in exon 4 of the Ectodysplasin A gene., Conclusion: We identified a novel gross deletion in the Ectodysplasin A gene in a male patient with X-linked hypohidrotic ectodermal dysplasia. Clinical and molecular genetic analysis are crucial to set an accurate diagnosis in patients with hypohidrotic ectodermal dysplasia. These results highlight the importance of the collagen domain of Ectodysplasin A, encoded by exon 4, for its function in vivo., Competing Interests: Declaration of Competing Interest 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., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

X-linked hypohidrotic ectodermal dysplasia (XLHED), caused by a genetic deficiency of ectodysplasin A1 (EDA1), is a rare developmental disorder of ectodermal derivatives such as hair, sweat glands, and teeth. The absence of sweat glands and perspiration can evoke life-threatening hyperthermia. As molecular genetic findings are not always conclusive, the concentrations of circulating EDA1 may help to distinguish between total and partial EDA1 deficiencies. We previously treated nine male patients with obvious signs of XLHED with a recombinant EDA1 replacement protein, Fc-EDA, either shortly after birth ( n = 3) or by prenatal administration in gestational week 26 and beyond ( n = 6). Here, we present the long-term follow-up for up to six years. In patients who had received Fc-EDA after birth, neither sweat glands nor sweating ability were detected at the age of 12-60 months. In contrast, prenatal EDA1 replacement resulted in ample sweat gland development and pilocarpine-inducible sweating in all treated subjects, who also attained more permanent teeth than their untreated affected relatives. Normal perspiration has persisted for six years in the two oldest boys treated repeatedly with Fc-EDA in utero. When they had a sauna, adequate thermoregulation was evidenced. Lower sweat production after single prenatal dosing may indicate a dose-response relationship. The absence of circulating EDA1 in five prenatally treated subjects proved that these children would have been unable to perspire if they had been left untreated. The sixth infant was shown to produce an EDA1 molecule that, albeit interacting with its cognate receptor, cannot activate EDA1 signaling. In conclusion, a causal treatment of XLHED before birth is feasible.

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., (© 2022 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals LLC.)

The Mexican tetra (Astyanax mexicanus) is one of the fresh water teleost fish models in evolutionary developmental biology. The existence of two morphs: eyed, pigmented surface fish and blind depigmented cavefish from multiple cave populations, provides a unique system to study adaptive radiation. Compared to the adult surface fish, cavefish have large oral jaws with an increased number of structurally-complex teeth. Early tooth development has not been studied in detail in cavefish populations. In this study, bone-stained growth series and vital dye staining was used to trace the development and replacement of dentitions in Pachón cavefish. Our results show that first tooth eruption was delayed in cavefish compared to the surface fish. In particular, the first tooth eruption cycle persisted until 35 days post fertilization (dpf). Unlike surface fish, there are multicuspid teeth in cavefish first generation dentition. In addition to the teeth in the marginal oral jaw bones, Pachón cavefish have teeth in the ectopterygoid bone of the palatine roof. Next, we characterised the expression of ectodysplasin signalling pathway genes in tooth-forming regions of surface and cavefish. Interestingly, higher expression of Eda and Edar was found in cavefish compared to the surface fish. The altered ectodysplasin expression needs further investigation to confirm the different molecular mechanisms for tooth development in the oral and pharyngeal regions of surface fish and cavefish., Competing Interests: Declaration of competing interest The authors have no conflicting interests., (Copyright © 2022 Elsevier B.V. All rights reserved.)

EDA is a tumor necrosis factor (TNF) family member, which functions together with its cognate receptor EDAR during ectodermal organ development. Mutations of EDA have long been known to cause X-linked hypohidrotic dysplasia in humans characterized by primary defects in teeth, hair and sweat glands. However, the structural information of EDA interaction with EDAR is lacking and the pathogenic mechanism of EDA variants is poorly understood. Here, we report the crystal structure of EDA C-terminal TNF homology domain bound to the N-terminal cysteine-rich domains of EDAR. Together with biochemical, cellular and mouse genetic studies, we show that different EDA mutations lead to varying degrees of ectodermal developmental defects in mice, which is consistent with the clinical observations on human patients. Our work extends the understanding of the EDA signaling mechanism, and provides important insights into the molecular pathogenesis of disease-causing EDA variants., (© 2023. The Author(s).)

Background: Ectodermal dysplasias (EDs) are a large and complex group of disorders affecting the ectoderm-derived organs; the clinical and genetic heterogeneity of these conditions renders an accurate diagnosis more challenging. The aim of this study is to demonstrate the clinical utility of a targeted resequencing panel through enhancing the molecular and clinical diagnosis of EDs. Given the recent developments in gene and protein-based therapies for X-linked hypohidrotic ectodermal dysplasia, there is a re-emerging interest in identifying the genetic basis of EDs and the respective phenotypic presentations, in an aim to facilitate potential treatments for affected families., Methods: We assessed seventeen individuals, from three unrelated families, who presented with diverse phenotypes suggestive of ED. An extensive multidisciplinary clinical evaluation was performed followed by a targeted exome resequencing panel (including genes that are known to cause EDs). MiSeq TM data software was used, variants with Qscore >30 were accepted., Results: Three different previously reported hemizygous EDA mutations were found in the families. However, a complete genotype-phenotype correlation could not be established, neither in our patients nor in the previously reported patients., Conclusions: Targeted exome resequencing can provide a rapid and accurate diagnosis of EDs, while further contributing to the existing ED genetic data. Moreover, the identification of the disease-causing mutation in an affected family is crucial for proper genetic counseling and the establishment of a genotype-phenotype correlation which will subsequently provide the affected individuals with a more suitable treatment plan.

Objective: This study aims to investigate a novel pathogenic variant in a Chinese family of non-syndromic tooth agenesis (NSTA) and study the impact of the variant on related protein and pathway., Design: One NSTA family was collected. Whole exome sequencing and Sanger sequencing were performed on the proband with NSTA and his 5 family members. The pathogenic influence of the mutant is evaluated by bioinformatics analyses including evolutionary conservation analysis and secondary structure prediction. Molecular dynamics (MD) simulations and binding free energy calculations were then performed to explore changes in the tertiary structure and binding ability of the protein., Results: We found a novel missense ectodysplasin A receptor (EDAR) variant (c .1292 T > G; p.Ile431Arg) in all affected family members. The results of bioinformatics analyses revealed that the EDAR had harmful changes after mutation. MD simulations and the binding free energy calculations results showed that the mutant EDAR protein and EDAR/ectodysplasin-A receptor-associated adapter (EDARADD) complex displayed tertiary structural change, and EDAR possessed a lower affinity to EDARADD after mutation., Conclusions: We found a novel EDAR variant (c.1292 T > G; p.Ile431Arg) in one NSTA family, which affects the binding of EDAR and EDARADD., Competing Interests: Declaration of Competing Interest The authors do not have any conflict of interest., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

X-linked hypohidrotic ectodermal dysplasia (XLHED) is a rare genetic disorder characte-rised by abnormal development of the skin and its appendages, such as hair and sweat glands, the teeth, and mucous glands of the airways, resulting in serious, sometimes life-threatening complications like hyperthermia or recurrent respiratory infections. It is caused by pathogenic variants of the ectodysplasin A gene ( EDA ). Most affected males are hemizygous for EDA null mutations that lead to the absence or inactivity of the signalling protein ectodysplasin A1 (EDA1) and, thus, to the full-blown phenotype with inability to perspire and few if any teeth. There are currently no long-term treatment options for XLHED. ER004 represents a first-in-class protein replacement molecule designed for specific, high-affinity binding to the endogenous EDA1 receptor (EDAR). Its proposed mechanism of action is the replacement of missing EDA1 in yet unborn patients with XLHED. Once bound to EDAR, ER004 activates the EDA/NFκB signalling pathway, which triggers the transcription of genes involved in the normal development of multiple tissues. Following preclinical studies, named-patient use cases demonstrated significant potential of ER004 in affected males treated in utero during the late second and third trimesters of pregnancy. In order to confirm these results, we started the EDELIFE trial, a prospective, open-label, genotype-match controlled, multicentre clinical study to investigate the efficacy and safety of intra-amniotic ER004 administration as a prenatal treatment for male subjects with XLHED. This article summarises the rationale, the study protocol, ethical issues of the trial, and potential pitfalls.

Ectodysplasin A (EDA), a ligand of the TNF family, plays an important role in maintaining the homeostasis of the ocular surface. EDA is necessary for the development of the meibomian gland, the lacrimal gland, as well as the proliferation and barrier function of the corneal epithelium. The mutation of EDA can induce the destruction of the ocular surface resulting in keratopathy, abnormality of the meibomian gland and maturation of the lacrimal gland. Experimental animal studies showed that a prenatal ultrasound-guided intra-amniotic injection or postnatal intravenous administration of soluble recombinant EDA protein can efficiently prevent the development of ocular surface abnormalities in EDA mutant animals. Furthermore, local application of EDA could restore the damaged ocular surface to some extent. Hence, a recombinant EDA-based therapy may serve as a novel paradigm to treat ocular surface disorders, such as meibomian gland dysfunction and corneal epithelium abnormalities.

Pathogenic variants of the gene Eda cause X-linked hypohidrotic ectodermal dysplasia (XLHED), which is characterized by structural abnormalities or lack of ectodermal appendages. Signs of dysplasia are not restricted to derivatives of the ectodermal layer, but mesodermal abnormalities, such as craniofacial dysmorphism, are also frequently observed, suggesting close reciprocal interactions between the ectoderm and mesoderm; however, a causal link has remained unsubstantiated. We investigated the functional impact of defective ectodysplasin A1 (Eda1) signaling on postnatal bone homeostasis in Eda1-deficient Tabby mice. Interestingly, Eda1 was detected in wild-type mouse calvariae throughout postnatal lifetime. In calvariae, bone-lining Osterix (Osx)+ osteoblasts stained positive for Eda1, and osteoclasts were revealed as Eda receptor (Edar)-positive. Moreover, adult Eda1-deficient calvarial bone showed osteopetrosis-like changes with significantly diminished marrow space, which was maintained during adulthood. Concomitantly with osteopetrosis-like changes, Tabby calvarial bone and Tabby bone marrow-derived osteoclasts had far less osteoclastic activity-associated co-enzymes including cathepsin K, Mmp9, Trap, and Tcirg1 (V-type proton ATPase a3 subunit) compared with wild-type calvariae in vivo or osteoclasts in vitro, indicating that Eda1 deficiency may affect the activity of osteoclasts. Finally, we confirmed that nuclear Nfatc1-positive osteoclasts were strongly diminished during mature osteoclastic differentiation under M-CSF and RANKL in the Tabby model, while Fc-EDA treatment of Tabby-derived osteoclasts significantly increased nuclear translocation of Nfatc1. Furthermore, we identified enhanced Nfatc1 and NF-κB transcriptional activity following Fc-EDA treatment in vitro using luciferase assays. Overall, the results indicate that diminished expressions of osteoclastic activity-associated co-enzymes may lead to disturbed bone homeostasis in Tabby calvariae postnatally.

Background: Hypohidrotic ectodermal dysplasia (HED) is a congenital syndrome of mammals affecting organs and tissues of ectodermal origin characterized by absence or hypoplasia of hair, teeth, and eccrine glands. The disorder has been reported in several species, including humans, mice, dogs and cattle, associated with variants in genes affecting the ectodysplasin pathway, including the X-linked ectodysplasin A (EDA) gene. Until now, nine pathogenic variants have been found in the bovine EDA gene. Here we report a novel variant in EDA in a crossbreed male Belgian Blue calf with HED, and provide an overview of the phenotypic and allelic heterogeneity of EDA-related forms of HED in cattle., Case Presentation: A 45-day-old male crossbreed British Blue calf was referred with congenital hypotrichosis, oligodontia and omphalitis. On histopathological examination of the nasal planum, nasolabial glands and ducts were not observed. The density of hair follicles was low, and they were small, with a predominance of telogen-phase hairs, and some serocellular crusts. The phenotype of the calf resembled that of HED. Whole-genome sequencing (WGS) was performed and revealed a 21,899 base-pair deletion encompassing the coding exon 2 of EDA, predicted to result in an altered transcript and aberrant protein., Conclusions: The clinicopathological and genetic findings were consistent with a case of X-linked HED. A very similar EDA deletion has been previously reported in a family of Holstein cattle with HED. The newly identified hemizygous EDA loss-of-function variant is certainly pathogenic and therefore is the genetic cause for the observed phenotype. This case report provides an additional example of the potential of WGS-based precise diagnostics in livestock species such as cattle to increase the diagnostic yield in rare diseases., (© 2022. The Author(s).)

Ectodysplasin A (EDA) signaling is initially identified as morphogenic signaling regulating the formation of skin appendages including teeth, hair follicles, exocrine glands in mammals, feathers in birds and scales in fish. Gene mutation in EDA signaling causes hypohidrotic ectodermal dysplasia (HED), a congenital hereditary disease with malformation of skin appendages. Interestingly, emerging evidence suggests that EDA and its receptors can modulate the proliferation, apoptosis, differentiation and migration of cancer cells, and thus may regulate tumorigenesis and cancer progression. More recently, as a newly discovered hepatocyte factor, EDA pathway has been demonstrated to be involved in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) and type II diabetes by regulating glucose and lipid metabolism. In this review, we summarize the function of EDA signaling from skin appendage development to multiple other diseases, and discuss the clinical application of recombinant EDA protein as well as other potential targets for disease intervention.

Variation in lateral plating in stickleback fish represents a classical example of rapid and parallel adaptation in morphology. The underlying genetic architecture involves polymorphism at the ectodysplasin-A gene (EDA). However, lateral plate number is influenced by additional loci that remain poorly characterized. Here, we search for such loci by performing genome-wide differentiation mapping based on pooled whole-genome sequence data from a European stickleback population variable in the extent of lateral plating, while tightly controlling for the phenotypic effect of EDA. This suggests a new candidate locus, the EDA receptor gene (EDAR), for which additional support is obtained by individual-level targeted Sanger sequencing and by comparing allele frequencies among natural populations. Overall, our study illustrates the power of pooled whole-genome sequencing for searching phenotypically relevant loci and opens opportunities for exploring the population genetics and ecological significance of a new candidate locus for stickleback armor evolution., (© The Author(s) 2022. Published by Oxford University Press on behalf of Genetics Society of America.)

Objective: To discover novel ectodysplasin-A (EDA) and wingless-type MMTV integration site family, member 10A (WNT10A) mutations in tooth agenesis (TA) patients., Study Design: Case series., Place and Duration of Study: Guanghua School of Stomatology, Guangzhou, China, from March 2018 to August 2020., Methodology: EDA and WNT10A were analysed in eleven TA families by PCR and Sanger sequencing. Bioinformatics and structure modelling analyses were performed after identifying different variants, to predict the resulting conformational alterations in WNT10A and EDA., Results:  Two novel mutations (c.796C>A (p.L266I), c.769G>A (p.G257R)) in EDA and two reported mutations (c.637G>A (p.G213S), c.511C>T (p.R171C))in WNT 10A were detected. Combined with the 3D structural analysis, we discovered a correlation between alterations in hydrogen bond formation and the observed phenotypes, potentially affecting protein binding., Conclusions: The mutations were predicted to be pathogenic through bioinformatics analyses. In addition, by identifying novel mutations, our knowledge regarding the TA spectrum and tooth development was considerably expanded., Key Words:  Anodontia, EDA, WNT 10A, Whole exome sequencing, Odontogenesis.

Background: Elasmoid scales are one of the most common dermal appendages and can be found in almost all species of bony fish differing greatly in their shape. Whilst the genetic underpinnings behind elasmoid scale development have been investigated, not much is known about the mechanisms involved in moulding of scales. To investigate the links between gene expression differences and morphological divergence, we inferred shape variation of scales from two different areas of the body (anterior and posterior) stemming from ten haplochromine cichlid species from different origins (Lake Tanganyika, Lake Malawi, Lake Victoria and riverine). Additionally, we investigated transcriptional differences of a set of genes known to be involved in scale development and morphogenesis in fish., Results: We found that scales from the anterior and posterior part of the body strongly differ in their overall shape, and a separate look on scales from each body part revealed similar trajectories of shape differences considering the lake origin of single investigated species. Above all, nine as well as 11 out of 16 target genes showed expression differences between the lakes for the anterior and posterior dataset, respectively. Whereas in posterior scales four genes (dlx5, eda, rankl and shh) revealed significant correlations between expression and morphological differentiation, in anterior scales only one gene (eda) showed such a correlation. Furthermore, eda displayed the most significant expression difference between species of Lake Tanganyika and species of the other two younger lakes. Finally, we found genetic differences in downstream regions of eda gene (e.g., in the eda-tnfsf13b inter-genic region) that are associated with observed expression differences. This is reminiscent of a genetic difference in the eda-tnfsf13b inter-genic region which leads to gain or loss of armour plates in stickleback., Conclusion: These findings provide evidence for cross-species transcriptional differences of an important morphogenetic factor, eda, which is involved in formation of ectodermal appendages. These expression differences appeared to be associated with morphological differences observed in the scales of haplochromine cichlids indicating potential role of eda mediated signal in divergent scale morphogenesis in fish., (© 2022. The Author(s).)

Hypohidrotic ectodermal dysplasia (HED) is a rare genetic disorder caused by mutational inactivation of a developmental pathway responsible for generation of tissues of ectodermal origin. The X-linked form accounts for the majority of HED cases and is caused by Ectodysplasin (EDA) pathogenic variants. We performed a combined analysis of 29 X-linked hypohidrotic ectodermal dysplasia (XLHED) families (including 12 from our previous studies). In addition to the classical triad of symptoms including loss (or reduction) of ectodermal structures, such as hair, teeth, and sweat glands, we detected additional HED-related clinical features including facial dysmorphism and hyperpigmentation in several patients. Interestingly, global developmental delay was identified as an unusual clinical symptom in many patients. More importantly, we identified 22 causal pathogenic variants that included 15 missense, four small in-dels, and one nonsense, splice site, and large deletion each. Interestingly, we detected 12 unique (India-specific) pathogenic variants. Of the 29 XLHED families analyzed, 11 (38%) harbored pathogenic variant localized to the furin cleavage site. A comparison with HGMD revealed significant differences in the frequency of missense pathogenic variants; involvement of specific exons and/or protein domains and transition/transversion ratios. A significantly higher proportion of missense pathogenic variants (33%) localized to the EDA furin cleavage when compared to HGMD (7%), of which p.R155C, p.R156C, and p.R156H were detected in three families each. Therefore, the first comprehensive analysis of XLHED from India has revealed several unique features including unusual clinical symptoms and high frequency of furin cleavage site pathogenic variants., (© 2021 Wiley Periodicals LLC.)

X-linked hypohidrotic dysplasia (XLHED), caused by mutations in the EDA gene, is a rare genetic disease that affects the development and function of the teeth, hair, nails, and sweat glands. The structural and functional consequences of caused by an ectodysplasin-A (EDA) mutations on protein phenotype, stability, and posttranslational modifications (PTMs) have not been well investigated. The present investigation involves five missense mutations that cause XLHED (L56P, R155C, P220L, V251M, and V322A) in different domains of EDA (TM, furin, collagen, and tumor necrosis factor [TNF]) from previously published papers. The deleterious nature of EDA mutant variants was identified using several computational algorithm tools. The point mutations induce major drifts in the structural flexibility of EDA mutant variants and have a negative impact on their stability, according to the 3D protein modeling tool assay. Using the molecular docking technique, EDA/EDA variants were docked to 10 EDA interacting partners, retrieved from the STRING database. We found a novel biomarker CD68 by molecular docking analysis, suggesting all five EDA variants had lower affinity for EDAR, EDA2R, and CD68, implying that they would affect embryonic signaling between the ectodermal and mesodermal cell layers. In silico research such as gene ontology, subcellular localization, protein-protein interaction, and PTMs investigations indicates major functional alterations would occur in EDA variants. According to molecular simulations, EDA variants influence the structural conformation, compactness, stiffness, and function of the EDA protein. Further studies on cell line and animal models might be useful in determining their specific roles in functional annotations., (© 2021 Wiley Periodicals LLC.)

Background: Hypohidrotic ectodermal dysplasia (HED) is mainly caused by ectodysplasin A (EDA) gene mutation. Fetus with genetic deficiency of EDA can be prenatally corrected. This study aimed at revealing the pathogenesis of two HED families and making a prenatal diagnosis for one pregnant female carrier., Designs: Genomic DNA was extracted from two HED patients and sequenced using whole exome sequencing (WES). The detected mutations were confirmed in patients and family members using Sanger sequencing. The expression of soluble ectodysplasin A1 (EDA1) protein was studied by western blot. The transcriptional activity of NF-κB pathway was tested by dual luciferase assay. The genomic DNA of fetus was extracted from shed chorion cells and EDA gene was screened through Sanger sequencing., Results: We identified two novel EDA mutations: c.1136T>C (p.Phe379Ser) and c.[866G>C;868A>T] (p.[Arg289Pro;Ser290Cys]). Further examinations revealed that these two mutated EDA1 proteins showed completely impaired solubility, and the transcriptional NF-κB activation induced by these missense mutant-type EDA1 proteins was significantly reduced compared with wild-type EDA1. Furthermore, the analysis of amniotic fluid samples from a pregnant heterozygote indicated that the fetus was a c.1136T>C mutation female carrier., Conclusions: This study extended the mutation spectrum of X-linked hypohidrotic ectodermal dysplasia (XLHED) and applied prenatal diagnosis for the pregnant carrier, which can be helpful in genetic counseling, prenatal diagnosis, and intervention for the XLHED family., (© 2021 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals LLC.)

The ectodysplasin receptor (EDAR) is a tumor necrosis factor receptor (TNF) superfamily member. A substitution in an exon of EDAR at position 370 (EDARV370A) creates a gain of function mutant present at high frequencies in Asian and Indigenous American populations but absent in others. Its frequency is intermediate in populations of Mexican ancestry. EDAR regulates the development of ectodermal tissues, including mammary ducts. Obesity and type 2 diabetes mellitus are prevalent in people with Indigenous and Latino ancestry. Latino patients also have altered prevalence and presentation of breast cancer. It is unknown whether EDARV370A might connect these phenomena. The goals of this study were to determine 1) whether EDARV370A is associated with metabolic phenotypes and 2) if there is altered breast anatomy in women carrying EDARV370A. Participants were from two Latino cohorts, the Arizona Insulin Resistance (AIR) registry and Sangre por Salud (SPS) biobank. The frequency of EDARV370A was 47% in the Latino cohorts. In the AIR registry, carriers of EDARV370A (GG homozygous) had significantly (p < 0.05) higher plasma triglycerides, VLDL, ALT, 2-hour post-challenge glucose, and a higher prevalence of prediabetes/diabetes. In a subset of the AIR registry, serum levels of ectodysplasin A2 (EDA-A2) also were associated with HbA1c and prediabetes (p < 0.05). For the SPS biobank, participants that were carriers of EDARV370A had lower breast density and higher HbA1c (both p < 0.05). The significant associations with measures of glycemia remained when the cohorts were combined. We conclude that EDARV370A is associated with characteristics of the metabolic syndrome and breast density in Latinos., Competing Interests: The authors have declared that no competing interests exist.

Ectodermal dysplasia (ED) is a diverse group of genetic disorders caused by congenital defects of two or more ectodermal-derived body structures, namely, hair, teeth, nails, and some glands, e.g., sweat glands. Molecular pathogenesis of ED involves mutations of genes encoding key proteins of major developmental pathways, including ectodysplasin (EDA) and wingless-type (WNT) pathways. The most common ED phenotype is hypohidrotic/anhidrotic ectodermal dysplasia (HED) featuring hypotrichosis, hypohidrosis/anhidrosis, and hypodontia. Molecular diagnosis is fundamental for disease management and emerging treatments. We used targeted next generation sequencing to study EDA , EDAR , EDARADD , and WNT10A genes in 45 Egyptian ED patients with or without hypohidrosis. We present genotype and phenotype data of 28 molecularly-characterized patients demonstrating genetic heterogeneity, variable expressivity, and intrafamilial phenotypic variability. Thirteen mutations were reported, including four novel EDA mutations, two novel EDARADD , and one novel EDAR mutations. Identified mutations congregated in exons encoding key functional domains. EDA is the most common gene contributing to 85% of the identified Egyptian ED genetic spectrum, followed by EDARADD (10%) and EDAR (5%). Our cohort represents the first and largest cohort from North Africa where more than 60% of ED patients were identified emphasizing the need for exome sequencing to explore unidentified cases.

Previous studies have shown that microRNAs (miRNAs) are closely related to many viral infections. However, the molecular mechanism of how miRNAs regulate porcine epidemic diarrhea virus (PEDV) infection remains unclear. In this study, we first constructed a PEDV-infected IPEC-J2 cytopathic model to validate the relationship between miR-129a-3p expression levels and PEDV resistance. Secondly, we explored the effect of miR-129a-3p on PEDV infection by targeting the 3'UTR region of the ligand ectodysplasin ( EDA ) gene. Finally, transcriptome sequencing was used to analyze the downstream regulatory mechanism of EDA . The results showed that after 48 h of PEDV infection, IPEC-J2 cells showed obvious pathological changes, and miR-129a-3p expression was significantly downregulated ( p < 0.01). Overexpression of miR-129a-3p mimics inhibited PEDV replication in IPEC-J2 cells; silencing endogenous miR-129a-3p can promote viral replication. A dual luciferase assay showed that miR-129a-3p could bind to the 3'UTR region of the EDA gene, which significantly reduced the expression level of EDA ( p < 0.01). Functional verification showed that upregulation of EDA gene expression significantly promoted PEDV replication in IPEC-J2 cells. Overexpression of miR-129a-3p can activate the caspase activation and recruitment domain 11 ( CARD11 ) mediated NF-κB pathway, thus inhibiting PEDV replication. The above results suggest that miR-129a-3p inhibits PEDV replication in IPEC-J2 cells by activating the NF-κB pathway by binding to the EDA 3'UTR region. Our results have laid the foundation for in-depth study of the mechanism of miR-129a-3p resistance and its application in porcine epidemic diarrhea disease-resistance breeding.

Objective: To carry out genetic testing for a Chinese patient with X-linked hypohidrotic ectodermal dysplasia (XLHED) and explore its genotype-phenotype correlation., Methods: Clinical data of the patient was collected. Peripheral blood samples were taken from the patient, his parents and 100 unrelated healthy controls. Genetic variants were detected by using next-generation sequencing using a skin-disease panel through targeted capture and next generation sequencing. Candidate variant was verified by Sanger sequencing. All literature related to genetic testing of XLHED patients in China was searched in the database, and the genotypes and phenotypes of patients in the literature and the correlation between them were statistically analyzed., Results: A novel splice site variant c.655&#95;689del was detected in the patient but not among his parents and the 100 unrelated healthy controls. So far 61 variants of the EDA gene have been identified among Chinese patients with XLHED, which suggested certain degree of genotype-phenotype correlation., Conclusion: A novel c.655&#95;689del variant has been identified in the EDA gene, which has expanded the spectrum of EDA gene variant and facilitated delineation of the genotype-phenotype correlation of XLHED.

Background: Hypohidrotic Ectodermal Dysplasia (HED) is a genetic disorder which affects structures of ectodermal origin. X-linked hypohidrotic ectodermal dysplasia (XLHED) is the most common form of disease. XLHED is characterized by hypotrichosis, hypohydrosis and hypodontia. The cardinal features of classic HED become obvious during childhood. Identification of a hemizygous EDA pathogenic variant in an affected male confirms the diagnosis., Case Presentation: We report on a male newborn with the main clinical characteristics of the X-linked HED including hypotrichosis, hypodontia and hypohidrosis. Gene panel sequencing identified a new hemizygous missense variant of uncertain significance (VUS) c.1142G > C (p.Gly381Ala) in the EDA gene, located on the X chromosome and inherited from the healthy mother., Conclusion: Despite the potential functional impact of VUS remains uncharacterized, our goal is to evaluate the clinical potential consequences of missense VUS on EDA gene. Even if the proband's phenotype is characteristic for classic HED, further reports of patients with same clinical phenotype and the same genomic variant are needed to consider this novel VUS as responsible for the development of HED.

Background: Causative variants in genes of the EDA/EDAR/NF-κB pathway, such as EDA and EDARADD, have been widely identified in patients with non-syndromic tooth agenesis (NSTA). However, few cases of NSTA are due to ectodysplasin-A receptor (EDAR) variants. In this study, we investigated NSTA-associated variants in Chinese families., Methods: Peripheral blood samples were collected from the family members of 24 individuals with NSTA for DNA extraction. The coding region of the EDA gene of the 24 probands was amplified by PCR and sequenced to investigate new variants. Whole-exome sequencing and Sanger sequencing were then performed for probands without EDA variants detected by PCR., Results: A novel missense variant EDAR c.338G>A (p.(Cys113Tyr)) was identified in one family. In addition, three known EDA variants (c.865C>T, c.866G>A, and c.1013C>T) were identified in three families. Genotype-phenotype correlation analysis of EDAR gene mutation showed that NSTA patients were most likely to lose the maxillary lateral incisors and the maxillary central incisors were the least affected. The phenotype of mutations at codon 289 of EDA in NSTA affected patients was characterized by lateral incisors loss, rarely affecting the maxillary first molars., Conclusion: A novel EDAR missense variant c.338G>A (p.(Cys113Tyr)) was identified in a family with NSTA, extending the mutation spectrum of the EDAR gene. Genotype-phenotype correlation analyses of EDAR and EDA mutations could help to improve disease status prediction in NSTA families., (© 2021 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals LLC.)

Objective: To explore the clinical and genetic characteristics of a child with X-linked hypohidrotic ectodermal dysplasia (XLHED)., Methods: Clinical data of the child was collected. Peripheral blood samples were taken from the child and his parents with informed consent and subjected to copy number variation (CNV) analysis and whole exome sequencing (WES)., Results: The male infant manifested sparse hair, anhidrosis, anuresis due to polycystic kidney dysplasia, external genital malformation and anal atresia. WES has revealed a 406 bp hemizygous deletion at Xq13 (68 836 147-68 836 553) in the proband, which encompassed exon 1 of the EDA gene. A heterozygous deletion at the same site was detected in the mother, while no deletion or duplication of the site was detected in the father., Conclusion: The hemizygous deletion of EDA gene exon 1 probably underlay the ectodermal dysplasia in the proband. Above result has provided a basis for genetic counseling and prenatal diagnosis for the family.

Objective: To investigate the effects of ectodysplasin-A1 (EDA1) on the proliferation and cell cycle of ameloblast-like epithelial cells (LS8 cells). Methods: Wild EDA1 plasmid pCR3-Flag-EDA1-W (wild group), syndrome mutant EDA1 plasmid pCR3-Flag-EDA1-H252L (mutant group) and empty vector plasmid pCR3-Flag (control group) were transfected into LS8 cells. Cell proliferation was detected by methyl thiazolyl tetrazolium (MTT) assay and cell cycle was detected by flow cytometry. All tests were repeated three times. Results: Compared with the control group (0.105±0.032), the proliferation activity of the wild group (0.201±0.009) was significantly higher after 72 h ( P <0.05). Compared with the control group (0.168±0.054) and the mutant group (0.194±0.059), the proliferation activity of the wild group (0.386±0.066) was significantly higher after 96 h ( P <0.05). There was no significant difference between the mutant group and the control group at all time points ( P >0.05). In the G 0 /G 1 phase, compared with the control group (65.4%±2.1%) and the mutant group (66.6%±3.1%), the cell distribution ratio of the wild group (51.2%±1.1%) was significantly lower ( P <0.01). In the S phase, compared with the control group (23.1%±2.0%) and the mutant group (21.9%±1.8%), the cell distribution ratio of the wild type group (37.3%±2.4%) was significantly higher ( P <0.01). There was no significant difference in cell cycle distribution between the mutant group and the control group ( P <0.05). Conclusions: Wild EDA1 promotes the proliferation of LS8 cells and the transformation from G 0 /G 1 to S phase. The syndrome mutant EDA1 (EDA1-H252L) loses its function of regulating the cell proliferation and cell cycle of LS8 cells.

Objective: To investigate the clinical phenotype and genetic characteristics of a patient with hypohidrotic ectodermal dysplasia (HED) due to partial deletion of EDA gene., Methods: The child has presented with HED complicated with epilepsy. Family trio whole exome sequencing (Trio-WES), copy number variation sequencing (CNV-seq), and karyotype analysis were carried out to explore the underlying genetic etiology., Results: The proband, a 7-year-and-8-month-old boy, presented with thin curly hair, thin and sparse eyebrow, xerosis cutis, susceptibility to hyperthermia from childhood, hypohidrosis, sharp/sparse/absent teeth, saddle nose, prominent forehead, auricle adulation and seizure. He was found to have a normal chromosomal karyotype, and no abnormality was found by Trio-WES. Genome-wide CNV-seq revealed a 341.90 kb deletion at Xq13.1q13.1 (chrX: 68 796 566-69 138 468). As verified by PCR-electrophoresis, the deletion has removed part of the EDA gene. The deletion was derived from his mother with normal hair, mild xerosis cutis, and sparse, decidulated and nail-like teeth. The mother was detected with a heterozygous 242.10 kb deletion at Xq13.1q13.1 (chrX: 68 836 154-69 078 250)., Conclusion: Both the proband and his mother have carried a Xq13.1 microdeletion involving part of the EDA gene. The clinical phenotypes of the mother and the proband were consistent with the clinical characteristics of X-linked recessive HED, for which partial deletion of the EDA gene is probably accountable.

Background: X-linked hypohidrotic ectodermal dysplasia (XLHED), a rare genetic disorder, affects the normal development of ectodermal derivatives, such as hair, skin, teeth, and sweat glands. It is caused by pathogenic variants of the gene EDA and defined by a triad of hypotrichosis, hypo- or anodontia, and hypo- or anhidrosis which may lead to life-threatening hyperthermia. Although female carriers are less severely affected than male patients, they display symptoms, too, with high phenotypic variability. This study aimed to elucidate whether phenotypic differences in female XLHED patients with identical EDA genotypes might be explained by deviating X-chromosome inactivation (XI) patterns., Methods: Six families, each consisting of two sisters with the same EDA variant and their parents (with either mother or father being carrier of the variant), participated in this study. XLHED-related data like sweating ability, dental status, facial dysmorphism, and skin issues were assessed. We determined the women`s individual XI patterns in peripheral blood leukocytes by the human androgen receptor assay and collated the results with phenotypic features., Results: The surprisingly large inter- and intrafamilial variability of symptoms in affected females was not explicable by the pathogenic variants. Our cohort showed no higher rate of nonrandom XI in peripheral blood leukocytes than the general female population. Furthermore, skewed XI patterns in favour of the mutated alleles were not associated with more severe phenotypes., Conclusions: We found no evidence for preferential XI in female XLHED patients and no distinct correlation between XLHED-related phenotypic features and XI patterns. Phenotypic variability seems to be evoked by other genetic or epigenetic factors.

The mucosa microenvironment is critical for intestinal stem cell self-renewal and reconstruction of the epithelial barrier in inflammatory bowel disease (IBD), where the mechanisms underlying cross-talk between intestinal crypts and the microenvironment remain unclear. Here, we firstly identified miR-494-3p as an important protector in colitis. miR-494-3p levels were decreased and negatively correlated with the severity in human IBD samples, as well as in colitis mice. In colitis crypts, a notable cytokine-cytokine receptor, miR-494-3p-targeted EDA2R and the ligand EDA-A2, suppressed colonic stemness and epithelial repair by inhibiting β-catenin/c-Myc. In differentiated IECs, miR-494-3p inhibits macrophage recruitment, M1 activation and EDA-A2 secretion by targeting IKKβ/NF-κB in colitis. A miR-494-3p agomir system notably ameliorated the severity of colonic colitis in vivo. Collectively, our findings uncover a miR-494-3p-mediated cross-talk mechanism by which macrophage-induced intestinal stem cell impairment aggravates intestinal inflammation.

Objective: The aim of this case-control study was to investigate the association between non-syndromic hypodontia and nineteen common variants of candidate genes ectodysplasin A (EDA), paired box 9 (PAX9), msh homeobox 1 (MSX1) and axis inhibition protein 2 (AXIN2)., Settings and Sample Population: Sixty-one hypodontia cases were frequency-matched to 253 controls with no missing teeth (excluding the third molars)., Material and Methods: Self-report data and DNA samples were collected from each participant., Results: The sample had a mean age of 16.6 years (SD = 7.3), with most participants being female (59.6%), and of New Zealand European origin (75.4%). Using multiple logistic regression analysis, it was found that the T-allele of rs12853659 (EDA) and the G-allele of rs2428151 (EDA) were both associated with a higher risk of hypodontia (odds ratio, OR = 2.79, 95% CI = 1.11-7.01; and OR = 2.87, 95% CI = 1.04-7.94, respectively). The G-allele of rs2520378 (EDA) showed a protective effect with an OR of 0.61 (95% CI = 0.38-0.99). The EDA SNP findings were consistent with previous reports included in a meta-analysis. No associations were found with the PAX9, AXIN2 and MSX1 genes, after adjusting for sex and ethnicity., Conclusions: Common variants of the EDA genes are associated with specific phenotypes of non-syndromic hypodontia, thus confirming their role in the regulatory pathways of normal tooth development. However, larger samples are needed to investigate the association further., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Hypohidrotic ectodermal dysplasia (HED) is the most common form of ectodermal dysplasia and is mainly associated with mutations in the EDA, EDAR, and EDARADD responsible for the development of ectodermal-derived structures. HED displays different modes of inheritance according to the gene that is involved, with X-linked EDA-related HED being the most frequent form of the disease., Methods: Two families with tooth agenesis and manifestations of HED underwent clinical examination and EDA, EDAR, and EDARADD genetic analysis. The impact of the novel variant on the protein was evaluated through bioinformatics tools, whereas molecular modeling was used to predict the effect on the protein structure., Results: A novel missense variant was identified in the EDAR (c.287T>C, p.Phe96Ser) of a female child proband and her mother, accounting for autosomal dominant HED. The genetic variant c.866G>A (p.Arg289His) in EDA, which has been previously described, was observed in the male proband of another family confirming its role in X-linked HED. The inheritance model of the missense mutation showed a different relationship with X-linked HED and non-syndromic tooth agenesis., Conclusion: Our findings provide evidence of variable expression of HED in heterozygous females, which should be considered for genetic counseling, and different modes of inheritance related to tooth development., (© 2020 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals LLC.)

Introduction: Hypohidrotic ectodermal dysplasia (HED) is an X-linked recessive disorder, characterised by abnormally developed ectodermal tissues (sweat glands, enamel, hair, nails). HED is caused by mutations of the EDA1 gene (Xq13.1) which codes for ectodysplasin A, a transmembrane signalling protein, which plays a significant role in ectodermal differentiation. Here we present a case of prenatal testing for HED., Methods: An 11-month-old boy with no family history was clinically diagnosed with HED. Genomic DNA was isolated from the patient's white blood cells, and the possible existence of mutations suspected for HED development was investigated by an NGS gene panel. Total DNA was also isolated from blood samples of his parents. After mutation detection and genetic counselling, a prenatal HED test was performed during the 12th week of the mother's next pregnancy. Embryonic DNA was isolated from a sample of chorionic villi. Parts of the EDA1, AMELX (X chromosome), and SRY (Y chromosome) genes were amplified by PCR, using the corresponding primers., Results: The boy with HED was found to be a hemizygote for the c.595&#95;613del (p. Pro199PhefsTer75) deletion in the EDA1 gene. The fetus was male (XY) that did not carry the pathological mutation., Conclusion: The initial diagnosis of a family member with HED in a case with no family history poses the question whether this type of ectodermal dysplasia is autosomal dominant (and the case is due to a de novo mutation), autosomal recessive, or X-linked recessive. Molecular detection of the responsible mutation allows proper genetic counselling, carrier testing, and prevention by prenatal testing., (© 2021. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

Objective: To detect the ectodysplasin A ( EDA ) gene mutation in patients with hypohidro-tic ectodermal dysplasia (HED), and to analyze the distribution pattern of missing permanent teeth and the systemic manifestation of HED patients with EDA gene mutation., Methods: Twelve HED families were enrolled from clinic for genetic history collection, systemic physical examination and oral examination. Peripheral blood or saliva samples were collected from the probands and the family members to extract genomic DNA. PCR amplification and Sanger sequencing were utilized to detect the EDA gene variations, which were compared with the normal sequence (NM&#95;001399.5). The functional impact of EDA gene variants was then evaluated by functional prediction of mutation, conservation analysis and protein structure prediction. The pathogenicity of each EDA gene variation was assessed according to the stan-dards and guidelines of the American College of Medical Genetics and Genomics (ACMG). The systemic phenotype and missing permanent tooth sites of HED patients with EDA gene mutations were summarized, and the missing rate of each tooth position was analyzed and compared., Results: Eight out of twelve HED families were identified to carry EDA gene mutations, including: c.164T>C(p.Leu55Pro); c.457C>T (p.Arg153Cys); c.466C>T(p.Arg156Cys); c. 584G>A(p.Gly195Glu); c.619delG(p.Gly207Profs*73); c.673C>T(p.Pro225Ser); c.676C>T(p.Gln226*) and c.905T>G(p.Phe302Cys). Among them, c.164T>C(p.Leu55Pro); c.619delG(p.Gly207Profs*73); c.673C>T(p.Pro225Ser); c.676C>T(p.Gln226*) and c.905T>G(p.Phe302Cys) were novel mutations. The HED patients with EDA gene mutations in this study were all male. Our results showed that the average number of missing permanent teeth was 13.86±4.49, the average number of missing permanent teeth in the upper jaw was 13.14±5.76, the missing rate was 73.02%. And in the lower jaw, the average number of missing permanent teeth was 14.57±3.05, the missing rate was 80.95%. There was no significant difference in the number of missing teeth between the left and right sides of the permanent dentition ( P >0.05). Specifi-cally, the maxillary lateral incisors, the maxillary second premolars and the mandibular lateral incisors were more likely to be missing, while the maxillary central incisors, the maxillary and mandibular first molars had higher possibility of persistence., Conclusion: This study detected novel EDA gene pathogenic variants and summarized the distribution pattern of missing permanent teeth of HED patients, thus enriched the variation and phenotype spectrum of EDA gene, and provided new clinical evidence for genetic diagnosis and prenatal consultation.

Objective: To explore the genetic cause of a patient suspected for congenital ectodermal dysplasia with repeated hyperthermia and to assess the reproductive risk for his family., Methods: Medical whole-exome sequencing (WES) were used to detect single-nucleotide variations and low-coverage massively parallel copy number variation sequencing (CNV-seq) were employed to verify suspected CNVs. PCR and real-time quantitative PCR were applied to confirm the deletion of EDA gene., Results: The results of WES suggested that the patient carried a hemizygous deletion for chrX:69 243 016-69 395 730. CNV-seq indicated that the patient carried a deletion of approximately 0.12 Mb on Xq13.1, which encompassed the EDA gene. The PCR results confirmed that there was a hemizygous deletion of exons 3 to 8 of the EDA gene. The same deletion was not found in his mother., Conclusion: The congenital ectodermal dysplasia of the patient may be attributed to deletion of exons 3 to 8 of the EDA gene, which could be de novo or derive from germline mosaicism of his mother. The WES and CNV-seq are of great value for the diagnosis of rare diseases.

Objective: To detect variant of EDA gene in a fetus with absence of germ teeth detected by prenatal ultrasonography., Methods: Clinical data and amniotic fluid and peripheral venous blood samples of the pregnant woman were collected for the analysis. Following extraction of genome DNA, the coding regions of the EDA gene were amplified by PCR and subjected to next-generation sequencing. Candidate variant was verified by Sanger sequencing., Results: The pregnant woman was found to carry a heterozygous c.574G>A variant in the EDA gene, for which the fetus was hemizygous. Bioinformatic analysis suggested the variant to be pathogenic., Conclusion: Combined ultrasonographic and genetic findings suggested the fetus is affected with X-linked hypohidrotic ectodermal dysplasia due to pathogenic variant of the EDA gene.