Next generation sequencing panel target genes: possible diagnostic tool for ectodermal dysplasia related diseases.

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). MiSeqTM 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.

Different degree of loss-of-function among four missense mutations in the EDAR gene responsible for autosomal recessive hypohidrotic ectodermal dysplasia may be associated with the phenotypic severity.

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.

Appearance Says It All; A Rare Case Of Hypohidrotic Ectodermal Dysplasia.

Ectodermal Dysplasia (ED) is a rare genetic condition characterized by the involvement of ectoderm derivatives such as hair, nail, sweat glands, and teeth. It has many variants, but the two most common ones are hypohidrotic/anhidrotic ectodermal dysplasia and hidrotic ectodermal dysplasia. Herein, we present a case of a 20-year-old female with hypohidrotic ectodermal dysplasia who had anodontia, hypohidrosis, and hypotrichosis, and her condition went unrecognized until she was seen for gastroenteritis at a tertiary care center. This case report will help spread education and awareness regarding such a rare and under-recognized condition. Early diagnosis and intervention help improve the quality of life.

Ectodysplasin pathogenic variants affecting the furin-cleavage site and unusual clinical features define X-linked hypohidrotic ectodermal dysplasia in India.

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.

Two novel ectodysplasin A gene mutations and prenatal diagnosis of X-linked hypohidrotic ectodermal dysplasia.

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.

Prenatal Genetic Testing for X-Linked Hypohidrotic Ectodermal Dysplasia.

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_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.

[Prenatal diagnosis of a fetus with X-linked hypohidrotic ectodermal dysplasia].

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.

Emerging therapies in genodermatoses.

The human genome project yielded a compendium of genetic material that has allowed rapid advancement both in the technique of whole exome sequencing and also in the ability to identify single gene defects. The next generation of genetics has investigated how these genes interact in the development of disease, identifying pathways of illness and end organ tissue abnormal development. From the knowledge of single genes and pathways of genodermatosis development arises the opportunity to produce genetic therapies. This contribution reviews some of the exciting, emerging genetic therapies in genodermatoses.

Displasia ectodérmica hipohidrótica ligada al cromosoma X de novo por variante recurrente en un paciente mexicano / X-linked hypohidrotic ectodermal dysplasia by a de novo recurrent variant in a Mexican patient

Resumen Introducción: Las displasias ectodérmicas son un grupo de genodermatosis que se caracterizan por distrofia de las estructuras derivadas del ectodermo. De ellas, la variedad más común es la hipohidrótica, con una incidencia de 7/100,000 nacidos vivos observada en todos los grupos étnicos. La displasia ectodérmica hipohidrótica tiene distintas etiologías. La presentación más frecuente es la asociada a un patrón de herencia ligado al cromosoma X, causada por variantes patogénicas del gen EDA en Xq13.1. EDA codifica a la ectodisplasina A, una molécula de señalización que participa en la comunicación epitelio-mesénquima durante el desarrollo de la piel y los anexos. Caso clínico: Varón de 6 años con las características clínicas cardinales de la displasia ectodérmica hipohidrótica ligada al cromosoma X (DEHLX), que incluyen hipotricosis, oligodoncia e hipohidrosis. El análisis del gen EDA por secuenciación directa mostró la presencia de la variante patogénica c.466C>T, p.Arg156Cys, rs132630313 con presentación de novo en el paciente. Esta variante ya ha sido reportada en diferentes poblaciones, incluyendo familias mexicanas, y constituye un punto caliente para mutación en EDA. Se analizaron los hallazgos clínicos, la etiología y el manejo de la DEHLX, en la que de manera reciente se ha planteado la posibilidad de otorgar tratamiento prenatal para prevenir sus manifestaciones clínicas. Conclusiones: Se pone de relevancia que el análisis molecular en pacientes con DEHLX corrobora el diagnóstico clínico y permite brindar asesoramiento genético con bases moleculares.

Abstract Background: Ectodermal dysplasias are a group of genodermatoses characterized by dystrophy of ectodermal derived structures. The most frequent presentation of the ectodermal dysplasias is the hypohidrotic type, which has an incidence of 7/100,000 newborns and has been described in all ethnic groups. The hypohidrotic ectodermal dysplasia (HED) has different etiologies, and it is more frequently associated with an X-linked pattern of inheritance caused by pathogenic variants of the EDA gene in Xq13.1. EDA encodes the protein ectodisplasin A, a signal molecule which participates in epithelium and mesenchymal development of the skin. Case report: A 6 year-old male patient with the main clinical characteristics of the X-linked HED including hypotrichosis, hypodontia and hypohidrosis. The direct sequencing analysis of EDA in our patient detected a de novo pathogenic variant, c.466C>T, p.Arg156Cys, rs132630313. This variant has been previously described in different ethnic groups, including Mexican families, and is considered a mutational hotspot. The clinical characteristics, etiology and management of the X-linked HED, including the possibility of prenatal therapy in order to avoid the clinical manifestations are discussed. Conclusions: The molecular analysis in patients with X-linked HED is of relevance, as it enables to confirm the clinical diagnosis and also, it allows a genetic assessment with molecular bases.

[Linear lesions: A key dermatological feature of X-linked ectodermal dysplasia in a young girl]. / Lésions linéaires : un signe dermatologique clé de la dysplasie ectodermique liée à l'X chez la fille.

INTRODUCTION: X-linked hypo/anhidrotic ectodermal dysplasia (AED) is the most common form of AED. It is manifested in boys by involvement of the adnexa, teeth and sweat glands. In girls, signs are usually minor and may include linear lesions that are poorly known since they are reported infrequently or overlooked. Herein we report 3 cases. PATIENTS AND METHODS: There were two female patients who had been followed for several years, as well as the mother of one of the patients. Both of the younger patients had early diagnosis of DEA in childhood based on severe dental abnormalities, i.e. hypodontia and conical teeth, a typical facies, and cutaneous xerosis. The mother had milder signs and the diagnosis was made at the time of her daughter's diagnosis. All 3 had hypopigmented linear skin lesions (arms, buttocks or back), associated with a decrease in hair in one of them. Genetic analysis showed the R156H missense mutation at exon 3 of the EDA gene in all 3 patients. CONCLUSION: These hypopigmentation linear lesions, sometimes with hair loss, are well known to pediatric clinicians and dermatologists concerning early diagnosis of AED in girls, especially where the other signs are mild. Early diagnosis enables appropriate therapeutic management and genetic counseling regarding future pregnancy.

A case of body dysmorphic disorder in an adolescent with hypohidrotic ectodermal dysplasia.

We report the case of an adolescent with hypohidrotic ectodermal dysplasia, who had obsessive-compulsive disorder and was later diagnosed with body dysmorphic disorder (BDD). BDD is a highly distressing, adolescent-onset disorder that may lead to social isolation, the development of comorbid mental health disorders and suicidality. Patients typically lack insight into their BDD and frequently present to dermatologists for medical treatment. In this paper, we address the challenges faced when working with patients with BDD.

X-linked hypohidrotic ectodermal dysplasia by a de novo recurrent variant in a Mexican patient.

Background: Ectodermal dysplasias are a group of genodermatoses characterized by dystrophy of ectodermal derived structures. The most frequent presentation of the ectodermal dysplasias is the hypohidrotic type, which has an incidence of 7/100,000 newborns and has been described in all ethnic groups. The hypohidrotic ectodermal dysplasia (HED) has different etiologies, and it is more frequently associated with an X-linked pattern of inheritance caused by pathogenic variants of the EDA gene in Xq13.1. EDA encodes the protein ectodisplasin A, a signal molecule which participates in epithelium and mesenchymal development of the skin. Case report: A 6 year-old male patient with the main clinical characteristics of the X-linked HED including hypotrichosis, hypodontia and hypohidrosis. The direct sequencing analysis of EDA in our patient detected a de novo pathogenic variant, c.466C>T, p.Arg156Cys, rs132630313. This variant has been previously described in different ethnic groups, including Mexican families, and is considered a mutational hotspot. The clinical characteristics, etiology and management of the X-linked HED, including the possibility of prenatal therapy in order to avoid the clinical manifestations are discussed. Conclusions: The molecular analysis in patients with X-linked HED is of relevance, as it enables to confirm the clinical diagnosis and also, it allows a genetic assessment with molecular bases.

Introducción: Las displasias ectodérmicas son un grupo de genodermatosis que se caracterizan por distrofia de las estructuras derivadas del ectodermo. De ellas, la variedad más común es la hipohidrótica, con una incidencia de 7/100,000 nacidos vivos observada en todos los grupos étnicos. La displasia ectodérmica hipohidrótica tiene distintas etiologías. La presentación más frecuente es la asociada a un patrón de herencia ligado al cromosoma X, causada por variantes patogénicas del gen EDA en Xq13.1. EDA codifica a la ectodisplasina A, una molécula de señalización que participa en la comunicación epitelio-mesénquima durante el desarrollo de la piel y los anexos. Caso clínico: Varón de 6 años con las características clínicas cardinales de la displasia ectodérmica hipohidrótica ligada al cromosoma X (DEHLX), que incluyen hipotricosis, oligodoncia e hipohidrosis. El análisis del gen EDA por secuenciación directa mostró la presencia de la variante patogénica c.466C>T, p.Arg156Cys, rs132630313 con presentación de novo en el paciente. Esta variante ya ha sido reportada en diferentes poblaciones, incluyendo familias mexicanas, y constituye un punto caliente para mutación en EDA. Se analizaron los hallazgos clínicos, la etiología y el manejo de la DEHLX, en la que de manera reciente se ha planteado la posibilidad de otorgar tratamiento prenatal para prevenir sus manifestaciones clínicas. Conclusiones: Se pone de relevancia que el análisis molecular en pacientes con DEHLX corrobora el diagnóstico clínico y permite brindar asesoramiento genético con bases moleculares.

A Hypohidrotic Ectodermal Dysplasia Arising From a New Mutation in a Yorkshire Terrier Dog.

Hypohidrotic ectodermal dysplasias (HED) constitute a group of genetic disorders that affect ectodermal derivatives such as sweat glands, sebaceous glands, hair, and teeth. The vast majority of cases of HED are caused by a recessive mutation of the EDA gene located in the X chromosome. In these cases, affected individuals are usually male and have alopecia and hypotrichosis with characteristic distribution, in addition to malformed teeth and fewer than normal. From a canine HED isolated case (proband) andc in order to verify if this emerged from a new mutation, it was possible to construct a pedigree with 5 generations and 93 individuals representing an extended and informative family. The proband's mother crossed with 2 different males and generated 33 descendants in 9 gestations: 1 affected male (proband), 15 normal males, and 17 normal females, which together can be considered as 1 sibship. Through Bayesian inference, it was possible to establish that this case originated from a new mutation, with a 99.99% probability of the mother of the proband not being a carrier.

LEF1 haploinsufficiency causes ectodermal dysplasia.

Ectodermal dysplasias are a family of genodermatoses commonly associated with variants in the ectodysplasin/NF-κB or the Wnt/ß-catenin pathways. Both pathways are involved in signal transduction from ectoderm to mesenchyme during the development of ectoderm-derived structures. Wnt/ß-catenin pathway requires the lymphoid enhancer-binding factor 1 (LEF1), a nuclear mediator, to activate target gene expression. In mice, targeted inactivation of the LEF1 gene results in a complete block of development of multiple ectodermal appendages. We report two unrelated patients with 4q25 de novo deletion encompassing LEF1, associated with severe oligodontia of primary and permanent dentition, hypotrichosis and hypohidrosis compatible with hypohidrotic ectodermal dysplasia. Taurodontism and a particular alveolar bone defect were also observed in both patients. So far, no pathogenic variants or variations involving the LEF1 gene have been reported in human. We provide further evidence for LEF1 haploinsufficiency role in ectodermal dysplasia and delineate its clinical phenotype.

Hypohidrotic ectodermal dysplasia: a case report.

Hypohidrotic ectodermal dysplasia is a common variation of ectodermal dysplasia, characterized by hypohidrosis (or anhidrosis), hypotrichosis, hypodontia, and other distinct facial features. Furthermore, ocular tissues of ectodermal origin may also be affected in this disease. The most common ocular manifestations of hypohidrotic ectodermal dysplasia are dry eye, madarosis, alterations in the meibomian glands, abnormalities in the nasolacrimal duct, and infantile glaucoma. Herein, author reports a case of hypohidrotic ectodermal dysplasia in a 12-year-old Indian boy with dry eye and lacrimal sac mucocele.

A recurrent missense mutation in the EDAR gene causes severe autosomal recessive hypohidrotic ectodermal dysplasia in two consanguineous Kashmiri families.

BACKGROUND: Hypohidrotic ectodermal dysplasia (HED) is a rare congenital disorder arising from the abnormal development of ectoderm derived structures, including skin, hair, nails, teeth and glands. These patients have sparse hair on the whole body, including the scalp, as well as hypoplastic teeth. They have no resistance to heat as a result of abnormal sweat glands. In total, four genes, namely ectodysplasin A (EDA), ectodysplasin A receptor (EDAR), EDAR-associated death domain protein (EDARADD) and Wnt family member 10A (WNT10A), are known to be involved in the etiology of HED. METHODS: In the present study, we investigated two consanguineous Kashmiri families (A &B) with an autosomal recessive form of HED. Using whole exome sequencing and different bioinformatics tools, we detected a recurrent mutation causing severe HED. RESULTS: We identified an already known rare homozygous missense (NM_022336 c.1300 T>C; p.W434R; minor allele frequency 0.00007) variant in exon 12 of the EDAR gene. This variant segregated with a homozygous form in all patients and their obligate carriers were heterozygous. A panel of > 100 unrelated ethnically matched controls was screened, and the mutation was not identified outside the families. Furthermore, the candidate variant is predicted to be damaging by in silico software giving a CADD (Combined Annotation Dependent Depletion) score of 25.5, which indicates that the variant is among the top 1% of the deleterious variants in the human genome. CONCLUSIONS: The identification of the same homozygous mutation segregating with disease in two different families supports the important role of the gene in the development of the disorder and this may contribute to novel approaches, prenatal diagnosis and genetic counseling of families with EDAR related disorders.