Characterization of X-linked hypohidrotic ectodermal dysplasia (XL-HED) hair and sweat gland phenotypes using phototrichogram analysis and live confocal imaging

A Novel Ectodysplasin a Gene mutation of X-Linked Hypohidrotic Ectodermal Dysplasia

Introduction

Hypohidrotic ectodermal dysplasia (HED) is a genetic disorder that influences structures of ectodermal origin, such as teeth, hair, and sweat glands. Compared with autosomal recessive and dominant modes of inheritance, the X-linked HED (XLHED) characterized by Hypodontia/Oligodontia teeth, Absent/sparse hair, Anhidrosis/hypohidrosis, and characteristic facial features, is the most frequent and its primary cause is the mutation of ectodysplasin A (EDA) gene. This research aimed to expound the clinical and molecular features of a Chinese male with XLHED and to summarize and compare several previous findings.

Methods

Genomic DNA was obtained from the peripheral blood of the proband and his family members, then Sanger sequencing was used to perform a mutational analysis of EDA. Real-time quantitative PCR and Western blotting were used to detect EDA expression. The transcriptional activity of NF-κB was detected using a luciferase assay.

Results

The probandwith XLHED was identified a novel EDA mutation, c.1119G>C(p.M373I), that affected the molecular analysis of transmembrane protein exon8 mutations, inherited from the mother. He showed a severe multiple-tooth loss, with over 20 permanent teeth missing and sparse hair and eyebrows, dry, thin, and itching skin. Furthermore, his sweating function was abnormal to a certain extent.

Discussion

The functional study showed that this novel mutant led to a significant decrease in the EDA expression level and transcriptional activity of NF-κB. Our findings extend the range of EDA mutations in XLHED patients, which provides the basis and idea for further exploring the pathogenesis of XLHED.

Ectodermal Dysplasia - An Overview and Update

Ectodermal dysplasias are a heterogeneous group of disorders that are characterized by abnormal development of ectodermal structures like hair, teeth, nails, and sweat glands. Alhough they were earlier classified according to the structures affected and hence the clinical manifestations, recent developments inch towards a genetic basis for classification. They are currently divided into four groups of disorders based on the pathway involved, which includes the ectodysplasin/nuclear factor-kappa B (NFKB) pathway, wingless-type MMTV integration site family, member 10 ([wingless related integration site] WNT10), tumor protein p63 (TP63), and the structural group. In spite of attempts at the segregation of the various disorders, there is a great degree of overlap in clinical features among the conditions, which makes a thorough history-taking and clinical examination important in helping us arrive at a diagnosis and judge the various systems involved. A multidisciplinary approach forms the crux of the management of patients with ectodermal dysplasias and their families, with a focus on education, counseling, prosthesis, and an overall rehabilitative outlook. Special attention must also be paid to screening family members for varying severities of the disorders, and an attempt must be made at a genetic diagnosis with genetic counseling.

Cutaneous, Cranial, and Skeletal Defects in Children and Adults with Focal Dermal Hypoplasia

BACKGROUND

The diagnostic process for children and adults manifesting a constellation of ectodermal abnormalities requires a conscientious and highly structured process.

MATERIAL AND METHODS

Six girls (aged 6-month-8 years) and two older girls (aged 13 and 16 years) were born with variable skin lesions of varying intensities associated with noticeable cranial and skeletal malformation complexes. Cleft palate, abnormal dentition, and multiple papillomas were evident around the mouth, mostly bilateral but asymmetrical in the upper and lower limbs. Exaggerated frontal bossing (macrocephaly) and in some patients' microcephaly with variable skeletal defects of the craniocervical junction and diverse forms of lower limb deformities of syndactyly, polydactyly, and split-hand/foot (ectrodactyly).

RESULTS

All patients manifested the constellation of abnormalities with variable intensities ranging between alopecia, papillomas, striated skin pigmentations split-hand/foot (ectrodactyly), and major bone defects. A 3D reconstruction CT scan was directed mainly to further scrutinize children with pseudo cleft lip, submucus cleft, and cleft palate. Interstingly, they manifested massive demineralization of the cranium associated with severely defective dentition. A spine 3D reconstruction CT scan in two girls showed marked cystic cavitation of the upper jaw associated with excessive cavitation of the mastoid, causing tremendous frailty of the mastoid bone. A 3D sagittal CT scan showed odontoid hypoplasia and C1-2 instability associated with the rudimentary atlas and the persistence of extensive synchondrosis of the cervico-thoracic spine. The overall clinical and radiological phenotypic characterizations were consistent with the diagnosis of focal dermal hypoplasia (Goltz syndrome). Two children manifested heterozygous mutations in the PORCN gene, chromosome Xp11.

CONCLUSIONS

In this study, we believe it's a good opportunity to share our novel scientific findings, which are intriguing and can be inspiring to readers, and to further aid the current scientific literature with exceptionally new unveiling results. This is the first comprehensive study of the cranio-skeletal malformation complex in children with GS.

Co-Occurrence of Hypohidrotic Ectodermal Dysplasia and Food Protein-Induced Enterocolitis Syndrome: A Report of a New Ectodysplasin A Variant

Introduction

Ectodermal dysplasias (EDs) are a large group of rare and complex genetic disorders, affecting the development of two or more ectodermal structures. Hypohidrotic ED (HED) is the most frequent ED's phenotype and is characterized by hypodontia, hypotrichosis, and hypo/anhidrosis, leading to heat intolerance and hyperthermia.

Case Presentation

We report a case of a 2-year-old girl with hair and teeth abnormalities associated with severe digestive symptoms responsible for failure to thrive. Genetic analysis by mass sequencing in parallel on a 4,867-gene panel was performed in duo (index case and her mother). The girl showed the presence of a new de novo c.100dupG variant in EDA responsible for HED associated with a diagnosis of food protein-induced enterocolitis syndrome (FPIES).

Conclusion

We describe a patient with HED and a new EDA variant associated with a diagnosis of FPIES, both implicating increased intestinal permeability. The inclusion of FPIES as a possible digestive symptom of HED can be suggested, although it may occur only in a context of atopy.

Clinical, trichoscopy, and light microscopic findings in hypohidrotic ectodermal dysplasia: Report of 21 patients and a review of the literature

INTRODUCTION

Hypohidrotic ectodermal dysplasia (HED) is a genetic condition typified by alterations in skin structures including sweat glands, hair, nails, and teeth. Hair findings in HED have been poorly characterized in larger series.

OBJECTIVE

To characterize scalp and hair findings of patients with HED clinically and with trichoscopy and light microscopy.

METHODS

A cross-sectional study in 21 pediatric HED patients was performed using available clinical and scalp dermatoscopic images, as well as pulled-hair samples for clinical evaluation, trichoscopic, and light microscopic analyses.

RESULTS

Seventeen out of 21 patients (81%) were men. Twenty patients had straight hair. Sixteen patients had decreased hair density, 6 of whom had hair loss mainly in the temporal and occipital regions. Fourteen patients had hair whorls. On trichoscopy, we observed: single-hair follicular units (n = 19, 90%), scalp hyperpigmentation (n = 13, 62%), variable diameter of the hair shafts (n = 12, 57%), perifollicular scales (n = 8, 38%), scalp erythema (n = 8, 38%), and short curly pigtail hairs (n = 6, 29%). On light microscopy, findings included: hair shafts with irregular diameter (n = 7, 33%), heterogeneous hair color (n = 6, 29%), trichoptilosis (n = 2, 10%), and pili torti (n = 1, 5%).

CONCLUSIONS

In this series, hair findings in HED were similar to those described in previous studies. However, we describe two new clinical and two trichoscopic findings: decreased hair density mainly in the temporal and occipital regions, oblique upwards occipital hair follicles orientation, angled hairs, and short curly pigtail hairs. These heterogeneous findings may reflect the multiple factors and signaling pathways that can be affected in these syndromes.

The characterization of hypodontia, hypohidrosis, and hypotrichosis associated with X-linked hypohidrotic ectodermal dysplasia: A systematic review

The objective of this study was to review the published literature on X-linked hypohidrotic ectodermal dysplasia (XLHED) for the prevalence and characteristics of three features of XLHED: hypodontia, hypohidrosis, and hypotrichosis. A systematic search of English-language articles was conducted in May 2019 to identify publications with information on any of the three features of XLHED. We excluded studies with five or fewer participants, that did not specify X-linked inheritance or an EDA mutation, and discussed only management of features. The weighted means for total missing teeth, location of missing teeth, prevalence of reduced and absent sweating ability, and sparse or absent hair were analyzed across all studies. Additional findings for hypodontia, hypohidrosis, and hypotrichosis were summarized qualitatively. Twenty publications (18 studies) were accepted. Reported findings for males tended to be more informative than for carrier females. The weighted mean for missing teeth for affected males was 22.4 (range: 10-28) and carrier females was 3.4 (range: 0-22). The most common conserved teeth for males were the canines. The most common missing teeth for females were the maxillary lateral incisors. The weighted mean prevalence of reduced or absent sweating ability was 95.7% for males and 71.6% for females. The weighted mean prevalence for hypotrichosis was 88.1% for males and 61.6% for females. This systematic review provides insight into the prevalence, characteristics, and variability of the three classic features of XLHED. These findings provide detailed natural history information for families with XLHED as well as key characteristics that can aid in diagnosis.

Genetic Hair Disorders: A Review

Hair loss in early childhood represents a broad differential diagnosis which can be a diagnostic and therapeutic challenge for a physician. It is important to consider the diagnosis of a genetic hair disorder. Genetic hair disorders are a large group of inherited disorders, many of which are rare. Genetic hair abnormalities in children can be an isolated phenomenon or part of genetic syndromes. Hair changes may be a significant finding or even the initial presentation of a syndrome giving a clue to the diagnosis, such as Netherton syndrome and trichothiodystrophy. Detailed history including family history and physical examination of hair and other ectodermal structures such as nails, sweat glands, and sebaceous glands with the use of dermoscopic devices and biopsy all provide important clues to establish the correct diagnosis. Understanding the pathophysiology of genetic hair defects will allow for better comprehension of their treatment and prognosis. For example, in patients with an isolated hair defect, the main problem is aesthetic. In contrast, when the hair defect is associated with a syndrome, the prognosis will depend mainly on the associated condition. Treatment of many genetic hair disorders is focused on treating the primary cause and minimizing trauma to the hair.

Novel and Private EDA Mutations and Clinical Phenotypes of Korean Patients with X-Linked Hypohidrotic Ectodermal Dysplasia

X-linked hypohidrotic ectodermal dysplasia (XLHED; OMIM 305100) is the most common form of ectodermal dysplasia, presenting with the triad of hypotrichosis, hypodontia, and hypohidrosis. This disorder is caused by mutations in EDA, which encodes ectodysplasin A, a member of the tumor necrosis factor superfamily. In this study, we describe clinical and genetic characteristics of 10 Korean XLHED patients (9 males, 1 female) from 9 families. Nine out of the 10 patients manifested the cardinal triad of symptoms. Six patients had a positive family history, while 2 patients were brothers. The most common initial presentation was hypotrichosis or hypodontia, while 1 patient presented with recurrent high fever in early infancy. Sanger sequencing of the EDA gene was performed and revealed 9 different mutations. Three had been reported previously, and 6 were novel mutations. One female patient, carrying a previously reported missense mutation, might be affected by skewed X-inactivation. This is the first observational study investigating genetically confirmed XLHED patients in Korea. To provide appropriate supportive care and genetic counseling, clinicians should consider the possibility of XLHED in the differential diagnosis of recurrent fever in infants, as well as recognize the typical triad of symptoms.

Hair shaft structures in EDAR induced ectodermal dysplasia

Background

Mutations in the EDAR-gene cause hypohidrotic ectodermal dysplasia with defects in ectodermal appendage development including teeth, skin, exocrine glands and hair. Hair defects are sparsely described in genetically defined samples. The aim of this study was to investigate hair structures in three families with a heterozygous c.1072C > T mutation in the EDAR gene using scanning electron microscopy.

Methods

Three Swedish families, where some members had a known c.1072C > T mutation in the EDAR gene with an autosomal dominant inheritance (AD) were included (n = 37) of which 17 carried the mutation and 20 did not. Thirty-two age and gender matched not related individuals served as a reference group. Confirmation of the c.1072C > T mutation in the EDAR gene was performed by genomic sequencing. Hairs were subjected to blinded scanning electron microscopy examination and hair defects were categorized and scored.

Results

The minimum and maximum diameters of hairs were lower in the mutation group compared to the reference group. Subjects in the mutation group had to greater extent deep deformations in hair shafts compared to the non-mutation group and the reference group (p < 0.001).

Conclusions

Individuals with a c.1072C > T mutation in the EDAR-gene displayed more hair shaft deformations confirming the role of EDAR for human hair follicle development and postnatal hair follicle cycling.

The Gene Network Underlying Hypodontia

Mammalian tooth development is a precise and complicated procedure. Several signaling pathways, such as nuclear factor (NF)-κB and WNT, are key regulators of tooth development. Any disturbance of these signaling pathways can potentially affect or block normal tooth development, and presently, there are more than 150 syndromes and 80 genes known to be related to tooth agenesis. Clarifying the interaction and crosstalk among these genes will provide important information regarding the mechanisms underlying missing teeth. In the current review, we summarize recently published findings on genes related to isolated and syndromic tooth agenesis; most of these genes function as positive regulators of cell proliferation or negative regulators of cell differentiation and apoptosis. Furthermore, we explore the corresponding networks involving these genes in addition to their implications for the clinical management of tooth agenesis. We conclude that this requires further study to improve patients' quality of life in the future.

Genotype-phenotype correlation in boys with X-linked hypohidrotic ectodermal dysplasia

X-linked hypohidrotic ectodermal dysplasia (XLHED), the most frequent form of ectodermal dysplasia, is a genetic disorder of ectoderm development characterized by malformation of multiple ectodermal structures such as skin, hair, sweat and sebaceous glands, and teeth. The disease is caused by a broad spectrum of mutations in the gene EDA. Although XLHED symptoms show inter-familial and intra-familial variability, genotype-phenotype correlation has been demonstrated with respect to sweat gland function. In this study, we investigated to which extent the EDA genotype correlates with the severity of XLHED-related skin and hair signs. Nineteen male children with XLHED (age range 3-14 years) and seven controls (aged 6-14 years) were examined by confocal microscopy of the skin, quantification of pilocarpine-induced sweating, semi-quantitative evaluation of full facial photographs with respect to XLHED-related skin issues, and phototrichogram analysis. All eight boys with known hypomorphic EDA mutations were able to produce at least some sweat and showed less severe cutaneous signs of XLHED than the anhidrotic XLHED patients (e.g., perioral and periorbital eczema or hyperpigmentation, regional hyperkeratosis, characteristic wrinkles under the eyes). As expected, individuals with XLHED had significantly less and thinner hair than healthy controls. However, there were also significant differences in hair number, diameter, and other hair characteristics between the group with hypomorphic EDA mutations and the anhidrotic patients. In summary, this study indicated a remarkable genotype-phenotype correlation of skin and hair findings in prepubescent males with XLHED.