Hypohidrotic Ectodermal Dysplasia Research Articles

EDA Missense Variant in a Cat with X-Linked Hypohidrotic Ectodermal Dysplasia

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.

Novel homozygous frameshift insertion variant in the last exon of the EDARADD causing hypohidrotic ectodermal dysplasia in two siblings: case report and review of the literature

BackgroundHypohidrotic ectodermal dysplasia (HED) is a genetic disorder that results in the abnormal development of structures derived from ectodermal tissue. This rare condition predominantly affects the hair, nails, eccrine glands, and teeth. While HED can be caused by various genes, the EDA, EDAR, EDARADD, and WNT10A genes account for approximately 90% of cases. Notably, HED forms associated with variants in the EDA, EDAR, or EDARADD genes may exhibit similar phenotypes due to defects in a common signaling pathway. Proper interaction among the products of these genes is crucial for the activation of the nuclear factor (NF-κB) signaling pathway, which subsequently regulates the transcription of targeted genes. The EDARADD gene, in particular, harbors one of the rarest reported variants associated with HED.Case presentationFive-and two-years-old brothers born into consanguineous parents were examined at our outpatient medical genetics clinic at Sanliurfa Training and Research Hospital, Turkey. Both displayed the same classical phenotypic features of HED. The elder had a very sparse dark and brittle hair, sparse eyebrows and eyelashes, conical upper and lower premolar teeth with hypodontia, widely spaced teeth, very dry skin, mildly prominent forehead, and periorbital wrinkles. The younger one showed the same, but less severe, clinical features. After thorough examination and patient history evaluation, targeted next-generation sequencing analysis yielded the novel homozygous insertion variant c.322_323insCGGGC p.(Arg108ProfsTer7) in EDARADD. The mutation has not been reported to date in the literature.ConclusionsIn this report, we present two siblings exhibiting classical HED symptoms and a novel insertion variant of the EDARADD gene, which leads to a frameshift introducing a stop codon. Both brothers inherited such mutation from their parents, who were heterozygous carriers of the same variant. The present study may shed light about the pathogenic mechanisms underlying HED, and expand the spectrum of EDARADD gene variants associated with this condition.

A Case of Hypohidrotic Ectodermal Dysplasia in a 1-Year Old Filipino Male

Introduction: Hypohidrotic Ectodermal Dysplasia (HED) is the most common Ectodermal Dysplasia, a group of rare, inherited multisystemic disorders exhibiting developmental aberrations in ectodermal structures including the hair, teeth, nails, and sebaceous and sweat glands. HED is commonly X-linked, presenting with abnormalities of the hair and teeth accompanied by inability to sweat. This case report aims to present a case of X-linked HED in a 1-yearold Filipino male. Case Report: A 1-year-old Filipino male presented with reduced sweating since birth and heat intolerance. He had scalp and facial papules, slowly growing, sparse eyebrow and scalp hair, periorbital wrinkling with hyperpigmentation, everted lips, frontal bossing, absent tooth, and negative palmoplantar starchiodine test. Maternal male relatives had similar symptoms while females had little to no symptoms. He was diagnosed with HED. Skin punch biopsy with immunohistochemistry showed absence of eccrine glands on the plantar skin, which strengthened the diagnosis. Management of symptoms was mainly supportive and involved multidisciplinary collaboration with Pediatrics, Otorhinolaryngology, Dentistry, and Nutrition and Dietetics. Conclusion: This report underscores the critical role of Dermatologists in identifying key clinical signs of HED, which primarily relies on clinical assessment. A high level of suspicion is warranted when abnormalities in hair, teeth, and sweating are evident. It is crucial to consider other potential features in patients with symptoms of hypotrichosis, hypodontia and hypohidrosis, due to the varied manifestations of the disease. Early detection, comprehensive supportive treatment, and patient education are vital for improving the quality of life for those affected by HED.

Customized Prosthetic Oral Rehabilitation of a Child with Hypohidrotic Ectodermal Dysplasia: A Case Report

Customized Prosthetic Oral Rehabilitation of a Child with Hypohidrotic Ectodermal Dysplasia: A Case Report

Detection of an EDA mutation causing hypohidrotic ectodermal dysplasia in a Vietnamese patient

Hypohidrotic ectodermal dysplasia (HED) is a rare disease characterized by abnormal development of the structures derived from the ectoderm layer, including hair, teeth, nails, and sweat glands. The most observed form of HED, which is known as X-linked hypohidrotic ectodermal dysplasia (XLHED), is commonly attributed to genetic abnormalities in the ectodysplasin A (EDA) gene. We have successfully discovered a known mutation c.1045G>A (p.A349T) in a Vietnamese proband who displayed the main symptoms of XLHED using PCR and Sanger sequencing. Furthermore, the segregation of the mutation showed that the mother, who exhibited a normal phenotype, was a carrier of the mutation, while the father was hemizygous for the wild-type allele. The identification of the mutation c.1045G>A (p.A349T) contributes to HED research worldwide and can be used for genetic counseling in Vietnam.

Prenatal sonographic evidence of hypohidrotic ectodermal dysplasia and postnatal genetic testing of a family line of child.

Prenatal sonographic evidence of hypohidrotic ectodermal dysplasia and postnatal genetic testing of a family line of child.

Prevalence and Patient Characteristics of Ectodermal Dysplasias in Denmark

Ectodermal dysplasias constitute a group of rare genetic disorders of the skin and skin appendages with hypodontia, hypotrichosis, and hypohidrosis as cardinal features. There is a lack of population-based research into the epidemiology of ectodermal dysplasias. To establish a validated population-based cohort of patients with ectodermal dysplasia in Denmark and to assess the disease prevalence and patient characteristics. This nationwide cohort study used individual-level registry data recorded across the Danish universal health care system to identify patients with ectodermal dysplasias from January 1, 1995, to August 25, 2021. A 3-level search of the Danish National Patient Registry and the Danish National Child Odontology Registry was conducted to identify patients with diagnosis codes indicative of ectodermal dysplasias; patients registered in the Danish RAREDIS Database, the Danish Database of Genodermatoses, and local databases were also added. The search results underwent diagnosis validation and review of clinical data using medical records. Of 844 patient records suggestive of ectodermal dysplasias, 791 patients (93.7%) had medical records available for review. Positive predictive values of the diagnosis coding were computed, birth prevalence was estimated, and patient characteristics were identified. Data analysis was performed from May 4 to December 22, 2023. The identified and validated study cohort included 396 patients (median [IQR] age at diagnosis, 13 [4-30] years, 246 females [62.1%]), of whom 319 had confirmed ectodermal dysplasias and 77 were likely cases. The combined positive predictive value (PPV) for ectodermal dysplasia-specific diagnosis codes was 67.0% (95% CI, 62.7%-71.0%). From 1995 to 2011, the estimated minimum birth prevalence per 100 000 live births was 14.5 (95% CI, 12.2-16.7) for all ectodermal dysplasias and 2.8 (95% CI, 1.8-3.8) for X-linked hypohidrotic ectodermal dysplasias. A molecular genetic diagnosis was available for 241 patients (61%), including EDA (n = 100), IKBKG (n = 55), WNT10A (n = 21), TRPS1 (n = 18), EDAR (n = 10), P63 (n = 9), GJB6 (n = 9), PORCN (n = 7), and other rare genetic variants. The findings of this nationwide cohort study indicate that the prevalence of ectodermal dysplasias was lower than previously reported. Furthermore, PPVs of the search algorithms emphasized the importance of diagnosis validation. The establishment of a large nationwide cohort of patients with ectodermal dysplasias, including detailed clinical and molecular data, is a unique resource for future research in ectodermal dysplasias.

Compound heterozygous WNT10A missense variations exacerbated the tooth agenesis caused by hypohidrotic ectodermal dysplasia

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

Transcription factor FoxO1 regulates myoepithelial cell diversity and growth

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.

Understanding the effects of per- and polyfluoroalkyl substances on early skin development: Role of ciliogenesis inhibition and altered microtubule dynamics

Per- and polyfluoroalkyl substances (PFAS) are a class of highly stable chemicals, widely used in everyday products, and widespread in the environment, even in pregnant women. While epidemiological studies have linked prenatal exposure to PFAS with atopic dermatitis in children, little is known about their toxic effects on skin development, especially during the embryonic stage. In this study, we utilized human embryonic stem cells to generate non-neural ectoderm (NNE) cells and exposed them to six PFAS (perfluorooctanoic acid (PFOA), undecafluorohexanoic acid (PFHxA), heptafluorobutyric acid (PFBA), perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS) and perfluorobutyric acid (PFBS)) during the differentiation process to assess their toxicity to early skin development. Our results showed that PFOS altered the spindle-like morphology of NNE cells to a pebble-like morphology, and disrupted several NNE markers, including KRT16, SMYD1, and WISP1. The six PFAS had a high potential to cause hypohidrotic ectodermal dysplasia (HED) by disrupting the expression levels of HED-relevant genes. Transcriptomic analysis revealed that PFOS treatment produced the highest number (1156) of differentially expressed genes (DEGs) among the six PFAS, including the keratinocyte-related genes KRT6A, KRT17, KRT18, KRT24, KRT40, and KRT81. Additionally, we found that PFOS treatment disturbed several signaling pathways that are involved in regulating skin cell fate decisions and differentiation, including TGF-β, NOTCH, Hedgehog, and Hippo signaling pathways. Interestingly, we discovered that PFOS inhibited, by partially interfering with the expression of cytoskeleton-related genes, the ciliogenesis of NNE cells, which is crucial for the intercellular transduction of the above-mentioned signaling pathways. Overall, our study suggests that PFAS can inhibit ciliogenesis and hamper the transduction of important signaling pathways, leading potential congenital skin diseases. It sheds light on the underlying mechanisms of early embryonic skin developmental toxicity and provides an explanation for the epidemiological data on PFAS. Environmental implicationWe employed a model based on human embryonic stem cells to demonstrate that PFOS has the potential to elevate the risk of hypohidrotic ectodermal dysplasia. This is achieved by targeting cilia, inhibiting ciliogenesis, and subsequently disrupting crucial signaling pathways like TGF-β, NOTCH, Hedgehog, and Hippo, during the early phases of embryonic skin development. Our study highlights the dangers and potential impacts of six PFAS pollutants on human skin development. Additionally, we emphasize the importance of closely considering PFHxA, PFBA, PFHxS, and PFBS, as they have shown the capacity to modify gene expression levels, albeit to a lesser degree.

Identification of six novel mutations in EDA from 20 hypohidrotic ectodermal dysplasia families.

To investigate the genetic causes of 22 patients with clinically high suspicion of X-linked hypohidrotic ectodermal dysplasia from 20 unrelated Chinese families, expand the spectrum of ectodysplasin-A mutations, and provide more evidence for variants of uncertain significance. Whole-exome sequencing was performed and potentially pathogenic variants were verified by Sanger sequencing. Western blotting, real-time PCR and immunofluorescence analyses were performed to investigate the preliminary functions of the candidate variants. Nineteen ectodysplasin-A variants were identified, six of which were not previously reported. Among these variants, we identified a patient who carried two mutations in ectodysplasin-A and exhibited more severe phenotypes. Additionally, mutant protein expression levels decreased, whereas mRNA transcription levels increased. Cellular sublocalisation of the variants located in the tumour necrosis factor homologous domain showed that the proteins accumulated in the nucleus, whereas wild-type proteins remained in the cell membrane. A rare indel variant and two classical splicing variants that lead to exon 7 skipping were detected. This study provides definitive diagnoses for 20 families with suspected X-linked hypohidrotic ectodermal dysplasia and additional information on clinical heterogeneity and genotype-phenotype relationships.

A Missense Mutation in the Collagen Triple Helix of EDA Is Associated with X-Linked Recessive Hypohidrotic Ectodermal Dysplasia in Fleckvieh Cattle.

Mutations within the ectodysplasin A (EDA) gene have been associated with congenital hypotrichosis and anodontia (HAD/XHED) in humans, mice, dogs and cattle. We identified a three-generation family of Fleckvieh cattle with male calves exhibiting clinical and histopathological signs consistent with an X-linked recessive HAD (XHED). Whole genome and Sanger sequencing of cDNA showed a perfect association of the missense mutation g.85716041G>A (ss2019497443, rs1114816375) within the EDA gene with all three cases following an X-linked recessive inheritance, but normal EDAR and EDARADD. This mutation causes an exchange of glycine (G) with arginine (R) at amino acid position 227 (p.227G>R) in the second collagen triple helix repeat domain of EDA. The EDA variant was associated with a significant reduction and underdevelopment of hair follicles along with a reduced outgrowth of hairs, a complete loss of seromucous nasolabial and mucous tracheal and bronchial glands and a malformation of and reduction in number of teeth. Thermostability of EDA G227R was reduced, consistent with a relatively mild hair and tooth phenotype. However, incisors and canines were more severely affected in one of the calves, which correlated with the presence of a homozygous missense mutation of RNF111 (g.51306765T>G), a putative candidate gene possibly associated with tooth number in EDA-deficient Fleckvieh calves.

Smiles reimagined: The transformative power of overlay complete dentures in prosthodontic rehabilitation of ectodermal dysplasia patient

Ectodermal dysplasias (EDs) encompass a diverse set of conditions characterized by developmental abnormalities affecting ectodermal tissues. Hypohidrotic ectodermal dysplasia is a congenital syndrome marked by features such as sparse, delicate hair, skin and nail anomalies, reduced sweating capacity (attributed to a deficiency in sweat glands, resulting in sweat-related issues), and underdeveloped or missing teeth (partial or complete absence of primary and/or permanent dentition). In most instances, individuals with EDA can expect a typical lifespan and exhibit normal cognitive abilities. Nonetheless, the absence of sweat glands poses a risk of overheating, potentially leading to brain damage or even fatality in infancy if not promptly recognized. Therefore, early diagnosis holds significant importance. This case report presents a documented instance of ectodermal dysplasia, complemented by a comprehensive literature review.

Activation of wnt/β-catenin signaling pathway down regulated osteogenic differentiation of bone marrow-derived stem cells in an anhidrotic ectodermal dysplasia patient with EDA/EDAR/EDARADD mutation

ObjectiveTo explore the mechanism by which the Wnt/β-catenin pathway induces osteogenic differentiation of bone marrow-derived stem cells (BMSCs) in anhidrotic ectodermal dysplasia (AED) with an Ectodysplasin A (EDA)/EDA receptor (EDAR)/EDARADD mutation. MethodsAn AED patient served as the AED group, whereas the other patients without AED were included in the normal group. Peripheral venous blood collected from the AED patient was subjected to whole-genome resequencing. BMSCs from the mandible of patients with AED and normal individuals were isolated and cultured in vitro. Cell proliferation assay was performed to compare the growth speed of BMSCs between the AED and normal groups. CHIR-99021, an activator of the Wnt/β-catenin pathway and XAV-939, an inhibitor, was used to manage BMSCs in an osteogenic environment in both groups. The expression of β-catenin was detected by quantitative polymerase chain reaction, while that of RUNX2 was detected by western blotting. Alizarin red was used for staining. ResultsA novel mutation (c.152T > A in EDA) and two known mutations (c.1109T > C in EDAR and c.27G > A in EDARADD) were identified. The growth rate in the normal group was higher than that in the AED group. In the normal group, the number and size of calcified nodes and the expression of RUNX-2 increased with CHIR-99021 treatment, which could be inhibited by XAV-939. In contrast, CHIR-99021 inhibited osteogenesis in the AED group and this effect was promoted by XAV-939. ConclusionActivation of the Wnt/β-catenin pathway downregulates osteogenesis of BMSCs in AED patients with EDA/EDAR/EDARADD gene mutations. Further investigation in more AED patients is required, given the wide range of mutations involved in AED.

The oligodontia phenotype in a X-linked hypohidrotic ectodermal dysplasia patient with a novel EVC2 variant

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

Oligodontia in the Clinical Spectrum of Syndromes: A Systematic Review.

The aim of this systematic review was to describe the clinical and genetic features of syndromes showing oligodontia as a sign. The review was performed according to the PRISMA 2020 checklist guidelines, and the search was conducted using PubMed, Scopus, Lilacs, Web of science, Livivo, and EMBASE and supplemented by a gray literature search on Google Scholar and ProQuest, applying key terms relevant to the research questions. The systematic review identified 47 types of syndromes in 83 studies, and the most common was hypohidrotic ectodermal dysplasia, which was reported in 24 patients in 22 studies. Other common syndromes that reported oligodontia included Axenfeld-Rieger syndrome, Witkop's syndrome, Ellis-van Creveld syndrome, blepharocheilodontic syndrome, and oculofaciocardiodental syndrome. The X-linked mode of inheritance was the most reported (n = 13 studies), followed by the autosomal dominant (n = 13 studies). The review describes the main syndromes that may have oligodontia as a clinical sign and reinforces the need for orodental-facial examining for adequate diagnosis and treatment of the affected patients. Molecular analysis in order to better understand the occurrence of oligodontia is imperative.

Prosthetic Treatment Strategies for Improving Denture Retention in Pediatric Patients with Hypohidrotic Ectodermal Dysplasia: a Report of Two Cases

This report presents two cases concerning strategies for improving denture retention in pediatric patients with oligodontia caused by hypohidrotic ectodermal dysplasia (HED). Both patients presented with multiple missing teeth, conical canines, alveolar bone atrophy, and a skeletal Class III tendency. In the first case, a modified form of conical-crown-retained denture was used to cover the canines. This approach was carried out without tooth extraction or coping. In the second case of severe alveolar bone resorption and a distally tilted lower left canine, the tooth was restored with a hybrid ceramic crown. It was subsequently converted into a clasp-retained removable partial denture, utilizing a suction mechanism. Both patients are currently receiving regular check-ups for the maintenance of their prosthetic appliances and the evaluation of their growth patterns. This study presents innovative prosthetic treatment methods for pediatric patients with HED who have inadequate denture retention.

Psychosocial and behavioural impact of three clinical presentations of oligodontia in a tertiary hospital.

To investigate the psychosocial and behavioural impact of oligodontia across three presentation types and determine if presentation type can infer impact. Thirty patients, diagnosed and treated for oligodontia between 2006 and 2021, identified from hospital records. Patients received two questionnaires; the first was a modified version of a condition-specific questionnaire, the Cleft Research Questionnaire (CRQ),used to investigate demographic, life and treatment details and impacts, and the second, the Oral Health Impact Profile (OHIP-14) used to investigate the oral health related quality of life. Patients were assigned to three presentations (Types 1 to 3) of oligodontia identified according to the edentulous space present and complexity of prosthodontic treatment required. Hypothesis test to determine if there is a relationship between oligodontia type and study variables. Twenty-two questionnaires were completed and returned. There were 9 females. The age range was from 16 to 32 years. Eighteen patients had nonsyndromic and 4 oligodontia associated with anhidrotic ectodermal dysplasia. The main areas of impact were patient reported life less satisfying (64.5%, n=14)(pre-treatment), making friends (45%, N=10), school participation (45%, n=10), and public speaking (45%, n=10). No relationship was discovered between the degree of physical effect of the presentation type and study variables including the degree of psychosocial impact or life satisfaction. Oligodontia can have a negative functional and social impact on a patient prior to prosthodontic treatment. Prosthodontic treatment improved the life satisfaction for most patients. Psychosocial outcomes could not be inferred by the presentation type of oligodontia.

O02 A case for diagnosis: ectodermal dysplasia and severe myelodysplasia

Abstract A 13-year-old girl was referred to us by our paediatric colleagues due to vulval dermatitis. She had a history of congenital hypotrichosis, microcephaly, abnormal dentition, dyshidrosis manifest as recurrent febrile seizures in infancy, recurrent infections, neutropaenia and macrocytosis. Her father and younger brother have a similarly striking phenotype, with complete absence of scalp and body hair, abnormal teeth, abnormal sweating, but normal nails. In addition, the father has required a stem cell transplant for myelodysplastic syndrome. None of the family have keratoderma, cleft palate, ectrodactyly or cardiomyopathy. DNA from our index patient was sent to Cardiff for the ectodermal dysplasia (ED) plus 70 gene panel for next-generation sequencing, but no mutation was found. Our paediatric haematology colleagues sequentially arranged dyskeratosis congenita panel, myeloid panel, and whole-exome sequencing for the younger brother, which did not identify a causative mutation. Unusually, all three were found to have mosaic trisomy 18. The transmission of trisomy 18 from parent to child as a mosaic trait in both generations is extremely unusual, and mosaic trisomy 18 has not been previously reported to cause ED. We would appreciate any input on a genetic diagnosis for this family with a distinctive phenotype consistent with hypohidrotic ED associated with myelodysplasia, with extensive genetic testing revealing a potentially spurious or coincidental mosaic trisomy 18 in all three affected family members.

Rehabilitation with implant-supported overdentures in preteens patients with ectodermal dysplasia: A cohort study.

Hypohidrotic ectodermal dysplasia (HED) patients suffering of oligo-anodontia require early dental treatment to improve oral functions and reduce social impairment. The aim of this study was to evaluate the skeletal growth, implant and prosthetic survival rate, success, and complications after the rehabilitation with a maxillary denture and an implant-supported overdenture provided by a sliding bar in case of severe hypodontia/anodontia related to HED. This retrospective cohort study began in 2009. Nine patients over 7 years old with HED and associated oligo-anodontia who presented at the University of Bologna for dental treatment were included in the study. They were first treated with conventional dentures and then with a maxillary denture and an implant-supported overdenture with a sliding bar connected to two implants placed in the anterior mandible. The subjects treated were followed for 3-12 years. In each case, orthopanoramic and lateral cephalometric radiographic exam were taken before implant placement and annually after prosthetic load. Vertical and transverse dimensions of the mandible in the symphysis area at implant sites were taken on the lateral cephalometric radiography at the time of implant placement and after 5 years from the prosthetic loading to assess the presence or absence of an anterior mandibular growth. Biologic and mechanical complications were also recorded at every visit. A mandibular vertical growth under the implant apex, at the implant neck, and a sagittal growth of the symphysis after 5 years from the prosthetic loading were observed and measured. Implant and prosthetic success and survival rates were 100% after 8.1 years (mean) follow-up period. No complications were reported except in one patient, where the repositioning of a retentive cap on the counter bar in the superstructure was necessary after 3 years from the prosthetic loading. The present study suggests that the growth of the mandible near implant sites continues even after their positioning. Implants can be successfully placed and provide support for prosthetic rehabilitation in preteens patients with HED.