Ectodermal dysplasias: a clinical and molecular review

Ectodermal dysplasia and cholesteatoma: A cross-sectional analysis of otologic issues

OBJECTIVES

Previous studies have also associated cleft palate with increased cholesteatoma risk. Despite this close relation, the incidence of cholesteatoma and associated otologic issues in patients with ectodermal dysplasia types highly associated with cleft palate (EDT-ACPs) has not been formally analyzed. This study provides insight to guide clinicians caring for patients with ED types associated with cleft palate.

METHODS

Individuals with TP63 disorders and Goltz syndrome/Focal Dermal Hypoplasia in the National Foundation for Ectodermal Dysplasia database were contacted for participation in an online REDCap survey from Sept-Dec '22. Descriptive statistics were generated using SAS JMP Pro 17 statistical software.

RESULTS

65 individuals participated in the survey (response rate approx. 18 %). The median [IQR] age was 22 [14, 43], 41 (63 %) were female, and Ectrodactyly-Ectodermal Dysplasia-Cleft Lip/Palate Syndrome (EEC) was most common (n = 26, 40 %). We found that, among our respondents with a history of cleft palate, the incidence of cholesteatoma was 39 %. Among respondents without a history of cleft palate, the incidence of cholesteatoma was 13 % CONCLUSIONS: Otologic issues, such as cholesteatoma, can have permanent implications including hearing loss that can be minimized by early identification and treatment. The estimated incidence of cholesteatoma among our participants is far above the estimated incidence of cholesteatoma in the general population with and without a history of cleft palate, suggesting an independent contribution of EDT-ACPs to the risk of cholesteatoma.

A Novel De Novo NFKBIA Missense Mutation Associated to Ectodermal Dysplasia with Dysgammaglobulinemia

Background: Inborn errors of immunity (IEIs) are comprised of heterogeneous groups of genetic disorders affecting immune function. In this report, a 17-month-old Malay patient suspected of having Hyper IgM syndrome, a type of IEIs, was described. However, the diagnosis of Hyper IgM syndrome was excluded by the normal functional studies and the mild features of ectodermal dysplasia observed from a further clinical phenotype inspection. Methods: Whole-exome sequencing (WES) was performed to unravel the causative mutation in this patient. Results: The variant analysis demonstrated a novel missense mutation in NFKBIA (NM_020529:c.94A > T,NP_065390:p.Ser32Cys) and was predicted as damaging by in silico prediction tools. The NFKBIA gene encodes for IκBα, a member of nuclear factor kappa B (NF-κB) inhibitors, playing an important role in regulating NF-κB activity. The mutation occurred at the six degrons (Asp31-Ser36) in IκBα which were evolutionarily conserved across several species. Prediction analysis suggested that the substitution of Ser32Cys may cause a loss of the phosphorylation site at residue 32 and a gain of the sumoylation site at residue 38, resulting in the alteration of post-translational modifications of IκBα required for NF-κB activation. Conclusion: Our analysis hints that the post-translational modification in the NFKBIA Ser32Cys mutant would alter the signaling pathway of NF-κB. Our findings support the usefulness of WES in diagnosing IEIs and suggest the role of post-translational modification of IκBα.

Novel LRP6 Mutations Causing Non-Syndromic Oligodontia

The process of tooth formation is a series of reciprocal interactions between the ectoderm and mesoderm, and it is believed that many genetic factors are involved in this complex process. More than a dozen genes have been identified in non-syndromic tooth agenesis; however, the genetic etiology underlying tooth agenesis is not fully understood yet. In this study, we identified two novel LRP6 mutations in two non-syndromic oligodontia families. Both probands had 16 and 17 missing teeth in their permanent dentition. Mutational analysis identified a de novo frameshift mutation by a 1-bp insertion in exon 9 (NM_002336.2: c.1870dupA, p.(Met624Asnfs*29)) and a splicing donor site mutation in intron 8 (c.1762+2T>C). An in vitro splicing assay confirmed the deletion of exon 8, and the deletion would result in a frameshift. Due to the premature termination codons introduced by the frameshift, both mutant transcripts would be degraded by nonsense-mediated mRNA decay, resulting in haploinsufficiency.

Structural and functional foot disorders in patients with genodermatoses: a single-centre, retrospective chart review

Background

Skin lesions on the feet and foot deformities impair daily activities and decrease quality of life. Although substantial foot deformities occur in many genodermatoses, few reports have been published on this topic. Therefore, we performed a retrospective chart review to identify patients with genodermatoses and foot disorders. We included 16 patients, who were investigated clinically and with molecular biology.

Results

The following genodermatoses with foot deformities were detected: autosomal recessive congenital ichthyosis (ARCI, n = 7); palmoplantar keratodermas (PPKs, n = 6); ichthyosis follicularis, atrichia, and photophobia (IFAP, n = 1); ectrodactyly-ectodermal dysplasia-clefting (EEC, n = 1); and ichthyosis with confetti (IWC, n = 1). Foot problems not only varied in severity depending on the disease but also showed phenotypic heterogeneity among patients with the same condition. Foot deformities were most pronounced in patients with EEC (split foot) or IWC (contractures) and less severe in those with ARCI (clawed toes), IFAP (hollow feet), or PPK (no bone abnormalities in the feet).

Conclusion

Because a range of distinct genodermatoses involve foot abnormalities, early rehabilitation and other corrective measures should be provided to patients with foot involvement to improve gait and prevent/delay irreversible complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02207-x.

Report of a Novel ALOX12B Mutation in Self-Improving Collodion Ichthyosis with an Overview of the Genetic Background of the Collodion Baby Phenotype

Collodion baby is a congenital, transient phenotype encountered in approximately 70–90% of autosomal recessive congenital ichthyosis and is an important entity of neonatal erythroderma. The clinical outcome after this severe condition is variable. Genetic mutations of components of the epidermal lipoxygenase pathway have been implicated in the majority of self-improving collodion ichthyosis (SICI). In SICI, the shedding of the collodion membrane reveals clear skin or only mild residual manifestation of ichthyosis. Here we report the case of a girl born with a severe form of collodion baby phenotype, whose skin almost completely cleared within the first month of life. At the age of 3 years, only mild symptoms of a keratinization disorder remained. However, the severity of erythema and scaling showed mild fluctuations over time. To objectively evaluate the skin changes of the patient, we assessed the ichthyosis severity index. Upon sequencing of the ALOX12B gene, we identified a previously unreported heterozygous nonsense mutation, c.1607G>A (p.Trp536Ter) with the recurrent, heterozygous mutation c.1562A>G (p.Tyr521Cys). Thereby, our findings expand the genotypic spectrum of SICI. In addition, we summarize the spectrum of further genetic diseases that can present at birth as collodion baby, in particular the SICI.

LEF1 haploinsufficiency causes ectodermal dysplasia

Ectodermal dysplasias are a family of genodermatoses commonly associated with variants in the ectodysplasin/NF-κB or the Wnt/β-catenin pathways. Both pathways are involved in signal transduction from ectoderm to mesenchyme during the development of ectoderm-derived structures. Wnt/β-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.

Morphology of the Meibomian gland evaluated using meibography in patients with hypohidrotic ectodermal dysplasia

INTRODUCTION

Hypohidrotic ectodermal dysplasia (HED) is a rare disease that results from the abnormal development of the ectodermal germ layer in early embryogenesis. In these patients, hypoplasia of Meibomian glands is one of the most frequent ophthalmological manifestations. The main aim of this study is to evaluate the usefulness of meibography for the morphology of Meibomian glands in a group of patients with HED, and to compare it with a control group.

METHODS

A total of 14 eyes of 7 patients diagnosed with HED were included, and 32 eyes of 16 patients were included as a control group. The meibographic study was carried out using CA-800 Corneal Analyser (Topcon®). Grading of images was assessed by a meibomian gland atrophy score: grade 0, no alterations; grade 1, ≤25% gland atrophy; grade 2, 25% to 50% gland atrophy; grade 3, 51% to 75% gland atrophy; and grade 4 >75% gland atrophy. Both groups were compared using the Mann-Whitney U non-parametric test.

RESULTS

All patients with HED showed some degree of gland atrophy, with 57% showing severe atrophy (>75% of gland atrophy), 35.8% with a grade 3, and 7.2% grade 2. The mean grade of glandular atrophy in HED was 3 (1-4). In the control group, 62.5% had no involvement (grade 0), with 28.1% showing grade 1 and 9.4% grade 2 gland atrophy. The mean glandular atrophy grade within the control group was 0 (0-2). There were statistically significant differences between both groups.

CONCLUSIONS

Meibography is a simple diagnostic tool that allows to differentiate between patients without disease and those with HED.

Anatomical analysis of zygomatic bone in ectodermal dysplasia patients with oligodontia

Background

Abnormalities of some facial bones derived from the ectomesenchyme have been found in ectodermal dysplasia (ED) patients, but the characteristics of the zygoma are unknown.

Purpose

Comparison between ED patients and normal individuals to understand the anatomical features of the zygoma in ED patients.

Materials and Methods

Thirty patients diagnosed with ED based on clinical features and/or gene sequence tests and 80 normal individuals were recruited from 2016 to 2018. The thickness of the zygomatic body at 12 points on the superior, middle, and inferior areas and the length of four lines were measured on a three‐dimensional cone beam computed tomography image. Differences between ED patients and normal individuals were then compared.

Results

The zygomatic thicknesses and lengths were smaller in ED patients than in normal individuals. For ED patients, the largest thicknesses on the superior, middle, and inferior areas of the zygoma were 8.47 ± 1.49, 7.03 ± 1.56, and 5.99 ± 1.22 mm.

Conclusion

The development of zygomatic thickness on the inferior area and the zygomatic length were insufficient in ED patients with oligodontia. Consequently, zygomatic hypoplasia presented difficulties for the “quad approach” to zygomatic implants in this group of patients.

Oral Care Program for Successful Long-Term Full Mouth Habilitation of Patients with Hypohidrotic Ectodermal Dysplasia

Hypohidrotic ectodermal dysplasia (HED) is a rare congenital disorder that associates with dental manifestations of anodontia, hypodontia, and atrophic alveolar ridges. Although the disorder does not affect the life expectancy of the patient, it poses tremendous challenges on the patient's physical and psychosocial development. Early and multidisciplinary dental care can benefit HED children's development and improve their quality of life. This study presents two cases addressing the dental management continuously for 10 to 13 years in the dental school clinics. The keys to long-term success of the oral care program for HED patients at different age phases are reviewed and discussed, which can be summarized as early intervention, multidisciplinary collaborative care, and continuous recall.

Phenotypic Features and Salivary Parameters in Patients with Ectodermal Dysplasia: Report of Three Cases

Ectodermal dysplasia (ED) is a rare hereditary disorder affecting the development of ectoderm-derived organs and tissues. The aim of this study was to describe phenotypic features and the therapeutic approach in dentistry among three patients with ED, correlating their data with the literature. Additionally, to investigate the salivary gland disorders and their impacts on oral microbiota, we performed salivary tests, including salivary flow rate, salivary buffering capacity, and concentration levels of mutans streptococci, lactobacilli, and yeasts. All patients presented oligodontia, resulting in a significant masticatory dysfunction and aesthetic impairment. The counts of mutans streptococci (n=3) and yeasts (n=2) were high; on the other hand, the count of lactobacilli (n=3) was low. Therefore, salivary and microbiological tests showed that the patients with ED, particularly the hypohidrotic type, presented a high risk of enamel caries and susceptibility to oral infections, which may be likely triggered by reduction of salivary flow and/or possible immunological disorders.

Maxillary Bone Regeneration Based on Nanoreservoirs Functionalized ε-Polycaprolactone Biomembranes in a Mouse Model of Jaw Bone Lesion

Current approaches of regenerative therapies constitute strategies for bone tissue reparation and engineering, especially in the context of genetical diseases with skeletal defects. Bone regeneration using electrospun nanofibers' implant has the following objectives: bone neoformation induction with rapid healing, reduced postoperative complications, and improvement of bone tissue quality. In vivo implantation of polycaprolactone (PCL) biomembrane functionalized with BMP-2/Ibuprofen in mouse maxillary defects was followed by bone neoformation kinetics evaluation using microcomputed tomography. Wild-Type (WT) and Tabby (Ta) mice were used to compare effects on a normal phenotype and on a mutant model of ectodermal dysplasia (ED). After 21 days, no effect on bone neoformation was observed in Ta treated lesion (4% neoformation compared to 13% in the control lesion). Between the 21st and the 30th days, the use of biomembrane functionalized with BMP-2/Ibuprofen in maxillary bone lesions allowed a significant increase in bone neoformation peaks (resp., +8% in mutant Ta and +13% in WT). Histological analyses revealed a neoformed bone with regular trabecular structure, areas of mineralized bone inside the membrane, and an improved neovascularization in the treated lesion with bifunctionalized membrane. In conclusion, PCL functionalized biomembrane promoted bone neoformation, this effect being modulated by the Ta bone phenotype responsible for an alteration of bone response.

Medical sequencing of de novo ectodermal dysplasia in identical twins and evaluation of the potential eligibility for recombinant EDA therapy

The purpose of this study was to test two 8-year-old identical twins with ectodermal dysplasia (ED) and their unaffected parents for the presence of mutations in the EDA gene with the hypothesis that they might be carrying a de novo mutation in EDA and potentially eligible for recombinant EDA therapy. DNA was extracted using saliva samples obtained from the identical twin girls and both parents. PCR products of Ectodyplasin A (EDA), Ectodysplasin Receptor (EDAR), Ectodysplasin Receptor Associated Death Domain (EDARADD), and Connexin-30 (GJB6) were sequenced by the Sanger method and the results analyzed using a reference sequence. Exons and exon-intron boundaries of EDA, EDAR, EDARADD, and GJB6 were sequenced in both parents and the affected identical twin pair. No mutations were detected in EDA or GJB6. Genetic variants located in the intron of EDAR were found but determined to be non-contributory to the twins’ ED. A microsatellite polymorphism was detected in all four subjects in exon 4 of the EDARADD gene but determined not to be causal to the ED. There was a silent mutation detected in exon 6 of the EDARADD gene of both the daughters and their unaffected mother but also unlikely to be the cause of ED. These results suggest that ED of the subjects is caused by a de novo mutation in a gene not studied here. It is likely these subjects and their future offspring would not benefit from the development of recombinant EDA replacement therapy.

Clouston Syndrome: 25-year follow-up of a patient

Clouston syndrome is a rare genodermatosis that affects skin and annexes. It is a form of ectodermal dysplasia characterized by generalized hypotrichosis, palmoplantar hyperkeratosis and nail dystrophy. This paper reports a 25-year follow-up of a patient with Clouston syndrome, from childhood to adulthood, monitoring diagnosis and clinical course of the disease.

A nonsense mutation in the IKBKG gene in mares with incontinentia pigmenti

Ectodermal dysplasias (EDs) are a large and heterogeneous group of hereditary disorders characterized by abnormalities in structures of ectodermal origin. Incontinentia pigmenti (IP) is an ED characterized by skin lesions evolving over time, as well as dental, nail, and ocular abnormalities. Due to X-linked dominant inheritance IP symptoms can only be seen in female individuals while affected males die during development in utero. We observed a family of horses, in which several mares developed signs of a skin disorder reminiscent of human IP. Cutaneous manifestations in affected horses included the development of pruritic, exudative lesions soon after birth. These developed into wart-like lesions and areas of alopecia with occasional wooly hair re-growth. Affected horses also had streaks of darker and lighter coat coloration from birth. The observation that only females were affected together with a high number of spontaneous abortions suggested an X-linked dominant mechanism of transmission. Using next generation sequencing we sequenced the whole genome of one affected mare. We analyzed the sequence data for non-synonymous variants in candidate genes and found a heterozygous nonsense variant in the X-chromosomal IKBKG gene (c.184C>T; p.Arg62*). Mutations in IKBKG were previously reported to cause IP in humans and the homologous p.Arg62* variant has already been observed in a human IP patient. The comparative data thus strongly suggest that this is also the causative variant for the observed IP in horses. To our knowledge this is the first large animal model for IP.