Prevalence rates for ectodermal dysplasia syndromes.

BACKGROUND: Ectodermal dysplasias (EDs) are a heterogeneous group of genetic conditions affecting the development and/or homeostasis of two or more ectodermal derivatives, including hair, teeth, nails, and certain glands. There are currently 49 recognized EDs with molecularly confirmed etiology. The EDs are very rare disorders, individually and in aggregate. Very little is published regarding the prevalence of these rare disorders. As a result of the genomics revolution, rare diseases have emerged as a global health priority. The various disabilities arising from rare disorders, as well as diagnostic and treatment uncertainty, have been demonstrated to have detrimental effects on the health, psychosocial, and economic aspects of families affected by rare disorders. Contemporary research methodologies and databases can address what have been historic challenges encountered when conducting research on rare diseases. OBJECTIVE: In this study, we aim to ascertain period prevalence rates for several of the more common ectodermal dysplasia syndromes, by querying a large multicenter database of electronic health records, Oracle Real-World Data. METHODS: For each of the included ectodermal dysplasia syndromes a clinical definition was developed by a committee of international experts with interests in EDs. The clinical definitions were based upon a combination of clinical features and designated by ICD-9 and ICD-10 codes. The January 2023 version of the Oracle Real-World Data database was queried for medical records that coincided with the clinical definitions. For our study, there were 64,523,460 individual medical records queried. RESULTS: Period prevalence rates were calculated for the following ED disorders: hypohidrotic ectodermal dysplasia, found to be 2.99 per 100,000; ectodermal dysplasia and immunodeficiency 1, 0.23 per 100,000; Clouston syndrome, 0.15 per 100,000; ectrodactyly ectodermal dysplasia and cleft lip/palate syndrome, 0.61 per 100,000; ankyloblepharon-ectodermal defects-cleft lip/palate syndrome, 0.36 per 100,000; focal dermal hypoplasia, 0.10 per 100,000; and incontinentia pigmenti, 0.88 per 100,000. CONCLUSION: This study established estimated period prevalence rates for several of the ectodermal dysplasia syndromes, and it demonstrated the feasibility of utilizing large multicenter databases of electronic health records, such as Oracle Real World Data.

Amino-terminal residues of ΔNp63, mutated in ectodermal dysplasia, are required for its transcriptional activity.

p63, a member of the p53 family, is a crucial transcription factor for epithelial development and skin homeostasis. Heterozygous mutations in TP63 gene have been associated with human ectodermal dysplasia disorders. Most of these TP63 mutations are missense mutations causing amino acidic substitutions at p63 DNA binding or SAM domains that reduce or abolish the transcriptional activity of mutants p63. A significant number of mutants, however, resides in part of the p63 protein that apparently do not affect DNA binding and/or transcriptional activity, such as the N-terminal domain. Here, we characterize five p63 mutations at the 5' end of TP63 gene aiming to understand the pathogenesis of the diseases and to uncover the role of ΔNp63α N-terminus residues in determining its transactivation potential.

Clinical Variability in a Family with an Ectodermal Dysplasia Syndrome and a Nonsense Mutation in the TP63 Gene.

Mutations in the TP63 gene have been associated with a variety of ectodermal dysplasia syndromes, among which the clinically overlapping Ankyloblepharon-Ectodermal defects-Cleft lip/palate (AEC) and the Rapp-Hodgkin syndromes. We report a multiplex nonconsanguineous family of Ashkenazi-Jewish descent, in which the index patient presented with a persistent scalp skin lesion, dystrophic nails and light thin hair. Further evaluation revealed over 10 affected individuals in the kindred, over four generations, exhibiting varying degrees of ectodermal involvement. Analysis of the TP63 gene from four of the patients and from two healthy individuals of the same family was performed. Gene sequencing of the patients revealed a nonsense mutation leading to a premature termination codon (PTC) (p.Gln16X). The same mutation was found in all tested affected individuals in the family, but gave rise to marked phenotypic variability with minor clinical manifestations in some individuals, underscoring the clinical heterogeneity associated with the recently described PTC-causing mutations.

Modeling AEC-New approaches to study rare genetic disorders.

Ankyloblepharon-ectodermal defects-cleft lip/palate (AEC) syndrome is a rare monogenetic disorder that is characterized by severe abnormalities in ectoderm-derived tissues, such as skin and its appendages. A major cause of morbidity among affected infants is severe and chronic skin erosions. Currently, supportive care is the only available treatment option for AEC patients. Mutations in TP63, a gene that encodes key regulators of epidermal development, are the genetic cause of AEC. However, it is currently not clear how mutations in TP63 lead to the various defects seen in the patients' skin. In this review, we will discuss current knowledge of the AEC disease mechanism obtained by studying patient tissue and genetically engineered mouse models designed to mimic aspects of the disorder. We will then focus on new approaches to model AEC, including the use of patient cells and stem cell technology to replicate the disease in a human tissue culture model. The latter approach will advance our understanding of the disease and will allow for the development of new in vitro systems to identify drugs for the treatment of skin erosions in AEC patients. Further, the use of stem cell technology, in particular induced pluripotent stem cells (iPSC), will enable researchers to develop new therapeutic approaches to treat the disease using the patient's own cells (autologous keratinocyte transplantation) after correction of the disease-causing mutations.

Case report: Artificial thymic organoids facilitate clinical decisions for a patient with a TP63 variant and severe persistent T cell lymphopenia.

Pathogenic variants in the transcription factor TP63 are associated with clinically overlapping syndromes including ectrodactyly-ectodermal dysplasia clefting (EEC) and ankyloblepharon-ectodermal defects-cleft lip/palate (AEC). T cell lymphopenia has rarely been described in individuals with TP63 variants and the cause of the T cell defect is unclear. Here, we present a case of a female infant born with TP63-related syndrome and profound T cell lymphopenia, first uncovered through newborn screening. Flow cytometry analysis revealed low CD4+ naïve T cells and nearly absent CD8+ T cells with intact B and NK cell compartments. A de novo heterozygous pathogenic variant c.1040 G>A (C347Y) in exon 8 of TP63 was identified. An artificial thymic organoid system, to assess the intrinsic ability of the patient's hematopoietic cells to develop into T cells, was performed twice using separate peripheral blood samples. Ex vivo T cell differentiation was evident with the artificial organoid system, suggesting that a thymic stromal cell defect may be the cause of the T cell lymphopenia. Consistent with this, interrogation of publicly available data indicated that TP63 expression in the human thymus is restricted to thymic epithelial cells. Based on these data, congenital athymia was suspected and the patient received an allogenic cultured thymus tissue implant (CTTI). This is the first report of suspected congenital athymia and attempted treatment with CTTI associated with TP63 variant. At 9 months post-implant, peripheral lymphocyte analysis revealed measurable T cell receptor excision circles and presence of CD4+ recent thymic emigrants suggestive of early thymopoiesis. She will continue regular monitoring to ensure restoration of T cell immunity.

Ocular Manifestations in Patients Affected by p63-Associated Disorders: Ectrodactyly-Ectodermal Dysplasia-Clefting (EEC) and Ankyloblepharon-Ectodermal Defects-Cleft Lip Palate (AEC) Syndromes.

BACKGROUND/AIMS: The Ectrodactyly-Ectodermal dysplasia-Clefting (EEC) and Ankyloblepharon-ectodermal defect-cleft lip/palate (AEC) syndromes are rare autosomal dominant diseases caused by heterozygous mutations in the p63 gene. Patients are characterized by abnormalities of the skin, teeth, and hair and have limb defects, orofacial clefting and ectodermal dysplasia. In addition, they often show ocular surface alterations, leading to progressive corneal clouding and eventually blindness. Here, we present 8 cases describing patients affected by EEC (n = 6, with 5 sporadic and 1 familial cases) and AEC (n = 2, both sporadic cases) syndromes. We attempt to provide a description of the ocular disease progression over the years. METHODS: Clinical examinations and monitoring of ocular parameters for the assessment of limbal stem cell deficiency were constantly performed on patients between 2009 and 2023. Quantitative data and comparison with existing cases described in the literature are reported. RESULTS: The therapies supplied to patients were essential for the management of the symptoms, but unfortunately did not halt the progression of the pathology. CONCLUSIONS: A constant monitoring of the patients would help avoid the sudden worsening of symptoms. If the progression of the disease slows down, it would allow for the development of newer therapeutic strategies aimed at correcting the genetic defect.

Ocular manifestations of ectodermal dysplasia.

PURPOSE: The ectodermal dysplasias (EDs) constitute a group of disorders characterized by abnormalities in two or more ectodermal derivatives, including skin, hair, teeth, and sweat glands. The purpose of the current study was to evaluate ocular manifestations in pediatric patients with ED. METHODS: Retrospective case series including consecutive ED subjects who were treated in the ophthalmology department at the Children's Hospital of Philadelphia over a 12-year period (2009-2020). Main Outcome Measures were ocular and ocular adnexal abnormalities. RESULTS: Thirty subjects were included: 20 males (67%), mean age of 4.5 years (range 0.3-18). Patients with different subtypes were included, with the hypohidrotic ED and ectrodactyly-ectodermal dysplasia-clefting variants being most prevalent. Most common findings were: lacrimal drainage obstruction in 12 (40%) including punctal agenesis in 10 (33%), refractive errors in 13 (43%) and amblyopia in 6 (20%). A new finding of eyelid ptosis or eyelash ptosis was demonstrated in 11 subjects (37%), mostly associated with TP63 or EDA1 genes variants. CONCLUSION: Ectodermal dysplasias are associated with various ocular pathologies and amblyopia in the pediatric population. We report a possible genetic association between lash ptosis and EDA1 gene, and eyelid ptosis and TP63 or EDA1 genes variants.

Novel missense mutation of the TP63 gene in a newborn with Hay-Wells/Ankyloblepharon-Ectodermal defects-Cleft lip/palate (AEC) syndrome: clinical report and follow-up.

INTRODUCTION: Ankyloblepharon-ectodermal defects-cleft lip/palate (AEC) syndrome, also known as Hay-Wells syndrome, is a rare genetic syndrome with ectodermal dysplasia. About 100 patients have been reported to date. It is associated to a heterozygous mutation of the tumor protein p63 (TP63) gene, located on chromosome 3q28. Typical clinical manifestations include: filiform ankyloblepharon adnatum (congenital adherence of the eyelids), ectodermal abnormalities (sparse and frizzy hair, skin defects, nail alterations, dental changes and hypohidrosis), and cleft lip/palate. Diagnostic suspicion is based on clinical signs and confirmed by genetic testing. PATIENT'S PRESENTATION: We hereby report on a female newborn with erythroderma, thin lamellar desquamations, extensive skin erosions, sparse and wiry hair, filiform ankyloblepharon adnatum, agenesis of the lachrymal puncta, cleft palate and nail dysplasia. Her phenotype was compatible with AEC syndrome. Then, based on the clinical suspicion, sequencing analysis of the TP63 gene was performed, and revealed a de novo novel missense mutation. Eyelids adherence and cleft palate underwent surgical correction, while skin erosions were treated with topical antibiotics/antifungals and emollient/re-epithelizing creams. A surgical reconstruction is presently planned for the agenesis of the lachrymal puncta. The infant currently is 17 months of age and is included in a multidisciplinary follow-up. At present shows growth impairment and mild developmental delay, and typical signs of ectodermal dysplasia with small areas of dermatitis lesions on the scalp, without further abnormalities. CONCLUSIONS: Our report underlines the relevance of an early and careful clinical evaluation in neonates with ankyloblefaron, facial dysmorphism, and signs of ectodermal dysplasia. In these cases, the suspicion of AEC syndrome must be promptly raised, and sequencing analysis of TP63 early performed as well. An individualized, multidisciplinary and long-term follow-up should be guaranteed to affected subjects and their families, also to identify associated morbidities and prevent possible serious complications and adverse outcomes.