Ectodermal dysplasias: New perspectives on the treatment of so far immedicable genetic disorders

Attitudes of female carriers of X-linked hypohidrotic ectodermal dysplasia towards prenatal treatment and their decisions during a pregnancy with a male fetus

BACKGROUND

X-linked hypohidrotic ectodermal dysplasia (XLHED) is a severe genetic disorder that may be treatable with short-term protein replacement therapy during fetal development. This is currently being investigated in a multicenter clinical trial. Affected fetuses can be identified by the number of tooth germs during a routine ultrasound scan in mid-gestation. To understand the attitudes of female XLHED carriers towards prenatal treatment and ultrasonographic screening of the fetus, we analyzed an earlier and a very recent survey among those women and the actual decisions of potential trial participants.

METHODS

Initial analyses were based on a self-administered survey of 167 female XLHED carriers conducted in 2011. A similar questionnaire was completed 12 years later by 72 female XLHED carriers aged 18-45 years. Subsequently, both the path to diagnosis and further decision-making of the first 33 pregnant women screened for participation in the EDELIFE trial were investigated.

RESULTS

Most women diagnosed with XLHED considered this disease as an obstacle to having children: About one third had decided not to have children, another third would monitor their pregnancy using invasive genetic testing. In both surveys, a small number of women stated that they would consider termination of pregnancy depending on the test result. When it came to participating in the clinical trial, 80% were likely to take part (17% moderately likely, 63% very likely). Among the first pregnant women screened for this trial, 48% underwent invasive tests, while 52% relied on non-invasive tooth germ imaging for fetal XLHED diagnosis. One pregnancy with an affected fetus was terminated, another one resulted in a miscarriage, one woman declined to participate in the trial, and 12 women (80%) decided to have the affected fetuses treated.

CONCLUSION

Ultrasound-based screening and prenatal treatment of the fetus are viewed positively by the vast majority of female XLHED carriers.

Genetic profiling and diagnostic strategies for patients with ectodermal dysplasias in Korea

BACKGROUND

Ectodermal dysplasia (ED) is a rare genetic disorder that affects structures derived from the ectodermal germ layer.

RESULTS

In this study, we analyzed the genetic profiles of 27 Korean patients with ED. Whole exome sequencing (WES) was performed on 23 patients, and targeted panel sequencing was conducted on the remaining 4 patients. Among the patients in the cohort, 74.1% (20/27) tested positive for ED. Of these positive cases, EDA and EDAR mutations were found in 80% (16/20). Notably, 23.1% (3/13) of EDA-positive cases exhibited copy number variations. Among the 23 patients who underwent WES, we conducted a virtual panel analysis of eight well-known genes, resulting in diagnoses for 56.5% (13/23) of the cases. Additionally, further analysis of approximately 5,000 OMIM genes identified four more cases, increasing the overall positivity rate by approximately 17%. These findings underscore the potential of WES for improving the diagnostic yield of ED. Remarkably, 94.1% of the patients manifesting the complete triad of ED symptoms (hair/skin/dental) displayed detectable EDA/EDAR mutations. In contrast, none of the 7 patients without these three symptoms exhibited EDA/EDAR mutations.

CONCLUSIONS

When conducting molecular diagnostics for ED, opting for targeted sequencing of EDA/EDAR mutations is advisable for cases with classical symptoms, while WES is deemed an effective strategy for cases in which these symptoms are absent.

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.

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.

Rare Pediatric Genetic Case Report of X-linked Hypohidrotic Ectodermal Dysplasia Type 1

Ectodermal dysplasia (ED) is a rare disorder that appears differently in clinical cases and can present with a variety of combinations and severities of abnormalities that can involve a variety of tissues. The disease might appear clinically as hypotrichosis, hypohidrosis, or hypodontia, among other clinical manifestations. The patient, a five-year-old boy, was seen at the Taibah University Dental Clinic and was diagnosed with X-linked hypohidrotic ectodermal dysplasia type 1 based on clinical radiographic and genetic findings. Although there is no base data for reporting this case, the present case presentation could alert dental practitioners and expand scientific database knowledge on the dental and/or oral characteristics of this abnormality.

X-Linked Hypohidrotic Ectodermal Dysplasia (XLHED): A Case Report and Overview of the Diagnosis and Multidisciplinary Modality Treatments

Hypohidrotic ectodermal dysplasia (HED) is a rare genetic disorder caused by a mutation in either the ectodysplasin (EDA), ectodysplasin A receptor (EDAR), EDAR associated via death domain (EDARADD), or Wnt family member 10A (WNT10A) genes that result in impaired development of ectodermal-derived structures. The literature defines two types of ectodermal dysplasia, which are hypohidrotic and hidrotic. X-linked hypohidrotic ectodermal dysplasia (XLHED), also known as Christ-Siemens-Touraine syndrome, is the most common form and is a variant of ectodermal dysplasia characterized by a classical triad of hypo/adontia, hypohidrosis, and hypotrichosis; whereas, hidrotic type of ectodermal dysplasia, also known as Clouston syndrome, is characterized by a triad of onychodysplasia, hypotrichosis, and palmoplantar hyperkeratosis while sparing the sweat glands. Symptoms of XLHED can begin early in life between the ages of one month to 23 months. XLHED is more commonly seen in males due to the x-linked characteristics of the gene mutations. This disease can be diagnosed by physical exam alone, or in combination with molecular genetic testing. XLHED specifically has an estimated occurrence of one in every 20,000 newborns worldwide. Approximately 5,000 people in the United States have the disease.  In this case report, we present an adult patient diagnosed with XLHED. Our objective is to emphasize the significance of early diagnosis, advocate for a multidisciplinary management approach, and shed light on the potential of recombinant protein and targeted gene therapy for further research. By raising awareness of this condition, we aim to improve patient outcomes not only in newborns but also in adults who have already been diagnosed with XLHED.

Rare diseases of ectoderm: Translating discovery to therapy

Heritable conditions known as ectodermal dysplasias are rare and can be associated with marked morbidity, mortality, and a reduced quality of life. The diagnosis and care of individuals affected by one of the many ectodermal dysplasias presents myriad challenges due to their rarity and the diverse phenotypes. These conditions are caused by abnormalities in multiple genes and signaling pathways that are essential for the development and function of ectodermal derivatives. During a 2021 international conference focused on translating discovery to therapy, researchers and clinicians gathered with the goal of advancing the diagnosis and treatment of conditions affecting ectodermal tissues with an emphasis on skin, hair, tooth, and eye phenotypes. Conference participants presented a variety of promising treatment strategies including gene or protein replacement, gene editing, cell therapy, and the identification of druggable targets. Further, barriers that negatively influence the current development of novel therapeutics were identified. These barriers include a lack of accurate prevalence data for rare conditions, absence of an inclusive patient registry with deep phenotyping data, and insufficient animal models and cell lines. Overcoming these barriers will need to be prioritized in order to facilitate the development of novel treatments for genetic disorders of the ectoderm.

Protocol for the Phase 2 EDELIFE Trial Investigating the Efficacy and Safety of Intra-Amniotic ER004 Administration to Male Subjects with X-Linked Hypohidrotic Ectodermal Dysplasia

X-linked hypohidrotic ectodermal dysplasia (XLHED) is a rare genetic disorder characte-rised by abnormal development of the skin and its appendages, such as hair and sweat glands, the teeth, and mucous glands of the airways, resulting in serious, sometimes life-threatening complications like hyperthermia or recurrent respiratory infections. It is caused by pathogenic variants of the ectodysplasin A gene (EDA). Most affected males are hemizygous for EDA null mutations that lead to the absence or inactivity of the signalling protein ectodysplasin A1 (EDA1) and, thus, to the full-blown phenotype with inability to perspire and few if any teeth. There are currently no long-term treatment options for XLHED. ER004 represents a first-in-class protein replacement molecule designed for specific, high-affinity binding to the endogenous EDA1 receptor (EDAR). Its proposed mechanism of action is the replacement of missing EDA1 in yet unborn patients with XLHED. Once bound to EDAR, ER004 activates the EDA/NFκB signalling pathway, which triggers the transcription of genes involved in the normal development of multiple tissues. Following preclinical studies, named-patient use cases demonstrated significant potential of ER004 in affected males treated in utero during the late second and third trimesters of pregnancy. In order to confirm these results, we started the EDELIFE trial, a prospective, open-label, genotype-match controlled, multicentre clinical study to investigate the efficacy and safety of intra-amniotic ER004 administration as a prenatal treatment for male subjects with XLHED. This article summarises the rationale, the study protocol, ethical issues of the trial, and potential pitfalls.