HELIX Syndrome, a Claudinopathy with Relevant Dermatological Manifestations: Report of Two New Cases.

HELIX syndrome (Hypohidrosis-Electrolyte disturbances-hypoLacrimia-Ichthyosis-Xerostomia) (MIM#617671) (ORPHA:528105), described in 2017, is due to an abnormal claudin 10 b protein, secondary to pathogenic CLDN10 variants. So far, only ten families have been described. We aim to describe the phenotype in the first Spanish family identified, highlight the skin anomalies as an important clue, and expand the genotypic spectrum. Two adult brothers from consanguineous parents with suspected ectodermal dysplasia (ED) since early childhood were re-evaluated. A comprehensive phenotypic exam and an aCGH + SNP4 × 180 K microarray followed by Sanger sequencing of the CLDN10 gene were performed. They presented hypohidrosis, xerosis, mild ichthyosis, plantar keratosis, palm hyperlinearity, alacrima, and xerostomia. In adulthood, they also developed a salt-losing nephropathy with hypokalemia and hypermagnesemia. The molecular study in both patients revealed a novel pathogenic homozygous deletion of 8 nucleotides in exon 2 of the CLDN10 gene [CLDN10 (NM_0006984.4): c.322_329delGGCTCCGA, p.Gly108fs*] leading to a premature truncation of the protein. Both parents were heterozygous carriers. Hypohidrosis, ichthyosis, and plantar keratosis associated with alacrima and xerostomia should raise suspicion for HELIX syndrome, which also includes nephropathy and electrolyte disturbances in adults. Given the potential for ED misdiagnosis in infancy, it is important to include the CLDN10 gene in a specific genodermatosis next-generation sequencing (NGS) panel to provide early diagnosis, accurate management, and genetic counseling.

Congenital nail abnormalities.

Congenital nail disorders are an uncommon presenting symptom which can be difficult to diagnose and manage. Nail diseases in the pediatric population differ from those in adults in terms of diagnosis, approach and management. In most cases, they do not require treatment and resolve with growth. Physicians need to be able to recognize them, to reassure the parents. The most frequently encountered pathologies associated with nail disorder are syndactyly, acrosyndactyly, symbrachydactyly, macrodactyly, Wassel I thumb duplication, Kirner's deformity and congenital onychodysplasia of the index finger. Treatment usually consists in surgical correction of the deformity. Nail malformation can also be an aspect of a systemic disease. It may provide a clue for screening, and should not be overlooked. Nail conditions can be the first sign of nail-patella syndrome, ectodermal dysplasia, dyskeratosis congenita, epidermolysis bullosa, pachyonychia congenita or lung disease. Medical treatment is therefore discussed on a case-by-case basis.

Like Father, Like Daughter - Ectodermal Dysplasia-Syndactyly Syndrome: A Case Report.

Ectodermal dysplasia-syndactyly syndrome 1 (EDSS1) is an exceedingly rare condition associated with mutations in the PVL4 gene. It is characterised by sparse, brittle hair, eyebrows and eyelashes, abnormal dentition and nails, along with bilateral cutaneous syndactyly involving the fingers and toes. We report a 2-year-old girl who presented to us with bilateral complete simple syndactyly of the third and fourth web spaces of the hands, along with bilateral syndactyly of both feet involving the second to fourth toes. Upon examination, sparse hair and eyebrows, along with abnormal dentition, were noted. Thorough clinical examination and genetic analysis were conducted on the affected child and her father, who exhibited similar clinical features. Genetic analysis revealed a homozygous nonsense mutation in the PVL4 gene in both individuals. According to the literature, EDSS1 has been reported in only 10 families worldwide, and there are no reported cases from India. Level of Evidence: Level V (Therapeutic).

Large skin defect in Type V aplasia cutis congenita treated with conservative treatment: a case report.

Aplasia cutis congenita (ACC) is a congenital disorder that can be classified into nine types, with Type I ACC being the most common. Type V ACC associated with fetus papyraceus is a rare subtype of ACC. We report the case of a Type V ACC in a male newborn with extensive abdominal skin defects. The patient received conservative treatment using hydrogel foam and silicone foam dressings. Approximately five weeks later, the patient was discharged when more than 60% of the skin had completed epithelialization. After discharge from West China Second University Hospital, Chengdu , the patient continued to be followed up regularly at the Burns and Plastic Surgery Clinic at local hospital in Gansu. We followed up the child by telephone. After 4 months of follow-up, scar tissue formation was observed in the trunk area. The infant is 2 years and 5 months old now, physical examination did not reveal any organ problems.

Characterization of a New Variant in ARHGAP31 Probably Involved in Adams-Oliver Syndrome in a Family with a Variable Phenotypic Spectrum.

Adams-Oliver syndrome is a rare inherited condition characterized by scalp defects and limb abnormalities. It is caused by variants in different genes such as ARHGAP31. Here, we used an interdisciplinary approach to study a family with lower limb anomalies. We identified a novel variant in the ARHGAP31 gene that is predicted to result in a truncated protein with a constitutively activated catalytic site due to the loss of 688 amino acids involved in the C-terminal domain, essential for protein auto-inhibition. Pathogenic variants in ARHGAP31 exon 12, leading to a premature protein termination, are associated with Adams-Oliver syndrome. Bioinformatic analysis was useful to elucidate the impact of the identified genetic variant on protein structure. To better understand the impact of the identified variant, 3D protein models were predicted for the ARHGAP31 wild type, the newly discovered variant, and other pathogenetic alterations already reported. Our study identified a novel variant probably involved in Adams-Oliver syndrome and increased the evidence on the phenotypic variability in patients affected by this syndrome, underlining the importance of translational research, including experimental and bioinformatics analyses. This strategy represents a successful model to investigate molecular mechanisms involved in syndrome occurrence.

Aplasia cutis congenita type VII of the lower extremity: a favourable disease course with minimal conservative treatment.

Aplasia cutis congenita (ACC) is a group of rare heterogeneous disorders characterised by absent areas of skin at birth. The majority of cases involve the scalp region. ACC limited to one lower limb is extremely rare. We report an usual case of ACC limited to the left thigh of which healing occurred in utero. The case was managed conservatively and the disease course has been favourable with no limitations in limb function and an entirely normal development. Most cases of ACC are self-healing, justifying a conservative approach. This holds further true for ACC limited to one lower limb where the majority of cases reported to date show a favourable disease course with minimal conservative treatment.

PRKD1-related telangiectasia-ectodermal dysplasia-brachydactyly-cardiac anomaly syndrome: Case report and review of the literature.

Telangiectasia-ectodermal dysplasia-brachydactyly-cardiac anomaly (TEBC) syndrome is a rare autosomal dominant condition, recently linked to the protein kinase D1 (PRKD1) gene. The phenotype of TEBC remains incomplete at this point. Our aim is to improve the characterization of the clinical and molecular aspects of the TEBC syndrome. We report on the 8th patient carrying a heterozygous de novo variation of PRKD1 c.2134G > A, p. (Val712Met) identified by trio exome sequencing. The proband presents with partial atrioventricular septal defect, brachydactyly, ectodermal dysplasia, telangiectasia that developed in childhood, intellectual disability with microcephaly, multicystic renal dysplasia and moderate hormonal resistance. In view of this 8th description and review of the literature, it appears that neurodevelopmental disorders and microcephaly are frequently associated with PRKD1 missense variants, adding to the four main clinical signs described initially in the TEBC syndrome. Further descriptions are required to confirm the observed endocrine and kidney abnormalities. This should contribute to a more comprehensive understanding of the phenotypic spectrum and may help establish genotype-phenotype correlations. In the context of genotype-first strategy, accurate patient descriptions are fundamental. Characterization of specific syndromic associations is essential for variant interpretation support and patient follow-up, even in very rare diseases, such as the TEBC syndrome.

Three-Dimensional Modeling and Quantitative Assessment of Mandibular Volume in Ectodermal Dysplasia: A Case Series.

Background and Objectives: Ectodermal dysplasia (ED)-a genetic disorder-is characterized by severe tooth deficiency. We compared the mandibular volume and the sagittal and horizontal mandibular widths between patients with ED (ED group) and individuals without tooth deficiency (control group) using three-dimensional modeling. We hypothesized that the mandibular volume differs in ED cases owing to congenital tooth deficiency. Materials and Methods: We used previously obtained cone-beam computed tomography (CBCT) images of 13 patients with ED. The control group data comprised retrospective CBCT images of patients of similar age and sex with a skeletal relationship of class 1. Further, using the three-dimensional image analysis software, the tooth crowns were separated from the mandible, the mandible was reconstructed and the gonion-to-gonion distance in the mandible was marked, the distance to the menton point was measured, and the distance between the two condyles was measured and compared with the control group. Results: Overall, 46.2% and 53.8% of the participants were men and women, respectively. In the ED group, the mean age of the participants was 15.46 (range, 6-24) years, and the mean number of mandibular teeth was 4.62. Notably, the edentulous mandible volume of the ED group (27.020 mm3) was statistically significantly smaller than that of the control group (49.213 mm3) (p < 0.001). There was no difference between the two groups in terms of the marked points. For data analysis, the Shapiro-Wilk test, independent samples t-test, and Mann-Whitney U test were used. Conclusions: It has been considered that mandible volume does not develop in ED cases because of missing teeth. Modern practices, such as the CBCT technique and three-dimensional software, may be effective in identifying the true morphologic features, especially in patients with genetic syndromes affecting the maxillofacial structure.

RASopathies for Radiologists.

RASopathies are a heterogeneous group of genetic syndromes caused by germline mutations in a group of genes that encode components or regulators of the Ras/mitogen-activated protein kinase (MAPK) signaling pathway. RASopathies include neurofibromatosis type 1, Legius syndrome, Noonan syndrome, Costello syndrome, cardiofaciocutaneous syndrome, central conducting lymphatic anomaly, and capillary malformation-arteriovenous malformation syndrome. These disorders are grouped together as RASopathies based on our current understanding of the Ras/MAPK pathway. Abnormal activation of the Ras/MAPK pathway plays a major role in development of RASopathies. The individual disorders of RASopathies are rare, but collectively they are the most common genetic condition (one in 1000 newborns). Activation or dysregulation of the common Ras/MAPK pathway gives rise to overlapping clinical features of RASopathies, involving the cardiovascular, lymphatic, musculoskeletal, cutaneous, and central nervous systems. At the same time, there is much phenotypic variability in this group of disorders. Benign and malignant tumors are associated with certain disorders. Recently, many institutions have established multidisciplinary RASopathy clinics to address unique therapeutic challenges for patients with RASopathies. Medications developed for Ras/MAPK pathway-related cancer treatment may also control the clinical symptoms due to an abnormal Ras/MAPK pathway in RASopathies. Therefore, radiologists need to be aware of the concept of RASopathies to participate in multidisciplinary care. As with the clinical manifestations, imaging features of RASopathies are overlapping and at the same time diverse. As an introduction to the concept of RASopathies, the authors present major representative RASopathies, with emphasis on their imaging similarities and differences. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Prevalence and Patient Characteristics of Ectodermal Dysplasias in Denmark.

Importance: 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. Objective: To establish a validated population-based cohort of patients with ectodermal dysplasia in Denmark and to assess the disease prevalence and patient characteristics. Design, Setting, and Participants: 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. Results: 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. Conclusions and Relevance: 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.

Heterozygous MAP3K20 variants cause ectodermal dysplasia, craniosynostosis, sensorineural hearing loss, and limb anomalies.

Biallelic pathogenic variants in MAP3K20, which encodes a mitogen-activated protein kinase, are a rare cause of split-hand foot malformation (SHFM), hearing loss, and nail abnormalities or congenital myopathy. However, heterozygous variants in this gene have not been definitively associated with a phenotype. Here, we describe the phenotypic spectrum associated with heterozygous de novo variants in the linker region between the kinase domain and leucine zipper domain of MAP3K20. We report five individuals with diverse clinical features, including craniosynostosis, limb anomalies, sensorineural hearing loss, and ectodermal dysplasia-like phenotypes who have heterozygous de novo variants in this specific region of the gene. These individuals exhibit both shared and unique clinical manifestations, highlighting the complexity and variability of the disorder. We propose that the involvement of MAP3K20 in endothelial-mesenchymal transition provides a plausible etiology of these features. Together, these findings characterize a disorder that both expands the phenotypic spectrum associated with MAP3K20 and highlights the need for further studies on its role in early human development.

Amniotic membrane dressings for treatment of aplasia cutis in newborns.

BACKGROUND: Aplasia cutis congenita (ACC) is a rare congenital skin defect characterized by a focal or extensive absence of the epidermis, dermis, and occasionally, subcutaneous tissue. When the wound caused by this defect is wide or deep, various treatments are used, including skin grafting. The amniotic membrane (AM) is a biological dressing that facilitates re-epithelialization as it contains mesenchymal cells and numerous growth factors. OBJECTIVE: To report the efficacy of AM dressings in treating the skin defects of ACC. METHOD: This study was conducted on five neonates diagnosed with ACC born between 2018 and 2022, referred to the Children's Medical Center in Tehran, Iran. AM dressings were applied on wounds larger than 1 cm2. The wounds were assessed weekly and, if required, an additional AM dressing was applied. RESULTS: The skin defects gradually re-epithelialized after application of the AM. The complete healing process took around 3.5 weeks on average. No hypertrophic scarring was observed. CONCLUSION: The application of AM dressing resulted in satisfactory cosmetic outcomes, with no hypertrophic scar formation. Complete healing occurred in all cases except one. The length of the hospital stay ranged from 2 to 6 weeks, depending on the size of the wound.

Scalp Closure in Midline Cutis Aplasia-An Absolute Indication for Preoperative Imaging.

The ideal evaluation and treatment of aplasia cutis congenita remains disputed. We present a case of midline scalp cutis aplasia that healed by secondary intention, leaving an area of residual alopecia. There were no clinical indicators of an underlying calvarial defect. Tissue expansion of the scalp was done in preparation for scalp closure. However, on the removal of the expanders and scalp advancement, an unrecognized midline calvarial defect in which a scar tract of herniated dura was found. This resulted in a dural tear, repaired with minimal hemorrhage. However, manipulation of the sagittal sinus resulted in a right subdural hemorrhage followed by cerebral ischemia and a stroke. On the basis of this clinical scenario, we recommend that all cases of midline scalp cutis aplasia undergo preoperative imaging with thin slices of the calvaria before performing scalp advancement-even if the only clinical indication for surgery is scalp alopecia without a palpable skull defect.

BTB domain mutations perturbing KCTD15 oligomerisation cause a distinctive frontonasal dysplasia syndrome.

INTRODUCTION: KCTD15 encodes an oligomeric BTB domain protein reported to inhibit neural crest formation through repression of Wnt/beta-catenin signalling, as well as transactivation by TFAP2. Heterozygous missense variants in the closely related paralogue KCTD1 cause scalp-ear-nipple syndrome. METHODS: Exome sequencing was performed on a two-generation family affected by a distinctive phenotype comprising a lipomatous frontonasal malformation, anosmia, cutis aplasia of the scalp and/or sparse hair, and congenital heart disease. Identification of a de novo missense substitution within KCTD15 led to targeted sequencing of DNA from a similarly affected sporadic patient, revealing a different missense mutation. Structural and biophysical analyses were performed to assess the effects of both amino acid substitutions on the KCTD15 protein. RESULTS: A heterozygous c.310G>C variant encoding p.(Asp104His) within the BTB domain of KCTD15 was identified in an affected father and daughter and segregated with the phenotype. In the sporadically affected patient, a de novo heterozygous c.263G>A variant encoding p.(Gly88Asp) was present in KCTD15. Both substitutions were found to perturb the pentameric assembly of the BTB domain. A crystal structure of the BTB domain variant p.(Gly88Asp) revealed a closed hexameric assembly, whereas biophysical analyses showed that the p.(Asp104His) substitution resulted in a monomeric BTB domain likely to be partially unfolded at physiological temperatures. CONCLUSION: BTB domain substitutions in KCTD1 and KCTD15 cause clinically overlapping phenotypes involving craniofacial abnormalities and cutis aplasia. The structural analyses demonstrate that missense substitutions act through a dominant negative mechanism by disrupting the higher order structure of the KCTD15 protein complex.

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

BACKGROUND: The 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. METHODS: The 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. RESULTS: Both 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 ß-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. CONCLUSIONS: Compound heterozygous WNT10A missense variations may exacerbate the number of missing teeth in HED caused by EDA variation.

A spectrum of TP63-related disorders with eight affected individuals in five unrelated families.

TP63-related disdorders broadly involve varying combinations of ectodermal dysplasia (sparse hair, hypohydrosis, tooth abnormalities, nail dysplasia), cleft lip/palate, acromelic malformation, split-hand/foot malformation/syndactyly, ankyloblepharon filiforme adnatum, lacrimal duct obstruction, hypopigmentation, and hypoplastic breasts and/or nipples. TP63-related disorders are associated with heterozygous pathogenic variants in TP63 and include seven overlapping phenotypes; Ankyloblepharon-ectodermal defects-cleft lip/palate syndrome (AEC), Ectrodactyly-ectodermal dysplasia-cleft lip/palate syndrome 3 (EEC3), Limb-mammary syndrome (LMS), Acro-dermo-ungual-lacrimal-tooth syndrome (ADULT), Rapp-Hodgkin syndrome (RHS), Split-hand/foot malformation 4 (SHFM4), and Orofacial cleft 8. We report on five unrelated families with 8 affected individuals in which the probands presented with varying combinations of ectodermal dysplasia, cleft lip/palate, split-hand/foot malformation, lacrimal duct obstruction, and ankyloblepharon filiforme adnatum. The clinical diagnosis involved AEC syndrome (2 patients), EEC3 syndrome (2 patients), and a yet hitherto unclassified TP63-related disorder. Sanger sequence analysis of the TP63 gene was performed revealing five different variants among which four were novel and three were de novo. The identificated TP63 variants co-segregated with the other affected individuals in the families. The abnormalities of ectoderm derived structures including hair, nails, sweat glands, and teeth should alert the physician to the possibility of TP63-related disorders particularly in the presence of orofacial clefting.