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Ichthyosis follicularis (IF) manifests as generalized spiny follicular projections found in syndromic diseases secondary to SREBF1 and MBTPS2 mutations. We sought the genetic cause of IF in two distinct families from a cohort of 180 patients with ichthyosis. In Family 1, the proband (Patient 1) presented with IF, bilateral sensorineural hearing loss and punctate palmoplantar keratoderma. Using DNA from peripheral blood lymphocytes, two compound heterozygous mutations, c.526A>G and c.35delG, were discovered in GJB2. In Family 2, the proband (Patient 2) presented with a previously unreported IF phenotype in the context of keratitis-ichthyosis-deafness syndrome, and whole-exome sequencing found a de novo heterozygous mutation, c.148G>A in GJB2. Histopathology was consistent with porokeratotic eccrine ostial and dermal duct naevus (PEODDN) and IF in Patients 1 and 2, respectively. Our findings add to the clinical and histopathological spectrum of IF and emphasize the association of PEODDN-like entities with GJB2 variants., (© 2022 British Association of Dermatologists.)

Introduction: Pemphigus vulgaris (PV) is a rare autoimmune disease that causes painful blistering. Interleukin-15 (IL-15) as a member of the immunoregulatory cytokines family is associated with the development of the chronic inflammatory or autoimmune disease. There is not much information available in the literature on the exact role IL-15 plays in PV., Objectives: The goal of this study was to evaluate the serum levels of IL-15 in patients with PV and assess the association of IL-15 with anti-desmoglein antibodies and the severity of the disease., Methods: Fifty-three individuals affected with active PV and 38 age- and gender-matched healthy controls were participated in this study. Disease severity was assessed using Autoimmune Bullous Skin Disorder Intensity Score (ABSIS). Serum levels of IL-15 (pg/mL) and anti-desmoglein antibodies (Dsg1, 3) were determined., Results: In the patient group, IL-15 serum levels were statistically higher than those in the control group (3.71 ± 1.5 vs. 0.79 ± 1.03, P < 0.001). A positive correlation was found between serum levels of IL-15 and ABSIS (r = 0.5, P = 0.04). We found no significant correlation between serum concentrations of IL-15 and antidesmoglein antibodies (Dsg1 or Dsg3)., Conclusions: An increase in serum level of IL-15 in patients with PV and its relationship with disease severity suggest that this cytokine possibly contributes to the pathogenesis of the disease and targeting IL-15 will likely provide a new insight into the treatment of this disease., Competing Interests: Competing interests: None., (©2022 Kheirodin et al.)

Recessive dystrophic epidermolysis bullosa (RDEB) manifests with blistering and erosions of the skin and mucous membranes due to mutations in COL7A1. The repetitive wound healing processes lead to extensive cutaneous scarring. The scarring is driven by inflammatory processes, particularly the TGF-β signaling pathways, resulting in excess synthesis and deposition of the extracellular matrix, especially collagen. There is currently no effective or specific treatment for RDEB. Losartan, an angiotensin II type 1 receptor antagonist, is an inhibitor of TGF-β activity. Previous preclinical studies with hypomorphic Col7a1 mice recapitulating features of RDEB have suggested that losartan may improve the clinical features of RDEB. In this case series, we assessed the effects of losartan on the clinical and histopathologic features in seven patients with RDEB; three females and four males; aged 18.1 ± 9.1 years. The diagnosis was based on characteristic clinical features and the presence of biallelic loss-of-function mutations in COL7A1. Daily oral administration of losartan (0.7 mg/kg) for six weeks resulted in subjective improvement of the clinical features, as judged by the treating physicians and the patients, and the severity of the disease objectively improved based on Birmingham Epidermolysis Bullosa Severity (BEBS) score (30.1 ± 12.8 versus 23.3 ± 10.4, before and after treatment, p = 0.018), accompanied by improvement of quality of life, as determined by the EB-QoL questionnaire (24.0 ± 8.1 versus 17.7 ± 5.5, p = 0.018). Histopathology of the selected lesions revealed after treatment increased number of mast cells, and enhanced microvasculature in the mid and lower dermis. The width of collagen bundles in dermis was suggested to be decreased in four samples and changed from dense to loose in appearance. In summary, this case series reports beneficial effects of losartan on RDEB as a potentially novel treatment., (© 2022 Wiley Periodicals LLC.)

An 82-year-old female patient presented with a recent onset of painful skin lesions in unilateral distribution on the abdominal area following the lines of Blaschko; the initial diagnosis of Varicella-Zoster infection was made. However, because the individual lesions appeared as hyperkeratotic papules and were unresponsive to antiviral therapy, a skin biopsy was performed, which revealed hyperkeratosis, suprabasal acantholysis and dyskeratosis with corps ronds and grains, consistent with acantholytic dyskeratotic acanthoma. Since this entity has been associated with Darier disease, whole-transcriptome sequencing by RNA-Seq was performed on RNA isolated from a lesion and from adjacent normal appearing skin, and a recently developed bioinformatics pipeline that can identify both genomic sequence variants and the presence of any of 926 viruses was applied. Two pathogenic missense mutations in the ATP2A2 gene were identified in the lesional but not in normal appearing skin, and no evidence of Varicella-Zoster infection was obtained. These findings confirm the diagnosis of segmental Darier disease due to postzygotic mutations in the ATP2A2 gene, and attest to the power of a novel single-step application of RNA-Seq in providing correct diagnosis in this rare genodermatosis., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

DST encodes bullous pemphigoid antigen-1 (BPAG1), a protein with eight tissue-specific isoforms expressed in the skin, muscle, brain and nerves. Accordingly, mutations in this gene are associated with epidermolysis bullosa simplex (EBS) and hereditary sensory and autonomic neuropathy type 6 (HSAN-VI). The genotypic spectrum is attested to by 19 distinct mutations but genotype-phenotype correlation for both disorders is not well established. In this study, we performed next-generation sequencing (NGS) on two families with different phenotypic presentations, one foetus (P1) with musculoskeletal and neurological malformations established by prenatal ultrasound and family history, and a 15-year-old female patient (P2) with skin blistering. P1 had a novel homozygous nonsense mutation, DST: NM&#95;001144769, c.3805C>T, p.R1269* within a region of genetic homozygosity (ROH). This mutation resides within the plakin domain of BPAG1 and ablates all isoforms of this protein, leading to novel extracutaneous phenotypes consistent with HSAN-VI in P1. P2 had a recurrent homozygous mutation DST: NM&#95;001723.7, c.3370C>T, p.Gln1124* that presented with giant, trauma-induced skin blisters without extracutaneous involvement. This mutation is located within the coiled-coil domain present in the skin isoform of DST, BPGA1-e, associated with EBS. In summary, we report two families with pathogenic DST variants and expand the spectrum of DST genotype and phenotypes., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Epidermolysis bullosa (EB), a phenotypically and genetically heterogeneous disorder, has been linked to mutations in the genes encoding structural proteins that reinforce skin integrity via dermal-epidermal adhesion. Breakdowns in these adhesion mechanisms result in four different subtypes of EB classified on the basis of the level of tissue separation within the cutaneous basement membrane zone (BMZ). Mutations in as many as 17 distinct genes that encode structural proteins in the BMZ have been linked to EB. Despite the clinical and histopathological confirmation of EB, many cases remain genetically unsolved. Technical advancements in next-generation sequencing have paved the way for the identification of genes involved in the pathophysiology of EB. Structural proteins have long been identified as the candidate molecules altered in EB, however, recently non-structural proteins, encoded for example by PLOD3, USB1, EXPH5, and KLHL24, involved in enzymatic modification or migration of structural proteins have been implicated. In this overview, we discuss recent work regarding these proteins vis-à-vis their function, associated clinical manifestations, and involvement in the pathogenesis of EB., Competing Interests: Declaration of Competing Interest None, (Copyright © 2022 Elsevier B.V. All rights reserved.)

Dyskeratosis Congenita (DC) is a rare and heterogeneous disease. This disorder is resulted from a defect in the telomere maintenance in stem cells. Telomerase RNA component, shelterin complex, and telomerase reverse transcriptase are mutated in this disease. Many studies have previously confirmed shorter leukocyte telomere length in DC. On the other hand, the association between telomere length and Coronavirus disease 2019 (COVID-19) indicated that people with a short telomere background mostly show more severe symptoms related to COVID-19, and the mortality rate among them increases as well. Because patients with DC have an abnormally short telomere length, in the current study, we hypothesized that they are at higher risk of developing symptomatic COVID-19 that requires further clinical care., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 Elsevier Ltd. All rights reserved.)

Human papillomavirus (HPV) infections can cause common warts, which usually resolve spontaneously or become recalcitrant, resistant to multiple treatments. In rare cases, they transform into cutaneous giant horns resulting in the tree-man syndrome (TMS). Defective β-HPVs can cause flat warts in epidermodysplasia verruciformis (EV), a genetic disorder. In typical EV, limited to the skin, the mutated genes are critical for keratinocyte-intrinsic immunity, whereas atypical, syndromic EV involves genes controlling T cells. Inborn errors of immunity due to mutations in distinct genes underlying recalcitrant warts and the α-HPV2‒driven TMS have been identified, all disrupting T-cell immunity. Collectively, these observations attest to the wide phenotypic spectrum of cutaneous infections caused by different HPV types at the intersection of the genetic diversity of the viral and human genomes., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Autosomal recessive cutis laxa (ARCL) is a heterogeneous disorder with three primary forms (ARCL 1, ARCL 2 and ARCL 3). Latent transforming growth factor beta binding protein 4 (LTBP4) anomalies cause ARCL1C and are connected to different problems in the skin and other organs. Herein, we present a seven month old Iranian boy with a clinical manifestation of ARCL1 with literature review of previous cases with attributes of ARCL1C., Methods: Considering the craniofacial characteristics and respiratory distress of the proband, cutis laxa (CL) was expected and whole-exome sequencing (WES) was performed., Results: In the proband, signs of CL were mainly located in the face, thorax, and abdomen. The prenatal investigation revealed a diaphragmatic hernia and certain uncommon signs, such as an atrial septal defect and pyloric stenosis. The WES showed a novel homozygous mutation (c.533-1G > A) in exon six of the LTBP4 gene., Conclusion: This report showed a new variant with uncommon clinical features, such as a stenosis atrial septal defect and pyloric stenosis, which causes ARCL1C. Unfortunately, the proband developed several heart problems and died at the age of seven months and seven days. Thus, a more in-depth evaluation is needed to clarify the different aspects of CL related to LTBP4 disorder., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Pseudoxanthoma elasticum (PXE) and generalized arterial calcification of infancy (GACI) are clinically distinct genetic entities of ectopic calcification associated with differentially reduced circulating levels of inorganic pyrophosphate (PPi), a potent endogenous inhibitor of calcification. Variants in ENPP1, the gene mutated in GACI, have not been associated with classic PXE. Here we report the clinical, laboratory, and molecular evaluations of ten GACI and two PXE patients from five and two unrelated families registered in GACI Global and PXE International databases, respectively. All patients were found to carry biallelic variants in ENPP1. Among ten ENPP1 variants, one homozygous variant demonstrated uniparental disomy inheritance. Functional assessment of five previously unreported ENPP1 variants suggested pathogenicity. The two PXE patients, currently 57 and 27 years of age, had diagnostic features of PXE and had not manifested the GACI phenotype. The similarly reduced PPi plasma concentrations in the PXE and GACI patients in our study correlate poorly with their disease severity. This study demonstrates that in addition to GACI, ENPP1 variants can cause classic PXE, expanding the clinical and genetic heterogeneity of heritable ectopic calcification disorders. Furthermore, the results challenge the current prevailing concept that plasma PPi is the only factor governing the severity of ectopic calcification., Competing Interests: The authors have declared that no competing interests exist.

Severe viral infections of the skin can occur in patients with inborn errors of immunity (IEI). We report an all-in-one whole-transcriptome sequencing-based method by RNA-Seq on a single skin biopsy for concomitantly identifying the cutaneous virome and the underlying IEI. Skin biopsies were obtained from healthy and lesional skin from patients with cutaneous infections suspected to be of viral origin. RNA-Seq was utilized as the first-tier strategy for unbiased human genome-wide rare variant detection. Reads unaligned to the human genome were utilized for the exploration of 926 viruses in a viral genome catalog. In 9 families studied, the patients carried pathogenic variants in 6 human IEI genes, including IL2RG, WAS, CIB1, STK4, GATA2, and DOCK8. Gene expression profiling also confirmed pathogenicity of the human variants and permitted genome-wide homozygosity mapping, which assisted in identification of candidate genes in consanguineous families. This automated, online, all-in-one computational pipeline, called VirPy, enables simultaneous detection of the viral triggers and the human genetic variants underlying skin lesions in patients with suspected IEI and viral dermatosis.

Background: Germline autosomal dominant and autosomal recessive mutations in PERP, encoding p53 effector related to PMP-22 (PERP), a component of epidermal desmosomes, have been associated with a spectrum of keratodermas. Monoallelic nonsense mutations cause Olmsted syndrome with severe periorificial keratoderma and palmoplantar keratoderma (PPK). Biallelic recessive frameshift and missense mutations are associated with milder forms of the disease, including generalised erythrokeratoderma and PPK., Objectives: To add new insights into the genotype-phenotype correlations as a consequence of PERP mutations and to provide a comprehensive review of the literature., Methods: Among 26 previously unresolved families within a cohort of 180 extended Iranian families with syndromic or non-syndromic ichthyosis, two families with shared clinical features were examined by whole-exome sequencing and genome-wide homozygosity mapping. Mycological and dermatopathological studies were performed to further characterise their atypical phenotypic presentations., Results: In two unrelated multiplex consanguineous families affected by ichthyosis, two novel biallelic PERP variants, NM&#95;022121.5, c.89T > C, p.Leu30Pro and c.466G > C, p.Gly156Arg, located inside of genomic homozygosity regions of the probands were detected. Interestingly, some patients had areas of scaly psoriasiform plaques on the background of generalised ichthyosis that appeared during active cutaneous fungal infections. Mycological examinations of these lesions revealed infections caused by Candida albicans, Epidermophyton floccosum, or Trichophyton rubrum. Histopathology of the psoriasiform lesions shared some features with psoriasis, which when combined with clinical presentation, led to incorrect diagnosis of guttate psoriasis or pustular psoriasis., Conclusions: PERP variants in ichthyosis patients can confer susceptibility to recalcitrant cutaneous fungal infections. Additionally, patients with episodic psoriasiform dermatitis in the setting of keratoderma should be considered for PERP genotyping and cutaneous fungal examinations., (© 2021 European Academy of Dermatology and Venereology.)

Purpose: Heritable ectopic mineralization disorders comprise a group of conditions with a broad range of clinical manifestations in nonskeletal connective tissues. We report the genetic findings from a large international cohort of 478 patients afflicted with ectopic mineralization., Methods: Sequence variations were identified using a next-generation sequencing panel consisting of 29 genes reported in association with ectopic mineralization. The pathogenicity of select splicing and missense variants was analyzed in experimental systems in vitro and in vivo., Results: A total of 872 variants of unknown significance as well as likely pathogenic and pathogenic variants were disclosed in 25 genes. A total of 159 distinct variants were identified in 425 patients in ABCC6, the gene responsible for pseudoxanthoma elasticum, a heritable multisystem ectopic mineralization disorder. The interpretation of variant pathogenicity relying on bioinformatic predictions did not provide a consensus. Our in vitro and in vivo functional assessment of 14 ABCC6 variants highlighted this dilemma and provided unambiguous interpretations to their pathogenicity., Conclusion: The results expand the ABCC6 variant repertoire, shed new light on the genetic heterogeneity of heritable ectopic mineralization disorders, and provide evidence that functional characterization in appropriate experimental systems is necessary to determine the pathogenicity of genetic variants., (Copyright © 2021 American College of Medical Genetics and Genomics. Published by Elsevier Inc. All rights reserved.)

Introduction: Clustered regularly interspaced short palindromic repeat and its associated protein (CRISPR-Cas)-based technologies generate targeted modifications in host genome by inducing site-specific double-strand breaks (DSBs) that can serve as a substrate for homology-directed repair (HDR) in both in vitro and in vivo models. HDR pathway could enhance incorporation of exogenous DNA templates into the CRISPR-Cas9-mediated DSB site. Owing to low rate of HDR pathway, the efficiency of accurate genome editing is diminished. Enhancing the efficiency of HDR can provide fast, easy, and accurate technologies based on CRISPR-Cas9 technologies. Methods: The current study presents an overview of attempts conducted on the precise genome editing strategies based on small molecules and modified CRISPR-Cas9 systems. Results: In order to increase HDR rate in targeted cells, several logical strategies have been introduced such as generating CRISPR effector chimeric proteins, anti-CRISPR proteins, modified Cas9 with donor template, and using validated synthetic or natural small molecules for either inhibiting non-homologous end joining (NHEJ), stimulating HDR, or synchronizing cell cycle. Recently, high-throughput screening methods have been applied for identification of small molecules which along with the CRISPR system can regulate precise genome editing through HDR. Conclusion: The stimulation of HDR components or inhibiting NHEJ can increase the accuracy of CRISPR-Cas-mediated engineering systems. Generating chimeric programmable endonucleases provide this opportunity to direct DNA template close proximity of CRISPR-Cas-mediated DSB. Small molecules and their derivatives can also proficiently block or activate certain DNA repair pathways and bring up novel perspectives for increasing HDR efficiency, especially in human cells. Further, high throughput screening of small molecule libraries could result in more discoveries of promising chemicals that improve HDR efficiency and CRISPR-Cas9 systems., (© 2022 The Author(s).)

Importance: Pyrin-associated autoinflammation with neutrophilic dermatosis (PAAND) is a monogenic autoinflammatory disorder with autosomal dominant inheritance and has been associated with monoallelic p.Ser242Arg and p.Glu244Lys variations in the MEFV gene. This dermatosis shares clinical features and pathogenesis with familial Mediterranean fever, although it is a clinically distinct entity., Objective: To identify the genetic basis of PAAND in a consanguineous family with 2 affected children and to prescribe an effective genotype-guided treatment., Design, Setting, and Participants: This case series study examined 2 siblings who presented with clinical features of PAAND. We sought the genetic basis of this disease with trio whole exome sequencing (trio-WES). Genome-wide homozygosity mapping provided additional evidence for causality of a sequence variant identified by trio-WES., Main Outcomes and Measures: Association of a biallelic MEFV variation with a new form of autosomal recessive PAAND was documented by genetic analysis. Response to treatment with colchicine and a low-dose steroid was assessed clinically and experimentally., Results: Two siblings, a girl (proband; age 5 years) and a boy (age 2.5 years) of Iranian-Azeri ancestry born to first-cousin consanguineous parents presented with clinical features of PAAND-recurrent episodes of maculopapular and pustular rash, gastrointestinal involvement resembling inflammatory bowel disease, and intussusception with generalized mesenteric lymphadenitis. A trio-WES test detected a previously unreported homozygous missense variation, p.Ser242Gly, in both patients' MEFV gene. Genome-wide homozygosity mapping revealed shared regions of homozygosity in the patients' DNA, including 1 on chromosome 16 harboring MEFV. Whole transcriptome sequencing by RNA-sequencing revealed that the variant MEFV transcript, among the inflammasome-associated transcripts, was most upregulated, and the cell-cell receptor interaction and innate immune system pathways were most positively enriched. Under the guidance of MEFV genotype, treatment with colchicine (1 mg/d) and low-dose prednisolone (2.5 mg every other day) was started, and the patients responded well., Conclusions and Relevance: This case series study demonstrated successful genotype-guided treatment with colchicine and low-dose prednisolone, a low-cost therapeutic option with minimal adverse effects, in patients with a novel form of autosomal recessive PAAND. This case report examines the genetic basis of PAAND in a consanguineous family with 2 affected children and seeks to prescribe an effective genotype-guided treatment.

Recessive dystrophic epidermolysis bullosa (RDEB) is a rare genodermatosis caused by mutations in the gene coding for type VII collagen (COL7A1). More than 800 different pathogenic mutations in COL7A1 have been described to date; however, the ancestral origins of many of these mutations have not been precisely identified. In this study, 32 RDEB patient samples from the Southwestern United States, Mexico, Chile, and Colombia carrying common mutations in the COL7A1 gene were investigated to determine the origins of these mutations and the extent to which shared ancestry contributes to disease prevalence. The results demonstrate both shared European and American origins of RDEB mutations in distinct populations in the Americas and suggest the influence of Sephardic ancestry in at least some RDEB mutations of European origins. Knowledge of ancestry and relatedness among RDEB patient populations will be crucial for the development of future clinical trials and the advancement of novel therapeutics., (© 2021 Wiley Periodicals LLC.)

We study a patient with the human papilloma virus (HPV)-2-driven "tree-man" phenotype and two relatives with unusually severe HPV4-driven warts. The giant horns form an HPV-2-driven multifocal benign epithelial tumor overexpressing viral oncogenes in the epidermis basal layer. The patients are unexpectedly homozygous for a private CD28 variant. They have no detectable CD28 on their T cells, with the exception of a small contingent of revertant memory CD4 + T cells. T cell development is barely affected, and T cells respond to CD3 and CD2, but not CD28, costimulation. Although the patients do not display HPV-2- and HPV-4-reactive CD4 + T cells in vitro, they make antibodies specific for both viruses in vivo. CD28-deficient mice are susceptible to cutaneous infections with the mouse papillomavirus MmuPV1. The control of HPV-2 and HPV-4 in keratinocytes is dependent on the T cell CD28 co-activation pathway. Surprisingly, human CD28-dependent T cell responses are largely redundant for protective immunity., Competing Interests: Declaration of interests L.D.N. receives compensation as Chief Editor of Frontiers in Immunology. T.W. serves on advisory boards for MSD (Merck Sharp and Dohme). J.-L.C. serves on the scientific advisory boards of ADMA Biologics Inc., Kymera Therapeutics, and Elixiron Immunotherapeutics. All other authors declare no competing interests., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Dermal fibroblasts are the most accessible cells in the skin that have gained significant attention in cell therapy. Applying dermal fibroblasts' regenerative capacity can introduce new patterns to develop cell-based therapies to treat skin disorders. Dermal fibroblasts originate from mesenchymal cells and are located within the dermis. These cells are mainly responsible for synthesizing glycosaminoglycans, collagens, and components of extracellular matrix supporting skin's structural integrity. Preclinical studies suggested that allogeneic and autologous dermal fibroblasts provide widespread and beneficial applications for wound healing, burn ulcers, and inherited skin disorders. In this regard, generating induced pluripotent stem cells (iPSCs) from fibroblasts and gene-edited fibroblasts are promising approaches for treating skin disorders. Here, we aimed to review literature about ongoing and completed clinical trials that applied fibroblasts and bioengineered fibroblasts as therapeutic agents for various skin disorders. This review explores cell therapy protocols from the earliest phase of allogeneic and autologous fibroblasts development in different benches to translating them into bedside-level treatment for skin disorders, particularly recessive dystrophic epidermolysis bullosa., (© 2021 Wiley Periodicals LLC.)

The Mendelian disorders of cornification consist of a highly heterogeneous group of diseases, and the majority of nonsyndromic cases belong to the family of autosomal recessive congenital ichthyosis. Mutations in SDR9C7 have been associated with autosomal recessive congenital ichthyosis, and clinical manifestations include mild to moderately dry, scaly skin with or without hyperkeratosis, palmoplantar keratoderma, and erythroderma. SDR9C7, with short-chain dehydrogenase and/or reductase activity, is known as nicotinamide adenine dinucleotide‒ or nicotinamide adenine dinucleotide phosphate‒dependent oxidoreductase and has been shown to be involved in the final step of epidermal lipid barrier formation by covalent binding of acylceramide to the cornified envelope. In this study, we present the clinical and molecular description of 19 patients with autosomal recessive congenital ichthyosis in five consanguineous families with SDR9C7 mutations. We also downregulated the expression of SDR9C7 in keratinocytes using the small interfering RNA technique in three-dimensional organotypic skin constructs. Our results demonstrated morphological and histological abnormalities in these constructs ex vivo, similar to those observed in patients with ichthyosis. Moreover, the results from keratinocyte migration and epidermal dye penetration assays provided evidence for the role of SDR9C7 in the disease pathomechanism. Collectively, our results indicate that SDR9C7 deficiency by itself is sufficient to disrupt epidermal barrier function leading to ichthyotic phenotype., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: Well-defined germ-line mutations in the PTCH1 gene are associated with syndromic multiple basal cell carcinomas (BCCs). Here, we used whole exome sequencing (WES) to identify the role of patched-1 in patients with multiple, unusually large BCCs., Methods: A 72-year old patient presenting with numerous BCCs progressing to large ulcerating lesions was enrolled. WES was used to identify the pathogenic gene locus., Results: Genetic work-up by WES identified a homozygous PTCH1 nonsense mutation in the tumor tissue but not present in her blood cells or in non-lesional skin. In addition, heterozygous missense mutations were identified in three cancer-associated genes ( EPHB2, RET , and GALNT12 ) in blood cells as well as in lesional and non-lesional skin. We also tested systemic immune therapy as a potentially beneficial approach to treat patients with numerous large BCCs on scatted areas of involvement. A rapid and sustained response to nivolumab was noted, suggesting that it is an efficacious drug for long-term therapeutic outcome., Conclusion: PTCH1 , EPHB2, RET , and GALNT12 may potentially contribute to the synergistic oncogene driven malignant transformation manifesting as multiple, unusually large BCCs., Competing Interests: Conflicts of interest: Prof Jouni Uitto is the Honorary Editor-in-Chief of the International Journal of Dermatology and Venereology. The article was subject to the journal's standard procedures, with peer review handled independently of this editor and the research group., (Copyright © 2021 Hospital for Skin Diseases (Institute of Dermatology), Chinese Academy of Medical Sciences, and Chinese Medical Association, published by Wolters Kluwer, Inc.)

Background: Among the approximately 8000 Mendelian disorders, >1000 have cutaneous manifestations. In many of these conditions, the underlying mutated genes have been identified by DNA-based techniques which, however, can overlook certain types of mutations, such as exonic-synonymous and deep-intronic sequence variants. Whole-transcriptome sequencing by RNA sequencing (RNA-seq) can identify such mutations and provide information about their consequences., Methods: We analyzed the whole transcriptome of 40 families with different types of Mendelian skin disorders with extensive genetic heterogeneity. The RNA-seq data were examined for variant detection and prioritization, pathogenicity confirmation, RNA expression profiling, and genome-wide homozygosity mapping in the case of consanguineous families. Among the families examined, RNA-seq was able to provide information complementary to DNA-based analyses for exonic and intronic sequence variants with aberrant splicing. In addition, we tested the possibility of using RNA-seq as the first-tier strategy for unbiased genome-wide mutation screening without information from DNA analysis., Results: We found pathogenic mutations in 35 families (88%) with RNA-seq in combination with other next-generation sequencing methods, and we successfully prioritized variants and found the culprit genes. In addition, as a novel concept, we propose a pipeline that increases the yield of variant calling from RNA-seq by concurrent use of genome and transcriptome references in parallel., Conclusions: Our results suggest that "clinical RNA-seq" could serve as a primary approach for mutation detection in inherited diseases, particularly in consanguineous families, provided that tissues and cells expressing the relevant genes are available for analysis., (© American Association for Clinical Chemistry 2021. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Epidermolysis bullosa (EB) is a genotypically heterogeneous group of disorders characterized by cutaneous blistering and erosions with a tremendous spectrum of severity. One of the distinct forms of EB, Kindler EB (KEB), manifests with blistering and poikiloderma; this subtype of EB is caused by mutations in the FERMT1 gene encoding kindlin-1. In this study, we investigated a patient clinically diagnosed as KEB with reduced FERMT1 gene expression and intensity of immunostaining for kindlin-1. Transmission electron microscopy showed lamina densa reduplication, frequently observed in KEB. However, no mutations were identified in FERMT1 in this patient with consanguineous parents, and this gene resided outside of genomic regions of homozygosity (ROH). Instead, whole-exome sequencing and homozygosity mapping identified a homozygous sequence variant at the +4 position of intron 2 in the USB1 gene, encoding an exoribonuclease required for processing of U6 snRNA, a critical component of spliceosomes. Examination of the patient's RNA by RNA-Seq confirmed the pathogenicity of this variant, causing aberrant splicing predicted to result in loss of function of USB1. Mutations in this gene have been reported in patients with poikiloderma and neutropenia, with a few reported cases in association with skin fragility, a condition distinct from the KEB phenotype. Transcriptome analysis revealed that several genes, expressed in the cutaneous basement membrane zone and previously associated with different subtypes of EB, were differentially downregulated at the mRNA level. EB-associated mRNA downregulation was confirmed at protein levels by skin immunofluorescence. These observations provide a novel mechanism for blistering and erosions in the skin as a result reduced presence of adhesion complexes critical for stable association of epidermis and dermis at the level of cutaneous basement membrane zone., Competing Interests: Declaration of Competing Interest None, (Copyright © 2021. Published by Elsevier B.V.)

Competing Interests: The authors have no funding or conflicts of interest to declare.

Arrhythmogenic right ventricular cardiomyopathy (ARVC), with skin manifestations, has been associated with mutations in JUP encoding plakoglobin. Genotype-phenotype correlations regarding the penetrance of cardiac involvement, and age of onset have not been well established. We examined a cohort of 362 families with skin fragility to screen for genetic mutations with next-generation sequencing-based methods. In two unrelated families, a previously unreported biallelic mutation, JUP: c.201delC; p.Ser68Alafs * 92, was disclosed. The consequences of this mutation were determined by expression profiling both at tissue and ultrastructural levels, and the patients were evaluated by cardiac and cutaneous work-up. Whole-transcriptome sequencing by RNA-Seq revealed JUP as the most down-regulated gene among 21 skin fragility-associated genes. Immunofluorescence showed the lack of plakoglobin in the epidermis. Two probands, 2.5 and 22-year-old, with the same homozygous mutation, allowed us to study the cross-sectional progression of cardiac involvements in relation to age. The older patient had anterior T wave inversions, prolonged terminal activation duration (TAD), and RV enlargement by echocardiogram, and together with JUP mutation met definite ARVC diagnosis. The younger patient had no evidence of cardiac disease, but met possible ARVC diagnosis with one major criterion (the JUP mutation). In conclusion, we identified the same biallelic homozygous JUP mutation in two unrelated families with skin fragility, but cardiac findings highlighted age-dependent penetrance of ARVC. Thus, young, phenotypically normal patients with biallelic JUP mutations should be monitored for development of ARVC.

Vitiligo is a multifactorial skin disease with established role of genetics and autoimmunity in its pathogenesis. Vitamin D receptor (VDR) polymorphisms have been suggested to correlate with risk of vitiligo in some ethnic populations. On the other hand, cathelicidin, one of the innate immune system components, has a role in development of some chronic skin diseases and VDR regulates the expression of cathelicidin. We aimed to determine the plasma level of cathelicidin and its association with the VDR gene polymorphisms as well as plasma vitamin D level in patients with vitiligo. Ninety vitiligo patients and 90 non-vitiligo controls participated in this study. Blood levels of 25(OH) vitamin D and cathelicidin were determined with ELISA. Genotyping for VDR polymorphisms (ApaI, TaqI, FokI and BsmI) was done with RFLP-PCR method. Mean blood level of cathelicidin was significantly higher in vitiligo patients as compared to controls (P < .0001). Mean blood level of vitamin D was significantly lower in patients than controls (P = .01). Statistically significant differences were not observed for both genotype and allele frequencies of BsmI, ApaI and TaqI polymorphisms. There was a borderline increased risk of vitiligo in over-dominant model of FokI polymorphism with OR = 1.8 and P = .051. Our findings was suggestive of the potential role of cathelicidin in the pathogenesis of vitiligo; however, future evaluations are needed to determine its precise mechanism. Genetic study of VDR gene polymorphism was suggestive of increased risk of vitiligo in association with a FokI polymorphism in Iranian population., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Keratitis-ichthyosis-deafness (KID) syndrome is caused by mutations in the GJB2 gene encoding connexin 26, a component of transmembrane hemichannels which form gap junction channels, critical for cell-cell communication. Here, we report two patients from two distinct families with KID syndrome with the same GJB2 mutation (p.Asp50Asn); in both cases the mutation was de novo, as the parents depicted the wild-type allele only. The patients' cutaneous manifestations were strikingly different illustrating the wide spectrum of phenotype of these patients, even with the same GJB2 mutation. One of the patients was treated with acitretin with dramatic improvement in his skin findings, illustrating the role of oral acitretin in treatment of patients with KID syndrome. Collectively, these patients attest to the phenotypic spectrum of KID syndrome, with therapeutic perspective., (© 2020 Wiley Periodicals LLC.)

H syndrome is a complex multi-organ disorder with autosomal recessive inheritance. The skin manifestations include early onset hyperpigmentation and hypertrichosis, followed by skin induration often diagnosed as scleromyxedema and morphea. There is no effective treatment. Our objective was to study the efficacy of mycophenolate mofetil in a patient with genetically confirmed H syndrome. We sought the genetic cause of H syndrome with whole-exome sequencing (WES) of the proband. Genome-wide homozygosity mapping (HM) provided additional evidence for causality of the variant suggested by WES. Here, we report a patient with characteristic clinical features of H syndrome, and the diagnosis was confirmed by identification of a homozygous SLC29A3 mutation (p.Gly437Arg). The patient was initially treated with prednisolone and cyclosporine, but after development of side-effects she was placed on mycophenolate mofetil. After the treatment with mycophenolate mofetil was initiated, resolution of hyperpigmentation was noted, and no new lesions developed during an 18-month follow-up period. Thus, mycophenolate mofetil could be considered as a safe and partially effective treatment of H syndrome., (© 2020 Wiley Periodicals LLC.)

Increasing evidence on the association of MTHFR gene polymorphism and serum homocysteine levels with autoimmune diseases such as vitiligo has made the MTHFR gene a very interesting candidate to be evaluated in different ethnicities and populations. We aimed to evaluate the levels of serum homocysteine and vitamin B12 and their associations with MTHFR C677T polymorphism in the Iranian population. This case-control study included 104 patients with vitiligo and 100 age- and sex-matched healthy control subjects. Serum vitamin B12 and homocysteine levels were measured by a chemiluminescence assay. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was used for genotyping the polymorphism. The mean serum homocysteine levels were significantly higher in cases than controls and associated with disease activity (p < .001). Furthermore, the homozygous MTHFR C677T variant genotype was associated with vitiligo development (adjusted OR: 3.52, 95% CI: 1.09-11.32, p = .02) and elevated homocysteine level (p < .001). There was no association between serum vitamin B12 levels and the MTHFR C677T genotype. The homozygous variant MTHFR C677T may be considered as a risk factor for both elevated homocysteine levels and the development of vitiligo in the Iranian population. Although these results are not conclusive, they could elucidate the contribution of genetic and immune-mediated inflammatory factors to the pathogenesis of vitiligo., (© 2020 John Wiley & Sons Ltd.)

The proper development and function of skin and hair are dependent on proteolytic activities. Specifically, the matriptase-prostasin cascade is a series of proteolytic reactions in the epidermis integral to normal regulation of desquamation. An increasing amount of research describing this pathway has recently become available, and the importance of this pathway is exhibited by the association of genetic defects in this pathway with human diseases of the skin and hair. Given the relevance of this pathway to dermatology, we provide a review of the current understanding of its relevance to distinct clinical entities, including ichthyosis-hypotrichosis and Netherton syndromes., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Defining the quality of life in the patients with epidermolysis bullosa (EB) is important in patient care and management. Evaluation of quality of life requires a valid and reliable scale. The Quality of Life in Epidermolysis Bullosa (EB-QoL) questionnaire, which is an English 17-item questionnaire, has emerged as a useful tool for assessing the quality of life in the patients with EB., Objective: This study aimed to evaluate the psychometric properties of the Farsi version of the EB-QoL questionnaire among a group of Iranian patients with EB., Methods: The Farsi version of the EB-QoL questionnaire was finalized after translation and back-translation. From the 100 patients with EB invited to participate in the study, 83 completed the questionnaire (response rate: 83%). Subsequently, the content validity and construct validity of the questionnaire were assessed. The reliability of the questionnaire was assessed with Cronbach's alpha. Moreover, the correlation between EB-QoL scores and EB severity scores (based on the Birmingham Epidermolysis bullosa severity score scale) was evaluated., Results: A total of 83 patients (40 male and 43 female) with a median age of 15 years (interquartile range, 9-24 years) and an age range between 3 and 43 years were enrolled in this study. Mean ± standard deviation scores from the EB-QoL questionnaire were 43.7 ± 9.9. The translated EB-QoL questionnaire showed a high internal consistency (Cronbach alpha = 0.90) and adequate item-total correlation. Also, there was a significant correlation between EB-QoL and EB severity scores ( r  = 0.39; p  < .001)., Conclusion: The Farsi version of EB-QoL questionnaire has acceptable validity and reliability. Thus, the questionnaire can be used for future studies to assess the quality of life among Iranian patients with EB., (© 2020 The Author(s).)

The patched tumor suppressor gene (PTCH1) encodes a receptor, which is a key component of the hedgehog signalling pathway. Mutations in PTCH1 are implicated in the development of sporadic basal cell carcinomas (BCC), as well as those in Gorlin Syndrome. Rarely, BCCs may develop in a linear pattern along lines of Blaschko due to cutaneous mosaicism. In cases in which there are other features of Gorlin syndrome, genomic analysis has demonstrated lesional mutations in the Hedgehog signalling pathway. Causative mutations, however, have not been firmly demonstrated in the cases of linear and segmental BCCs in otherwise healthy individuals. Herein, we report a case of a 31 year-old Caucasian woman with linear development of multiple superficial BCCs in a Blaschkoid distribution without other characteristic findings of Gorlin syndrome. Genomic analysis of lesional skin by whole-exome sequencing identified a novel heterozygous mutation PTCH1: NM&#95;000264.3, Exon 15, c.2336-2337insGGTAGGA, p.Asp779Glufs*13 in PTCH1, shared by two discrete samples within the lesion, while no mutations were found in the non-lesional skin or peripheral blood. Given the young age of our patient and linear distribution of BCCs on non-sun exposed skin, our findings suggest segmental mosaicism. The patient was treated with topical 5% imiquimod with histologically confirmed clearance of BCCs in 2 months., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Mendelian disorders with cutaneous manifestations comprise a genotypically heterogeneous group of over 1,000 diseases, and in most of them mutant genes have been identified. Mutation detection approaches in these diseases have largely focused on DNA analysis by next-generation sequencing techniques, including gene-targeted sequencing panels as well as whole-exome and whole-genome sequencing. Genome-wide homozygosity mapping (HM), based on DNA polymorphism, has also assisted in the identification of candidate genes in families with consanguinity. However, specific pathogenic variants have not been disclosed in many individual patients when analyzed by next-generation sequencing, and in particular, DNA-based analysis failed to identify many of the mutations impacting on splicing or gene expression. Whole-transcriptome sequencing by RNA sequencing (RNA-Seq), with appropriate bioinformatics, provides a robust tool to identify additional mutations to facilitate genetic diagnosis in genodermatoses. RNA-Seq can be used for variant calling and HM similar to DNA-based approaches, but it also allows for the identification of mutations that result in aberrant transcriptome expression, as displayed by heatmap analysis, and altered splicing patterns of RNA, as visualized by Sashimi plots. Thus, clinical RNA-Seq extends molecular diagnostics of rare genodermatoses, and it could provide a reliable first-tier diagnostic approach to extend mutation databases in patients with heritable skin diseases., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Next-generation sequencing (NGS) is helpful in diagnosing complex genetic disorders and phenotypes, particularly when more than one overlapping condition is present. From a large cohort of 362 families with clinical manifestations of skin and mucosal fragility, referred by several major medical centers, one patient was found by NGS to have two overlapping heritable skin diseases, recessive dystrophic epidermolysis bullosa (RDEB; COL7A1 mutations) and acrodermatitis enteropathica (AE; SLC39A4 mutations). The pathogenicity of the variants was studied at gene expression as well as ultrastructural and tissue levels. Although there is no specific treatment for RDEB except avoiding trauma, supplementation with oral zinc (3 mg·kg -1 ·day -1 ) for the AE resulted in rapid amelioration of the skin findings. This case demonstrates the power of NGS in identifying two genetically unlinked diseases that led to effective treatment with major clinical benefits as an example of genomics-guided treatment., (© 2020 Wiley Periodicals, Inc.)

The heritable forms of keratinization disorders, including various forms of ichthyosis and keratodermas, comprise a phenotypically heterogeneous group of diseases which can be divided into syndromic and non-syndromic forms. In the non-syndromic forms, the clinical manifestations are limited to the cutaneous structures while the syndromic ones are associated with a spectrum of extracutaneous manifestations. The inheritance in different families can be autosomal dominant, autosomal recessive or either X-linked dominant or recessive. Currently at least 67 distinct genes have been associated with different forms of ichthyosis. These genes can be grouped on the basis of their physiological involvement, including genes encoding structural components of epidermis, those involved in epidermal lipid metabolism, or those critical for cell-cell adhesion, and keratinocyte differentiation. This overview highlights some of the recent progress made in understanding the molecular genetics of keratinization disorders, and presents selected, recently characterized cases as representative of different forms of heritable ichthyosis.

Background: Recessive forms of congenital ichthyosis encompass a group of rare inherited disorders of keratinization leading to dry, scaly skin. So far, 13 genes have been implicated, but there is a paucity of data on genotype-phenotype correlation in some populations., Objectives: We compiled an English cohort of 146 individuals with recessive ichthyosis and assessed genotype-phenotype correlation., Methods: Deep phenotyping was undertaken by history-taking and clinical examination. DNA was screened for mutations using a next-generation sequencing ichthyosis gene panel and Sanger sequencing., Results: Cases were recruited from 13 National Health Service sites in England, with 65% of patients aged < 16 years at enrolment. Pathogenic biallelic mutations were found in 83% of cases, with the candidate gene spread as follows: TGM1 29%, NIPAL4 12%, ABCA12 12%, ALOX12B 9%, ALOXE3 7%, SLC27A4 5%, CERS3 3%, CYP4F22 3%, PNPLA1 2%, SDR9C7 1%. Clinically, a new sign, an anteriorly overfolded ear at birth, was noted in 43% of patients with ALOX12B mutations. The need for intensive care stay (P = 0·004), and hand deformities (P < 0·001), were associated with ABCA12 mutations. Self-improving collodion ichthyosis occurred in 8% of the cases (mostly TGM1 and ALOX12B mutations) but could not be predicted precisely from neonatal phenotype or genotype., Conclusions: These data refine genotype-phenotype correlation for recessive forms of ichthyosis in England, demonstrating the spectrum of disease features and comorbidities, as well as the gene pathologies therein. Collectively, the data from these patients provide a valuable resource for further clinical assessment, improving clinical care and the possibility of future stratified management. What's already known about this topic? Recessive forms of ichthyosis are rare but often difficult to diagnose. Mutations in 13 genes are known to cause recessive forms of ichthyosis: ABCA12, ALOX12B, ALOXE3, CERS3, CYP4F22, LIPN, NIPAL4, PNPLA1, SDR9C7, SLC27A4, SULT2B1, ST14 and TGM1. Some phenotypic features may associate with certain gene mutations, but paradigms for genotype-phenotype correlation need refining. What does this study add? The genotypic spectrum of recessive ichthyosis in England (based on 146 cases) comprises TGM1 (29%), NIPAL4 (12%), ABCA12 (12%), ALOX12B (9%), ALOXE3 (7%), SLC27A4 (5%), CERS3 (3%), CYP4F22 (3%), PNPLA1 (2%) and SDR9C7 (1%). New or particular phenotypic clues were defined for mutations in ALOX12B, ABCA12, CYP4F22, NIPAL4, SDR9C7 and TGM1, either in neonates or in later life, which allow for greater diagnostic precision. In around 17% of cases, the molecular basis of recessive ichthyosis remains unknown., (© 2019 British Association of Dermatologists.)

Spherical nucleic acids (SNAs) are nanostructures consisting of highly oriented, dense layers of oligonucleotides arranged in a spherical 3D geometry. Owing to their unique properties and function, SNAs occupy a material space distinct from 'DNA nanotechnology' and DNA origami. Over the past two decades SNAs have revolutionized gene regulation, drug delivery, gene therapy, and molecular diagnostics, and show promise for both antisense and RNAi therapy. We focus here on recent advances in the synthesis and application of SNAs in gene and drug delivery, diagnostics, and immunomodulation, as well as on the utility of nanoflares as intracellular mRNA detection systems., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Hypotrichosis with juvenile macular dystrophy (HJMD) is an autosomal recessive disorder characterized by abnormal growth of scalp hair and juvenile macular degeneration leading to blindness. We have explored the genetic basis of HJMD in a large consanguineous family with 12 affected patients, 1-76 years of age, with characteristic phenotypes., Methods: We first applied genome-wide homozygosity mapping to 10 affected individuals for linkage analysis to identify the genomic region of the defective gene. All affected individuals shared a 7.2 Mb region of homozygosity on chromosome 16q21-22.3, which harbored 298 genes, including CDH3, previously associated with HJMD. However, whole-exome sequencing (WES) failed to identify the causative mutation in CDH3., Results: Further investigation revealed a missense variant in a gene closely linked to CDH3 (1.4 Mb distance: FHOD1: c.1306A>G, p.Arg436Gly). This variant was homozygous in all affected individuals and heterozygous in 18 out of 19 obligate carriers. While this variant was found by bioinformatics predictions to be likely pathogenic, a knock-in mouse for this variant, made by the CRISPR/Cas, showed no disease phenotype. However, using whole-genome sequencing (WGS), we were able to identify a novel Alu recombination-mediated deletion in CDH3:c.del161-811&#95;246 + 1,044., Conclusion: WGS was able to identify a deep intronic deletion mutation, not detected by WES., (© 2019 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals, Inc.)