CRISPR/Cas9-based targeted genome editing for correction of recessive dystrophic epidermolysis bullosa using iPS cells.

Recessive dystrophic epidermolysis bullosa (RDEB) is a severe inherited skin disorder caused by mutations in the COL7A1 gene encoding type VII collagen (C7). The spectrum of severity depends on the type of mutation in the COL7A1 gene. C7 is the major constituent of anchoring fibrils (AFs) at the basement membrane zone (BMZ). Patients with RDEB lack functional C7 and have severely impaired dermal-epidermal stability, resulting in extensive blistering and open wounds on the skin that greatly affect the patient's quality of life. There are currently no therapies approved for the treatment of RDEB. Here, we demonstrated the correction of mutations in exon 19 (c.2470insG) and exon 32 (c.3948insT) in the COL7A1 gene through homology-directed repair (HDR). We used the clustered regulatory interspaced short palindromic repeats (CRISPR) Cas9-gRNAs system to modify induced pluripotent stem cells (iPSCs) derived from patients with RDEB in both the heterozygous and homozygous states. Three-dimensional human skin equivalents (HSEs) were generated from gene-corrected iPSCs, differentiated into keratinocytes (KCs) and fibroblasts (FBs), and grafted onto immunodeficient mice, which showed normal expression of C7 at the BMZ as well as restored AFs 2 mo postgrafting. Safety assessment for potential off-target Cas9 cleavage activity did not reveal any unintended nuclease activity. Our findings represent a crucial advance for clinical applications of innovative autologous stem cell-based therapies for RDEB.

Whole-Transcriptome Analysis by RNA Sequencing for Genetic Diagnosis of Mendelian Skin Disorders in the Context of Consanguinity.

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.

Ancestral patterns of recessive dystrophic epidermolysis bullosa mutations in Hispanic populations suggest sephardic ancestry.

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.

Mutations in the cholesterol transporter gene ABCA5 are associated with excessive hair overgrowth.

Inherited hypertrichoses are rare syndromes characterized by excessive hair growth that does not result from androgen stimulation, and are often associated with additional congenital abnormalities. In this study, we investigated the genetic defect in a case of autosomal recessive congenital generalized hypertrichosis terminalis (CGHT) (OMIM135400) using whole-exome sequencing. We identified a single base pair substitution in the 5' donor splice site of intron 32 in the ABC lipid transporter gene ABCA5 that leads to aberrant splicing of the transcript and a decrease in protein levels throughout patient hair follicles. The homozygous recessive disruption of ABCA5 leads to reduced lysosome function, which results in an accumulation of autophagosomes, autophagosomal cargos as well as increased endolysosomal cholesterol in CGHT keratinocytes. In an unrelated sporadic case of CGHT, we identified a 1.3 Mb cryptic deletion of chr17q24.2-q24.3 encompassing ABCA5 and found that ABCA5 levels are dramatically reduced throughout patient hair follicles. Collectively, our findings support ABCA5 as a gene underlying the CGHT phenotype and suggest a novel, previously unrecognized role for this gene in regulating hair growth.

Type VII collagen regulates expression of OATP1B3, promotes front-to-rear polarity and increases structural organisation in 3D spheroid cultures of RDEB tumour keratinocytes.

Type VII collagen is the main component of anchoring fibrils, structures that are integral to basement membrane homeostasis in skin. Mutations in the gene encoding type VII collagen COL7A1 cause recessive dystrophic epidermolysis bullosa (RDEB) an inherited skin blistering condition complicated by frequent aggressive cutaneous squamous cell carcinoma (cSCC). OATP1B3, which is encoded by the gene SLCO1B3, is a member of the OATP (organic anion transporting polypeptide) superfamily responsible for transporting a wide range of endogenous and xenobiotic compounds. OATP1B3 expression is limited to the liver in healthy tissues, but is frequently detected in multiple cancer types and is reported to be associated with differing clinical outcome. The mechanism and functional significance of tumour-specific expression of OATP1B3 has yet to be determined. Here, we identify SLCO1B3 expression in tumour keratinocytes isolated from RDEB and UV-induced cSCC and demonstrate that SLCO1B3 expression and promoter activity are modulated by type VII collagen. We show that reduction of SLCO1B3 expression upon expression of full-length type VII collagen in RDEB cSCC coincides with acquisition of front-to-rear polarity and increased organisation of 3D spheroid cultures. In addition, we show that type VII collagen positively regulates the abundance of markers implicated in cellular polarity, namely ELMO2, PAR3, E-cadherin, B-catenin, ITGA6 and Ln332.

Characterization of individuals at high risk of developing melanoma in Latin America: bases for genetic counseling in melanoma.

PURPOSE: CDKN2A is the main high-risk melanoma-susceptibility gene, but it has been poorly assessed in Latin America. We sought to analyze CDKN2A and MC1R in patients from Latin America with familial and sporadic multiple primary melanoma (SMP) and compare the data with those for patients from Spain to establish bases for melanoma genetic counseling in Latin America. METHODS: CDKN2A and MC1R were sequenced in 186 Latin American patients from Argentina, Brazil, Chile, Mexico, and Uruguay, and in 904 Spanish patients. Clinical and phenotypic data were obtained. RESULTS: Overall, 24 and 14% of melanoma-prone families in Latin America and Spain, respectively, had mutations in CDKN2A. Latin American families had CDKN2A mutations more frequently (P = 0.014) than Spanish ones. Of patients with SMP, 10% of those from Latin America and 8.5% of those from Spain had mutations in CDKN2A (P = 0.623). The most recurrent CDKN2A mutations were c.-34G>T and p.G101W. Latin American patients had fairer hair (P = 0.016) and skin (P < 0.001) and a higher prevalence of MC1R variants (P = 0.003) compared with Spanish patients. CONCLUSION: The inclusion criteria for genetic counseling of melanoma in Latin America may be the same criteria used in Spain, as suggested in areas with low to medium incidence, SMP with at least two melanomas, or families with at least two cases among first- or second-degree relatives.Genet Med 18 7, 727-736.

The Importance of Esophagography in Patients With Recessive Dystrophic Epidermolysis Bullosa.

OBJECTIVE: The purpose of this study was to assess esophageal damage in patients with recessive dystrophic epidermolysis bullosa (RDEB) with or without dysphagia. SUBJECTS AND METHODS: Fourteen patients with either severe generalized or another generalized form of RDEB recruited through a research and support foundation were evaluated for obstructive esophageal lesions by means of barium esophagography. RESULTS: All patients, even those without dysphagia, had at least one stenosis; five patients had two stenoses. Stenotic lesions occurred most often (74%) in the upper third of the esophagus. CONCLUSION: Esophageal stenosis is a common complication in patients with RDEB, even when they do not have dysphagia. We recommend regular esophagographic examinations of all patients with RDEB.

Fatal Outcome from Brain Vascular Lesions in a Neonate with Blue Rubber Bleb Nevus Syndrome.

The most common cause of death in blue rubber bleb nevus syndrome is gastrointestinal bleeding. Here we present a case of central nervous system bleeding that resulted in death.

Lethal Keratitis, Ichthyosis, and Deafness Syndrome Due to the A88V Connexin 26 Mutation.

Keratitis-ichthyosis-deafness syndrome is a well-characterized disease that has been related to mutations in the GJB6 gene. Clinical features such as erythrokeratoderma, palmoplantar keratoderma, alopecia, and progressive vascularizing keratitis, among others, are well known in this entity. In this report we describe a newborn female patient diagnosed with keratitis-ichthyosis-deafness syndrome with a lethal outcome due to sepsis. The patient harbored the mutation A88V that has been previously reported in lethal cases.

Hypertrichosis lanuginosa congenita treated with diode laser epilation during infancy.

We report the case of a girl with hypertrichosis lanuginosa congenita treated with diode laser depilation since the age of 9 months. The treatment was well tolerated, and neither general nor local anesthesia was needed. A reduction of approximately 80% of facial and body hair was noted, which improved her condition significantly.

[Mutation in the ED1, Ala349Thr in a patient with X-linked hypohidrotic ectodermal dysplasia]. / Mutación en el gen EDA1, Ala349Thr en paciente con displasia ectodérmica hipohidrótica ligada a X.

Hypohidrotic ectodermal dysplasia (HED) is a very rare disease characterized by the absence of eccrine glands, dry skin, scanty hair, and dental abnormalities. It is caused by mutations within the ED1 gene, which encodes a protein, ectodysplasin-A (EDA). Clinical characteristic are frontal bossing, saddle nose, pointed chin, a prominent supraorbital ridge with periorbital hyperpigmenta-tion, and anodontia. Those affected show great intolerance to heat. We report the first Mexican 2-year-old boy with an Ala349Thr missense mutation from Tamaulipas, México.

Cutaneous adverse effects due to personal protective measures during COVID-19 pandemic: a study of 101 patients.

BACKGROUND: Coronavirus Disease 2019 (COVID-19) is a viral illness caused by the novel coronavirus SARS-CoV-2 which spreads via droplets from an infected person. There has been an unprecedented rise in the use of personal protective equipment and practice of personal hygiene measures against COVID-19. The extended use of protective measures (PM) can lead to ill effects on the skin. Our aim was to investigate PM-induced dermatoses amongst healthcare workers and the general population during the COVID-19 pandemic. METHODS: A cross-sectional study was conducted over a period of 2 months. The study subjects were patients who presented to dermatology outpatient clinics or sought teleconsultation for skin problems related to the use of PMs against COVID-19. A detailed history was obtained and cutaneous examination was documented for all the patients in a pre-set proforma. Diagnoses of the adverse skin effects were formulated based upon history and clinical examination. RESULTS: A total of 101 cases with cutaneous adverse effects due to the use of PMs against COVID-19 were included in the study. The general population and healthcare workers were affected similarly, comprising of 54.5% and 45.5%, respectively. The mean age of the study participants was 36.71 ± 15.72 years. The most common culprit material was soap and water (56.4%). Contact dermatitis was found to be the most common adverse effect in the majority of our patients (72.3%). The most common symptom reported was pruritus (45.5%). The wearing of personal protective equipment for a longer duration was significantly associated with multiple symptoms (P = 0.026). CONCLUSION: The enhanced use of different PMs against COVID-19 can result in a variety of adverse skin effects. In our study, the use of soap and water was the most common culprit PM, and contact dermatitis was the most common adverse effect noted.

A novel AAGAB mutation in a Peruvian family with punctate palmoplantar keratoderma.

Buschke-Fischer-Brauer (BFB) disease is a rare keratoderma characterized by multiple hyperkeratotic lesions on the palms and soles, with an autosomal dominant pattern. In several countries, some genetic alterations have been associated with this clinical entity. A 68-year-old Peruvian woman presenting with hyperkeratotic lesions on both her palms and soles was diagnosed with BFB keratoderma. After sequencing of the genes that had previously been related to this disease, a mutation (c.249C>G) that was predicted to generate a termination codon (Tyr83*) was found in the alpha and gamma adaptin binding protein P34 gene (AAGAB). After treatment with 30% urea plus 10% salicylic acid, the patient experienced an improvement in her condition. Here we report a novel mutation in the AAGAB gene of a patient diagnosed with BFB keratoderma and a treatment that improved her symptoms.

Physiotherapy for epidermolysis bullosa: clinical practice guidelines.

Epidermolysis bullosa (EB) is characterized by skin fragility with blister formation occurring spontaneously or following minor trauma such as gentle pressure or friction. Current physiotherapy practice is based on anecdotal care, clinical expertise and creative problem solving with caregivers and individuals with EB. Evidence based intervention is needed to establish a foundation of knowledge and to guide international practitioners to create and improve standards of care to effectively work with individuals living with EB. This clinical practice guideline (CPG) was created for the purpose of providing evidence based interventions and best clinical practices for the physiotherapy management of individuals with EB. A survey was conducted within the EB community and six outcomes were identified as a priority to address in physiotherapy management, including (1) attaining developmental motor milestones, (2) identifying safe and functional mobility in the natural environment, (3) encouraging ambulation endurance, (4) supporting safe ability to bear weight, (5) improving access to physiotherapy services, and (6) optimizing interaction with the community. A systematic literature review was conducted and articles were critically analyzed by an international panel consisting of thirteen members: healthcare professionals (including physiotherapist, doctors, and occupational therapist), caregivers, and individuals with EB. Recommendations were formulated from evidence and panel consensus. An external panel of twelve were invited to improve the quality and gather feedback on draft manuscript and recommendations. This CPG describes the development of recommendations for physiotherapy management including several best practice interventions. This guideline lays the foundational work for physiotherapist throughout the world to provide high quality services while improving and maintaining functional mobility and independence within the EB community. The CPG outlines limitations in the evidence available and possible future research needed to improve physiotherapy practice.

The importance of diagnostic imaging of mycetoma in the foot.

BACKGROUND: Mycetoma is a chronic, localized infection caused by fungi and bacteria. It usually affects the skin, subcutaneous tissue, and bone of exposed areas with deformity of the affected limb, ulcers, and fistula; however, pain is not severe, therefore the patient comes late to hospital for care. OBJECTIVE: To establish the diagnosis of mycetoma in the foot by imaging and identify the principal radiological signs. MATERIALS AND METHODS: Six patients with foot mycetoma were evaluated with plain x-ray, ultrasound, and magnetic resonance (MR) after confirming the diagnosis by histopathology and culture. RESULTS: All patients presented the MR "dot-in-circle" sign; four presented "punched out" bone lesions on plain x-ray. The six patients had fistulas, ulceration, a seropurulent exudate, edema, and a foot deformity. Four patients had N. brasiliensis infection with positive anti-Nocardia IgG antibodies, and only half presented bone lesions. CONCLUSION: Characteristic findings were foot deformity, edema, bone lesions, ulcers, fistulas and the presence of the "dot-in-circle" sign. We recommend a comprehensive study of patients with plain x-ray and MR.

Thrombospondin-1 Is a Major Activator of TGF-ß Signaling in Recessive Dystrophic Epidermolysis Bullosa Fibroblasts.

Mutations in the gene encoding collagen VII cause the devastating blistering disease recessive dystrophic epidermolysis bullosa (RDEB). RDEB is characterized by severe skin fragility and nonhealing wounds aggravated by scarring and fibrosis. We previously showed that TSP1 is increased in RDEB fibroblasts. Because transforming growth factor-ß (TGF-ß) signaling is also increased in RDEB, and TSP1 is known to activate TGF-ß, we investigated the role of TSP1 in TGF-ß signaling in RDEB patient cells. Knockdown of TSP1 reduced phosphorylation of smad3 (a downstream target of TGF-ß signaling) in RDEB primary fibroblasts, whereas overexpression of collagen VII reduced phosphorylation of smad3. Furthermore, inhibition of TSP1 binding to the LAP/TGF-ß complex decreased fibrosis in engineered extracellular matrix formed by RDEB fibroblasts, as evaluated by picrosirius red staining and analyses of birefringent collagen fibrillar deposits. We show that collagen VII binds TSP1, which could potentially limit TSP1-LAP association and subsequent TGF-ß activation. Our study suggests a previously unreported mechanism for increased TGF-ß signaling in the absence of collagen VII in RDEB patient skin. Moreover, these data identify TSP1 as a possible target for reducing fibrosis in the tumor-promoting dermal microenvironment of RDEB patients.

Epithelial HMGB1 Delays Skin Wound Healing and Drives Tumor Initiation by Priming Neutrophils for NET Formation.

Regenerative responses predispose tissues to tumor formation by largely unknown mechanisms. High-mobility group box 1 (HMGB1) is a danger-associated molecular pattern contributing to inflammatory pathologies. We show that HMGB1 derived from keratinocytes, but not myeloid cells, delays cutaneous wound healing and drives tumor formation. In wounds of mice lacking HMGB1 selectively in keratinocytes, a marked reduction in neutrophil extracellular trap (NET) formation is observed. Pharmacological targeting of HMGB1 or NETs prevents skin tumorigenesis and accelerates wound regeneration. HMGB1-dependent NET formation and skin tumorigenesis is orchestrated by tumor necrosis factor (TNF) and requires RIPK1 kinase activity. NETs are present in the microenvironment of keratinocyte-derived tumors in mice and lesional and tumor skin of patients suffering from recessive dystrophic epidermolysis bullosa, a disease in which skin blistering predisposes to tumorigenesis. We conclude that tumorigenicity of the wound microenvironment depends on epithelial-derived HMGB1 regulating NET formation, thereby establishing a mechanism linking reparative inflammation to tumor initiation.