Epidermolytic Hyperkeratosis Research Articles

Ихтиоздың сирек кездесетін клиникалық түрі - бір жақтық ихтиозформалы эритродермия: Клиникалық жағдай

Congenital ichthyosis is one of the hereditary dermatoses that develop due to a violation of the keratinization process. The clinical manifestation of ichthyosis is characterized by dryness of the skin during physical examination and scaling of different degrees of clarity. Congenital ichthyosis can be classified as one of the most difficult and urgent problems in the field of dermatology and pediatrics due to the fact that the pathogenesis of this pathology is not fully studied, its persistent course, and the difficulty of achieving positive treatment results.In addition, despite many common features, types of ichthyosis are distinguished based on clinical and histological appearance: simple ichthyosis, recessive X-doubled ichthyosis, classic lamellar ichthyosis, bullous and non-bullous congenital ichthyosiform erythroderma. In all these types of ichthyosis, there is a violation of cellular kinetics and their physiological exfoliation process, resulting in excessive keratinization of the skin in the primary manifestation. During ichthyosis, there is a violation of the barrier function of the skin, loss of water between the epidermis and inability of the skin to retain moisture. In this article, we have shared a patient with these symptoms who was diagnosed with unilateral ichthyosiform erythroderma, one of the rare forms of ichthyosis encountered in our practice. This article is informative for general practitioners, neonatologists, pediatricians, dermatovenerologists and geneticists.

Epidermolytic Ichthyosis Sine Epidermolysis–A Case Report and Molecular Analysis

Epidermolytic ichthyosis (EI) is a rare genodermatosis disorder. We report a 39-year-old woman with EI, who presented with generalized erythroderma since birth, followed by generalized hyperkeratosis later in life. The physical examination revealed generalized hyperkeratosis without blistering or erosion. The histopathological studies revealed hyperkeratosis with parakeratosis and psoriasiform hyperplasia, without significant epidermolysis. The Sanger sequencing revealed a missense mutation—c.467G>A (p.Arg156His)—in the KRT10 gene, confirming the diagnosis of EI. The genotype-phenotype correlations in EI patients are multifactorial. Thus, molecular analysis can confirm the diagnosis in cases of an unclear medical history or histological inconclusiveness.

273 Serum interleukin-18 as a disease-specific marker of epidermolytic ichthyosis: a potential therapeutic target

Epidermolytic ichthyosis (EI) is a major form of congenital ichthyosis and characterized by erythroderma, marked scales, bulla, and erosions at birth. EI is recently classified as keratinopathic ichthyoses and caused mainly by heterozygous mutations in the KRT1 or KRT10 genes, encoding keratin (K) 1 or K10, respectively. No effective treatment strategy for EI has been established yet. To investigate disease-specific markers and novel therapeutic targets in EI, we examined serum samples for 9 patients with congenital ichthyoses including five EI patients, one ichthyosis with confetti patient, one Netherton syndrome patient, and two autosomal recessive congenital ichthyosis patients.

278 Gene therapy of an EPPK-causing K9 variant using a CRISPR/Cas9 nickase mediated approach in primary keratinocytes

Epidermolytic palmoplantar keratoderma (EPPK) is a rare, autosomal dominantly inherited skin disorder. The disease is often caused by heterozygous point mutations in the keratin 9 gene coding for type I intermediate filament (IF) protein keratin 9 (K9). The integration of mutant K9 into the IF cytoskeleton has a dominant negative effect resulting in IF fragility and massive thickening of palmoplantar skin. The aim of this project was to correct the IF fragility in EPPK patient-derived primary keratinocyte (KC) cultures by gene editing.

Interleukin-18 as a severity marker and novel potential therapeutic target for epidermolytic ichthyosis.

Epidermolytic ichthyosis (EI) is a major form of nonsyndromic inherited ichthyosis, characterized by erythroderma, marked hyperkeratosis and scale, bulla and erosion at birth, associated with KRT1/KRT10 mutations. The cytokine and chemokine profiles in EI are poorly understood, and specific treatment options have not been established. To explore novel biomarkers and therapeutic targets in patients with EI. We analysed cytokine levels in serum and skin samples from 10 patients with inherited ichthyosis, including seven patients with EI. Wild-type and mutant KRT1 constructs were established and transfected into HaCaT cells, an immortalized keratinocyte cell line, for in vitro immunoblotting and immunocytochemistry analyses. Multiplex cytokine/chemokine analysis revealed that 10 cytokines/chemokines [interleukin (IL)-1β, IL-4, IL-17A, IL-16, IL-18, IL-1 receptor-α, macrophage colony-stimulating factor, interferon-α2, basic fibroblast growth factor and monocyte chemotactic protein-3] were significantly increased in patients with EI. Furthermore, IL-18 levels were significantly higher in patients with EI [n = 7; 2714.1 (1438.0) pg mL-1] than in healthy controls [n = 11; 218.4 (28.4) pg mL-1, P < 0.01]. Immunohistochemical analyses showed that IL-18 expression was elevated in skin samples from patients with EI. Serum IL-18 levels correlated with the severity of ichthyosis, as measured by the Ichthyosis Scoring System. Immunoblotting analysis revealed that mature IL-18 levels were increased in the supernatant of mutant KRT1 expressing HaCaT cells. Additionally, these cells showed NLRP3 aggregation in the cytoplasm and ASC clustered around mutant keratin aggregations. These findings suggest that mutant keratin might promote the activation of the NLRP3 inflammasome and its downstream caspase-1-mediated IL-18 release in keratinocytes from patients with EI. Our results suggest that serum IL-18 is a severity marker released from the skin of patients with EI. Blockade of IL-18 may be a useful novel therapeutic option for patients with EI.

Epidermolytic ichthyosis complicated by staphylococcal scalded skin syndrome in the newborn.

Epidermolytic ichthyosis is characterized by erythema and blistering at birth. We present a neonate with epidermolytic ichthyosis who had a subtle change in clinical findings while hospitalized, including increased fussiness, erythema, and a change in her skin odor, which represented superimposed staphylococcal scalded skin syndrome. This case highlights the unique challenge of recognizing cutaneous infections in neonates with blistering skin disorders and emphasizes the importance of having a high suspicion for superinfection in this population.

A de novo variant in the keratin 1 gene (KRT1) in a Chinese shar-pei dog with severe congenital cornification disorder and non-epidermolytic ichthyosis

A 3-months old Chinese shar-pei puppy with ichthyosis was investigated. The dog showed generalized scaling, alopecia and footpad lesions. Histopathological examinations demonstrated a non-epidermolytic hyperkeratosis. The parents of the affected puppy did not show any skin lesions. A trio whole genome sequencing analysis identified a heterozygous de novo 3 bp deletion in the KRT1 gene in the affected dog. This variant, NM_001003392.1:c.567_569del, is predicted to delete a single asparagine from the conserved coil 1A motif within the rod domain of KRT1, NP_001003392.1:p.(Asn190del). Immunohistochemistry demonstrated normal levels of KRT1 expression in the epidermis and follicular epithelia. This might indicate that the variant possibly interferes with keratin dimerization or another function of KRT1. Missense variants affecting the homologous asparagine residue of the human KRT1 cause epidermolytic hyperkeratosis. Histologically, the investigated Chinese shar-pei showed a non-epidermolytic ichthyosis. The finding of a de novo variant in an excellent functional candidate gene strongly suggests that KRT1:p.Asn190del caused the ichthyosis phenotype in the affected Chinese shar-pei. To the best of our knowledge, this is the first description of a KRT1-related non-epidermolytic ichthyosis in domestic animals.

Distinct skin microbiome community structures in congenital ichthyosis.

The ichthyoses are rare genetic keratinizing disorders that share the characteristics of an impaired epidermal barrier and increased risk of microbial infections. Although ichthyotic diseases share a T helper (Th) 17 cell immune signature, including increased expression of antimicrobial peptides, the skin microbiota of ichthyoses is virtually unexplored. To analyse the metagenome profile of skin microbiome for major congenital ichthyosis subtypes. Body site-matched skin surface samples were collected from the scalp, upper arm and upper buttocks of 16 healthy control participants and 22 adult patients with congenital forms of ichthyosis for whole metagenomics sequencing analysis. Taxonomic profiling showed significant shifts in bacteria and fungi abundance and sporadic viral increases across ichthyosis subtypes. Cutibacterium acnes and Malassezia were significantly reduced across body sites, consistent with skin barrier disruption and depletion of lipids. Microbial richness was reduced, with specific increases in Staphylococcus and Corynebacterium genera, as well as shifts in fungal species, including Malassezia. Malassezia globosa was reduced at all body sites, whereas M. sympodialis was reduced in the ichthyotic upper arm and upper buttocks. Malassezia slooffiae, by contrast, was strikingly increased at all body sites in participants with congenital ichthyosiform erythroderma (CIE) and lamellar ichthyosis (LI). A previously undescribed Trichophyton species was also detected as sporadically colonizing the skin of patients with CIE, LI and epidermolytic ichthyosis subtypes. The ichthyosis skin microbiome is significantly altered from healthy skin with specific changes predominating among ichthyosis subtypes. Skewing towards the Th17 pathway may represent a response to the altered microbial colonization in ichthyosis. What is already known about this topic? The skin microbiome of congenital ichthyoses is largely unexplored. Microbes play an important role in pathogenesis, as infections are common. The relative abundances of staphylococci and corynebacteria is increased in the cutaneous microbiome of patients with Netherton syndrome, but extension of these abundances to all congenital ichthyoses is unexplored. What does this study add? A common skin microbiome signature was observed across congenital ichthyoses. Distinct microbiome features were associated with ichthyosis subtypes. Changes in microbiome may contribute to T helper 17 cell immune polarization. What is the translational message? These data provide the basis for comparison of the microbiome with lipidomic and transcriptomic alterations in these forms of ichthyosis and consideration of correcting the dysbiosis as a therapeutic intervention.

34997 Melanocytic staining of focal acantholytic dyskeratosis and epidermolytic hyperkeratosis within dysplastic nevi

Incidental focal acantholytic dyskeratosis (FAD) and epidermolytic hyperkeratosis (EHK) are histologic findings often seen in ordinary and dysplastic nevi biopsies. The incidence of FAD and EHK are statistically increased within dysplastic nevi, suggesting these histologic patterns reflect cellular epidermal damage and have potential diagnostic utility. While the occurrence of FAD and EHK within dysplastic nevi samples is well-documented, neither have been examined with melanocytic immunostains.

478 CRISPER/Cas 9 mediated introduction of the keratin 1 mutation in mice that are identified in patients with epidermolytic ichthyosis

Mutations in the KRT1 cause epidermolytic ichthyosis (EI). There is a strong demand for the development of novel treatment measures. A mutation of c. 1436 T >C; p. Ile 479 Thr of K1 was identified in our case with severe palmoplantar keratoderma, and exaggerated skin lesion on joint skin. Our in silico survey revealed that this amino acid change caused a severe conformational alteration in the K1 protein, strongly suggesting that it interfered with the formation of the K1 / K10 coiled- coil complex.

Inflammatory linear verrucous epidermal nevus (ILVEN) encompasses a spectrum of inflammatory mosaic disorders.

Inflammatory linear verrucous epidermal nevus (ILVEN) is a rare skin disease characterized by pruritic erythematous scaly plaques distributed along the lines of Blaschko. Two cases of ILVEN with CARD14 mutations and one case with a GJA1 mutation have been previously reported. To elucidate the genetic cause of a cohort of patients diagnosed based on clinical and histopathological evaluation with ILVEN. We recruited patients diagnosed with ILVEN based on clinical and histopathological criteria. Exome sequencing of affected skin with or without blood/saliva was performed and germline and somatic pathogenic variants were identified. Five patients were enrolled. All had skin lesions from birth or early childhood. Two patients developed psoriasis vulgaris after the diagnosis of ILVEN. The first had a germline heterozygous CARD14 mutation and a post-zygotic hotspot mutation in KRT10. The histopathologic evaluation did not show epidermolytic hyperkeratosis. The second had a post-zygotic hotspot mutation in HRAS. Her ILVEN became itchy once psoriasis developed. One patient was re-diagnosed with linear porokeratosis based on a germline mutation in PMVK and a post-zygotic second-hit mutation. Two patients were re-diagnosed with congenital hemidysplasia with ichthyosiform nevus and limb defect nevus based on germline NSDHL mutations. ILVEN is a clinical descriptor for a heterogenous group of mosaic inflammatory disorders. Genetic analysis has the potential to more precisely categorize ILVEN and permits pathogenesis-directed therapies in some cases.

Quality of Life among Pediatric Patients and their Families Suffering from Congenital Ichthyosis - A Cross-Sectional Study

Introduction: Ichthyosis are a heterogeneous group of hereditary skin disorders characterized by dryness, hyperkeratosis, and desquamation. The purpose of this study was to evaluate quality of life (QoL) of patients with ichthyosis and their families. Materials and Methods: A total of 72 patients were enrolled and 60 patients completed the study. The study instrument included Infants' Dermatitis Life Quality Index and Children's Dermatology Life Quality Index for pediatric patients (5–16 years) and Dermatitis Family Impact Questionnaire (DFI) for family members. Results: Questionnaires were completed in 60 children. The patients had predominantly ichthyosis vulgaris (n = 46), lamellar ichthyosis (n = 10), nonbullous ichthyosiform erythroderma (n = 3), and bullous ichthyosiform erythroderma (n = 1). Male: female ratio was 1:1.5. Large effect on QoL was seen in 77.8% and 66.6% of ichthyosis vulgaris and lamellar, ichthyosis, respectively. Mean score of DFI was 9.94 ± 7.23. Conclusion: The present study reports a poor QoL among pediatric patients suffering from ichthyosis and their families. Psychosocial and mental support is needed for patients and their immediate caregivers/families for this chronic skin disease.

Nonsense mutations in KRT1 caused recessive epidermolytic palmoplantar keratoderma with knuckle pads

Epidermolytic palmoplantar keratoderma (EPPK) is characterized by diffuse hyperkeratosis affecting palms and soles with suprabasal epidermolysis or vacuolar degeneration histopathologically. The disorder is caused by heterozygous mutations in KRT9 or KRT1. Dominant-negative mutations in KRT1 could also result in epidermolytic ichthyosis with EPPK, a more severe entity affecting the entire body. To investigate the genetic basis and pathogenesis of two unrelated patients with EPPK and knuckle pads, both of whom were born to consanguineous parents of Chinese origin. Next-generation sequencing was applied to the two patients using genomic DNA extracted from peripheral blood. Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR), immunofluorescence (IF) staining and Western blot (WB) were employed to evaluate mRNA and protein expression level. Ultrastructural changes of skin lesion were analysed using transmission electron microscopy. Two novel homozygous mutations, c.457C>T (p.Gln153*) and c.33C>G (p.Tyr11*) in KRT1, were identified in patients 1 and 2 respectively. The nonsense mutations were predicted to result in nonsense-mediated mRNA decay and absence of keratin 1, which was confirmed in the skin lesions from patient 1. Upregulated keratin 2 was detected both in the affected and unaffected skin samples from patient 1, while the protein abundance and distribution pattern of keratin 10 remained unchanged. An aberrant and clumped staining pattern of keratin 9 was noted in the palmar skin of patient 1. Homozygous 'knockout' mutations in KRT1 resulted in EPPK with knuckle pads rather than epidermolytic ichthyosis. We speculated that sparing of non-acral skin might be due to compensatory effect of keratin 2 upregulation by forming heterodimer with keratin 10.

Transcriptomic Analysis of the Major Orphan Ichthyosis Subtypes Reveals Shared Immune and Barrier Signatures

Preliminary work suggested upregulation of inflammatory pathways in patients with common forms of ichthyosis. However, a comprehensive characterization of skin from various ichthyosis subtypes is unavailable, precluding the development of targeted treatments. Thus, we sought to characterize the immune and barrier profiles of common and subtype-specific skin transcriptomes in a large group of patients with ichthyosis. We performed a global RNA-sequencing analysis in 54 patients with ichthyosis (7 with Netherton syndrome, 13 with epidermolytic ichthyosis, 16 with lamellar ichthyosis, and 18 with congenital ichthyosiform erythroderma) and 40 healthy controls. Differentially expressed genes were defined on the basis of fold changes > 2 and false discovery rate < 0.05 criteria. We found robust and significant T helper (Th) 22/Th17 skewing in all subtypes (e.g., IL-17A/C/F, S100A7/8/9/12; P < 0.001) with modest changes in Th2 pathway, primarily in Netherton syndrome, and Th1 skewing in congenital ichthyosiform erythroderma. Across all subtypes (less evident in epidermolytic ichthyosis), lipid metabolism and barrier junction markers were downregulated (e.g., FA2H, CDH10/11/12/2; P < 0.05), whereas epidermal cornification and proliferation measures were upregulated (e.g., SPRR1A/1B/2C/2G, EREG; P < 0.05). Our findings suggest that the common ichthyosis variants share aberrations in Th17/Th22 and barrier function, with minimal Th2 modulation. This may help to elucidate the pathogeneses of these subtypes and inform the development of subtype-specific treatments.

Abstract 60: Rickets in congenital bullous ichthyosiform erythroderma

Introduction: Congenital ichthyosiform erythroderma (CIE), also known as bullous congenitalichthyosiform erythroderma is a rare type of the ichthyosis family of skin diseases which occurs in 1 in 200,000 to 300,000 births. CIE comes under the umbrella term autosomal recessive congenital ichthyosis (ARCI), which include non-syndromic congenital ichthyosis such as harlequinichthyosis and lamellar ichthyosis. Ichthyosiform erythroderma due to keratinizing disordersmaysuppress cutaneous vitamin D synthesis, leading to vitamin D deficiency and rickets.Description: A 8 year 10 months old female child presented with poor height gain from 5 years and inward bending of knees from 5 years. h/o hyperpigmented hyperkeratotic scaly dry skinfrombirth. She was diagnosed with Bullous ichythosiform erythroderma and was prescribed emollients by a dermatologist. She is born out of non-consangienous marriage, second in birth order has an elder and youngersibling who are apparently normal. Ichythyosis present from birth more during winter season. h/o delayed dentition present. No h/o constipation or weight gain. h/o delayed motor milestones present. Language and social skills normal. o/e height is 78 cms @ < -10.8 SDS; height age <2 years weight 10 kg @ < - 6 SDS ; weight age < 2 years inward bending of knees + ; forward bending of tibia + ; ichthyosis over lower limbs, abdomen and upper limb. Her labs showed low Vit D levels of 8.7 ng/ml; calcium of 7.5 mg/dl (8- 10 mg/dl); phosphorus 2.6 mg/ml (2.5-4.8 mg/dl); elevated serum Alkaline phosphatase of 1450 IU/L; serum PTH of 181 pg/ml; normal thyroid and renal profile. She was started on oral vitamin D3 supplements and calcium supplements.Discussion: Ichthyosiform erythroderma is of two types, one inherited as an autosomal dominant and the other as an autosomal recessive trait. The recessive form is nonbullous and is associated with growth retardation, oligophrenia, spastic paralysis, genital hypoplasia, hypotrichia and shortened life expectancy. In the autosomal dominant or bullous form, however, life expectancy is not shortened, and the associated symptoms include only seborrhoea of the head an probably polydipsia. Both types begin at birth and are localized mostly on the flexor surfaces. Nonbullous congenital ichthyosiform erythroderma is characterized by prominent erythroderma and fine white, superficial semiadherent scales. The majority of affected individuals are present at birth as collodion babies. Skin histology shows hyperkeratosis, an increase in stratum corneum thickness, a normal or prominent granular layer and increased mitoses. Development of skeletal features in this condition can be explained by the fact that the maintenance of healthy skeleton requires vitamin D, the main source of which is biosynthesis in the skin. Epidermal hyperproliferation disturbs this synthesis and results in rickets.

Superficial epidermolytic ichthyosis: A rare disorder with the unusual absence of blistering

Superficial epidermolytic ichthyosis (SEI), formerly known as ichthyosis bullosa of Siemens (IBS), is an extremely rare keratinization disorder with superficial peeling, with an estimated prevalence of 1:500,000, caused by a variety of mutations in the keratin 2E gene. The clinical features include hyperkeratosis and blistering, but these are milder than in epidermolytic hyperkeratosis. The treatment is symptomatic and involves keratolytics and emollients. Herein, we report a case of SEI with the unusual absence of spontaneous blistering.

A child with epidermolytic ichthyosis, generalized erythema, and erosions.

A child with epidermolytic ichthyosis, generalized erythema, and erosions.

Identification of a Novel KRT9 Frameshift Mutation in a Chinese Pedigree with Epidermolytic Palmoplantar Keratoderma

Epidermolytic palmoplantar keratoderma (EPPK) is an autosomal dominant genodermatosis caused by variants of keratin 9 (KRT9) or KRT1 gene. In this study causative gene mapping in a Chinese EPPK family was performed with Two-point linkage analysis and haplotyping. Positive linkage results were obtained on 17q (Zmax=2.06, θmax=0.0) at D17S799, which indicated KRT9 to be the most responsible gene for the family. Subsequently, direct sequencing identified a novel frameshift mutation caused by a 5bp deletion (∆GGAGG) in KRT9 in all affected individuals but not in the unaffected members or the 50 unrelated controls. The frameshift changed the encoding of the following nine amino acids and resulted in a readthrough translation in exon 7. The data revealed that the novel frameshift mutation in KRT9 was responsible for the Chinese EPPK pedigree. The researchers’ findings broaden the spectrum of KRT9 variants and provide further evidence for the highly genetic heterogeneity of EPPK.

Skin Erosions in a Newborn.

Skin Erosions in a Newborn.

159 CRISPR/Cas9 nickase mediated gene therapy in primary keratinocytes derived from patients with EPPK

Epidermolytic palmoplantar keratoderma (EPPK) is a rare, autosomal dominantly inherited skin disorder. The disease is often caused by heterozygous point mutations in the keratin 9 gene (KRT9) coding for the type I intermediate filament (IF) protein keratin 9 (K9), whose expression is confined to the suprabasal layers of palmoplantar epidermis. Integration of mutant K9 into the IF cytoskeleton has a dominant negative effect resulting in massive thickening and making it prone to develop fissures, infections, and severely impairing the flexibility of hands and feet. The aim of this project is to correct the IF fragility in EPPK patient-derived primary keratinocyte (KC) cultures by establishing a CRISPR/Cas9 D10A double-nicking approach to induce non-homologous end joining (NHEJ) mediated silencing of the mutant disease-causing allele while leaving the wild-type (WT) allele intact. To avoid the risk of integrations into the genome, we used ribonucleoproteins to transfect KCs. We show that mutant K9 massively reduces cytoskeleton stability, resulting in IF clumping upon stress. Moreover, we demonstrate successful targeting and NHEJ of KRT9 using a pair of gRNAs, one of which targets the mutation in an allele specific manner. Using sequencing, we identified single cell clones with a premature STOP-codon on the mutated allele. These clones show a stable K9 IF structure after stress application, similar to the WT controls. Taken together, these results demonstrate CRISPR/Cas9 nickase-mediated rescue of IF fragility due to mutant K9 in primary cultured KCs.