In-person validation of the Ichthyosis Scoring System.

BACKGROUND: Ichthyoses are a heterogeneous group of skin disorders characterized by scaling and erythema. Recognizing the variability of scale and erythema by region and ichthyosis subtype, we developed the Ichthyosis Scoring System (ISS) to quantify severity. We previously found ISS to have high inter- and intrarater reliability in evaluating photographic images. To confirm ISS clinical utility, we examined its performance at the 2022 Foundation for Ichthyosis and Related Skin Types conference. METHODS: Sixty-five participants were evaluated by 3 of 9 medical professionals trained to score ichthyosis scale and erythema using ISS. Intrarater and interrater intraclass correlation coefficients (ICC) were analyzed using one-way and two-way random effects models, respectively. RESULTS: Intrarater reliability was excellent (ICC = 0.931, 95% CI, 0.921-0.940) for scale and good (ICC = 0.876, 95% CI, 0.853-0.899) for erythema scoring. Compared to photo validation with excellent intrarater reliability ratings for both scale (ICC = 0.956, 95% CI, 0.925-0.974) and erythema (ICC = 0.913, 95% CI, 0.855-0.949), ISS demonstrated equivalent reliability for live use. Overall interrater reliability for 10 body sites showed excellent (ICC >0.9) and good (ICC >0.75) agreement and consistency for both scale and erythema. Palms were an exception, demonstrating moderate (ICC >0.5) interrater agreement and consistency for erythema evaluation. CONCLUSIONS: ISS is a reliable measure of global and regional ichthyosis severity during in-person evaluations. Ease-of-use, accessibility, and content validity in both live and photographic evaluation endorse ISS as a standard for ichthyosis severity analysis.

Topical trametinib for epidermal and sebaceous nevi in a child with Schimmelpenning-Feuerstein-Mims syndrome.

We present the case of a 20-month-old girl with Schimmelpenning-Feuerstein-Mims (SFM) syndrome with extensive head, neck, and torso skin involvement successfully managed with topical trametinib. Trametinib interferes downstream of KRAS and HRAS in the MAPK signaling pathway, of which KRAS was implicated in our child's pathogenic variant. Although other dermatologic conditions have shown benefit from oral trametinib, its topical use has not been well reported. Our patient showed benefit from the use of twice-daily topical trametinib, applied to the epidermal and sebaceous nevi over a 16-month period, leading to decreased pruritus and thinning of the plaques.

Association of Somatic ATP2A2 Damaging Variants With Grover Disease.

Importance: Grover disease (GD), a truncal eruption that typically occurs in older individuals, is exacerbated by sweating, irradiation, cancers, medications, kidney failure, and organ transplantation. The pathobiology of GD remains unknown. Objective: To determine if damaging somatic single-nucleotide variants (SNVs) are associated with GD. Design, Setting, and Participants: In this retrospective case series, we identified consecutive patients from a dermatopathology archive over a 4-year period (January 2007 to December 2011) who had 1 biopsy with a clinical diagnosis of GD confirmed via histopathologic findings and another non-GD biopsy. Participant DNA was extracted from both biopsy tissues and sequenced to high depth with a 51-gene panel to screen for SNVs in genes previously associated with acantholysis and Mendelian disorders of cornification. Analysis took place between 2021 and 2023. Main Outcomes and Measures: Comparative analysis of sequencing data from paired GD and control tissue was employed to identify SNVs predicted to affect gene function, which were exclusive to, or highly enriched in, GD tissue. Results: Overall, 12 of 15 cases of GD (12 men and 3 women; mean [SD] age, 68.3 [10.0] years) were associated with C>T or G>A ATP2A2 SNVs in GD tissue; all were predicted to be highly damaging via combined annotation dependent depletion (CADD) scores, and 4 were previously associated with Darier disease. In 9 cases (75%), the GD-associated ATP2A2 SNV was absent from control tissue DNA, and in 3 cases (25%), ATP2A2 SNVs were enriched 4- to 22-fold in GD vs control tissue. Conclusions and Relevance: In this case series study of 15 patients, damaging somatic ATP2A2 SNVs were associated with GD. This discovery expands the spectrum of acantholytic disorders associated with ATP2A2 SNVs and highlights the role of somatic variation in acquired disorders.

Nagashima-type palmoplantar keratoderma: Case series and two novel variants.

Nagashima-type palmoplantar keratoderma (PPK) is an autosomal recessive PPK. We report four patients, highlight two new genetic variants, and emphasize the possibility of misdiagnosing the condition. Concomitant atopic dermatitis, specifically, may make correct diagnosis challenging. Clinicians should consider the diagnosis of Nagashima-type PPK in patients presenting with mild PPK with transgrediens and understand the importance of individualized multimodal treatment regimens.

Secukinumab responses vary across the spectrum of congenital ichthyosis in adults.

IMPORTANCE: Treatment of congenital ichthyoses primarily focuses on reversing skin scaling and is not pathogenesis based. Recent studies showed Th17 immune skewing, as in psoriasis, across the spectrum of ichthyosis, suggesting that targeting this pathway might broadly reduce disease severity. OBJECTIVE: To determine whether secukinumab, an IL-17A inhibitor, can improve ichthyosis across several congenital ichthyosis subtypes. DESIGN: Exploratory 16-week double-blind, randomized, placebo-controlled trial comparing secukinumab 300 mg every 4wks to placebo (1:1 randomization) in adults with the four major congenital ichthyosis subtypes (NCT03041038), followed by a 16-week open-label phase to evaluate response of the placebo-first group and a 20-week extension for safety. Significant differences in secukinumab- vs. placebo-treated subjects at Wk16 in the Ichthyosis Area Severity Index (IASI) score and lack of increased mucocutaneous bacterial and/or fungal infections were the co-primary efficacy and safety endpoints, respectively. SETTING: Two tertiary referral centers: Northwestern University Feinberg School of Medicine, Chicago, and Mount Sinai Icahn School of Medicine, New York. PARTICIPANTS: Twenty subjects ≥ 18 yo with genotype-confirmed epidermolytic ichthyosis, Netherton syndrome, lamellar ichthyosis, or congenital ichthyosiform erythroderma with at least moderate erythroderma. RESULTS: IL-17A inhibition did not significantly reduce severity or increase mucocutaneous infections among the 18 who completed the 16-week double-blind phase. Five patients with 29-50% clinical improvement at Wk32 requested drug continuation. Th17-related biomarkers were not significantly reduced vs. baseline or placebo-treated levels. LIMITATIONS: Small sample size; heterogeneous ichthyosis subsets. CONCLUSION: IL-17 inhibition with secukinumab is safe, but not efficacious across the spectrum of adult ichthyoses. GOV REGISTRATION NUMBER: NCT03041038; first posted on 02/02/2017.

Segmental basaloid follicular hamartomas derive from a post-zygotic SMO p.L412F pathogenic variant and express hair follicle development-related proteins in a pattern that distinguish them from basal cell carcinomas.

Basaloid follicular hamartomas (BFH) are benign small basaloid skin tumors that can present as solitary or multiple lesions. Congenital BFH lesions arranged in a segmental distribution have been described, suggesting they derive from a somatic post-zygotic mutational event. Previously, BFH were described in Happle-Tinschert syndrome, which results from a post-zygotic SMO variant and is characterized by segmental BFH with variable involvement of the teeth, skeleton, and central nervous system. Here, we describe two patients with isolated segmental BFH and no systemic involvement. Paired whole exome sequencing of BFH and normal tissue revealed a pathogenic SMO c.1234 C>T, p.L412F variant restricted to BFH tissue. We characterized the proliferation index and expression of Hedgehog and Wnt/beta-catenin pathway related proteins in segmental BFH compared to sporadic basal cell carcinomas (BCCs) and found that segmental BFH had a lower proliferation index. Although segmental BFH expressed a similar level of Gli-1 compared to BCCs, levels of LEF-1 and SOX-9 expression in BFH were weaker for both and patchier for LEF-1. Our results show that a somatic SMO activating variant causes segmental BFH. Since these patients are prone to developing BCCs, differences in SOX9, LEF1, and Ki-67 expression can help distinguish between these two basaloid lesions.

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

BACKGROUND: 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. OBJECTIVE: To elucidate the genetic cause of a cohort of patients diagnosed based on clinical and histopathological evaluation with ILVEN. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Development and Initial Validation of a Novel System to Assess Ichthyosis Severity.

IMPORTANCE: A comprehensive, user-friendly system to assess global ichthyosis disease burden is imperative to improving the care of patients with ichthyosis, identifying appropriate participants for clinical trials, and quantifying treatment outcomes. To our knowledge, there is currently no validated scale to objectively and systematically measure ichthyosis severity across the entire body. OBJECTIVE: To create and evaluate a comprehensive and user-friendly instrument to measure total body ichthyosis severity in adults and children. DESIGN, SETTING, PARTICIPANTS: In this qualitative study, ichthyosis experts participated in the content development of the Ichthyosis Scoring System (ISS). The body was divided into 10 regions, and Likert scales (0-4) were created to quantify scale and erythema, with extensive descriptors and photographic standards. An 83-image teaching set was created from photographs of participants with ichthyosis. Two cohorts of dermatologists (11 total) independently scored all test photographs twice to evaluate interrater and intrarater reliabilities. Participants were enrolled worldwide from referral centers and patient advocacy groups. Participants of all ages, races, and ethnicities were included in the creation of ISS, and dermatologists with varying experience and areas of expertise participated as raters to evaluate the ISS. The study was conducted from 2019 to 2021, and the data were analyzed in 2021. MAIN OUTCOMES AND MEASURES: Intraclass correlation coefficients determined overall reliabilities. RESULTS: Across both cohorts of 11 dermatologists in total, the intraclass correlation coefficients for total, scale and erythema scores were greater than 0.90 (95% CI, 0.77-0.97), greater than 0.91 (95% CI, 0.79-0.98), and greater than 0.88 (95% CI, 0.72-0.97), respectively. Most body sites exhibited moderate to good interrater reliabilities for scale and erythema. Intrarater reliabilities were good to excellent. CONCLUSIONS AND RELEVANCE: The results of this qualitative study demonstrate reproducibility and suggest that the ISS is a reliable system to measure global ichthyosis severity in adults and children.

Erratum: Cutaneous and hepatic vascular lesions due to a recurrent somatic GJA4 mutation reveal a pathway for vascular malformation.

[This corrects the article DOI: 10.1016/j.xhgg.2021.100028.].

The Genomic and Phenotypic Landscape of Ichthyosis: An Analysis of 1000 Kindreds.

IMPORTANCE: Ichthyoses are clinically and genetically heterogeneous disorders characterized by scaly skin. Despite decades of investigation identifying pathogenic variants in more than 50 genes, clear genotype-phenotype associations have been difficult to establish. OBJECTIVE: To expand the genotypic and phenotypic spectra of ichthyosis and delineate genotype-phenotype associations. DESIGN, SETTING, AND PARTICIPANTS: This cohort study recruited an international group of individuals with ichthyosis and describes characteristic and distinguishing features of common genotypes, including genotype-phenotype associations, during a 10-year period from June 2011 to July 2021. Participants of all ages, races, and ethnicities were included and were enrolled worldwide from referral centers and patient advocacy groups. A questionnaire to assess clinical manifestations was completed by those with a genetic diagnosis. MAIN OUTCOMES AND MEASURES: Genetic analysis of saliva or blood DNA, a phenotyping questionnaire, and standardized clinical photographs. Descriptive statistics, such as frequency counts, were used to describe the cases in the cohort. Fisher exact tests identified significant genotype-phenotype associations. RESULTS: Results were reported for 1000 unrelated individuals enrolled from around the world (mean [SD] age, 50.0 [34.0] years; 524 [52.4%] were female, 427 [42.7%] were male, and 49 [4.9%] were not classified); 75% were from the US, 12% from Latin America, 4% from Canada, 3% from Europe, 3% from Asia, 2% from Africa, 1% from the Middle East, and 1% from Australia and New Zealand. A total of 266 novel disease-associated variants in 32 genes were identified among 869 kindreds. Of these, 241 (91%) pathogenic variants were found through multiplex amplicon sequencing and 25 (9%) through exome sequencing. Among the 869 participants with a genetic diagnosis, 304 participants (35%) completed the phenotyping questionnaire. Analysis of clinical manifestations in these 304 individuals revealed that pruritus, hypohydrosis, skin pain, eye problems, skin odor, and skin infections were the most prevalent self-reported features. Genotype-phenotype association analysis revealed that the presence of a collodion membrane at birth (odds ratio [OR], 6.7; 95% CI, 3.0-16.7; P < .001), skin odor (OR, 2.8; 95% CI, 1.1-6.8; P = .02), hearing problems (OR, 2.9; 95% CI, 1.6-5.5; P < .001), eye problems (OR, 3.0; 95% CI, 1.5-6.0; P < .001), and alopecia (OR, 4.6; 95% CI, 2.4-9.0; P < .001) were significantly associated with TGM1 variants compared with other ichthyosis genotypes studied. Skin pain (OR, 6.8; 95% CI, 1.6-61.2; P = .002), odor (OR, 5.7; 95% CI, 2.0-19.7; P < .001), and infections (OR, 3.1; 95% CI, 1.4-7.7; P = .03) were significantly associated with KRT10 pathogenic variants compared with disease-associated variants in other genes that cause ichthyosis. Pathogenic variants were identified in 869 (86.9%) participants. Most of the remaining individuals had unique phenotypes, enabling further genetic discovery. CONCLUSIONS AND RELEVANCE: This cohort study expands the genotypic and phenotypic spectrum of ichthyosis, establishing associations between clinical manifestations and genotypes. Collectively, the findings may help improve clinical assessment, assist with developing customized management plans, and improve clinical course prognostication.

CARD14-associated papulosquamous eruption (CAPE) in pediatric patients: Three additional cases and review of the literature.

CARD14-associated papulosquamous eruption (CAPE) is a proposed term that encompasses features ranging from psoriasis to pityriasis rubra pilaris (PRP) in association with CARD14 mutations. The early onset of the disease, prominent facial involvement, family history of an autosomal dominant trait, and poor response to conventional treatment are characteristics of CAPE that distinguish it from classical psoriasis and PRP. We describe the clinical features, family history, and response to therapy in three unrelated children with CAPE and compare these characteristics with those of previously described pediatric patients. Testing for CARD14 mutations in children with early onset of features of psoriasis or pityriasis rubra pilaris and resistance to conventional therapy should be considered.

Kindler epidermolysis bullosa-like skin phenotype and downregulated basement membrane zone gene expression in poikiloderma with neutropenia and a homozygous USB1 mutation.

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.

Cutaneous and hepatic vascular lesions due to a recurrent somatic GJA4 mutation reveal a pathway for vascular malformation.

The term "cavernous hemangioma" has been used to describe vascular anomalies with histology featuring dilated vascular spaces, vessel walls consisting mainly of fibrous stromal bands lined by a layer of flattened endothelial cells, and an irregular outer rim of interrupted smooth muscle cells. Hepatic hemangiomas (HHs) and cutaneous venous malformations (VMs) share this histologic pattern, and we examined lesions in both tissues to identify genetic drivers. Paired whole-exome sequencing (WES) of lesional tissue and normal liver in HH subjects revealed a recurrent GJA4 c.121G>T (p.Gly41Cys) somatic mutation in four of five unrelated individuals, and targeted sequencing in paired tissue from 9 additional HH individuals identified the same mutation in 8. In cutaneous lesions, paired targeted sequencing in 5 VMs and normal epidermis found the same GJA4 c.121G>T (p.Gly41Cys) somatic mutation in three. GJA4 encodes gap junction protein alpha 4, also called connexin 37 (Cx37), and the p.Gly41Cys mutation falls within the first transmembrane domain at a residue highly conserved among vertebrates. We interrogated the impact of the Cx37 mutant via lentiviral transduction of primary human endothelial cells. We found that the mutant induced changes in cell morphology and activated serum/glucocorticoid-regulated kinase 1 (SGK1), a serine/threonine kinase known to regulate cell proliferation and apoptosis, via non-canonical activation. Treatment with spironolactone, an inhibitor of angiogenesis, suppressed mutant SGK1 activation and reversed changes in cell morphology. These findings identify a recurrent somatic GJA4 c.121G>T mutation as a driver of hepatic and cutaneous VMs, revealing a new pathway for vascular anomalies, with spironolactone a potential pathogenesis-based therapy.

Cutaneous mosaicism: Special considerations for women.

Genetic mosaicism results from postzygotic mutations during embryogenesis. Cells harboring pathogenic mutations distribute throughout the developing embryo and can cause clinical disease in the tissues they populate. Cutaneous mosaicism is readily visualized since affected tissue often follows predetermined patterns, such as lines of Blaschko. Due to its clinical accessibility, cutaneous mosaicism is well suited for genetic analysis. An individual's unaffected tissue can be used as an intrapatient genetic control, a technique that has yielded insight into the genetic etiologies of many disorders, several of which bear mutations in genes that would otherwise be embryonic-lethal. Particular mosaic diseases can also disproportionally impact women. Two such diseases, incontinentia pigmenti (IP) and congenital hemidysplasia with ichthyosiform erythroderma and limb defects (CHILD) syndrome, arise from mutations on the X chromosome. Both diseases result in fetal demise in males in most cases, thus making the two diseases largely specific to women. Women with McCune-Albright Syndrome, caused by somatic mutations in GNAS, often experience precocious puberty and infertility as a result of uncontrolled cAMP regulation in affected tissue. Women with cutaneous mosaicism carry a risk of transmission to offspring when gonosomal mosaicism is present, yet cutaneous disease burden does not correlate with germline transmission risk. Cutaneous mosaic disease represents a biologically unique set of disorders that can warrant special clinical attention in women.