Functional genotype-phenotype associations in recessive dystrophic epidermolysis bullosa.

BACKGROUND: Genotype-phenotype associations in recessive dystrophic epidermolysis bullosa (RDEB) have been difficult to elucidate. OBJECTIVE: To investigate RDEB genotype-phenotype associations and explore a functional approach to genotype classification. METHODS: Clinical examination and genetic testing of RDEB subjects, including assessment of clinical disease by RDEB subtype and extent of blistering. Genotypes were evaluated according to each variant's effect on type VII collagen function per updated literature and subsequently categorized by degree of impact on VII collagen function as low-impact (splice/missense, missense/missense), medium-impact (premature termination codon [PTC]/missense, splice/splice), and high-impact (PTC/PTC, PTC/splice). Genotype-phenotype associations were investigated using Kruskal-Wallis and Fisher's exact tests, and age-adjusted regressions. RESULTS: Eighty-three participants were included. High-impact variants were associated with worse RDEB subtype and clinical disease, including increased prevalence of generalized blistering (55.6% for low-impact vs 72.7% medium-impact vs 90.4% high-impact variants, P = .002). In age-adjusted regressions, participants with high-impact variants had 40.8-fold greater odds of squamous cell carcinoma compared to low-impact variants (P = .02), and 5.7-fold greater odds of death compared to medium-impact variants (P = .05). LIMITATIONS: Cross-sectional design. CONCLUSION: Functional genotype categories may stratify RDEB severity; high-impact variants correlated with worse clinical outcomes. Further validation in larger cohorts is needed.

Online, home-based dystrophic epidermolysis bullosa registry.

Genetic testing is the gold standard for diagnosing different epidermolysis bullosa (EB) subtypes; however, testing rates are low. We conducted a pilot study to test feasibility of a novel, home-based registry that involved patients with EB submitting self-reported clinical symptoms using secure, online surveys (REDCap) and submitting buccal swabs for exome sequencing of EB-related genes (GeneDx). In total, 50 EB participants were enrolled, with an average age of 17 years and an average distance of 198 miles from EB specialty centers. All buccal swabs (N = 24) provided sufficient DNA for sequencing without causing mucosal trauma and 80% of participants were found to have pathogenic variants in COL7A1, the gene mutated in DEB. Participants with recessive dystrophic EB (RDEB) reported a higher prevalence of esophageal dilations (65.7% vs. 0%, p = .009) and mitten deformities of the feet (57.1% vs. 0%, p = .047) compared to non-RDEB participants.

A retrospective analysis of diagnostic testing in a large North American cohort of patients with epidermolysis bullosa.

BACKGROUND: Accurate diagnosis of epidermolysis bullosa (EB) has significant implications for prognosis, management, and genetic counseling. OBJECTIVE: To describe diagnostic testing patterns and assess diagnostic concordance of transmission electron microscopy (TEM), immunofluorescence mapping (IFM), and genetic analysis for EB. METHODS: A retrospective cohort included patients enrolled in the Epidermolysis Bullosa Clinical Characterization and Outcomes Database from January 1, 2004, to July 8, 2019. Tests concluding the same EB type (EB simplex, junctional EB, dominant dystrophic EB, and recessive dystrophic EB) were considered concordant; those concluding different EB types were considered discordant; and those with nonspecific/nondefinitive results were equivocal. RESULTS: A total of 970 diagnostic tests were conducted from 1984 to 2018 in 771 patients. Genetic analyses were performed chronologically later than IFM or TEM (P < .001). The likelihood of undergoing genetic analysis was greater for junctional EB and recessive dystrophic EB, and the same for dominant dystrophic EB as compared with EB simplex. TEM results in 163 patients were equivocal (55%), concordant (42%), and discordant (3%). IFM results in 185 patients were equivocal (54%), concordant (42%), and discordant (4%). LIMITATIONS: Retrospective design. CONCLUSIONS: Diagnostic testing has shifted in favor of genetic analysis. TEM and IFM frequently offer equivocal findings when compared to the specificity afforded by genetic analysis.

Patient-reported outcomes and quality of life in recessive dystrophic epidermolysis bullosa: A global cross-sectional survey.

BACKGROUND: A spectrum of skin disease severity exists in patients with recessive dystrophic epidermolysis bullosa (RDEB). OBJECTIVE: To characterize the patient-reported outcomes and quality of life (QOL) in patients with RDEB. METHODS: A cross-sectional study of patients with RDEB surveyed through the global EBCare Registry. Patient-reported outcomes included skin disease severity, wound characteristics, pain, itch, extracutaneous symptoms, and medications. QOL was measured by using the validated Quality of Life in Epidermolysis Bullosa instrument. RESULTS: A total of 85 patients with RDEB reported 1226 wounds (937 recurrent wounds and 289 chronic open wounds). Overall skin disease severity was self-reported as mild (26%; 22/83), moderate (48%; 40/83), or severe (25%; 21/83). Worsening skin disease severity was significantly associated with larger wounds, increased opiate use, anemia, gastrostomy tube use, infections, osteoporosis, and squamous cell carcinoma. Larger wound size was associated with worse quality of life scores. LIMITATIONS: All data were self-reported from an online epidermolysis bullosa patient registry. CONCLUSIONS: This study shows a significant correlation between larger wound size with worsening skin disease severity and quality of life in participants with RDEB. Worsening skin disease severity significantly correlated with key clinical manifestations. These results show that patients with RDEB are able to self-report their skin disease severity and wounds.

Neuronal delivery of Hedgehog directs spatial patterning of taste organ regeneration.

How organs maintain and restore functional integrity during ordinary tissue turnover or following injury represents a central biological problem. The maintenance of taste sensory organs in the tongue was shown 140 years ago to depend on innervation from distant ganglion neurons, but the underlying mechanism has remained unknown. Here, we show that Sonic hedgehog (Shh), which encodes a secreted protein signal, is expressed in these sensory neurons, and that experimental ablation of neuronal Shh expression causes loss of taste receptor cells (TRCs). TRCs are also lost upon pharmacologic blockade of Hedgehog pathway response, accounting for the loss of taste sensation experienced by cancer patients undergoing Hedgehog inhibitor treatment. We find that TRC regeneration following such pharmacologic ablation requires neuronal expression of Shh and can be substantially enhanced by pharmacologic activation of Hedgehog response. Such pharmacologic enhancement of Hedgehog response, however, results in additional TRC formation at many ectopic sites, unlike the site-restricted regeneration specified by the projection pattern of Shh-expressing neurons. Stable regeneration of TRCs thus requires neuronal Shh, illustrating the principle that neuronal delivery of cues such as the Shh signal can pattern distant cellular responses to assure functional integrity during tissue maintenance and regeneration.

Distinguishing malignant from benign microscopic skin lesions using desorption electrospray ionization mass spectrometry imaging.

Detection of microscopic skin lesions presents a considerable challenge in diagnosing early-stage malignancies as well as in residual tumor interrogation after surgical intervention. In this study, we established the capability of desorption electrospray ionization mass spectrometry imaging (DESI-MSI) to distinguish between micrometer-sized tumor aggregates of basal cell carcinoma (BCC), a common skin cancer, and normal human skin. We analyzed 86 human specimens collected during Mohs micrographic surgery for BCC to cross-examine spatial distributions of numerous lipids and metabolites in BCC aggregates versus adjacent skin. Statistical analysis using the least absolute shrinkage and selection operation (Lasso) was employed to categorize each 200-µm-diameter picture element (pixel) of investigated skin tissue map as BCC or normal. Lasso identified 24 molecular ion signals, which are significant for pixel classification. These ion signals included lipids observed at m/z 200-1,200 and Krebs cycle metabolites observed at m/z < 200. Based on these features, Lasso yielded an overall 94.1% diagnostic accuracy pixel by pixel of the skin map compared with histopathological evaluation. We suggest that DESI-MSI/Lasso analysis can be employed as a complementary technique for delineation of microscopic skin tumors.

Patient-reported outcomes and quality of life in dominant dystrophic epidermolysis bullosa: A global cross-sectional survey.

INTRODUCTION: Dystrophic epidermolysis bullosa is a debilitating skin condition, without curative treatment. Previous research has focused on the recessive variant, which is known to cause severe disease. Limited work focusing on the clinical manifestations and outcomes of dominant dystrophic epidermolysis bullosa is found (DDEB). METHODS: Analysis of an online survey of 42 DDEB patients. RESULTS: Self-reported severity of disease did not correlate with size of the wound or number of dressing changes, but did correlate with severity of pain reported in the last 12 months (3.4 mild vs 6.8 severe disease, P = 0.0002). Patients with severe DDEB also reported more severe internal disease symptoms, such as difficulty swallowing (62.5%, P = 0.01) and greater analgesic use during dressing changes (4.4% mild vs 81.3% severe, P = <0.001). DISCUSSION: Patient perception of disease severity in DDEB appears to be most impacted by pain, presence of chronic open wounds, difficulty swallowing, difficulty walking, and anal strictures. As research on DDEB increases, future studies focused on these symptoms might be the most impactful for DDEB patients. However, distinguishing DDEB from other subtypes remains a challenge.

Clinical characteristics associated with increased wound size in patients with recessive dystrophic epidermolysis bullosa.

As more therapeutic clinical trials focus on treatment of individual wounds in patients with recessive dystrophic epidermolysis bullosa, it has become crucial to understand the baseline clinical characteristics of these wounds. To investigate these features, we administered an RDEB-specific wound survey. Forty participants reported on location, size, pain, infection frequency, wound type, and duration of 189 wounds; a subset of 22 participants reported on pruritus in 63 wounds. Increased wound size was significantly associated with increased pain, increased pruritus, longer wound duration, increased infection frequency, and patients with mutations resulting in truncated type VII collagen.

Phase 2 trial of a neurokinin-1 receptor antagonist for the treatment of chronic itch in patients with epidermolysis bullosa: A randomized clinical trial.

BACKGROUND: Chronic pruritus causes major morbidity in epidermolysis bullosa (EB). The substance P-neurokinin 1 receptor (SP-NK1) pathway is a promising target for treating EB-related pruritus. OBJECTIVE: To evaluate the safety and efficacy of the oral NK1 receptor antagonist serlopitant in treating moderate-severe pruritus in EB. METHODS: The study randomized 14 patients to serlopitant or placebo for 8 weeks, followed by a 4-week washout and optional open-label extension. The primary end point was change in itch as measured by the Numeric Rating Scale. Secondary end points were change in itch during dressing changes and wound size. RESULTS: We observed greater itch reduction with serlopitant, equivalent to a 0.64-point comparative reduction on the 11-point Numeric Rating Scale by week 8, although this failed to meet statistical significance (P = .11). More serlopitant patients achieved ≥3-point reduction compared with placebo (43% vs 14%, P = .35). In post hoc analysis excluding 1 patient with a concurrent seborrheic dermatitis flare, serlopitant achieved significantly greater median itch reduction from baseline by week 4 (-2 points vs 0, P = .01). We observed no statistically significant differences in secondary end points. Serlopitant was well-tolerated. LIMITATIONS: Small sample size due to disease rarity. CONCLUSION: The potential itch reduction with serlopitant observed in this trial will be pursued by a larger powered trial (NCT03836001).

Financial burden of epidermolysis bullosa on patients in the United States.

Individuals with epidermolysis bullosa (EB), a group of genodermatoses with skin fragility, often require specialized and expensive bandaging. We analyzed the results from an online survey of 249 EB patients and caregivers living in the United States to investigate the financial impact of EB. Of respondents with severe EB subtypes (recessive dystrophic and junctional), 73% reported a major or moderate financial impact and 26% spent greater than $1000 per month on wound care supplies. These results demonstrate the high financial burden associated with epidermolysis bullosa in the United States and support the need for a federally funded EB bandage program.

GLI activation by atypical protein kinase C ι/λ regulates the growth of basal cell carcinomas.

Growth of basal cell carcinomas (BCCs) requires high levels of hedgehog (HH) signalling through the transcription factor GLI. Although inhibitors of membrane protein smoothened (SMO) effectively suppress HH signalling, early tumour resistance illustrates the need for additional downstream targets for therapy. Here we identify atypical protein kinase C ι/λ (aPKC-ι/λ) as a novel GLI regulator in mammals. aPKC-ι/λ and its polarity signalling partners co-localize at the centrosome and form a complex with missing-in-metastasis (MIM), a scaffolding protein that potentiates HH signalling. Genetic or pharmacological loss of aPKC-ι/λ function blocks HH signalling and proliferation of BCC cells. Prkci is a HH target gene that forms a positive feedback loop with GLI and exists at increased levels in BCCs. Genome-wide transcriptional profiling shows that aPKC-ι/λ and SMO control the expression of similar genes in tumour cells. aPKC-ι/λ functions downstream of SMO to phosphorylate and activate GLI1, resulting in maximal DNA binding and transcriptional activation. Activated aPKC-ι/λ is upregulated in SMO-inhibitor-resistant tumours and targeting aPKC-ι/λ suppresses signalling and growth of resistant BCC cell lines. These results demonstrate that aPKC-ι/λ is critical for HH-dependent processes and implicates aPKC-ι/λ as a new, tumour-selective therapeutic target for the treatment of SMO-inhibitor-resistant cancers.

Risk of Melanoma With Phosphodiesterase Type 5 Inhibitor Use Among Patients With Erectile Dysfunction, Pulmonary Hypertension, and Lower Urinary Tract Symptoms.

BACKGROUND: Phosphodiesterase type 5 inhibitors (PDE5is), a treatment for erectile dysfunction, pulmonary hypertension (pHTN), and lower urinary tract symptoms (LUTS), have been implicated in melanoma development. AIM: We sought to determine the association between PDE5i use and melanoma development among patients with erectile dysfunction, pHTN, and LUTS. METHODS: This was a retrospective cohort study of subjects contained within the Truven Health MarketScan claims database, which provides information on insurance claims in the United States for privately insured individuals, from 2007-2015. Individuals taking PDE5i were identified through pharmacy claims. A comparison group of men diagnosed with conditions for which PDE5i are prescribed was assembled. OUTCOMES: Cox proportional hazard models were used to estimate the hazard ratio (HR) (95% CI) of incident melanoma, basal cell carcinoma, and squamous cell carcinoma. RESULTS: Of 610,881 subjects prescribed PDE5i, 636 developed melanoma (0.10%). The control group had 8,711 diagnoses of melanoma. There was an association between increased PDE5i tablet use and melanoma (HR 1.05, 95% CI 1.05-1.09). This association was also present between PDE5i use and basal cell carcinoma (HR 1.04, 95% CI 1.02-1.07) and squamous cell carcinoma (HR 1.04, 95% CI 1.01-1.07). In patients with pHTN and LUTS prescribed PDE5is, there was no relationship between exposure and melanoma incidence (HR 0.74, 95% CI 0.48-1.13; and HR 1.03, 95% CI 0.97-1.10, respectively). CLINICAL IMPLICATIONS: There is little evidence for a clinically relevant association between PDE5i use and melanoma incidence. STRENGTHS & LIMITATIONS: Our current work represents the largest study to date evaluating the relationship between PDE5i use and melanoma risk, and the first to examine all current indications of PDE5i use among men and women. Limitations include a patient population limited to commercially insured individuals, unknown patient medication compliance, and lack of information on patient skin type, lifestyle, and sun-exposure habits. CONCLUSION: There is a slight association between higher-volume PDE5i use and development of melanoma, basal cell carcinoma, and squamous cell carcinoma. This association among all skin cancers implies that confounding may account for the observed association. Shkolyar E, Li S, Tang J, et al. Risk of Melanoma With Phosphodiesterase Type 5 Inhibitor Use Among Patients With Erectile Dysfunction, Pulmonary Hypertension, and Lower Urinary Tract Symptoms. J Sex Med 2018;15:982-989.

Serlopitant for the treatment of chronic pruritus: Results of a randomized, multicenter, placebo-controlled phase 2 clinical trial.

BACKGROUND: The substance P/neurokinin 1 receptor pathway is critical in chronic pruritus; anecdotal evidence suggests that antagonism of this pathway can reduce chronic itch. OBJECTIVE: To assess the safety and efficacy of the substance P/neurokinin 1 receptor antagonist serlopitant in treating chronic pruritus. METHODS: Eligible patients with severe chronic pruritus who were refractory to antihistamines or topical steroids were randomized to serlopitant, 0.25, 1, or 5 mg, or to placebo, administered once daily for 6 weeks as monotherapy or with midpotency steroids and emollients. The primary efficacy end point was percentage change in visual analog scale pruritus score from baseline. RESULTS: Serlopitant treatment resulted in a dose-dependent decrease in pruritus. The mean percentage decreases from baseline visual analog scale pruritus scores were statistically significantly larger with the 1- and 5-mg doses of serlopitant (P = .022 and P = .013, respectively) than with placebo at week 6. No significant safety or tolerability differences were detected among the groups. LIMITATIONS: The sample size was insufficient for subgroup analyses of the efficacy of serlopitant for chronic pruritus on the basis of underlying conditions. CONCLUSIONS: Serlopitant, 1 mg and 5 mg daily, was associated with a statistically significant reduction in chronic pruritus and was well tolerated (NCT01951274).

Melanoma risk prediction using a multilocus genetic risk score in the Women's Health Initiative cohort.

BACKGROUND: Single-nucleotide polymorphisms (SNPs) associated with melanoma have been identified though genome-wide association studies. However, the combined impact of these SNPs on melanoma development remains unclear, particularly in postmenopausal women who carry a lower melanoma risk. OBJECTIVE: We examine the contribution of a combined polygenic risk score on melanoma development in postmenopausal women. METHODS: Genetic risk scores were calculated using 21 genome-wide association study-significant SNPs. Their combined effect on melanoma development was evaluated in 19,102 postmenopausal white women in the clinical trial and observational study arms of the Women's Health Initiative dataset. RESULTS: Compared to the tertile of weighted genetic risk score with the lowest genetic risk, the women in the tertile with the highest genetic risk were 1.9 times more likely to develop melanoma (95% confidence interval 1.50-2.42). The incremental change in c-index from adding genetic risk scores to age were 0.075 (95% confidence interval 0.041-0.109) for incident melanoma. LIMITATIONS: Limitations include a lack of information on nevi count, Fitzpatrick skin type, family history of melanoma, and potential reporting and selection bias in the Women's Health Initiative cohort. CONCLUSION: Higher genetic risk is associated with increased melanoma prevalence and incidence in postmenopausal women, but current genetic information may have a limited role in risk prediction when phenotypic information is available.

Association study of genetic variation in DNA repair pathway genes and risk of basal cell carcinoma.

DNA repair plays a critical role in protecting the genome from ultraviolet radiation and maintaining the genomic integrity of cells. Genetic variants in DNA repair-related genes can influence an individual's DNA repair capacity, which may be related to the risk of developing basal cell carcinoma (BCC). We comprehensively assessed the associations of 2,965 independent single-nucleotide polymorphisms (SNPs) across 165 DNA repair pathway genes with BCC risk in a genome-wide association meta-analysis totaling 17,187 BCC cases and 287,054 controls from two data sets. After multiple testing corrections, we identified three SNPs (rs2805831 upstream of XPA: OR = 0.93, P = 1.35 × 10-6 ; rs659857 in exon of MUS81: OR = 1.06, P = 3.09 × 10-6 and rs57343616 in 3' UTR of NABP2: OR = 1.11, P = 6.47 × 10-6 ) as significantly associated with BCC risk in meta-analysis, and all of them were nominally significant in both data sets. Furthermore, rs659857 [T] was significantly associated with decreased expression of MUS81 mRNA in the expression quantitative trait locus (eQTL) analysis. Our findings suggest that the inherited common variation in three DNA repair genes-XPA, MUS81 and NABP2-may be involved in the development of BCC. To our knowledge, our study is the first report thoroughly examining the effects of SNPs across DNA repair pathway genes on BCC risk based on a genome-wide association meta-analysis.

Association between genetic variation within vitamin D receptor-DNA binding sites and risk of basal cell carcinoma.

An increasing number of studies have reported a protective association between vitamin D and cancer risk. The vitamin D endocrine system regulates transcriptional programs involved in inflammation, cell growth and differentiation through the binding of vitamin D receptor (VDR) to specific VDR elements. However, limited attention has been given to the role of variation within VDR binding sites in the development of basal cell carcinoma (BCC). Across 2,776 previously identified VDR binding sites, we identified 2,540 independent single-nucleotide polymorphisms (SNPs) and examined their associations with BCC risk in a genome-wide association meta-analysis totaling 17,187 BCC cases and 287,054 controls from two data sets. After multiple testing corrections, we identified two SNPs at new loci (rs16917546 at 10q21.1: odds ratio (OR) = 1.06, p = 3.16 × 10-7 and rs79824801 at 12q13.3: OR = 1.10, p = 1.88 × 10-5 ) for the first time as independently related to BCC risk in meta-analysis; and both SNPs were nominally significant in two data sets. In addition, the SNP rs3769823 within VDR binding site at a previously reported BCC susceptibility locus (2q33.1, rs13014235) also exhibited a significant association (OR = 1.12, p = 3.99 × 10-18 ). A mutually adjusted model suggested that rs3769823 explained the signal in this region. Our findings support the hypothesis that inherited common variation in VDR binding sites affects the development of BCC.

Height, height-related SNPs, and risk of non-melanoma skin cancer.

BACKGROUND: Adult height has been associated with risk of several site-specific cancers, including melanoma. However, less attention has been given to non-melanoma skin cancer (NMSC). METHODS: We prospectively examined the risk of squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) in relation to adult height in the Nurses' Health Study (NHS, n=117 863) and the Health Professionals Follow-up Study (HPFS, n=51 111). We also investigated the relationships between height-related genetic markers and risk of BCC and SCC in the genetic data sets of the NHS and HPFS (3898 BCC cases, and 8530 BCC controls; 527 SCC cases, and 8962 SCC controls). RESULTS: After controlling for potential confounding factors, the hazard ratios were 1.09 (95% CI: 1.02, 1.15) and 1.10 (95% CI: 1.07, 1.13) for the associations between every 10 cm increase in height and risk of SCC and BCC respectively. None of the 687 height-related single-nucleotide polymorphisms (SNPs) was significantly associated with the risk of SCC or BCC, nor were the genetic scores combining independent height-related loci. CONCLUSIONS: Our data from two large cohorts provide further evidence that height is associated with an increased risk of NMSC. More studies on height-related genetic loci and early-life exposures may help clarify the underlying mechanisms.