Darier's disease: epidemiology, pathophysiology, and management

Darier disease: Current insights and challenges in pathogenesis and management

Darier disease is a rare autosomal dominant genodermatosis caused by mutations in the ATP2A2 gene encoding for sarcoendoplasmic reticulum Ca2+ ATPase isoform 2. The skin disease is characterized by a chronic relapsing course with recurrent reddish-brown keratotic papules and plaques located mainly in seborrhoeic areas. Due to chronic inflammation and epidermal barrier defects of the skin, patients often develop severe bacterial and viral superinfections. Therapeutic options are limited, mainly symptomatic and in most cases unsatisfactory in the long term. Patients are advised to avoid aggravating factors such as high temperature, high humidity, UV radiation and mechanical irritation. To prevent superinfection, antiseptics and periodic use of topical corticosteroids are fundamental in treatment. In case of bacterial and viral superinfection, systemic anti-infective therapy is often necessary. Currently, the most effective treatment option for extensive and persistent skin lesions is systemic retinoids, which are thought to mainly target the epidermal compartment (e.g. by reducing hyperkeratosis). One hallmark of Darier disease patients is chronic skin inflammation. We and others have previously reported Th17 cells in the dermal infiltrate of inflamed Darier disease skin. Counteracting inflammation by blocking the IL-23/IL-17 axis improved skin manifestations in a small cohort of previously therapy-resistant patients over 1 year. Furthermore, several other topical treatment options for mild disease as well as various ablative therapies and surgical excision have been proposed to be effective in some patients with hypertrophic skin lesions. This article aims to outline the pathogenesis, clinical features, diagnosis/differential diagnosis and available treatment modalities of Darier disease.

Pumping the Breaks on Acantholytic Skin Disorders: Targeting Calcium Pumps, Desmosomes, and Downstream Signaling in Darier, Hailey-Hailey, and Grover Disease

Acantholytic skin disorders, by definition, compromise intercellular adhesion between epidermal keratinocytes. The root cause of blistering in these diseases traces back to direct disruption of adhesive cell-cell junctions, exemplified by autoantibody-mediated attack on desmosomes in pemphigus. However, genetic acantholytic disorders originate from more indirect mechanisms. Darier disease and Hailey-Hailey disease arise from mutations in the endoplasmic reticulum calcium pump, SERCA2, and the Golgi calcium/manganese pump, SPCA1, respectively. Though the disease-causing mutations have been known for nearly 25 years, the mechanistic linkage between dysregulation of intracellular ion stores and weakening of cell-cell junctions at the plasma membrane remains puzzling. The molecular underpinnings of a related idiopathic disorder, Grover disease, are even less understood. Due to an incomplete understanding of acantholytic pathology at the molecular level, these disorders lack proven, targeted treatment options, leaving patients with the significant physical and psychological burdens of chronic skin blistering, infections, and pain. This article aims to review what is known at the molecular, cellular, and clinical levels regarding these under-studied disorders and to highlight knowledge gaps and promising ongoing research. Armed with this knowledge, our goal is to aid investigators in defining essential questions about disease pathogenesis and to accelerate progress toward novel therapeutic strategies.

Kaposi's Varicelliform Eruption: A Serious and Potentially Fatal Complication of Darier's Disease

Darier's disease (DD) is an autosomal dominant genetic disorder characterized by skin barrier dysfunction and chronic skin inflammation predisposing patients to secondary infections. Kaposi's varicelliform eruption (KVE), a severe viral infection, most commonly caused by herpes simplex virus (HSV), represents a life-threatening complication in these patients. The authors present the case of a 48-year-old woman with DD, who developed a progressive painful vesiculopustular eruption accompanied by systemic symptoms, including fever, bilateral otalgia, and ocular pain. The initial skin lesions, confined to the scapular region, rapidly spread to the face, periorbital region, and external ears. Clinical examination revealed vesiculopustular lesions, conjunctival hyperemia, and ear involvement. Laboratory testing confirmed HSV-1/2 immunoglobulin M (IgM) positivity, and blood cultures grew Staphylococcus aureus, indicating bacterial superinfection. The patient was treated with intravenous acyclovir and flucloxacillin, leading to significant clinical improvement. Clinicians should maintain a high index of suspicion for KVE in patients with DD presenting with vesicular rashes, particularly when systemic symptoms or rapid progression is observed. This case underscores the importance of early recognition of KVE in DD patients to facilitate timely antiviral and antibacterial treatment, reducing the risk of severe complications such as vision loss and permanent auditory impairment.

Case report: Multiple cryotherapy sessions in localized Darier's disease: a rare clinical presentation and literature review

Darier's disease (DD), a rare hereditary acantholytic dermatosis with high penetrance but variable expressivity, has about 10% of its cases presenting as localized lesions, known as Localized Darier's Disease (LDD). To date, only a very small number of non-segmental LDD cases have been reported. This study reports a case of a 27-year-old Chinese male with LDD, who presented with yellow-brown papules and plaques on the inner side of the right thigh for 1 month. The diagnosis of localized keratosis follicularis was confirmed through dermatoscopic examination and histopathological assessment of the skin lesion. After repeated applications of cryotherapy combined with the use of emollients, while avoiding physical friction and sun exposure, the rash gradually subsided. The patient experienced no adverse reactions after treatment. The occurrence of LDD on the inner thigh, a relatively rare site, provides new insights into the affected areas of LDD, further expands the clinical manifestations of the disease, and offers valuable experience for clinicians in recognizing and managing LDD at different sites, aiding in the optimization of diagnostic and therapeutic strategies.

Patients with Darier disease have an increased risk of keratinocyte carcinoma: a Swedish registry-based nationwide cohort study

BACKGROUND

Darier disease is a genodermatosis which manifests as hyperkeratotic papules and superficial erosions mainly in seborrheic skin areas. This retrospective registry-based cohort study aimed to estimate the association between Darier disease and skin cancer.

RESULTS

Patients diagnosed with Darier disease were identified from the patient registry of Sahlgrenska University Hospital (Gothenburg, Sweden) in 2016-2020. The local cohort included 13 patients. Verification of Darier disease diagnosis in the National Patient Registry showed positive predictive value of more than 90%. National Patient Registry was searched for Darier disease in 2001-2020, Swedish Cancer Registry for cancers and Prescribed Drug Register for medications. The national cohort included 770 patients and tenfold matched control cohort. Patients with Darier disease had an increased relative risk of keratinocyte carcinoma (basal cell carcinoma and cutaneous squamous cell carcinoma combined) (hazard ratio [HR], 1.6, 95% confidence interval [CI], 1.0-2.5, P = 0.036). The risk increase was significant for basal cell carcinoma (HR, 1.8, 95% CI, 1.1-2.9, P = 0.012), whereas there was a trend for cutaneous squamous cell carcinoma, (HR, 1.9, 95% CI, 0.9-4.1, P = 0.086) and cutaneous melanoma (HR, 2.4, 95% CI, 0.9-6.2, P = 0.083). Standardized incidence ratio for keratinocyte cancers was 2.9 (95% CI, 2.4-3.3. The results were consistent in two subgroup analyses adjusting for use of retinoid and/or immunosuppressive drugs.

CONCLUSION

Patients with Darier disease have an increased risk of skin cancer, particularly keratinocyte carcinoma. This risk was consistent even when known risk modifiers for keratinocyte carcinoma were excluded in sensitivity analyses. The results support previously proposed molecular links between Darier disease and skin cancer, but further investigations are needed. Additional studies are also required to develop clinical management recommendations for Darier disease. In the meantime, dermatologists should be aware of the cancer risk in these patients and remain vigilant, as detecting cancer can be challenging in hyperkeratotic and/or eroded skin.

Microbial imbalance in Darier disease: Dominance of various staphylococcal species and absence of Cutibacteria

Darier disease (DD) is a rare autosomal dominant genodermatosis characterized by erythematous papules and plaques mainly involving sebaceous areas, such as the face, chest and back. Skin microbiome plays an essential role in maintaining skin homeostasis. A disturbed skin microbiome may contribute to the exacerbation of DD. We investigated the bacterial composition of two predilectional sites in DD patients and healthy individuals. We also measured the microbiome composition of deeper skin layers, where diversity was significantly reduced compared to the superficial layer of the skin from the same area. The microbiome of DD patients at lesional sites differed from that of non-lesional skin areas; moreover, non-lesional sites were different from those of the controls. Lesional areas were dominated by Staphylococcus species, such as S. aureus, S. epidermidis, S. hominis, S. sciuri, and S. equorum. However, levels of Cutibacterium acnes (formerly Propionibacterium acnes) and C. acnes subspecies defendens were significantly lower in lesional sites than in non-lesional sites. A significant decrease was measured in the levels of these two bacteria between non-lesional and control samples. Our findings may indicate that alterations in the skin microbiome could contribute to the inflammation of skin lesions in DD.

A Rare Case of Darier Disease Flaring Up During Pregnancy

Darier disease (DD), which was also known as keratosis follicularis or Darier-White disease, is an autosomal dominant hereditary illness. The illness typically first manifests in adolescence and progresses as a woman reaches reproductive age. Research on the potential effects of DD on the skin and fetus, especially when it affects the groin and vulva, is insufficient. We report a unique case of multiple folliculitis encompassing the skin of the axilla, breasts, belly, and groin during pregnancy. This condition was associated with recurrent episodes of chronic DD that flared up during each pregnancy and was safely delivered vaginally.

Dantrolene corrects cellular disease features of Darier disease and may be a novel treatment

Darier disease (DD) is a rare severe acantholytic skin disease caused by mutations in the ATP2A2 gene that encodes for the sarco/endoplasmic reticulum calcium ATPase isoform 2 (SERCA2). SERCA2 maintains endoplasmic reticulum calcium homeostasis by pumping calcium into the ER, critical for regulating cellular calcium dynamics and cellular function. To date, there is no treatment that specifically targets the disease mechanisms in DD. Dantrolene sodium (Dl) is a ryanodine receptor antagonist that inhibits calcium release from ER to increase ER calcium levels and is currently used for non-dermatological indications. In this study, we first identified dysregulated genes and molecular pathways in DD patient skin, demonstrating downregulation of cell adhesion and calcium homeostasis pathways, as well as upregulation of ER stress and apoptosis. We then show in various in vitro models of DD and SERCA2 inhibition that Dl aided in the retention of ER calcium and promoted cell adhesion. In addition, Dl treatment reduced ER stress and suppressed apoptosis. Our findings suggest that Dl specifically targets pathogenic mechanisms of DD and may be a potential treatment.

Diagnosis and management of longitudinal erythronychia: A clinical review by an expert panel

Longitudinal erythronychia (LE) is defined as a longitudinal red band of the nail(s) and is classified as localized (involvement of 1 nail) or polydactylous (involvement of more than 1 nail). The differential diagnosis is distinct for these classifications. The etiologies of localized longitudinal erythronychia are most frequently benign subungual neoplasms and less often malignancies. Polydactylous longitudinal erythronychia is typically secondary to regional or systemic diseases, including lichen planus and Darier disease. LE is a common but underrecognized clinical finding. Increased dermatologist awareness of the clinical characteristics and differential diagnosis for LE is necessary given the possibility for malignancy and associated systemic disease. In this clinical review, the clinical features, differential diagnosis, evaluation, and management of LE are described.

Desmosomes at a glance

Desmosomes are relatives of ancient cadherin-based junctions, which emerged late in evolution to ensure the structural integrity of vertebrate tissues by coupling the intermediate filament cytoskeleton to cell-cell junctions. Their ability to dynamically counter the contractile forces generated by actin-associated adherens junctions is particularly important in tissues under high mechanical stress, such as the skin and heart. Much more than the simple cellular 'spot welds' depicted in textbooks, desmosomes are in fact dynamic structures that can sense and respond to changes in their mechanical environment and external stressors like ultraviolet light and pathogens. These environmental signals are transmitted intracellularly via desmosome-dependent mechanochemical pathways that drive the physiological processes of morphogenesis and differentiation. This Cell Science at a Glance article and the accompanying poster review desmosome structure and assembly, highlight recent insights into how desmosomes integrate chemical and mechanical signaling in the epidermis, and discuss desmosomes as targets in human disease.

Unmet Needs in Darier's Disease from a Patient's Perspective: Lessons Learnt from the German Registry

The MDHHgermany registry was initiated to characterize the "real-life" situation of affected individuals with Darier's disease (DD; Morbus Darier, MD) and Hailey-Hailey disease (HH), including their treatment and healthcare. To gain deeper insights into medical care of patients with DD, various aspects such as demographics, subjective symptoms, patient satisfaction with medical care, past and current therapies were explored. Patients with diagnosed DD were included. Subjective symptoms such as itch, pain and burning sensation were assessed. Individual therapy goals were recorded and patients assessed previous/current therapies along with satisfaction of medical care and treatment. A total of 55 patients were recruited; 47 patients were eligible for the analysis. Pruritus was rated the most bothersome symptom. Some 42.6% had not received systemic treatment so far or systemic therapies were rated ineffective (32.6%). Most commonly oral retinoids were prescribed, followed by corticosteroids. Patient satisfaction with medical care and treatment proved to be mediocre. This "real-life" data show an alarming unmet need regarding patients' satisfaction with medical care and treatment, evidenced by the reported lack of disease control. Further studies and interventions are needed to improve the spectrum of available therapies. MDHHgermany provides a foundational platform for future clinical trials, epidemiological studies, and pathophysiological analyses.

Acitretin induced primary hypothyroidism in Darier's disease: A rare case report

ABSTRACT

Acitretin is a synthetic, second-generation retinoid mainly used for the treatment of Darier's disease (DD), which impacts biological processes by binding to a nuclear receptor from the corticosteroid/thyroid receptor superfamily, thereby altering gene expression. Our report outlines the case of a 41-year-old male patient who has received a clinical diagnosis of DD and does not exhibit any other coexisting comorbidities, who developed hypothyroidism posttreatment with acitretin, an unusual and rare side effect of the drug. His baseline routine investigations fell within normal limits before the initiation of acitretin. Acitretin-induced hypothyroidism was treated with thyroxine. Although a good therapeutic response was seen with acitretin, it could not be continued due to the development of side effects and was continued on topical therapy. This case emphasizes the likelihood of adverse effects linked to therapeutic levels of acitretin in patients without any prior history and signifies the critical importance of consistent blood monitoring throughout drug therapy.

Darier disease is associated with neurodegenerative disorders and epilepsy

Darier disease (DD) is a rare monogenetic skin disorder with limited data on its potential association with neurological disorders. This study aimed to investigate the association between DD and neurological disorders, specifically Parkinson's disease, dementias, and epilepsy. Using Swedish national registers in a period spanning between 1977 and 2013, 935 individuals with DD were compared with up to 100 comparison individuals each, randomly selected from the general population based on birth year, sex, and county of residence at the time of the first diagnosis of DD. Individuals with DD had increased risks of being diagnosed with Parkinson's disease (RR 2.1, CI 1.1; 4.4), vascular dementia (RR 2.1, CI 1.0; 4.2), and epilepsy, (RR 2.5, CI 1.8; 3.5). No association of DD with other dementias were detected. This study demonstrates a new association between DD and neurodegenerative disorders and epilepsy, underlining the need for increased awareness, interdisciplinary collaboration, and further research to understand the underlying mechanisms. Early identification and management of neurological complications in DD patients could improve treatment strategies and patient outcomes. The findings also highlight the role of SERCA2 in the pathophysiology of neurological disorders, offering new targets for future research and potentials for novel treatments.

ALA-PDT combined with 2940 nm ablative fractional Er:YAG laser for Darier's disease

Darier's disease is a rare, genetically determined dyskeratotic skin disorder. Although many conventional treatments have been reported, management of Darier's disease remains challenging. Most patients are at high risk of recurrence during long-term follow-up. Here, we present two patients who were successfully treated with ALA photodynamic therapy (PDT) and ablative 2940 nm Er:YAG fractional laser. Both patients exhibited significant improvements in the affected areas with moderate pain, transient erythema and edema. Remission durations of up to 2 years were observed in both patients after combination treatment. Our findings suggest that the combination of ALA-PDT and 2940 nm fractional Er:YAG laser may be an effective, safe and well-tolerated treatment option for Darier's disease.

Dermoscopy as a Noninvasive Diagnostic Tool for Hailey-Hailey Disease and Darier Disease

INTRODUCTION

Hailey-Hailey disease (HHD) and Darier disease (DD) are rare genetic disorders for which differential diagnosis, especially in less obvious cases, can be difficult. The diagnosis is based on the clinical picture and family history, and is confirmed by histopathologic examination. Dermoscopy is a noninvasive technique that is primarily used at the present time to diagnose skin cancers. However, in the past few years this technique has also been increasingly used as a noninvasive diagnostic tool of inflammatory skin diseases. The aim of the study was to evaluate whether dermoscopy is a useful noninvasive diagnostic tool for HHD and DD.

METHODS

We performed an observational retrospective case series study involving 13 patients with HHD (n = 8) and DD (n = 5). The presence or absence of standardized dermoscopic features of inflammatory diseases (according to International Dermoscopy Society [IDS] guidelines) was assessed in these patients.

RESULTS

The most distinctive feature of HHD was white clouds separated by pink furrows, visible in all cases (8/8; 100.0%). Another distinctive clue of HHD was the crumbled fabric pattern seen in six patients with HHD (6/8; 75.0%). These dermoscopic findings were not present in patients with DD. The most typical features of DD in the dermoscopic examination was star-like or oval-shaped yellow areas surrounded by whitish halo, visible in all patients (5/5; 100.0%). Another distinctive dermoscopic clue of DD was pinkish homogeneous structureless background, which was present in all patients (5/5, 100.0%). These latter two features were not observed in patients with HHD.

CONCLUSION

Dermoscopy reveals distinctive features of HHD and DD, respectively. Therefore, we conclude that dermoscopy can be an excellent complementary noninvasive tool in the diagnostic process of patients with HHD and DD.

Diagnosis and management of vulvar Darier disease: A case report

Darier disease is an autosomal dominant disorder with hyperkeratotic papules affecting primarily seborrheic areas of the upper chest, back, forehead, scalp, nasolabial folds, ears, and, less frequently, the oral mucosa. A typical eruption consists of keratotic and crusted skin-colored papules and plaques. Pruritus occurs in 80% of patients, and pain is rare. Lesions can be triggered by exposure to ultraviolet light, heat, or stress. Secondary infections of the lesions are a common complication. A definitive diagnosis is obtained by a biopsy showing histological features such as acantholysis, suprabasal clefts, and "corps rond and grains". Here we present a 37-year-old woman admitted to the gynecology department with pruritic lesions she had noticed on her vulva and perineum for three months. A vulvar biopsy led to the diagnosis of Darier disease. She was referred to the dermatology department and treated with oral acitretin since systemic retinoids are offered as the first-line treatment of the disease.

Incidence and Prevalence of 73 Different Genodermatoses: A Nationwide Study in Sweden

This retrospective registry-based cohort study aimed to estimate the incidence and prevalence of genodermatoses in the Swedish population and to analyse associated healthcare usage. Patients diagnosed with genodermatoses were identified from the patient registry of Sahlgrenska University Hospital (Gothenburg, Sweden) between 2016 and 2020. Clinical data from medical records were used to verify diagnoses recorded in the National Patient Registry (NPR). The NPR was then searched for International Classification of Diseases, Tenth Revision (ICD-10) codes Q80-82 and Q84 from 2001 to 2020. The local cohort included 298 patients with 36 unique genodermatosis diagnoses. Verification of these diagnoses in the NPR showed positive predictive values of over 90%. The NPR search yielded 13,318 patients with 73 unique diagnoses, including ichthyoses (n = 3,341; 25%), porokeratosis (n = 2,277; 17%), palmoplantar keratodermas (n = 1,754; 13%), the epidermolysis bullosa group (n = 1011; 7%); Darier disease (n = 770; 6%), Hailey-Hailey disease (n = 477; 4%) and Gorlin syndrome (n = 402; 3%). The incidence and prevalence of each diagnosis were calculated based on the nationwide cohort and are reported. A total of 149,538 outpatient visits were registered, a mean of 4.6 visits per patient. This study provides a valuable resource for the epidemiology of genodermatoses by reporting on the incidence and prevalence of 73 different genodermatoses.

Exacerbation of Very Late-Onset Darier Disease With COVID-19 Infection: A Case Report

Darier disease is an uncommon hereditary skin disorder characterized by the presence of hyperkeratotic papules and plaques affecting seborrheic areas. The uniqueness of this case lies in the exceptionally late-onset pattern of Darier disease, involving an 82-year-old female patient, and its correlation with COVID-19 infection. The patient had a history of a scaly and itchy rash limited to her arms, initially misdiagnosed as dermatitis, which persisted and worsened over three months. The manifestation of classical features of Darier disease coincided with her recent contraction of COVID-19. This instance emphasizes the varying manifestations of Darier disease that appear very late in life, which could result from new mutations or partial penetrance. Additionally, this case points out the potential worsening of Darier disease when combined with a COVID-19 infection. It highlights the need to be aware of atypical clinical progressions and the potential for increased severity of skin disorders during COVID-19. More studies are essential to grasp the relationship between COVID-19 and inherited skin conditions, aiming to improve patient treatment and care approaches.

Architecture and dynamics of a desmosome-endoplasmic reticulum complex

The endoplasmic reticulum (ER) forms a dynamic network that contacts other cellular membranes to regulate stress responses, calcium signalling and lipid transfer. Here, using high-resolution volume electron microscopy, we find that the ER forms a previously unknown association with keratin intermediate filaments and desmosomal cell-cell junctions. Peripheral ER assembles into mirror image-like arrangements at desmosomes and exhibits nanometre proximity to keratin filaments and the desmosome cytoplasmic plaque. ER tubules exhibit stable associations with desmosomes, and perturbation of desmosomes or keratin filaments alters ER organization, mobility and expression of ER stress transcripts. These findings indicate that desmosomes and the keratin cytoskeleton regulate the distribution, function and dynamics of the ER network. Overall, this study reveals a previously unknown subcellular architecture defined by the structural integration of ER tubules with an epithelial intercellular junction.

Mendelian Disorders in an Interstitial Cystitis/Bladder Pain Syndrome Cohort

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic pain disorder causing symptoms of urinary frequency, urgency, and bladder discomfort or pain. Although this condition affects a large population, little is known about its etiology. Genetic analyses of whole exome sequencing are performed on 109 individuals with IC/BPS. One family has a previously reported SIX5 variant (ENST00000317578.6:c.472G>A, p.Ala158Thr), consistent with Branchiootorenal syndrome 2 (BOR2). A likely pathogenic heterozygous variant in ATP2A2 (ENST00000539276.2:c.235G>A, p.Glu79Lys) is identified in two unrelated probands, indicating possible Darier-White disease. Two private heterozygous variants are identified in ATP2C1 (ENST00000393221.4:c.2358A>T, p.Glu786Asp (VUS/Likely Pathogenic) and ENST00000393221.4:c.989C>G, p.Thr330Ser (likely pathogenic)), indicative of Hailey-Hailey Disease. Sequence kernel association test analysis finds an increased burden of rare ATP2C1 variants in the IC/BPS cases versus a control cohort (p = 0.03, OR = 6.76), though does not survive Bonferroni correction. The data suggest that some individuals with IC/BPS may have unrecognized Mendelian syndromes. Comprehensive phenotyping and genotyping aid in understanding the range of diagnoses in the population-based IC/BPS cohort. Conversely, ATP2C1, ATP2A2, and SIX5 may be candidate genes for IC/BPS. Further evaluation with larger numbers is needed. Genetically screening individuals with IC/BPS may help diagnose and treat this painful disorder due to its heterogeneous nature.

Insights into the role of intracellular calcium signaling in the neurobiology of neurodevelopmental disorders

Calcium (Ca²⁺) comprises a critical ionic second messenger in the central nervous system that is under the control of a wide array of regulatory mechanisms, including organellar Ca²⁺ stores, membrane channels and pumps, and intracellular Ca²⁺-binding proteins. Not surprisingly, disturbances in Ca²⁺ homeostasis have been linked to neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases. However, aberrations in Ca²⁺ homeostasis have also been implicated in neuropsychiatric disorders with a strong neurodevelopmental component including autism spectrum disorder (ASD) attention-deficit hyperactivity disorder (ADHD) and schizophrenia (SCZ). While plasma membrane Ca²⁺ channels and synaptic Ca²⁺-binding proteins have been extensively studied, increasing evidence suggests a prominent role for intracellular Ca²⁺ stores, such as the endoplasmic reticulum (ER), in aberrant neurodevelopment. In the context of the current mini-review, we discuss recent findings implicating critical intracellular Ca²⁺-handling regulators such as the sarco-ER Ca²⁺ ATPase 2 (SERCA2), ryanodine receptors (RyRs), inositol triphosphate receptors (IP₃Rs), and parvalbumin (PVALB), in the emergence of ASD, SCZ, and ADHD.

A Case of Darier's Disease with a Novel Missense Mutation in ATP2A2 Successfully Treated with Calcipotriol/Betamethasone Dipropionate Two-Compound Ointment

Darier’s disease (DD) is a rare autosomal dominant genodermatosis caused by mutations in the ATP2A2 gene, which encodes for the sarcoendoplasmic reticulum calcium ATPase type 2 isoform (SERCA2). In epidermal keratinocytes, the decrease in SERCA2 inhibits the transportation of desmosomal proteins to the plasma membrane, resulting in acantholysis and dyskeratosis. We present the first case of DD with a novel missense mutation in the ATP2A2 gene and successfully treated with calcipotriol/betamethasone dipropionate two-compound ointment. A 34-year-old Japanese woman presented with erythema and scales on the scalp and clusters of keratotic papules on the neck and groin. Similar symptoms were observed in her father, younger sister, and daughter. Histopathological examination revealed corps ronds in the granular layer and grains in the horny layer of the epidermis and acantholytic lacuna just above the basal layer. She was diagnosed with DD. A novel heterozygous missense mutation, c.616A>C (p.Asn206His), was detected in the ATP2A2 gene in both the patient and her daughter. The patient was treated with calcipotriol/betamethasone dipropionate two-compound ointment, which resulted in improvement of the skin eruption. This two-compound topical ointment may be a promising therapeutic strategy in the treatment for DD.

Therapeutic Options for the Treatment of Darier's Disease: A Comprehensive Review of the Literature

Darier's disease (also known as keratosis follicularis or dyskeratosis follicularis) is an autosomal dominant inherited disorder which manifests as hyperkeratotic greasy papules in the first or second decade of life. Aside from symptom management and behavioral modifications to avoid triggers, there are currently no validated treatments for Darier's disease (DD). However, a variety of treatments have been proposed in the literature including retinoids, steroids, vitamin D analogs, photodynamic therapy, and surgical excision. The purpose of this review article is to identify therapeutic options for treating DD and to outline the evidence underlying these interventions. A search was conducted in Medline for English language articles from inception to July 4, 2020. Our search identified a total of 474 nonduplicate studies, which were screened by title and abstract. Of these, 155 full text articles were screened against inclusion/exclusion criteria, and 113 studies were included in our review. We identified Grade B evidence for the following treatments of DD: oral acitretin, oral isotretinoin, systemic Vitamin A, topical tretinoin, topical isotretinoin, topical adapalene gel, topical 5-flououracil, topical calciptriol and tacalcitol (with sunscreen), grenz ray radiation, and x-ray radiation. All other evidence for treatments of DD consisted of case reports or case series, which is considered grade C evidence. Considering the quality and quantity of evidence, clinicians may consider initiating a trial of select topical or oral retinoids first in patients with localized or generalized DD, respectively.

Validity of First-Time Diagnoses of Darier's Disease in the Danish National Patient Registry

Purpose

Darier's disease (DD) is a rare genetic skin disease, characterized by yellow-brown, scaly, crusted papules in seborrheic areas and specific nail changes. This study aimed to validate all first-time diagnoses of DD in Danish National Patient Registry (DNPR). The intent of the study is validation of DNPR for epidemiological and clinical studies on DD.

Patients and Methods

We identified all patients in DNPR who received their first-time diagnosis of DD between January 1, 1977 and December 31, 2018 (International Classification of Diseases [ICD]-8 code 75721 until the end of 1993: ICD-10 code Q828F thereafter). We restricted to diagnoses from departments of dermatology, where these patients are managed. We validated diagnoses against information from medical records, using predefined data extraction sheets and validation criteria. We classified diagnoses as probable when characteristic clinical features were present; confirmed when there was also genetic confirmation, histopathological confirmation and/or positive family history, or rejected (remaining patients). We estimated positive predictive values (PPVs) with 95% confidence intervals (CIs) for diagnoses overall and stratified by ICD classification, sex, age at diagnosis, year of diagnosis, type of diagnosis, and type of contact.

Results

We identified 277 first-time diagnoses of DD, of which 229 (82.7%) stemmed from departments of dermatology. Medical records were available for 196 (85.6%) of these. The overall PPVs for probable and confirmed DD were 89.3% (95% CI: 84.2–92.9) and 81.1% (95% CI: 75.1–86.0), respectively. The PPV for probable ICD-8 diagnosis (95.8% (95% CI: 82.1–99.5)) was slightly higher than that of probable ICD-10 diagnosis (88.4% (95% CI: 82.7–92.3)).

Conclusion

The validity of first-time diagnoses of DD recorded by departments of dermatology in the DNPR is relatively high, making DNPR suitable for epidemiological studies on DD in Denmark, as well as a useful source for recruitment to clinical studies on DD.

Darier and Hailey-Hailey disease: update 2021

The autosomal-dominant genodermatoses Darier disease and Hailey-Hailey disease present special challenges to dermatologists. Despite their similar pathogenesis featuring impaired adhesion of suprabasal keratinocytes as a result of defective ATPases in epidermal calcium channels, the two diseases differ considerably in clinical presentation and therapeutic options. Darier disease is characterized by reddish brown, keratotic papules in seborrheic and intertriginous areas, which may coalesce into extensive lesions. Individuals affected with Hailey-Hailey disease primarily develop intertriginous papulovesicles and small blisters, which often evolve into erythematous plaques with erosions and painful fissures. Quality of life is significantly reduced because of complaints (itch, burning sensation, pain), body malodor and chronicity. Therapeutic options remain limited. Antiseptics and intermittent topical corticosteroids are a cornerstone of therapy, and systemic anti-infective treatment is often required in cases of superinfection. Ablative surgical interventions such as dermabrasion and CO₂ laser surgery can lead to long-term remissions in intertriginous Hailey-Hailey disease, while temporary relief may also be achieved by intralesional injections of botulinum toxin. Of the systemic medications available for Darier disease, acitretin, which is approved for this purpose, has the best supporting evidence. The efficacy of immunosuppressants and immune modulators is inconsistent. Low-dose naltrexone produces more satisfactory results in Hailey-Hailey than Darier disease. The present CME article summarizes current knowledge of the two dermatoses, taking recent developments into account.

Darier's Disease Flare following COVID-19 Vaccine

Darier's disease is a rare genodermatosis characterized clinically by dyskeratotic papules in the seborrheic and intertriginous areas and nail abnormalities. Dyskeratosis and acantholysis are typical histological findings. Darier's disease is not known to be inflammatory by nature as inflammation occurs primarily due to local infections, and it may therefore differ from inflammatory dermatoses such as psoriasis and cutaneous lupus in response to antigen stimulation. Known triggers of Darier's disease primarily include exogenous factors such as sun exposure, friction, or infection. We present a case of a 47-year-old white female with a flare of Darier's disease 2 days following her first vaccination with COVID-19 vaccine (ChAdOx1-s [recombinant]) (Vaxzevria^® [previously known as COVID-19 vaccine AstraZeneca]). In this case report, we discuss possible mechanisms linking the vaccination and the flare of Darier's disease. We consider inflammatory mechanisms as well as a random co-occurrence. Due to the close time-related association between the disease flare and the COVID-19 vaccination, we find an urge to make other clinicians aware of a possible association.

Calcium Channels: Noteworthy Regulators and Therapeutic Targets in Dermatological Diseases

Dysfunctional skin barrier and impaired skin homeostasis may lead to or aggravate a series of dermatologic diseases. A large variety of biological events and bioactive molecules are involved in the process of skin wound healing and functional recovery. Calcium ions (Ca²⁺) released from intracellular stores as well as influx through plasma membrane are essential to skin function. Growing evidence suggests that calcium influx is mainly regulated by calcium-sensing receptors and channels, including voltage-gated, transient potential receptor, store-operated, and receptor-operated calcium channels, which not only maintain cellular Ca²⁺ homeostasis, but also participate in cell proliferation and skin cell homeostasis through Ca²⁺-sensitive proteins such as calmodulin (CaM). Furthermore, distinct types of Ca²⁺ channels not merely work separately, they may work concertedly to regulate cell function. In this review, we discussed different calcium-sensing receptors and channels, including voltage-gated, transient receptor potential, store-operated, and receptor-operated calcium channels, particularly focusing on their regulatory functions and inherent interactions as well as calcium channels-related reagents and drugs, which is expected to bridge basic research and clinical applications in dermatologic diseases.

Preclinical assessment of dual CYP26[A1/B1] inhibitor, DX308, as an improved treatment for keratinization disorders

Background

Retinoid‐based therapies are commonly used in the treatment of disorders of keratinization and other skin disorders but can result in non‐specific effects and adverse reactions. Use of retinoic acid metabolism blocking agents (RAMBAs) such as DX308 may address these shortcomings.

Objectives

Characterize the therapeutic potential of recently discovered, CYP26‐selective RAMBA, DX308.

Materials and Methods

Preliminary in vitro assessment of potential off‐target activity, metabolic and toxicologic profiling. Studies to assess safety and efficacy of topical treatment in correcting abnormal skin morphology in rhino mice. Extensive gene expression profiling by RNA sequencing and qPCR in 3D epidermis grown with keratinocytes (KCs) from keratinization disorders and healthy controls, to investigate modulation of retinoid biopathways.

Results

In vitro, DX308 does not interact with off‐target nuclear receptors or CYP450s, is not genotoxic, and is stable in skin, despite vigorous hepatic metabolism. In vivo, topical DX308 induces comedolysis and epidermal thickening without apparent adverse effects. Gene expression profiling shows potent modulation of retinoid‐responsive genes by DX308 in both healthy and keratinization disorder KCs. Pathway analysis suggests DX308 may inhibit inflammatory and immune responses in KCs.

Conclusions

These preliminary studies suggest that DX308 is an efficacious topical therapeutic with a favourable metabolic and safety profiles. DX308 may present an improved therapeutic alternative for the treatment of keratinization disorders and other retinoid‐responsive skin ailments.

An Update on the Cutaneous Manifestations of Darier Disease

BACKGROUND

Knowledge about the clinical features of Darier disease, an orphan autosomal-dominant genetic disorder, is sparse and has been evaluated only in few studies.

OBJECTIVES

To investigate the clinical features of a large group of patients with Darier disease, and to explore for associations between disease characteristics and severity of the disease.

METHODS

Seventy-six individuals with Darier disease were evaluated utilizing a structured questionnaire-based interview, a physical examination, and a retrospective assessment of their medical records.

RESULTS

The most frequent locations of lesions were hands (99%) and fingernails (93%). Wart-like lesions on the hands were more visible after soaking them in water for 5 minutes, we therefore named this phenomenon the "wet hand sign". Oral involvement was found in 43% of patients, while 48% of women and 16% of men showed genital lesions. Patients with severe Darier disease had a tenfold greater risk of developing genital lesions than those with mild disease (P = .01). Most patients (88%) in our study exhibited a combination of the four types of the disease patterns of distribution (flexural, seborrheic, nevoid, and acral).

CONCLUSIONS

Documentation of disease on the hands and fingernails provides a highly sensitive means to aid in the diagnosis of Darier disease. It is important to evaluate mucosal lesions including genital and oral mucosa.

Management of Darier disease: A review of the literature and update

Darier disease (DD) is a rare type of inherited keratinizing disorder with no definitive therapeutic approach. The objective of this study is to provide a detailed literature review of all the available treatment modalities of Darier disease, including those that are both surgical and non surgical, to compare their efficacies and to propose a novel therapeutic approach. A complete search of the literature for all articles describing the different treatments of Darier disease, with no restrictions on patients' ages, gender or nationalities, was performed with the use of PubMed. A total of 68 articles were included in the study: 3 prospective studies, 44 case reports/case series and 21 letters/correspondences/clinical images. The treatments described were topical, oral or physical. Retinoids (isotretinoin, tazarotene and adapalene) and fluorouracil were the two most effective topical treatments. Oral retinoids were the most effective oral therapy and were prescribed in the cases of generalized Darier disease. For localized and resistant skin lesions, physical therapies including surgical excision, dermabrasion and CO2 laser ablation were the first line choices. Limitations of this article include the inability to verify the accuracy of the published data, the relatively small sample size, the absence of randomized controlled clinical trials and possible unidentified confounding factors in various studies. In every therapeutic approach to Darier disease, consideration of patient comorbidities, disease distribution, severity and treatment accessibility is essential. Large and randomized clinical trials are necessary for the comparison of the efficacy and the safety of all the treatments of Darier disease and settling a consensus for management.

Type 1 Segmental Darier Disease: Case Report and Discussion of the Treatment Options

Darier disease is a rare type of autosomal dominant genodermatosis, and it is caused by a mutation in the gene coding for the endoplasmic reticulum membrane calcium pump Ca²⁺-ATPase type 2, leading to compromised intercellular adhesion. Moreover, this condition is characterized by multiple keratotic greasy papules with a seborrheic distribution and is worsened by heat and sun exposure, sweating, and friction. Occasionally, it may be associated with nail abnormalities and may involve the mucosa. Unilateral segmental Darier disease is a rare variant characterized by unilateral eruption of erythematic keratotic papules not associated with other conditions. Herein, we report a case of type 1 segmental Darier disease. Furthermore, the main characteristics and treatment options are discussed.

Characterization of CYP26B1-Selective Inhibitor, DX314, as a Potential Therapeutic for Keratinization Disorders

Inhibition of CYP450-mediated retinoic acid (RA) metabolism by RA metabolism blocking agents increases endogenous retinoids and is an alternative to retinoid therapy. Currently available RA metabolism blocking agents (i.e., liarozole and talarozole) tend to have fewer adverse effects than traditional retinoids but lack target specificity. Substrate-based inhibitor DX314 has enhanced selectivity for RA-metabolizing enzyme CYP26B1 and may offer an improved treatment option for keratinization disorders such as congenital ichthyosis and Darier disease. In this study, we used RT-qPCR, RNA sequencing, pathway, upstream regulator, and histological analyses to demonstrate that DX314 can potentiate the effects of all-trans-RA in healthy and diseased reconstructed human epidermis. We unexpectedly discovered that DX314, but not all-trans-RA or previous RA metabolism blocking agents, appears to protect epidermal barrier integrity. In addition, DX314-induced keratinization and epidermal proliferation effects are observed in a rhino mice model. Altogether, the results indicate that DX314 inhibits all-trans-RA metabolism with minimal off-target activity and shows therapeutic similarity to topical retinoids in vitro and in vivo. Findings of a barrier-protecting effect require further mechanistic study but may lead to a unique strategy in barrier-reinforcing therapies. DX314 is a promising candidate compound for further study and development in the context of keratinization disorders.

ATP2A2 SINE Insertion in an Irish Terrier with Darier Disease and Associated Infundibular Cyst Formation

A 4-month-old female Irish Terrier presented with a well demarcated ulcerative and crusting lesion in the right ear canal. Histological analysis revealed epidermal hyperplasia with severe acantholysis affecting all suprabasal layers of the epidermis, which prompted a presumptive diagnosis of canine Darier disease. The lesion was successfully treated by repeated laser ablation of the affected epidermis. Over the course of three years, the dog additionally developed three dermal nodules of up to 4 cm in diameter that were excised and healed without complications. Histology of the excised tissue revealed multiple infundibular cysts extending from the upper dermis to the subcutis. The cysts were lined by squamous epithelium, which presented with abundant acantholysis of suprabasal keratinocytes. Infundibular cysts represent a novel finding not previously reported in Darier patients. Whole genome sequencing of the affected dog was performed, and the functional candidate genes for Darier disease (ATP2A2) and Hailey-Hailey disease (ATP2C1) were investigated. The analysis revealed a heterozygous SINE insertion into the ATP2A2 gene, at the end of intron 14, close to the boundary of exon 15. Analysis of the ATP2A2 mRNA from skin of the affected dog demonstrated a splicing defect and marked allelic imbalance, suggesting nonsense-mediated decay of the resulting aberrant transcripts. As Darier disease in humans is caused by haploinsufficiency of ATP2A2, our genetic findings are in agreement with the clinical and histopathological data and support the diagnosis of canine Darier disease.

Darier disease is associated with heart failure: a cross-sectional case-control and population based study

Human data supporting a role for endoplasmic reticulum (ER) stress and calcium dyshomeostasis in heart disease is scarce. Darier disease (DD) is a hereditary skin disease caused by mutations in the ATP2A2 gene encoding the sarcoendoplasmic-reticulum Ca2+ ATPase isoform 2 (SERCA2), which causes calcium dyshomeostasis and ER stress. We hypothesized that DD patients would have an increased risk for common heart disease. We performed a cross-sectional case-control clinical study on 25 DD patients and 25 matched controls; and a population-based cohort study on 935 subjects with DD and matched comparison subjects. Main outcomes and measures were N-terminal pro-brain natriuretic peptide, ECG and heart diagnosis (myocardial infarction, heart failure and arrythmia). DD subjects showed normal clinical heart phenotype including heart failure markers and ECG. The risk for heart failure was 1.59 (1,16-2,19) times elevated in DD subjects, while no major differences were found in myocardial infarcation or arrhythmias. Risk for heart failure when corrected for cardivascular risk factors or alcohol misuse was 1.53 (1.11-2.11) and 1.58 (1,15-2,18) respectively. Notably, heart failure occurred several years earlier in DD patients as compared to controls. We conclude that DD patients show a disease specific increased risk of heart failure which should be taken into account in patient management. The observation also strenghtens the clinical evidence on the important role of SERCA2 in heart failure pathophysiology.

Hypertrichotic patches as a mosaic manifestation of Proteus syndrome

BACKGROUND

Proteus syndrome is an overgrowth disorder caused by a mosaic activating AKT1 variant. Hair abnormalities in Proteus syndrome have rarely been reported, and frequencies of such findings have not been elucidated.

OBJECTIVE

To define the types and frequencies of hair findings in individuals with Proteus syndrome.

METHODS

A cross-sectional study was conducted of individuals with clinical features of Proteus syndrome and a confirmed pathogenic variant in AKT1 evaluated between November 1996 and June 2019 at the National Institutes of Health Clinical Center. Medical records were reviewed for patterning, density, and color of hair on the body and scalp.

RESULTS

Of 45 individuals evaluated, 29 (64%) had asymmetric hypertrichosis on the body. This included unilateral blaschkoid hypertrichotic patches overlying normal skin or epidermal nevi in 16 (36%), unilateral nonblaschkoid hypertrichotic patches in 11 (24%), and unilateral limb hypertrichosis in 10 (22%). Diffuse, scattered, or patchy changes in scalp hair density or color were present in 11 individuals (24%).

LIMITATIONS

The retrospective, observational design, and limited longitudinal follow-up.

CONCLUSIONS

Asymmetric variations in hair distribution, thickness, length, and color contribute to the overall mosaic appearance of the skin in Proteus syndrome, an observation that provides novel insights into the role of phosphoinositide 3-kinase (PI3K)-protein kinase B (AKT) signaling in skin appendage development.