Persistent Cutaneous Lesions of Darier Disease and Second-Hit Somatic Variants in ATP2A2 Gene.

Importance: Darier disease (DD) is a rare genetic skin disorder caused by heterozygous variants in the ATP2A2 gene. Clinical manifestations include recurrent hyperkeratotic papules and plaques that occur mainly in seborrheic areas. Although some of the lesions wax and wane in response to environmental factors, others are severe and respond poorly to therapy. Objective: To investigate the molecular mechanism underlying the persistency of skin lesions in DD. Design, Setting, and Participants: In this case series, DNA was extracted from unaffected skin, transient and persistent lesional skin, and blood from 9 patients with DD. Genetic analysis was used using paired-whole exome sequencing of affected skin and blood or by deep sequencing of ATP2A2 of affected skin. Chromosomal microarray analysis was used to reveal copy number variants and loss of heterozygosity. All variants were validated by Sanger sequencing or restriction fragment length polymorphism. Interventions or Exposures: Paired whole-exome sequencing and deep sequencing of ATP2A2 gene from blood and skin samples isolated from persistent, transient lesions and unaffected skin in patients with DD. Main Outcomes and Measures: Germline and somatic genomic characteristics of persistent and transient cutaneous lesions in DD. Results: Of 9 patients with DD, all had heterozygous pathogenic germline variants in the ATP2A2 gene, 6 were female. Participant age ranged from 40 to 69 years on enrollment. All 11 persistent skin lesions were associated with second-hit somatic variants in the ATP2A2 gene. The somatic variants were classified as highly deleterious via combined annotation-dependent depletion (CADD) scores or affect splicing, and 3 of them had been previously described in patients with DD and acrokeratosis verruciformis of Hopf. Second-hit variants in the ATP2A2 gene were not identified in the transient lesions (n = 2) or the normal skin (n = 2). Conclusions and Relevance: In this study, persistent DD lesions were associated with the presence of second-hit somatic variants in the ATP2A2 gene. Identification of these second-hit variants offers valuable insight into the underlying mechanisms that contribute to the lasting nature of persistent DD lesions.

Acral peeling in Nagashima type palmo-plantar keratosis patients reveals the role of serine protease inhibitor B 7 in keratinocyte adhesion.

Acral peeling skin syndrome (APSS) is a heterogenous group of genodermatoses, manifested by peeling of palmo-plantar skin and occasionally associated with erythema and epidermal thickening. A subset of APSS is caused by mutations in protease inhibitor encoding genes, resulting in unopposed protease activity and desmosomal degradation and/or mis-localization, leading to enhanced epidermal desquamation. We investigated two Arab-Muslim siblings with mild keratoderma and prominent APSS since infancy. Genetic analysis disclosed a homozygous mutation in SERPINB7, c.796C > T, which is the founder mutation in Nagashima type palmo-plantar keratosis (NPPK). Although not previously formally reported, APSS was found in other patients with NPPK. We hypothesized that loss of SERPINB7 function might contribute to the peeling phenotype through impairment of keratinocyte adhesion, similar to other protease inhibitor mutations that cause APSS. Mis-localization of desmosomal components was observed in a patient plantar biopsy compared with a biopsy from an age- and gender-matched healthy control. Silencing of SERPINB7 in normal human epidermal keratinocytes led to increased cell sheet fragmentation upon mechanical stress. Immunostaining showed reduced expression of desmoglein 1 and desmocollin 1. This study shows that in addition to stratum corneum perturbation, loss of SERPINB7 disrupts desmosomal components, which could lead to desquamation, manifested by skin peeling.

Parental mosaic cutaneous-gonadal GJB2 mutation: From epidermal nevus to inherited ichthyosis-deafness syndrome.

Ichthyosis and deafness syndrome is a group of devastating genodermatoses caused by heterozygous mutations in GJB2, encoding the gap junction protein connexin 26. These syndromes are characterized by severe skin disease, hearing loss, recurrent infections, and cutaneous neoplasms. Cutaneous somatic mutations in the same gene are associated with porokeratotic eccrine ostial dermal duct nevus. Here we report a family in which a parent presented with localized epidermal nevus and his child suffered with hystrix-like ichthyosis with deafness. Histologic examination of the parent's cutaneous lesion revealed verrucous epidermal nevus without features of porokeratotic eccrine ostial dermal duct nevus. Genetic analysis identified the same pathogenic variant, GJB2 c.148G>A (p.D50N), in DNA extracted from the parent's cutaneous lesion and the child's leukocytes, but not in the parent's leukocytes. This study expands the phenotypic heterogeneity of GJB2 mosaic variants in addition to porokeratotic eccrine ostial dermal duct nevus, and emphasizes the importance of molecular diagnosis of mosaic skin diseases considering the risk of severe inherited diseases in the offspring.

Concomitant variants in NF1, LZTR1 and GNAZ genes probably contribute to the aggressiveness of plexiform neurofibroma and warrant treatment with MEK inhibitor.

Neurofibromatosis 1 (NF1) is caused by germline mutations in the NF1 gene and manifests as proliferation of various tissues, including plexiform neurofibromas. The plexiform neurofibroma phenotype varies from indolent to locally aggressive, suggesting contributions of other modifiers in addition to somatic loss of NF1. In this study, we investigated a life-threatening plexiform neurofibroma in a 9-month-old female infant with NF1. Germline mutations in two RASopathy-associated genes were identified using whole-exome sequencing-a de novo pathogenic variant in the NF1 gene, and a known pathogenic variant in the LZTR1 gene. Somatic analysis of the plexiform neurofibroma revealed NF1 loss of heterozygosity and a variant in GNAZ, a gene encoding a G protein-coupled receptor. Cells expressing mutant GNAZ exhibited increased ERK 1/2 activation compared to those expressing wild-type GNAZ. Taken together, we suggest the variants in NF1, LZRT1 and GNAZ act synergistically in our patient, leading to MAPK pathway activation and contributing to the severity of the patient's plexiform neurofibromatosis. After treatment with the MEK inhibitor, trametinib, a prominent clinical improvement was observed in this patient. This case study contributes to the knowledge of germline and somatic non-NF1 variants affecting the NF1 clinical phenotype and supports use of personalized, targeted therapy.

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.

The Role of Desmoglein 1 in Gap Junction Turnover Revealed through the Study of SAM Syndrome.

An effective epidermal barrier requires structural and functional integration of adherens junctions, tight junctions, gap junctions (GJ), and desmosomes. Desmosomes govern epidermal integrity while GJs facilitate small molecule transfer across cell membranes. Some patients with severe dermatitis, multiple allergies, and metabolic wasting (SAM) syndrome, caused by biallelic desmoglein 1 (DSG1) mutations, exhibit skin lesions reminiscent of erythrokeratodermia variabilis, caused by mutations in connexin (Cx) genes. We, therefore, examined whether SAM syndrome-causing DSG1 mutations interfere with Cx expression and GJ function. Lesional skin biopsies from SAM syndrome patients (n = 7) revealed decreased Dsg1 and Cx43 plasma membrane localization compared with control and nonlesional skin. Cultured keratinocytes and organotypic skin equivalents depleted of Dsg1 exhibited reduced Cx43 expression, rescued upon re-introduction of wild-type Dsg1, but not Dsg1 constructs modeling SAM syndrome-causing mutations. Ectopic Dsg1 expression increased cell-cell dye transfer, which Cx43 silencing inhibited, suggesting that Dsg1 promotes GJ function through Cx43. As GJA1 gene expression was not decreased upon Dsg1 loss, we hypothesized that Cx43 reduction was due to enhanced protein degradation. Supporting this, PKC-dependent Cx43 S368 phosphorylation, which signals Cx43 turnover, increased after Dsg1 depletion, while lysosomal inhibition restored Cx43 levels. These data reveal a role for Dsg1 in regulating epidermal Cx43 turnover.

Combination therapy of cyclosporine and anti-tumor necrosis factor α in psoriasis: a case series of 10 patients.

Combination therapy has become important in treating psoriasis, using synergism between different mechanisms to maximize efficacy and minimize toxicity. Little has been published on the combination of cyclosporine and anti-tumor necrosis factor (TNF) α agents. In this study, a retrospective chart review was made of the effects of this combination therapy in 10 patients with recalcitrant psoriasis. Treatment included a conditioning phase with cyclosporine, 3.14 ± 0.37 mg/kg for 4.6 ± 2 weeks, and a combination phase during which etanercept/adalimumab were initiated and cyclosporine was tapered over 10.2 ± 3.7 weeks. Treatment success, evaluated after each phase, was classified as complete recovery (CR, more than 75% improvement), partial response (PR, 25-75% improvement), and no response (NR, less than 25% improvement). All patients reached CR at the end of the combination therapy. Two were still on combination therapy after 12 and 20 weeks. Adverse event occurred in three cases, all in the conditioning phase. We conclude that combination therapy with cyclosporine and anti-TNF α appears to offer an effective and safe approach to treatment of psoriasis.

An unusual co-occurrence of Langerhans cell histiocytosis and Rosai-Dorfman disease: report of a case and review of the literature.

BACKGROUND: The co-occurrence of Langerhans cell histiocytosis (LCH; disorder characterized by proliferation of Langerhans cells) and Rosai-Dorfman disease (RDD; histiocytic entity that is one of the non-Langerhans cell diseases) is extremely rare and raises several questions regarding the nature of the diseases. METHODS: We describe a 10-year-old boy who presented with a 3-month history of right scalp swelling. Clinical, pathological, and imaging evaluation disclosed multiple LCH of bone and cutaneous RDD. RESULTS: After initiating prednisone and vinblastine therapy, the patient developed an asymptomatic diffuse papular eruption. Biopsy revealed cutaneous RDD. Treatment was continued with a good response of bone LCH and significant amelioration of the cutaneous findings. CONCLUSIONS: Co-occurrence of LCH and RDD is a rare phenomenon. Various explanations, including the role of chemotherapy, are suggested based on our and several previously reported cases.

Infantile haemangiomas and quality of life.

OBJECTIVE: To determine the quality of life (QOL) and self-esteem of children with infantile haemangiomas using objective measures. DESIGN: Twenty-one children, 5-8 years old, with a diagnosis of head or neck haemangioma measuring 2 cm or more, were compared with 22 children with no history of haemangioma. SETTING: A tertiary medical centre in the north of Israel. INTERVENTIONS: Demographic and clinical details were collected, followed by two questionnaires-Paediatric Quality of Life Inventory (PedsQL) and Harter pictorial scale of Perceived Competence and Social Acceptance for young children-answered by children and parents of the two groups. MAIN OUTCOME MEASURES: QOL and self-esteem of the children in the two groups. RESULTS: There were no significant differences in QOL indices or self-perception scores between children with and without haemangioma (86.6±10.3 vs 80.1±15.07, p=0.23 and 3.62±0.2 vs 3.72±0.21, p=0.17, respectively). Interestingly, parents of children with haemangioma reported higher QOL of their children than parents of children without haemangioma (86.4±9.6 vs 77.1±14.9, p<0.03). Likewise, a positive correlation between parents' scored PedsQL and children's scored PedsQL was found (0.56, p=0.008). CONCLUSIONS: The findings raise a question about aggressive as opposed to more conservative treatment, especially in the era of propranolol.