Background: Secukinumab has demonstrated sustained long‐term efficacy with a favourable safety profile in various psoriatic disease manifestations in adults.Objectives: Here, the efficacy and safety of two secukinumab dosing regimens [low dose (LD) and high dose (HD)] in paediatric patients with severe chronic plaque psoriasis over one year are reported.Methods: In this multicentre, double‐blind study (NCT02471144), patients aged 6 to <18 years with severe chronic plaque psoriasis were stratified and randomized by weight (<25 kg, 25 to <50 kg, ≥50 kg) and age (6 to <12 years, 12 to <18 years) to receive low‐dose (LD: 75/75/150 mg) or high‐dose (HD: 75/150/300 mg) subcutaneous secukinumab or placebo or etanercept 0.8 mg/kg (up to a max of 50 mg).Results: Overall, 162 patients were randomized to receive secukinumab LD (n = 40) or HD (n = 40), etanercept (n = 41) or placebo (n = 41). The co‐primary objectives of the study were met with both secukinumab doses (LD and HD) showing superior efficacy compared to placebo (P < 0.0001) with respect to PASI 75 response (80.0%, 77.5% vs. 14.6%) and IGA mod 2011, 0 or 1 response (70%, 60% vs. 4.9%) at Week 12. Both secukinumab doses were superior to placebo (P < 0.0001) with respect to PASI 90 response at Week 12 (72.5%, 67.5% vs. 2.4%). The efficacy of both doses was sustained to Week 52 with secukinumab achieving higher responses vs. etanercept (PASI 75/90/100: LD, 87.5%/75.0%/40.0% and HD, 87.5%/80.0%/47.5.% vs. etanercept, 68.3%/51.2%/22.0% and IGA 0 or 1: LD, 72.5% and HD, 75.0% vs. etanercept, 56.1%). The safety profile of secukinumab was consistent with the adult Phase 3 studies, with no new safety signals identified.Conclusions: Both doses of secukinumab demonstrated high and sustained efficacy up to Week 52 with a favourable safety profile in paediatric patients with severe chronic plaque psoriasis.

Mitochondrial DNA (mtDNA) has been suggested to drive immune system activation, but the induction of interferon signaling by mtDNA has not been demonstrated in a Mendelian mitochondrial disease. We initially ascertained two patients, one with a purely neurological phenotype and one with features suggestive of systemic sclerosis in a syndromic context, and found them both to demonstrate enhanced interferon-stimulated gene (ISG) expression in blood. We determined each to harbor a previously described de novo dominant-negative heterozygous mutation in ATAD3A, encoding ATPase family AAA domain–containing protein 3A (ATAD3A). We identified five further patients with mutations in ATAD3A and recorded up-regulated ISG expression and interferon α protein in four of them. Knockdown of ATAD3A in THP-1 cells resulted in increased interferon signaling, mediated by cyclic GMP-AMP synthase (cGAS) and stimulator of interferon genes (STING). Enhanced interferon signaling was abrogated in THP-1 cells and patient fibroblasts depleted of mtDNA. Thus, mutations in the mitochondrial membrane protein ATAD3A define a novel type I interferonopathy.

Epidermal differentiation disorders (EDDs) encompass inherited conditions characterized by abnormal epidermal differentiation, including nonsyndromic and syndromic subtypes with more extensive cutaneous involvement or palmoplantar keratoderma. Nonsyndromic EDDs (nEDDs) are defined as disorders that primarily affect large areas of skin and adnexal structures without alterations in extracutaneous tissues resulting from the underlying genetic change. To facilitate the development of targeted therapies and to provide clinicians with clearer therapeutic guidance, we have developed a new nomenclature for EDDs that includes the causative altered gene and the nEDD subgroup designation, sometimes with a clinical or histological descriptor or acronym. Historically, many nEDDs have been named on the basis of phenotypic characteristics or associations that are now considered outdated or inappropriate. For example, the term ‘harlequin ichthyosis’ evokes potentially stigmatizing images. Similarly, the word ‘ichthyosis’ is derived from the Greek ichthys, meaning fish, and the Greek hystrix, meaning porcupine, further emphasizing the need to abandon derogatory terminology. As a result, the clinical relevance of the previous classification, which included eponymous and/or descriptive titles, has diminished. In the new, gene-based classification, old terms considered pejorative, such as ichthyosis, vulgaris, hystrix and harlequin have been eliminated and eponyms have been replaced. Among the 53 genetically distinct nEDDs are conditions formerly known as autosomal recessive congenital ichthyosis, erythrokeratodermia variabilis et progressiva, Hailey–Hailey disease and Darier–White disease. This review outlines the updated nomenclature and classifications of nEDDs, linked to detailed clinical descriptions and representative photographs to guide practitioners.

Epidermal necrolysis (EN) encompasses Stevens-Johnson syndrome (SJS, < 10% of the skin affected), Lyell syndrome (toxic epidermal necrolysis, TEN, with ≥30% of the skin affected) and an overlap syndrome (10 to 29% of the skin affected). These rare diseases are caused, in 85% of cases, by pharmacological treatments, with symptoms occurring 4 to 28 days after treatment initiation. Mortality is 20 to 25% during the acute phase, and almost all patients display disabling sequelae (mostly ocular impairment and psychological distress). The objective of this French national diagnosis and care protocol (protocole national de diagnostic et de soins; PNDS), based on a critical literature review and on a multidisciplinary expert consensus, is to provide health professionals with an explanation of the optimal management and care of patients with EN. This PNDS, written by the French National Reference Center for Toxic Bullous Dermatoses was updated in 2017 ( https://www.has-sante.fr/portail/jcms/c_1012735/fr/necrolyse-epidermique-syndromes-de-stevens-johnson-et-de-lyell ). The cornerstone of the management of these patients during the acute phase is an immediate withdrawal of the responsible drug, patient management in a dermatology department, intensive care or burn units used to dealing with this disease, supportive care and close monitoring, the prevention and treatment of infections, and a multidisciplinary approach to sequelae. Based on published data, it is not currently possible to recommend any specific immunomodulatory treatment. Only the culprit drug and chemically similar molecules must be lifelong contraindicated.

Importance Olmsted syndrome is a genodermatosis characterized by painful and mutilating palmoplantar keratoderma (PPK) that progresses from infancy onward and lacks an effective treatment. It is most often caused by mutations in the transient receptor potential vanilloid 3 (TRPV3)gene. In animal models and keratinocyte cell lines, TRPV3 signaling leads to epidermal growth factor receptor (EGFR) transactivation. Objective To examine the possibility of blocking EGFR transactivation with the inhibitor erlotinib hydrochloride to treat PPK in patients with Olmsted syndrome due toTRPV3mutations. Design, Setting, and Participants In this case series, 3 patients from 2 unrelated families who hadTRPV3-mutation–associated PPK were treated with erlotinib from May 5, 2018, through May 13, 2019. Main Outcomes and Measures Clinical follow-up included evaluation of PPK progression, pain and interventions for pain, as well as erlotinib dose adjustment based on treatment effect, plasma levels, and tolerance. Results The 3 patients (2 brothers aged 15 and 17 years and a 13-year-old girl) had severe palmoplantar hyperkeratosis, intolerable pain with erythromelalgia, severe growth delay, anorexia, and insomnia, which had been progressing since infancy despite numerous therapies. Two patients were confined to wheelchairs owing to intense pain and joint restrictions because of hyperkeratosis. All patients experienced depression and did not engage in social activities. Within 3 months of initiating therapy with erlotinib, hyperkeratosis and pain disappeared. All patients were able to touch the ground with their feet, wear shoes, and walk. Anorexia and insomnia remitted and paralleled improved growth. In addition, the patients resumed social activities. These improvements were sustained across 12 months of treatment and follow-up. The doses of erlotinib used were lower than those used in oncology, and only mild to moderate adverse effects were noted. Conclusions and Relevance The findings of this study report improvement of PPK in patients with Olmsted syndrome caused byTRPV3mutations when treated with erlotinib. Targeting EGFR transactivation with erlotinib therapy may result in clinical remission in an orphan disease that lacks an effective intervention.

UNC93B1 is a transmembrane domain protein mediating the signaling of endosomal Toll-like receptors (TLRs). We report five families harboring rare missense substitutions (I317M, G325C, L330R, R466S, and R525P) in UNC93B1 causing systemic lupus erythematosus (SLE) or chilblain lupus (CBL) as either autosomal dominant or autosomal recessive traits. As for a D34A mutation causing murine lupus, we recorded a gain of TLR7 and, to a lesser extent, TLR8 activity with the I317M (in vitro) and G325C (in vitro and ex vivo) variants in the context of SLE. Contrastingly, in three families segregating CBL, the L330R, R466S, and R525P variants were isomorphic with respect to TLR7 activity in vitro and, for R525P, ex vivo. Rather, these variants demonstrated a gain of TLR8 activity. We observed enhanced interaction of the G325C, L330R, and R466S variants with TLR8, but not the R525P substitution, indicating different disease mechanisms. Overall, these observations suggest that UNC93B1 mutations cause monogenic SLE or CBL due to differentially enhanced TLR7 and TLR8 signaling.