Care of the newborn with ichthyosis

Developing a Core Outcome Set for Netherton Syndrome: An International Multi-Stakeholder e-Delphi Consensus Study

INTRODUCTION

Netherton syndrome (NS; OMIM#256500) is a rare and severe disorder of epidermal maturation and keratinization caused by pathogenic variants in the serine protease inhibitor Kazal type 5 (SPINK5), leading to severe skin barrier impairment. Although effective treatment is crucial for NS patients, there is a lack of knowledge on what the best treatment options are for these patients. Large heterogeneity in reported outcomes and measurement instruments hinders accurate comparison of treatment results across studies and the development of a treatment guideline. Therefore, we aimed to develop a core outcome set (COS) for NS that can be used in clinical care and research.

METHODS

This study was performed in accordance with the recommendations of the Core Outcome Measures in Effectiveness Trials (COMET) initiative. After identification of outcomes through a literature search and classification based on the International Classification of Functioning and taxonomies published by the COMET initiative, discussion groups were organized at the 2nd International Netherton Congress 2022 to finalize the provisional outcome list. Through a 2-round e-Delphi, 41 stakeholders (patients and family members, professionals, and representatives of industry) from 14 countries rated the importance of the outcomes using a 9-point Likert scale. An online consensus meeting attended by 14 stakeholders finalized the COS.

RESULTS

The COS for NS comprised 21 outcomes in 10 domains. These included four "skin" outcomes, two "sensation" outcomes, two "side-effects of treatment" outcomes, one "vitality" outcome, one "emotional functioning" outcome, two "physical development" outcomes, two "nutrition" outcomes, two "infections" outcomes, two "allergies" outcomes, and three "assessment results" outcomes.

CONCLUSION

In this study, consensus was reached on 21 outcomes to be included in the COS for NS. The selection of outcomes in the COS underlines that NS not only affects the skin but is a disease requiring a broad multidisciplinary approach in clinical care and research. International implementation of this COS will lead to more uniform reporting, thereby enabling comparison of study results, which may facilitate future treatment guideline development. The next step is to further conceptually define the outcomes and reach consensus on how to measure these.

INTRODUCTION

Netherton syndrome (NS; OMIM#256500) is a rare and severe disorder of epidermal maturation and keratinization caused by pathogenic variants in the serine protease inhibitor Kazal type 5 (SPINK5), leading to severe skin barrier impairment. Although effective treatment is crucial for NS patients, there is a lack of knowledge on what the best treatment options are for these patients. Large heterogeneity in reported outcomes and measurement instruments hinders accurate comparison of treatment results across studies and the development of a treatment guideline. Therefore, we aimed to develop a core outcome set (COS) for NS that can be used in clinical care and research.

METHODS

This study was performed in accordance with the recommendations of the Core Outcome Measures in Effectiveness Trials (COMET) initiative. After identification of outcomes through a literature search and classification based on the International Classification of Functioning and taxonomies published by the COMET initiative, discussion groups were organized at the 2nd International Netherton Congress 2022 to finalize the provisional outcome list. Through a 2-round e-Delphi, 41 stakeholders (patients and family members, professionals, and representatives of industry) from 14 countries rated the importance of the outcomes using a 9-point Likert scale. An online consensus meeting attended by 14 stakeholders finalized the COS.

RESULTS

The COS for NS comprised 21 outcomes in 10 domains. These included four "skin" outcomes, two "sensation" outcomes, two "side-effects of treatment" outcomes, one "vitality" outcome, one "emotional functioning" outcome, two "physical development" outcomes, two "nutrition" outcomes, two "infections" outcomes, two "allergies" outcomes, and three "assessment results" outcomes.

CONCLUSION

In this study, consensus was reached on 21 outcomes to be included in the COS for NS. The selection of outcomes in the COS underlines that NS not only affects the skin but is a disease requiring a broad multidisciplinary approach in clinical care and research. International implementation of this COS will lead to more uniform reporting, thereby enabling comparison of study results, which may facilitate future treatment guideline development. The next step is to further conceptually define the outcomes and reach consensus on how to measure these.

Autosomal recessive ALOX12B gene and consecutive collodion baby

Autosomal recessive congenital ichthyosis is a type of inherited ichthyosis which is a rare cluster of genetic disorders leading to defective keratinisation. The combined prevalence for lamellar ichthyosis and congenital ichthyosiform erythroderma is almost 1 per 200 000-300 000 people. Among all the mutations in this gene, missense and frameshift mutations are most common which account for 80% of the cases. Our patient had a mutation in R-type arachidonate 12-lipoxygenase gene (ALOX12B, OMIM*603741).

Collodion baby: A rare case report

INTRODUCTION

Collodion baby "CB" is an extremely rare dermatological condition. Approximately 1 in 100,000 births are identified as infants with CB syndrome, including stillbirths (Dyer et al., 2013). A cornified substance replaces the newborn's skin, giving the body a varnished or parchment-like appearance.

CASE PRESENTATION

Patient aged 30 years, third gesture, third pare, admitted for premature delivery of 8 months. After labor management, she gave birth 2 h after admission to the maternity ward of a living newborn female weighing 2400 g. The initial physical examination revealed large, thick scales all over the body. Examination of the head and neck revealed an abnormal parchment-like membrane covering the head and sparse hairs. Excessive scaling around the mouth gives a typical fish-like appearance. No other obvious abnormalities were observed.

CLINICAL DISCUSSION

CB is an extremely rare dermatological condition. This is a disorder secondary to cornification. These children are generally born prematurely, and are not diagnosed until after birth. Due to the presence of a tight membrane, these babies develop numerous complications such as eclabium, ectropion, limited movement of the extremities and fingers. Treatment consists mainly of support, such as the use of intravenous fluids, incubators, tube feeding and emollients.

CONCLUSION

The collodion baby is a newborn characterized by an altered skin barrier, exposing him or her to numerous complications. Fortunately, the mortality rate has fallen thanks to improved neonatal care.

A Unique Case of Harlequin Ichthyosis in the Tertiary Health Care System in a Rural Area

Harlequin ichthyosis (HI) is a severe and rare genetic anomaly that affects skin development and leads to the formation of thick, diamond-shaped plates of keratinized skin. The adenosine triphosphate binding cassette A 12 (ABCA12) gene, which is essential for the transportation of lipids required for the skin's barrier function, has mutations that result in this condition. The affected individuals exhibit distinct clinical features, including thickened skin, deep cracks, and fissures, which can result in significant physical and functional impairments. HI is usually apparent at birth, with affected infants presenting with tight and rigid skin that restricts movement and normal growth. The condition is associated with various complications, including difficulty breathing, feeding difficulties, and increased susceptibility to infections. Due to the impaired skin barrier, affected individuals are also prone to dehydration and temperature dysregulation. In this case report, we present a unique case of ichthyosis in a nine-month-old child. Despite advances in medical care, HI remains a challenging condition with a high mortality rate, particularly in the neonatal period. However, with early detection, appropriate interventions, and an improved understanding of the underlying molecular mechanisms, there is hope for enhanced management and improved quality of life for individuals living with HI.

Chronic activation of Toll-like receptor 2 induces an ichthyotic skin phenotype

BACKGROUND

Ichthyosis defines a group of chronic conditions that manifest phenotypically as a thick layer of scales, often affecting the entire skin. While the gene mutations that lead to ichthyosis are well documented, the actual signalling mechanisms that lead to scaling are poorly characterized; however, recent publications suggest that common mechanisms are active in ichthyotic tissue and in analogous models of ichthyosis.

OBJECTIVES

To determine common mechanisms of hyperkeratosis that may be easily targeted with small-molecule inhibitors.

METHODS

We combined gene expression analysis of gene-specific short hairpin RNA (shRNA) knockdowns in rat epidermal keratinocytes (REKs) of two genes mutated in autosomal recessive congenital ichthyosis (ARCI), Tgm1 and Alox12b, and proteomic analysis of skin scale from patients with ARCI, as well as RNA sequencing data from rat epidermal keratinocytes treated with the Toll-like receptor 2 (TLR2) agonist Pam3CSK4.

RESULTS

We identified common activation of the TLR2 pathway. Exogenous TLR2 activation led to increased expression of important cornified envelope genes and, in organotypic culture, caused hyperkeratosis. Conversely, blockade of TLR2 signalling in keratinocytes from patients with ichthyosis and our shRNA models reduced the expression of keratin 1, a structural protein overexpressed in ichthyosis scale. A time course of TLR2 activation in REKs revealed that although there was rapid initial activation of innate immune pathways, this was rapidly superseded by widespread upregulation of epidermal differentiation-related proteins. Both nuclear factor kappa B phosphorylation and GATA3 upregulation was associated with this switch, and GATA3 overexpression was sufficient to increase keratin 1 expression.

CONCLUSIONS

Taken together, these data define a dual role for TLR2 activation during epidermal barrier repair that may be a useful therapeutic modality in treating diseases of epidermal barrier dysfunction.

Developmental cataract in congenital ichthyosis

A teenage boy who was previously diagnosed to have congenital ichthyosis presented to the eye clinic with complaints of gradually decreasing vision in both eyes since childhood. The best-corrected distance visual acuity was 20/125 in the right eye and 20/40 in the left eye. Clinical examination revealed developmental cataracts in both eyes. He underwent cataract surgery in the right eye and visual acuity improved to 20/25. Hence, we conclude that congenital ichthyosis can be associated with developmental cataracts. Cataract surgery helps in restoring vision in those with visually significant cataracts.

Harlequin ichthyosis newborn: A case report

Harlequin ichthyosis is a rare and severe genetic skin disorder that occurs within the developing foetus. Harlequin ichthyosis is the most severe and devastating form of autosomal recessive congenital ichthyoses. It is caused by mutations in the lipid transporter adenosine triphosphate binding cassette A 12. Here, we reported a case of harlequin ichthyosis with no family history. No abnormalities were detected in prenatal sonography. A 24-year-old pregnant woman with premature rupture of membrane and labour pain was referred to a hospital in Shoushtar city, Iran. The mother delivered a male baby with harlequin ichthyosis. The infant baby died on the 5th day. Harlequin ichthyosis is associated with adenosine triphosphate binding cassette A 12 gene mutation; therefore, genetic screening and counselling for susceptible parents should be taken into account. Prenatal diagnosis of harlequin ichthyosis principally via sonographic techniques is important in managing the disorder.

Harlequin ichthyosis: A case report and literature review

Harlequin ichthyosis is a rare autosomal recessive disorder occurring in 1: 3,000,000 birth characterized by thick keratin skin with a scaly appearance. Preterm deliveries, early, and consanguinity of marriage are some risk factors. Antenatal checkup of DNA for ABCA12 mutation helps in diagnosis but ultrasonography in places was not available.

Novel mutations of the ABCA12, KRT1 and ST14 genes in three unrelated newborns showing congenital ichthyosis

Background

Congenital ichthyosis (CI) is a heterogeneous group of genetic disorders characterized by generalized dry skin, scaling and hyperkeratosis, often associated to erythroderma. They are rare diseases, with overall incidence of 6.7 in 100,000. Clinical manifestations are due to mutations in genes mostly involved in skin barrier formation. Based on clinical presentation, CI is distinguished in non-syndromic and syndromic forms. To date, mutations of more than 50 genes have been associated to different types of CI.

Cases presentation

We report on three Italian unrelated newborns showing clinical signs compatible with different forms of CI of variable severity, namely Harlequin ichtyosis (HI), epidermolytic ichtyosis (EI) and autosomal recessive ichtyosis with hypotrichosis (ARIH). Target next generation sequencing (NGS) analysis identified three novel mutations of the ABCA12, KRT1 and ST14 genes, respectively associated to such congenital ichtyoses, not reported in literature. Genomic investigation allowed to provide the more appropriate management to each patient, based on an individualized approach.

Conclusions

Our report highlights the wide genetic heterogeneity and phenotypic variability of CI. It expands the current knowledge on such diseases, widening their genomic database, and providing a better clinical characterization. Furthermore, it underlines the clinical relevance of NGS, which is essential to address the management of patients. Indeed, it may guide towards the most adequate approach, preventing clinical obstinacy for subjects with more severe forms and unfavorable outcomes (together with the support, in such situations, of bioethicists included within the multidisciplinary care team), as well as reassuring families in those with milder course and favorable evolution.

Outcomes of Systemic Treatment in Children and Adults With Netherton Syndrome: A Systematic Review

Background

Comèl-Netherton syndrome (NS) is a rare disease caused by pathogenic variants in the SPINK5 gene, leading to severe skin barrier impairment and proinflammatory upregulation. Given the severity of the disease, treatment of NS is challenging. Current treatment regimens are mainly topical and supportive. Although novel systemic treatment options for NS have been suggested in recent literature, little is known about their outcomes.

Objective

to provide an overview of systemic treatment options and their outcomes in adults and children with NS.

Methods

Embase, MEDLINE, Web of Science, Cochrane Central Register of Controlled Trials, and Google Scholar were searched up to July 22, 2021. Empirical studies published in English language mentioning systemic treatment in NS were enrolled. Studies that did not define a treatment period or report at least one outcome were excluded. Methodological quality was evaluated by the Joanna Briggs Institute critical appraisal checklist for case reports or case series. Overall quality of evidence of the primary outcome, skin, was assessed by the GRADE approach.

Results

36 case series and case reports were included. The effects of 15 systemic therapies were described in 48 patients, of which 27 were children. Therapies included retinoids, prednisolone, cyclosporine, immunoglobulins, and biologicals. In retinoids both worsening (4/15 cases) and improvement (6/15 cases) of the skin was observed. Use of prednisolone and cyclosporine was only reported in one patient. Immunoglobulins (13/15 cases) and biologicals (18/21 cases) showed improvement of the skin. Certainty of evidence was rated as very low.

Conclusion

NS is a rare disease, which is reflected in the scarce literature on systemic treatment outcomes in children and adults with NS. Studies showed large heterogeneity in outcome measures. Adverse events were scarcely reported. Long-term outcomes were reported in a minority of cases. Nonetheless, a general beneficial effect of systemic treatment was found. Immunoglobulins and biologicals showed the most promising results and should be further explored. Future research should focus on determining a core outcome set and measurement instruments for NS to improve quality of research.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=217933, PROSPERO (ID: 217933).

It's more than just lubrication of the skin: parents' experiences of caring for a child with ichthyosis

Background: The ichthyoses are a group of genetic skin disorders, characterized by excessive amounts of dry, thickened skin, which may be fragile, inelastic and prone to fissures and infection. Skin care is time consuming and demanding, and, usually performed by the parents.

Methods: We aimed to explore parental experience of caring for a child with ichthyosis, and collected data using semistructured interview, and thematic analysis.

Results: Our analysis revealed four main themes: Parents' and others' reactions to the child's difference, Experiences with healthcare services, It's all skin care, and Impact on relationships.

Conclusion: After birth of a child with severe ichthyosis, the parents experienced emotional distress and stigmatization due to the different appearance of the skin and healthcare professionals' lack of knowledge. Skin care caused pain in the child, was time consuming, and caused financial burdens. This study can guide healthcare professionals on where to focus future efforts in meeting the clinical and psychological needs of parents caring for a child with ichthyosis.

Wound Healing and Wound Care in Neonates: Current Therapies and Novel Options

GENERAL PURPOSE

To provide wound care information that considers the specific physiology of neonates.

TARGET AUDIENCE

This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care.

LEARNING OBJECTIVES/OUTCOMES

After participating in this educational activity, the participant will:1. Differentiate the use of hydrocolloids, hydrogels, foam dressings, and barrier creams in the neonatal population.2. Identify issues related to the use of solvents, alginates, collagen dressings, and negative-pressure wound therapy in neonates.

ABSTRACT

OBJECTIVETo discuss what is known about the wound milieu in premature and full-term neonates, including the unique challenges pediatric clinicians face, the therapies that have proven effective, and the therapies contraindicated for use in neonatal wound healing to guide treatment that accounts for the specific physiological characteristics of this often overlooked population.

DATA SOURCES

Data were collected on neonatal wound healing from a wide variety of sources, including PubMed, Google Scholar, journals, and textbooks.

STUDY SELECTION

Selection criteria included publications focused on the differences and nuances of wound healing in neonates in comparison with all other age groups.

DATA EXTRACTION

Data were extracted based on articles covering wound healing therapies with proven effectiveness in neonates. Terms for neonatal wound care were compiled, and then a comprehensive literature search was performed by the authors.

DATA SYNTHESIS

Although many therapies are safe for treatment of older children and adolescents, most have not been explicitly tested for neonatal use. This article reviews therapies with proven effectiveness and/or specific concerns in the neonatal population.

CONCLUSION

This review sheds light on the advantages and disadvantages of current standards of care regarding wound healing for neonates to direct researchers and clinicians toward developing treatments specifically for this delicate population.

Juvenile idiopathic arthritis in infants with Harlequin Ichthyosis: two cases report and literature review

Background

Harlequin Ichthyosis is the most severe variant of congenital autosomal recessive ichthyosis, associated with severe morbidity and potentially lethal in early life. At birth, patients present thick and plaque-like scales all over the body, with consequent cutaneous and extra-cutaneous complications, such as poor thermoregulation, recurrent infections, pain, electrolytes imbalance and joint contractures. Juvenile Idiopathic Arthritis usually manifests before the age of 16 years and persists for more than 6 weeks. The association between these two pathologies has been described in the literature as a very rare event, which creates diagnostic and therapeutic challenge.

Case presentation

We describe two patients affected by Harlequin Ichthyosis who early developed Juvenile Idiopathic Arthritis. Both patients were treated with retinoids, ibuprofen and long-acting intra-articular glucocorticoids; due to polyarticular involvement, one child was also treated with weekly oral methotrexate.

Conclusions

The association between Harlequin Ichthyosis and Juvenile Idiopathic Arthritis is rare and the pathophysiological mechanism that binds them is still unknown. Nonetheless caregivers should be aware of the possible occurrence of Juvenile Idiopathic Arthritis at very early ages in children affected by Harlequin Ichthyosis.

Ischemic Risk in Collodion Baby: An Orthopaedic Perspective

Collodion baby is a rare condition in which the baby is born surrounded by membranes called collodion membranes. The evolution of these membranes is towards cracking and peeling. Sometimes, retraction leads to hypoperfusion or ischemia (especially of fingers and toes). In case of acute ischemia, surgery is necessary. We report the case of a newborn in which surgery was necessary to free both fingers and toes from constrictive bands responsible for ischemia. In the absence of surgery, the constrictive bands can lead to amputation (pseudoainhum). The purpose of this case report is to expose the management and the role of an orthopaedic surgeon in the treatment of a collodion baby.

Management of congenital ichthyoses: European guidelines of care, part two

These guidelines for the management of congenital ichthyoses have been developed by a multidisciplinary group of European experts following a systematic review of the current literature, an expert conference held in Toulouse in 2016, and a consensus on the discussions. These guidelines summarize evidence and expert-based recommendations and intend to help clinicians with the management of these rare and often complex diseases. These guidelines comprise two sections. This is part two, covering the management of complications and the particularities of some forms of congenital ichthyosis.

Inherited Nonsyndromic Ichthyoses: An Update on Pathophysiology, Diagnosis and Treatment

Hereditary ichthyoses are due to mutations on one or both alleles of more than 30 different genes, mainly expressed in the upper epidermis. Syndromic as well as nonsyndromic forms of ichthyosis exist. Irrespective of etiology, virtually all types of ichthyosis exhibit a defective epidermal barrier that constitutes the driving force for hyperkeratosis, skin scaling, and inflammation. In nonsyndromic forms, these features are most evident in severe autosomal recessive congenital ichthyosis (ARCI) and epidermolytic ichthyosis, but to some extent also occur in the common type of non-congenital ichthyosis. A correct diagnosis of ichthyosis-essential not only for genetic counseling but also for adequate patient information about prognosis and therapeutic options-is becoming increasingly feasible thanks to recent progress in genetic knowledge and DNA sequencing methods. This paper reviews the most important aspects of nonsyndromic ichthyoses, focusing on new knowledge about the pathophysiology of the disorders, which will hopefully lead to novel ideas about therapy.

Particularities of the management and the treatment in a rare sepsis with Candida tropicalis of a Collodion baby: Case report

RATIONALE

Collodion baby is a rare autosomal recessive disorder. It can be the first expression of some forms of ichthyosis.

PATIENT CONCERNS

The authors present the case of a newborn diagnosed with severe Collodion baby syndrome who required prolonged hospitalization in the intensive care unit because of infectious complications like the fungal sepsis and other bacterial superinfections.

DIAGNOSES

The case has many diagnostic and therapeutic particularities and management difficulties. Skin culture, dermatological and genetic exam were required.

INTERVENTIONS

The treatment required multidisciplinary involvement: neonatologist, pediatrician, geneticist, dermatologist, psychologist, ophthalmologist, audiologist.

OUTCOMES

The evolution during hospitalization was slowly favorable, but later, after a few months, it developed some complications.

LESSONS

In our case, skin injuries, total parenteral nutrition, aggressive and prolonged antibiotic therapy, intravenous devices, high hospitalization duration were risk factors for colonization and sepsis with fungi, especially in the neonatal period, sometimes with severe evolution and prognosis.

Improved Management of Harlequin Ichthyosis With Advances in Neonatal Intensive Care

Harlequin ichthyosis (HI) is the most severe phenotype of the autosomal recessive congenital ichthyoses. HI is caused by mutations in the lipid transporter adenosine triphosphate binding cassette A 12 (ABCA12). Neonates are born with a distinct clinical appearance, encased in a dense, platelike keratotic scale separated by deep erythematous fissures. Facial features are distorted by severe ectropion, eclabium, flattened nose, and rudimentary ears. Skin barrier function is markedly impaired, which can lead to hypernatremic dehydration, impaired thermoregulation, increased metabolic demands, and increased risk of respiratory dysfunction and infection. Historically, infants with HI did not survive beyond the neonatal period; however, recent advances in neonatal intensive care and coordinated multidisciplinary management have greatly improved survival. In this review, the authors combine the growing HI literature with their collective experiences to provide a comprehensive review of the management of neonates with HI.

Collodion Baby with TGM1 gene mutation

Collodion baby (CB) is normally diagnosed at the time of birth and refers to a newborn infant that is delivered with a lambskin-like membrane encompassing the total body surface. CB is not a specific disease entity, but is a common phenotype in conditions like harlequin ichthyosis, lamellar ichthyosis, nonbullous congenital ichthyosiform erythroderma, and trichothiodystrophy. We report a CB that was brought to our department and later diagnosed to have TGM1 gene c.984+1G>A mutation. However, it could not be ascertained whether the infant had lamellar ichthyosis or congenital ichthyosiform erythroderma (both having the same mutation). The infant was lost to follow-up.

Ichthyosis with confetti: clinics, molecular genetics and management

Ichthyosis with confetti (IWC) is an autosomal dominant congenital ichthyosis also known as ichthyosis variegata or congenital reticular ichthyosiform erythroderma. It manifests at birth with generalized ichthyosiform erythroderma or with a collodion baby picture. The erythrodermic and ichthyotic phenotype persists during life and its severity may modify. However, the hallmark of the disease is the appearance, in childhood or later in life, of healthy skin confetti-like spots, which increase in number and size with time. IWC is a very rare genodermatosis, with a prevalence <1/1,000,000 and only 40 cases reported worldwide. The most important associated clinical features include ear deformities, mammillae hypoplasia, palmoplantar keratoderma, hypertrichosis and ectropion. IWC is due to dominant negative mutations in the KRT10 and KRT1 genes, encoding for keratins 10 and keratin 1, respectively. In this context, healthy skin confetti-like spots represent “repaired” skin due to independent events of reversion of keratin gene mutations via mitotic recombination. In most cases, IWC clinical suspicion is delayed until the detection of white skin spots. Clinical features, which may represent hint to the diagnosis of IWC even before appearance of confetti-like spots, include ear and mammillae hypoplasia, the progressive development of hypertrichosis and, in some patients, of adherent verrucous plaques of hyperkeratosis. Altogether the histopathological finding of keratinocyte vacuolization and the nuclear staining for keratin 10 and keratin 1 by immunofluorescence are pathognomonic. Nevertheless, mutational analysis of KRT10 or KRT1 genes is at present the gold standard to confirm the diagnosis. IWC has to be differentiated mainly from congenital ichthyosiform erythroderma. Differential diagnosis also includes syndromic ichthyoses, in particular Netherton syndrome, and the keratinopathic ichthyoses. Most of reported IWC cases are sporadic, but familial cases with autosomal dominant mode of inheritance have been also described. Therefore, knowledge of the mutation is the only way to properly counsel the couples. No specific and satisfactory therapy is currently available for IWC. Like for other congenital ichthyoses, topical treatments (mainly emollients and keratolytics) are symptomatic and offer only temporary relief. Among systemic treatments, retinoids, in particular acitretin, improve disease symptoms in most patients. Although at present there is no curative therapy for ichthyoses, treatments have improved considerably over the years and the best therapy for each patient is always the result of both physician and patient efforts.

Epidemiology, medical genetics, diagnosis and treatment of harlequin ichthyosis in Japan

Ichthyoses are a group of disorders marked by whitish, brown or dark-brown scales on the skin of almost the whole body. Harlequin ichthyosis (HI) is the most severe form. Neonatal death from HI was once common. Due to intensive neonatal care and, probably, to the early introduction of oral retinoids, HI outcome has improved. For definitive diagnosis and the exclusion of other disorders, such as lamellar ichthyosis, which also shows a collodion baby phenotype, it is helpful to refer to electron microscopy of abnormal or absent lamellar granules and a heavy accumulation of lipid droplets in the keratinocytes. ATP-binding cassette transporter A12 (ABCA12) is known as the causative gene of HI. Severe ABCA12 deficiency results in malformation of intercellular lipid layers in the cornified layers and leads to epidermal lipid barrier disruption. In HI patients, at least one mutation on each allele must be a truncation or deletion mutation to cause serious loss of ABCA12 function. Identification of the gene underlying HI has enabled DNA-based prenatal diagnosis for HI at the earlier stages of pregnancy with low risk. There are no curative treatments for HI. Abca12-deficient mice were created as a model of HI. Treatment of the model mice with retinoid or steroid has not been successful.

Fetal inhibition of inflammation improves disease phenotypes in harlequin ichthyosis

Harlequin ichthyosis (HI) is a severe skin disease which leads to neonatal death in ∼50% of cases. It is the result of mutations in ABCA12, a protein that transports lipids required to establish the protective skin barrier needed after birth. To better understand the life-threatening newborn HI phenotype, we analysed the developing epidermis for consequences of lipid dysregulation in mouse models. We observed a pro-inflammatory signature which was characterized by chemokine upregulation in embryonic skin which is distinct from that seen in other types of ichthyosis. Inflammation also persisted in grafted HI skin. To examine the contribution of inflammation to disease development, we overexpressed interleukin-37b to globally suppress fetal inflammation, observing considerable improvements in keratinocyte differentiation. These studies highlight inflammation as an unexpected contributor to HI disease development in utero, and suggest that inhibiting inflammation may reduce disease severity.