Recent advances in the genetics and management of harlequin ichthyosis

Compound heterozygous ABCA12 variants identified in a Chinese patient with congenital ichthyosiform erythroderma: Advancing genotype-phenotype correlations and literature review

BACKGROUND

Ichthyosis is a common keratotic skin disease with high clinical, etiological and genetic heterogeneity. There are four types of non-syndromic hereditary ichthyoses, among which autosomal recessive congenital ichthyosis (ARCI) is a heterogeneous group of recessive Mendelian disorders. ARCI present with different phenotypes and ABCA12 pathogenic variants have been shown to cause complex ARCI phenotypes, including harlequin ichthyosis (HI), lamellar ichthyosis (LI) and congenital ichthyosiform erythroderma (CIE).

METHODS

A sporadic male patient, clinically diagnosed with CIE, was enrolled in this study. Exome sequencing was combined with Sanger sequencing to confirm the diagnosis and identify the pathogenic variants. In silico predictions were made using multiple software programs, and the identified variants were interpreted using the ACMG guidelines. A review of all literature reported ABCA12 variants was performed to explore genotype-phenotype correlations.

RESULTS

Compound heterozygous ABCA12 variants [c.5381+1G>A and c.5485G>C (p.Asp1829His)] (NM_173076) were identified. The two variants were not detected in the public database. c.5381+1G>A is predicted to affect ABCA12 mRNA splicing and Asp1829 is highly conserved among various species. In silico analysis suggested that these two variants were responsible for the phenotype of the patient. Genotype-phenotype correlation analysis showed that biallelic truncation variants and/or exon/amino acid deletions in ABCA12 are the most common causes of HI. Biallelic missense variants are most common in LI and CIE.

CONCLUSIONS

The compound heterozygous ABCA12 variants caused the CIE phenotype observed in the patient. The spectrum of ABCA12 pathogenic variants were broaden. Genotype-phenotype correlation analysis provided detailed evidence which can be used in future prenatal diagnosis and can inform the need for genetic counselling for patients with ABCA12-related ARCIs.

Retinoid Therapy in a Case of Harlequin Ichthyosis with a Short Literature Review

Harlequin ichthyosis (HI) is a genetically inherited epidermal disorder due to the mutation of the ABCA12 gene, which is responsible for lipid transportation, and presents with large keratinised scales characterised by deep erythematous fissures, with ectropion and eclabium. A moderate number of cases and a high mortality rate have been recorded. In this case report, a pregnant lady gave birth to a 33-week-old premature foetus with characteristic symptoms of HI. After admitting him to the NICU, a multidisciplinary treatment approach was conducted with paediatric dermatologists, ophthalmologists, urologists, and dieticians. The prognosis is positive, with desquamation of the hyperkeratotic plate revealing an erythematous and shiny skin. A short literature review on HI characteristics, diagnostic aids, and management has also been added.

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.

Mutational Spectrum of the ABCA12 Gene and Genotype–Phenotype Correlation in a Cohort of 64 Patients with Autosomal Recessive Congenital Ichthyosis

Autosomal recessive congenital ichthyosis (ARCI) is a non-syndromic congenital disorder of cornification characterized by abnormal scaling of the skin. The three major phenotypes are lamellar ichthyosis, congenital ichthyosiform erythroderma, and harlequin ichthyosis. ARCI is caused by biallelic mutations in ABCA12, ALOX12B, ALOXE3, CERS3, CYP4F22, NIPAL4, PNPLA1, SDR9C7, SULT2B1, and TGM1. The most severe form of ARCI, harlequin ichthyosis, is caused by mutations in ABCA12. Mutations in this gene can also lead to congenital ichthyosiform erythroderma or lamellar ichthyosis. We present a large cohort of 64 patients affected with ARCI carrying biallelic mutations in ABCA12. Our study comprises 34 novel mutations in ABCA12, expanding the mutational spectrum of ABCA12-associated ARCI up to 217 mutations. Within these we found the possible mutational hotspots c.4541G>A, p.(Arg1514His) and c.4139A>G, p.(Asn1380Ser). A correlation of the phenotype with the effect of the genetic mutation on protein function is demonstrated. Loss-of-function mutations on both alleles generally result in harlequin ichthyosis, whereas biallelic missense mutations mainly lead to CIE or LI.

Case Report: Novel rare mutation c.6353C > G in the ABCA12 gene causing harlequin ichthyosis identified by whole exome sequencing

BACKGROUND

Harlequin ichthyosis (HI) is a severe rare genetic disease that mainly affects the skin. Neonates with this disease are born with thick skin and large diamond-shaped plates covering most of their bodies. Affected neonates lose the ability to control dehydration and regulate temperature and are more susceptible to infections. They also face respiratory failure and feeding problems. These clinical symptoms are factors associated with high mortality rates of neonates with HI. Until now, there are still no effective treatments for HI patients and most patients die in the newborn period. Mutation in the ABCA12 gene, which encodes an adenosine triphosphate-binding cassette (ABC) transporter, has been demonstrated as the major cause of HI.

CASE PRESENTATION

In this study, we report the case who is one infant that was born prematurely at 32 gestational weeks with the whole body covered with thick plate-like scales of skin. The infant was severely infected with mild edema, multiple cracked skins full of the body, yellow discharge, and necrosis of fingers and toes. The infant was suspected to be affected by HI. Whole exome sequencing (WES) was performed as a tool for detecting the novel mutation in one prematurely born Vietnam infant with HI phenotype. And after that, the mutation was confirmed by the Sanger sequencing method in the patient and the members of his family. In this case, one novel mutation c.6353C > G (p.S2118X, Hom) in the ABCA12 gene, was detected in the patient. The mutation has not been reported in any HI patients previously. This mutation was also found in a heterozygous state in the members of the patient's family, including his parents, an older brother, and an older sister who are no symptoms.

CONCLUSIONS

In this study, we identified a novel mutation in a Vietnamese patient with HI by whole exome sequencing. The results for the patient and the members of his family will be helpful in understanding the etiology of the disease, diagnosing carriers, assisting in genetic counseling, and emphasizing the need for DNA-based prenatal screening for families with a history of the disease.

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.

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.

Management of Harlequin Ichthyosis: A Brief Review of the Recent Literature

Harlequin ichthyosis (HI) is a life-threatening genetic disorder that largely affects the skin of infants. HI is the most severe form of the autosomal recessive disorder known as ichthyosis. It is caused by mutations in the A12 cassette (lipid-transporter adenosine triphosphate-binding cassette A12). Neonates affected by this disease are born with specific morphological characteristics, the most prominent of which is the appearance of platelet keratotic scales separated by erythematous fissures. The facial features include eclabium, ectropion, a distinct flattened nose, and dysplastic ears. A common finding among those with HI is impaired skin barrier function. The purpose of the present narrative review is to assess the most recent literature regarding the management of HI. Emphasis is given to surgical management and consultation, to the indications for timing and surgical intervention, to the risks that are presented with surgery, and to the details of the surgical procedure itself. Management of HI requires a multidisciplinary team of experts, and specific guidelines are needed in order for the risks to be minimized and viability to be increased.

Harlequin Ichthyosis (HI) Associated with Atrial Septal Defect (ASD) and Choanal Atresia

Harlequin ichthyosis (HI) is a severe form of congenital ichthyosis with autosomal recessive inheritance. Incidence of harlequin ichthyosis is 1 in 3,00,000 live births. We report a case of HI associated with bilateral choanal atresia and atrial septal defects, which is a rare association in this skin disorder. A-month-old preterm male baby born out of consanguineous marriage presented with features of armour-like scales and erythema all over body, ectropion, eclabium and fissures over flexures. The patient was born with a colloidion membrane at birth. The baby was operated for bilateral choanal atresia soon after birth because he developed cyanosis upon breast feeding which improved on crying. Upon flexible nasal endoscopy, diagnosis of membranous type of choanal atresia was confirmed by ENT (ear, nose, throat) surgeon. Heart auscultation revealed a murmur in our patient. Electrocardiogram and 2D Echocardiography was reported as atrial septal defect (4.5 mm OsASD). The patient was started on acitretin (1 mg/kg/day) and emollients after complete evaluation and is currently on regular follow up. Harlequin ichthyosis is linked to mutation of ABCA12 gene. It is often associated with eclabium, ectropion, hypoplastic nose, ears and fingers. Congenital heart diseases are rarely reported with HI in literature. This makes it mandatory to screen HI patients for internal defects.

Case Report: Prenatal Diagnosis of a Fetus With Harlequin Ichthyosis Identifies Novel Compound Heterozygous Variants: A Case Report

Background

Harlequin ichthyosis (HI) is the most severe form of the keratinizing disorders, and it is characterized by whole-body hard stratum corneum. ABCA12 has been identified as the major disease-causing gene of HI.

Methods

A case of HI was prenatally diagnosed by ultrasonography and genetic tests. The fetus had been found with dentofacial deformity and profound thickening of the palm and plantar soft tissues. Chromosomal microarray analysis (CMA) and whole exome sequencing (WES) were then performed on the amniotic fluid to identify germline pathogenic variants for the fetus. Candidate variants were verified by Sanger sequencing.

Results

Compound heterozygous frameshift variants (p.Q719QfsX21; p.F2286LfsX6) of ABCA12 were identified for the fetus, suggesting the former variants were maternally inherited and the latter paternally inherited. The fetus was terminated.

Conclusion

A prenatal molecular diagnosis is an important approach for the prevention of HI. In the study, we provided a successful case of genetic counseling for a family with an HI baby.

Prenatal diagnosis of harlequin ichthyosis by ultrasonography: a case report

Autosomal recessive congenital ichthyosis is a genetically and phenotypically heterogeneous group of skin disorders, including harlequin ichthyosis (HI), lamellar ichthyosis, and bullous congenital ichthyosiform erythroderma. HI is the most phenotypically severe autosomal recessive congenital ichthyosis associated with the mutation of the adenosine triphosphate—binding cassette subfamily A member 12 (ABCA12) gene. The clinical manifestations include generalized hyperkeratotic plaques and deep fissures, ectropion, eclabium, and contractures. However, the severe HI may easily be misdiagnosed as epidermolysis bullosa or syndromic ichthyosis. Meanwhile, no consensus exists about the best used in clinical trials or clinical practice when more elaborate scoring systems have been proposed to evaluate skin xerosis, palmoplantar keratoderma, and disease extension an accurate prenatal diagnosis is necessary. Until the ABCA12 gene was identified as the pathogenic gene, prenatal diagnosis of HI had been performed by the invasive techniques of fetal skin biopsy. Now, advances in ultrasound technology and fetal DNA-based analysis have replaced it. The mortality rate is markedly high and prompt; prenatal diagnosis of neonate HI is critical for appropriate perinatal and postnatal management. It is also essential to prepare parents for future pregnancies and reduce the family’s physical and mental distress and financial burden. This report presents a rare case of harlequin ichthyosis diagnosed by the ultrasound and discusses the significance of prenatal ultrasound diagnosis and molecular diagnosis in the prenatal diagnosis of HI.

Prenatal diagnosis of harlequin ichthyosis: a case report

Harlequin ichthyosis (HI) is a rare and severe form of ichthyosis and is characterized by thickened, hard, armor-like plates of skin that cover the entire body. This disease is caused by mutations in the adenosine triphosphate-binding cassette transporter protein A12 gene, and the pattern of inheritance is autosomal recessive. Prenatal sonographic diagnosis of HI has not been frequently reported. Here, we report a case of HI detected at 28 weeks of gestation and discuss with the sonographic findings and a brief review of literature. The diagnosis was reached mainly based on 2-dimensional and 3-dimensional ultrasound findings. Three-dimensional ultrasound applications help recognize facial morphology, and thus, greatly contributes to prenatal diagnoses.

Prenatal diagnosis of congenital harlequin ichthyosis with fetal MRI

Most of the fetal deformities are caused due to genetic abnormalities. Although magnetic resonance imaging (MRI) may be used to accurately diagnose these deformities, it has been reported that gene analysis is a more accurate diagnostic method. Harlequin ichthyosis (HI) or Ichthyosis fetalis (IF) is a rare and extremely severe hereditary skin disorder with autosomal recessive inheritance. The ultrasound features have been described well and the diagnosis can be made with a fair degree of confidence. However, the final diagnosis needs to be established by prenatal invasive tests. In the present study, we describe the diagnosis of HI in the third trimester on fetal MRI referred to our department with suspicion of anterior encephalocele which was later confirmed through postnatal genetic evaluation.

Nursing care for a newborn with Lamellar Ichthyosis: a case study in a neonatal unit

OBJECTIVE

To present the nursing care of a newborn with Lamellar Ichthyosis admitted to the neonatal intensive care unit of a public children's hospital in a municipality in the state of Paraná, Brazil.

METHOD

A qualitative intralocal study implementing the Case Study methodology, in which a real case was explored in a delimited system with data collection from multiple sources of information during 66 days of hospitalization in 2016.

RESULTS

The nursing care present in the protocol was based on: maintaining skin integrity through hydration and continuous lubrication with emollients, temperature control, nutrition and prevention of secondary infections.

CONCLUSION

Through the case study, it is affirmed that implementation of the Nursing Process, especially the care plan, was essential for the multidisciplinary success of the treatment. There was improvement in the skin and mucous membranes, as well as prevention of infections, culminating in favorable survival conditions and the autonomy of parents for home care.

Cholesterol homeostasis: Links to hair follicle biology and hair disorders

Lipids and lipid metabolism are critical factors in hair follicle (HF) biology, and cholesterol has long been suspected of influencing hair growth. Altered cholesterol homeostasis is involved in the pathogenesis of primary cicatricial alopecia, mutations in a cholesterol transporter are associated with congenital hypertrichosis, and dyslipidaemia has been linked to androgenic alopecia. The underlying molecular mechanisms by which cholesterol influences pathways involved in proliferation and differentiation within HF cell populations remain largely unknown. As such, expanding our knowledge of the role for cholesterol in regulating these processes is likely to provide new leads in the development of treatments for disorders of hair growth and cycling. This review describes the current state of knowledge with respect to cholesterol homeostasis in the HF along with known and putative links to hair pathologies.

Harlequin fetus born from Consanguinity: A deleterious case report

Harlequin Ichthyosis (HI) is a dreadful skin disorder with steady rise of cases with prolonged survival. Harlequin fetus follows an autosomal recessive pattern with the incidence of 1in 300,000 live births. In the succeeding case report, a male child was born with keratinized and kaleidoscopic diamond pattern of skin suggestive of HI. He was born at 36th week of gestation from consanguineous marriage. The newborn remained under extensive intensive care in a tertiary care unit where he breathed his last on 11th day after birth. Prenatal diagnosis and genetic counseling is of vital importance due to the association of ABCA12 mutation with HI.

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.

Two successive cases of fetal harlequin ichthyosis: A case report

Harlequin ichthyosis (HI) is a genetic skin disorder characterized by thickening and splitting of the skin. In fetuses presenting with the disorder, the mortality rate is markedly high. A number of fetal HI cases have been documented. The present study reports a case of a pregnant woman who underwent two successive pregnancies at the ages of 35 and 36, respectively, with both fetuses presenting with HI. The first fetus was delivered alive though succumbed shortly after birth, while the second fetus was stillborn and birthed by induced labor. The fetuses exhibited typical features of fetal HI, including thick, platelike scaling and fissuring, which act as a nidus for infection. The present study is the first to report two cases of fetal HI from successive pregnancies in the same woman. Improved understanding of the genetic basis of HI indicates that genetic screening for candidate gene mutations related to HI, particularly mutations in the adenosine triphosphate binding-cassette transporter ABCA12, may prove beneficial in prenatal diagnosis. Establishing methods for early diagnosis of fetal HI may reduce the physical and mental distress to parents and relatives.

Prenatal diagnose of a fetus with Harlequin ichthyosis in a Chinese family

OBJECTIVE

Harlequin ichthyosis (HI) was the most severe form of ichthyoses, which leaded to neonatal death in 50% of cases. It was the result of mutations in ABCA12 gene. With the development of ultrasound skills and genetic analysis, HI could be prenatal diagnosed.

CASE REPORT

Here, we reported a case of HI, which was prenatal diagnosed by ultrasound examination and genetic analysis. The fetus was found that severe ectropion, eclabium, flattened nose, and rudimentary ears by ultrasound at 20 weeks gestation. A molecular genetic analysis was performed and revealed two mutations in the ABCA12 gene. One of two mutations were not reported in the past. The fetus was terminated.

CONCLUSION

HI was associated with the poor prognosis of HI neonates. Prenatal ultrasound and genetic analysis were important for prenatal diagnosis of HI and were helpful to give sufficient prenatal counsels for the family with HI baby.

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.

Harlequin Ichthyosis: A Surgical Perspective

Limb constriction or encasement in patients with harlequin ichthyosis can cause tissue injury resulting in necrosis and auto-amputation. Surgical release of constrictive plaques has been previously demonstrated, but the perioperative and intraoperative considerations surrounding this infrequent intervention have not been discussed in detail. This report documents a case of harlequin ichthyosis requiring surgical treatment, focusing on the importance of early surgical consultation, risks of surgery, indications for and timing of surgical intervention, and the details of the operation.

Harlequin ichthyosis: a novel compound mutation of ABCA12 with prenatal diagnosis

Harlequin ichthyosis (HI) is the most severe form of recessive congenital ichthyosis, and is frequently lethal. We describe a family with prenatal diagnosis of HI in two siblings. We applied genomic capture and massively parallel sequencing to detect all mutations in 20 genes, including ABCA12, with inherited mutations that predispose to congenital ichthyosis. Sequence analysis of the ABCA12 gene identified two mutations, c.5232 G>A (p.Trp1744*) in exon 34 and c.6443 C>A (p.Pro2148Gln) in exon 44, each in a heterozygous state. Sanger sequencing confirmed that each parent was a heterozygous carrier for one of the variants. The spectrum of mutations identified in this study and previous studies reveals a novel compound mutation of ABCA12.

Facial features in Harlequin ichthyosis: Clinical findings about 4 cases

We report 4 cases of Harlequin ichthyosis, which is a rare and severe congenital ichthyosis involving the face. Facial appearance consists in severe ectropion, conjonctival edema, eclabium, flattened ears, broadened nose and large, thick, plate-like skin scales. Recent advances in neonatal care have been made, such as retinoid therapy, and have led to an increased survival rate. Early surgical correction of ectropion may be required because of ocular complications.

Harlequin Ichthyosis: Prenatal Diagnosis of a Rare Yet Severe Genetic Dermatosis

Harlequin Ichthyosis (HI) is an extremely rare genetic skin disorder. It is the most severe type of ichthyosis. It is characterized by thickened, dry, rough and armor like plates of skin with deep cracks in between. Alternative names for HI include- keratosis diffusafetalis, ichthyosis congenital, icthyosis fetalis, harlequin fetus and icthyosis congenital gravior. It is an autosomal recessive disorder with the majority of affected individuals being homozygous for mutation in the ABCA 12 gene. This condition presents with a wide range of severity and symptoms. Affected neonates usually do not survive beyond first few days of life. We are presenting prenatal diagnosis of a case of this rare condition.

Photoletter to the editor: Lamellar ichthyosis and arthrogryposis in a premature neonate

Lamellar ichthyosis is a rare congenital disorder characterized by collodion membrane at birth and facial anomalies (eclabium and ectropion). The major underlying genetic defect is in TGM1, with mutations of this gene found in 50% of patients. An early diagnosis is fundamental in view of establishing a specific treatment due to the severity of the disease. We report a case of severe lamellar ichthyosis and arthrogryposis, without the typical facial presentation, negative for TGM1 mutations. The clinical improvement was achieved only after treatment with oral retinoids, highlighting the importance of early diagnosis and prompt administration of a specific therapy.