Updated mutational spectrum and genotype-phenotype correlations in ichthyosis patients with ABCA12 pathogenic variants.

Autosomal recessive congenital ichthyoses (ARCI) is a genetically heterogeneous condition that can be caused by pathogenic variants in at least 12 genes, including ABCA12. ARCI mainly consists of congenital ichthyosiform erythroderma (CIE), lamellar ichthyosis (LI) and harlequin ichthyosis (HI). The objective was to determine previously unreported pathogenic variants in ABCA12 and to update genotype-phenotype correlations for patients with pathogenic ABCA12 variants. Pathogenic variants in ABCA12 were detected using Sanger sequencing or a combination of Sanger sequencing and whole-exome sequencing. To verify the pathogenicity of a previously unreported large deletion and intron variant, cDNA analysis was performed using total RNA extracted from hair roots. Genetic analyses were performed on the patients with CIE, LI, HI and non-congenital ichthyosis with unusual phenotypes (NIUP), and 11 previously unreported ABCA12 variants were identified. Sequencing of cDNA confirmed the aberrant splicing of the variant ABCA12 in the patients with the previously unreported large deletion and intron variant. Our findings expand the phenotype spectrum of ichthyosis patients with ABCA12 pathogenic variants. The present missense variants in ABCA12 are considered to be heterogenous in pathogenicity, and they lead to varying disease severities in patients with ARCI and non-congenital ichthyosis with unusual phenotypes (NIUP).

Identification and In Silico Analysis of a Homozygous Nonsense Variant in TGM1 Gene Segregating with Congenital Ichthyosis in a Consanguineous Family.

Background and Objectives: Lamellar ichthyosis is a rare skin disease characterized by large, dark brown plate-like scales on the entire body surface with minimum or no erythema. This phenotype is frequently associated with a mutation in the TGM1 gene, encoding the enzyme transglutaminase 1 which plays a catalytic role in the formation of the cornified cell envelop. The present study aimed to carry out clinical and genetic characterization of the autosomal recessive lamellar ichthyosis family from Balochistan. Materials and Methods: A consanguineous family with lamellar ichthyosis was enrolled from Balochistan, Pakistan. PCR amplification of all the exons and splice site junctions of the TGM1 gene followed by Sanger sequencing was performed on the genomic DNA. The identified variant was checked by In silico prediction tools to evaluate the effect of the variant on protein. Results: Sanger sequencing identified a homozygous nonsense variant c.131G >A (p.Trp44*) in the TGM1 gene that segregated in the autosomal recessive mode of inheritance in the family. The identified variant results in premature termination of transcribed mRNA and is predicted to cause a truncated or absent translation product transglutaminase-1 (TGase-1) accompanied by loss of catalytic activity, causing a severe clinical phenotype of lamellar ichthyosis in the patients. Conclusions: Here, we report a consanguineous lamellar ichthyosis family with a homozygous nonsense variant in the TGM1 gene. The variant is predicted as pathogenic by different In silico prediction tools.

Ceramide profiling of stratum corneum in Sjögren-Larsson syndrome.

BACKGROUND: Sjögren-Larsson syndrome (SLS) is a neurocutaneous disorder whose causative gene is the fatty aldehyde dehydrogenase ALDH3A2 and of which ichthyosis is the major skin symptom. The stratum corneum contains a variety of ceramides, among which ω-O-acylceramides (acylceramides) and protein-bound ceramides are essential for skin permeability barrier formation. OBJECTIVES: To determine the ceramide classes/species responsible for SLS pathogenesis and the enzymes that are impaired in SLS. METHODS: Genomic DNA was collected from peripheral blood samples from an SLS patient and her parents, and whole-genome sequencing and Sanger sequencing were performed. Lipids were extracted from stratum corneum samples from the SLS patient and healthy volunteers and subjected to ceramide profiling via liquid chromatography coupled with tandem mass spectrometry. RESULTS: A duplication (c.55_130dup) and a missense mutation (p.Lys447Glu) were found in the patient's ALDH3A2 gene. The patient had reduced levels of all acylceramide classes, with total acylceramide levels at 25 % of healthy controls. Reductions were also observed for several nonacylated ceramides: ceramides with phytosphingosine or 6-hydroxysphingosine in the long-chain base moiety were reduced to 24 % and 41 % of control levels, respectively, and ceramides with an α-hydroxy fatty acid as the fatty acid moiety were reduced to 29 %. The fatty acid moiety was shortened in many nonacylated ceramide classes. CONCLUSION: These results suggest that reduced acylceramide levels are a primary cause of the ichthyosis symptoms of SLS, but reductions in other ceramide classes may also be involved.

Congenital lamellar ichthyosis complicated with erosive pseudo pustulosis: A rare clincal entity. About a case and review of the literature.

INTRODUCTION: Lamellar ichthyosis is a rare congenital disorder that can be encountered by plastic surgeon in a daily practice. Its clinical diagnosis makes it an significant pathology to identify and to know how to treat. MATERIAL AND METHODS: We report the case of a patient suffering from lamellar ichthyosis complicated by erosive pseudo pustulosis of the scalp. Our treatment protocol with two intra-lesional delayed-corticoids (Kenacort ®) injections three months apart showed significant clinical improvement of the lesions. DISCUSSION: Congenital lamellar ichthyosis regroups various clinical presentations. Most of the therapeutic strategies described in the literature involve local and systemic treatments, weighing on patients and leading to modest results. Surgical treatment or hyaluronic injections have also been reported but they raise problematics regarding morbidity and efficiency. CONCLUSION: Our therapeutic strategy by two Kenacort ® injections three months apart is simple, reproductible and has shown efficiency in the treatment of our patient suffering from congenital lamellar ichthyosis complicated with erosive pseudo pustulosis of the scalp.

Harlequin fetus: A case report.

Harlequin ichthyosis (HI) is the most severe type of congenital ichthyosis. It is extremely rare with very few cases reported in India. It is inherited in an autosomal recessive fashion. The importance of antenatal diagnosis by ultrasonography, DNA-based molecular studies on chorionic villus sampling, and amniocentesis has been emphasized. We report a new case of HI in an infant, diagnosed postnatally by correlation of clinical and histopathological features on skin biopsy. The infant succumbed on the second day of birth despite intensive supportive care. A short review of the literature regarding the condition is also presented.

Whole-exome sequencing identified a novel pathogenic mutation of the CYP4F22 gene in a Chinese patient with autosomal recessive congenital ichthyosis and in vitro study of the mutant CYP4F22 protein.

Autosomal recessive congenital ichthyosis (ARCI) is a heterogeneous group of rare cornification disorders. Of the 14 genes already known to cause ARCI, CYP4F22 is a relatively new genetic etiology, the mutation spectrum of which has yet to be profiled. Using whole-exome sequencing in family trios, we identified the compound heterozygous mutations, c.844C>T (p.R282W) and c.1189C>T (p.R397C), of the CYP4F22 gene (NM_173483.4) in a Chinese neonatal boy with a congenital ichthyosis phenotype. In combination with multiple in silico analyses and the following in vitro functional studies, we provided evidence to classify these two variations as pathogenic mutations and demonstrated that both variants significantly reduced the CYP4F22 protein amount. Interestingly, the reduction of both mutant CYP4F22 protein could be recovered by trichostatin A (TSA) treatment, suggesting some deacetylation factors involved in regulating the mutant CYP4F22 protein and implying TSA might be a potential candidate compound for congenital ichthyosis caused by CYP4F22 variations.

Acral Melanoma in an Elderly Patient with Congenital Ichthyosis Vulgaris.

Ichthyoses are a heterogeneous group of skin disorders featuring erythroderma and generalized scaling. The relationship between ichthyosis and melanoma has not been well-characterized. Herein we present a unique case of acral melanoma of the palm developing in an elderly patient with congenital ichthyosis vulgaris. Biopsy revealed a superficially spreading melanoma with ulceration. To the best of our knowledge, no acral melanomas have been reported so far in patients with congenital ichthyosis. Nevertheless, considering the potential for invasion and metastasis, patients with ichthyosis vulgaris should undergo regular clinical and dermatoscopic screening for melanoma.

Prenatal diagnosis of a rare variant of harlequin ichthyosis with literature review.

BACKGROUND: Harlequin ichthyosis (HI) is a rare and severe genetic skin disorder that occurs within the developing foetus. Due to the extremely poor prognosis, prenatal diagnosis becomes very important, especially for foetuses with no family history. There are few reports on prenatal diagnosis in PubMed. CASE PRESENTATION: We report two cases of HI with no family history who were diagnosed by prenatal ultrasound. We searched for reports on the prenatal ultrasonic diagnosis of HI over nearly two decades and summarized the sonographic features of HI, the reasons for missed diagnoses and matters needing attention. A total of 10 articles of congenital harlequin ichthyosis diagnosed by prenatal ultrasound in PubMed were retrieved. There have been even fewer reports of late-trimester disease with no family history. Combining the two cases we reported with the literature review, we summarize the ultrasonic image characteristics of HI. CONCLUSION: HI can be easily detected by 2D ultrasound combined with 3D, but attention should be paid to a systematic examination in the third trimester of pregnancy according to the clinical characteristics of the disease.

Bebé colodión: presentación de la ictiosis lamelar / Collodion baby: A case of lamellar ichthyosis

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Preclinical Evaluation of a Modified Herpes Simplex Virus Type 1 Vector Encoding Human TGM1 for the Treatment of Autosomal Recessive Congenital Ichthyosis.

Autosomal recessive congenital ichthyosis (ARCI) is a diverse group of cornification diseases associated with severe clinical complications and decreased quality of life. Germline mutations in the TGM1 gene, which encodes the enzyme TGM1, are the predominant cause of ARCI. These TGM1 mutations trigger the abnormal epidermal differentiation and impaired cutaneous barrier function observed in patients with ARCI. Unfortunately, current ARCI therapies focus solely on symptomatic relief. Thus, there is a significant unmet need for therapeutic strategies aimed at correcting the TGM1 deficiency underlying ARCI. In this study, we investigated the ability of KB105, a gene therapy vector encoding full-length human TGM1, to deliver functional human TGM1 to keratinocytes. In vitro, KB105 efficiently infected TGM1-deficient human keratinocytes, produced TGM1 protein, and rescued transglutaminase enzyme function. In vivo studies demonstrated that both single and repeated topical KB105 administration induced TGM1 protein expression in the target epidermal layer without triggering fibrosis, necrosis, or acute inflammation. Toxicity and biodistribution assessments on repeat dosing indicated that KB105 was well-tolerated and restricted to the dose site. Overall, our results demonstrate that rescuing TGM1 deficiency in patients with ARCI through topical KB105 application represents a promising strategy for safely and noninvasively treating this debilitating disease.

Harlequin ichthyosis from birth to 12 years.

A neonate was born with generalised, erythrodermic, thick, fissured skin, severe ectropion, hypoplastic auricles and limb abnormalities. A clinical diagnosis of harlequin ichthyosis was made, allowing supportive therapies to be commenced promptly. Oral acitretin was initiated on day 3 of life, complemented by an intensive skin care regimen. Rehydration, prevention and treatment of infection, temperature control and nutritional support were all essential to see him through the neonatal period. Nearly 12 years later, this child continues to receive multidisciplinary input and enjoys a good quality of life.

Sight-threatening Complication of Cicatricial Ectropion in a Patient with Lamellar Ichthyosis - Case Report.

We report a case of lamellar ichthyosis and sight-threatening complications of cicatricial ectropion in an adult male patient which was surgically managed with tectonic penetrating keratoplasty. We present a case of autosomal-recessive lamellar ichthyosis in a 47-year-old man who was referred to our outpatient eye clinic for treatment of primary keratouveitis of the right eye with keratolysis and exudation in the anterior chamber. A diagnosis of cicatricial ectropion with serious lagophthalmos was established on examination. The patient underwent tectonic penetrating keratoplasty, cataract extraction, and intra-ocular lens placement with no perioperative complications. The patient was subsequently treated with oral fluconazole 200 mg once daily for 12 days due to a positive fungal culture for Candida albicans and systemic oral acyclovir 250 mg 3 times per day for 12 days as prophylaxis for a labial herpetic infection. Post-operative complications included corneal rejection and nonhealing neurotropic epithelial defect of the graft. Long-term treatment with topical cyclosporine (Ikervis®) and dexamethasone led to resolution of the corneal rejection. Lubrication with artificial tears containing hyaluronic acid, perfluorohexyl octane (Evotears®), and vitamin A ointment led to symptomatic relief of dry eye disease. The patient was referred to a dermatologist and was started on systemic retinoid acitretin at a dose of 0.5 mg/kg per day. Ten months after surgery, the patient's visual acuity was 0.1 based on the Snellen chart and the corneal graft was stable. Infection in the cornea can rapidly progress to corneal melting in patients with severe cicatricial ectropion. A good patient outcome depends on the interdisciplinary approach to patient management by the ophthalmologist, dermatologist, and plastic surgeon.

3D model of harlequin ichthyosis reveals inflammatory therapeutic targets.

The biology of harlequin ichthyosis (HI), a devastating skin disorder caused by loss-of-function mutations in the gene ABCA12, is poorly understood, and to date, no satisfactory treatment has been developed. We sought to investigate pathomechanisms of HI that could lead to the identification of new treatments for improving patients' quality of life. In this study, RNA-Seq and functional assays were performed to define the effects of loss of ABCA12 using HI patient skin samples and an engineered CRISPR/Cas9 ABCA12 KO cell line. The HI living skin equivalent (3D model) recapitulated the HI skin phenotype. The cytokines IL-36α and IL-36γ were upregulated in HI skin, whereas the innate immune inhibitor IL-37 was strongly downregulated. We also identified STAT1 and its downstream target inducible nitric oxide synthase (NOS2) as being upregulated in the in vitro HI 3D model and HI patient skin samples. Inhibition of NOS2 using the inhibitor 1400W or the JAK inhibitor tofacitinib dramatically improved the in vitro HI phenotype by restoring the lipid barrier in the HI 3D model. Our study has identified dysregulated pathways in HI skin that are feasible therapeutic targets.

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.

Ictiosis Lamelar autosómica recesiva: revisión de la literatura y caso clínico / Autosomal recessive lamellar ichthyosis: review of the literature and clinical case

Resumen Las ictiosis congénitas autosómicas recesivas (ICAR) son poco frecuentes a nivel mundial con una incidencia de 1:300,000 nacimientos, se caracterizan por trastornos de la queratinización, entre sus variantes engloban las formas no sindrómicas de ictiosis, como la ictiosis laminar (IL), la eritrodermiaictiosiforme congénita (EIC) y actualmente se incluyen la ictiosis arlequín, el bebé colodión autorresolutivo, el bebé colodión autorresolutivoacral y la ictiosis en traje de baño. Desde el punto de vista genético son heterogéneas, originadas por una mutación en el gen de la transglutaminasa 1 y se las haasociado a TGM1, ALOXE3, ALOX12B, NIPAL4, CYP4F22 y ABCA12. Clínicamente, la ictiosis se caracteriza principalmente por piel gruesa, escamas laminares adherentes con hendiduras profundas. En este trabajo pretende revisar los conocimientos actuales en el campo de las ICAR, incluyendo aspectos clínicos, histológicos, ultraestructurales, genético-moleculares, tratamiento,y también su manejo clínico.

Abstract The autosomal recessive congenital ichthyosis (ARCI) is a rare worldwide condition with an incidence of (1: 300,000 births), characterized by disorders of keratinization, among its variants encompass the non-syndromic forms of ichthyosis, such as laminar ichthyosis (IL) , congenital ichthyosiform erythroderma (EIC) and currently include harlequin ichthyosis, self-healing colodion baby, acral self-healing colodion baby and ichthyosis in swimsuits. From a genetic point of view, they're heterogeneous, originated by a mutation in the gene of transglutaminase 1 and associated with TGM1, ALOXE3, ALOX12B, NIPAL4, CYP4F22 and ABCA12. Clinically, ichthyosis is mainly characterized by thick skin, adherent lamellar scales with deep clefts. The aim of this work is to review the current knowledge in the field of ICAR, including clinical, histological, ultrastructural, genetic-molecular and therapeutic aspects as well as its clinical management.

Homeostatic Function of Dermokine in the Skin Barrier and Inflammation.

Dermokine is a chiefly skin-specific secreted glycoprotein localized in the upper epidermis, and its family consists of three splice variants in mice and five in humans. To investigate the pathophysiological impact of dermokine, we generated mice deficient for two (ßγ) or all dermokine isoforms (αßγ). Both variants, especially dermokine αßγ-deficient mice exhibited scale and wrinkle formation resembling ichthyosis accompanied by transepidermal water imbalance at the neonatal stage. Several dermokine αßγ-deficient mice died by postnatal day 21 when reared under low humidity. Moreover, the cornified envelope was vulnerable, and skin barrier lipid ceramides were reduced in the epidermis of dermokine αßγ-deficient mice. cDNA microarray and quantitative reverse transcriptase-PCR assays of the epidermis revealed the upregulation of small proline-rich protein and late cornified envelope family members, as well as antimicrobial peptides in the dermokine αßγ-deficient mice. These barrier gene signatures were similar to that seen in psoriasis, whereas recent studies demonstrated that congenital ichthyosis has gene profiles resembling psoriasis. In line with these findings, adult dermokine αßγ-deficient mice exhibited aggravated phenotypes in psoriasis-like dermatitis models but not in allergic dermatitis models. Dermokine may play a regulatory role in inflammatory dyskeratotic diseases, such as congenital ichthyosis and psoriasis, in the crosstalk between barrier dysfunction and inflammation.

A novel mutation of ABHD5 gene in a Chanarin Dorfman patient with unusual dermatological findings.

BACKGROUND: Chanarin Dorfman Syndrome (CDS) is a rare autosomal recessive disorder characterized by the multisytemic accumulation of neutral lipids inside the cytoplasmic lipid droplets. This condition is caused by mutations in the abhydrolase domain containing 5 gene (ABHD5). In CDS the skin involvement is the prevalent and always observed clinical feature, consisting of a non-bullous congenital ichthyosiform erythroderma (NCIE). Moreover, a variable involvement of the liver and neuromuscular system can be also observed. In this report, we aimed to perform the clinical and genetic characterization of a patient affected by CDS with atypical dermatological findings, considering this rare inborn error of neutral lipid metabolism. METHODS: Genomic DNA samples obtained from patient and his parents were used to perform the sequencing of the ABHD5 exons and their intron/exon boundaries. Bioinformatic analyses were performed to investigate the possible effect of the identified mutation on protein structure. RESULTS: Here we present the case of a 29-year-old male patient with CDS, who, for long time, has been misdiagnosed as pityriasis rubra pilaris (PRP). He has a history of increasing hyperlipidemia; hepatomegaly associated with hepatosteatosis was also detected. ABHD5 molecular analysis revealed a novel missense mutation, the c.811G > A (p.G271R). Bioinformatic investigations showed that the variant has a deleterious effect on ABHD5 function, probably causing an incorrect folding of the mutant protein. CONCLUSIONS: These results highlihts the importance of genetic testing for ABHD5 in unresolved cases of patients presenting unusual skin lesions, that resemble PRP, associated with a history of hyperlipidemia and nonalcoholic fatty liver.

Biogeographical origin and timing of the founder ichthyosis TGM1 c.1187G > A mutation in an isolated Ecuadorian population.

An unusually high frequency of the lamellar ichthyosis TGM1 mutation, c.1187G > A, has been observed in the Ecuadorian province of Manabí. Recently, the same mutation has been detected in a Galician patient (Northwest of Spain). By analyzing patterns of genetic variation around this mutation in Ecuadorian patients and population matched controls, we were able to estimate the age of c.1187G > A and the time to their most recent common ancestor (TMRCA) of c.1187G > A Ecuadorian carriers. While the estimated mutation age is 41 generations ago (~1,025 years ago [ya]), the TMRCA of Ecuadorian c.1187G > A carrier haplotypes dates to just 17 generations (~425 ya). Probabilistic-based inferences of local ancestry allowed us to infer a most likely European origin of a few (16% to 30%) Ecuadorian haplotypes carrying this mutation. In addition, inferences on demographic historical changes based on c.1187G > A Ecuadorian carrier haplotypes estimated an exponential population growth starting ~20 generations, compatible with a recent founder effect occurring in Manabí. Two main hypotheses can be considered for the origin of c.1187G > A: (i) the mutation could have arisen in Spain >1,000 ya (being Galicia the possible homeland) and then carried to Ecuador by Spaniards in colonial times ~400 ya, and (ii) two independent mutational events originated this mutation in Ecuador and Galicia. The geographic and cultural characteristics of Manabí could have favored a founder effect that explains the high prevalence of TGM1 c.1187G > A in this region.