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).

Cross-Sectional Study on Autosomal Recessive Congenital Ichthyoses: Association of Genotype with Disease Severity, Phenotypic, and Ultrastructural Features in 74 Italian Patients.

BACKGROUND: Autosomal recessive congenital ichthyoses (ARCIs) are a clinically heterogeneous group of keratinization disorders characterized by generalized skin scaling due to mutations in at least 12 genes. The aim of our study was to assess disease severity, phenotypic, and ultrastructural features and to evaluate their association with genetic findings in ARCI patients. METHODS: Clinical signs and symptoms, and disease severity were scored in a single-center series of patients with a genetic diagnosis of ARCI. Skin ultrastructural findings were reviewed. RESULTS: Seventy-four consecutive patients (mean age 11.0 years, range 0.1-48.8) affected with lamellar ichthyosis (50/74, 67.5%), congenital ichthyosiform erythroderma (18/74, 24.3%), harlequin ichthyosis (two/74, 2.7%), and other minor ARCI subtypes (four/74, 5.4%) were enrolled. Mutated genes were as follows: TGM1 in 18/74 (24.3%) patients, ALOX12B in 18/74 (24.3%), CYP4F22 in 12/74 (16.2%), ABCA12 in nine/74 (12.2%), ALOXE3 in seven/74 (9.5%), NIPAL4 in seven/74 (9.5%), and CERS3, PNPLA1, and SDR9C7 in 1 patient each (1.4%). Twenty-five previously undescribed mutations in the different ARCI causative genes, as well as two microduplications in TGM1, and two microdeletions in CYP4F22 and NIPAL4 were identified. The mean ichthyosis severity score in TGM1- and ABCA12-mutated patients was significantly higher than in all other mutated genes, while the lowest score was observed in CYP4F22-mutated patients. Alopecia, ectropion, and eclabium were significantly associated with TGM1 and ABCA12 mutations, and large, thick, and brownish scales with TGM1 mutations. Among specific phenotypic features, psoriasis-like lesions as well as a trunk reticulate scale pattern and striated keratoderma were present in NIPAL4-mutated patients. Ultrastructural data available for 56 patients showed a 100% specificity of cholesterol clefts for TGM1-mutated cases and revealed abnormal lamellar bodies in SDR9C7 and CERS3 patients. CONCLUSION: Our study expands the phenotypic and genetic characterization of ARCI by the description of statistically significant associations between disease severity, specific clinical signs, and different mutated genes. Finally, we highlighted the presence of psoriasis-like lesions in NIPAL4-ARCI patients as a novel phenotypic feature with diagnostic and possible therapeutic implications.

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.

Scanning electron microscopy of the collodion membrane from a self-healing collodion baby

AbstractSelf-healing collodion baby is a well-established subtype of this condition. We examined a male newborn, who was covered by a collodion membrane. The shed membrane was examined with scanning electron microscopy. The outer surface showed a very compact keratin without the normal elimination of corneocytes. The lateral view of the specimen revealed a very thick, horny layer. The inner surface showed the structure of lower corneocytes with polygonal contour. With higher magnifications villous projections were seen in the cell membrane.

Relato de caso: bebê arlequim – ictiose congênita / Case report: baby harlequin - congenital ichthyosis

Feto arlequim é uma variante grave da ictiose congenita, uma herança autossômica recessiva que causa alteração da queratinização da pele, que incide em cerca de 1/100.000 nascimentos e está geralmente associada a consaguinidade dos pais. Manifesta-se ao nascimento como uma pele espessada que evolui para rachaduras generalizadas, comprometendo as suas funções básicas e predispondo a infecções. Relata-se o caso de um RN do sexo feminino, cujos pais não referem nenhum grau de parentesco. A mesma foi mantida em isolamento em incubadora, mas feleceu no nono dia de vida por insuficiência respiratória restritiva.

Harlequin fetus is a variant of severe congenital ichthyosis, an autosomal recessive heredity make change in the keratinization of skin, which appear around 1/100.000 births and is usually associated with consaguineus parents. At birth it seems like a thicken skin that develops into widespread cracks, affecting its basics functions and predisposes to infections. We report the case of a female newborn, whose parents don’t mention any degree of kinship. The baby stood on isolation in incubator, but died at ninth day of life from restrictive respiratory failure.

Bebé colodión. Comunicación de 14 casos / Collodion baby. Report of fourteen patients

El término bebé colodión se refiere a una condición transitoria del recién nacido que consiste en la presencia de una membrana translúcida y adherente que recubre casi completamente la superficie corporal. Constituye una manifestación inicial común a varias entidades; las más frecuentes son la ictiosis lamelar y la eritrodermia ictiosiforme congénita no ampollar. A continuación presentamos una serie de 14 pacientes que nacieron como bebé colodión y una revisión actualizada de la literatura.

Ictiose lamelar: caso clínico e diagnóstico diferencial / Ictiose lamelar: case report and differential diagnosis

Os autores relatam um caso de uma criança do sexo feminino com ictose congênita, de pais näo consangüíneos, diagnosticado no Hospital Universitário da UFSC. A paciente apresentava descamaçäo cutânea generalizada e palmo-plantar, ectrópio, eclábio e distrofia ungueais em membros superiores, além de alteraçöes histopatologicas que indicaram o diagnóstico de ictiose lamelar recessiva. O tratamento foi realizado com cremes hidratantes e queratolíticos. Os autores apresentam comentários sobre o diagnóstico diferencial e tratamento das formas mais comuns desta patologia