Genetic testing and new variants in diagnosis of congenital ichthyoses.

BACKGROUND: The aim of this study was to evaluate how diagnostic practice in congenital ichthyoses has evolved during the years 2000-2020 and what kind of gene variants of congenital ichthyosis have been found. METHODS: The study cohort of this register-based research consisted of a total of 88 patients, whose diagnostic testing was conducted, and ichthyosis diagnoses set at the Department of Dermatology and the Department of Clinical Genetics at Tampere University Hospital during the years 2000-2020. RESULTS: Diagnosis of ichthyosis was confirmed with genetic testing in 33 cases, and with conventional diagnostic methods, such as clinical findings, skin biopsy and family history of ichthyoses, in 55 cases. We observed four novel variants in patients with the clinical diagnoses of congenital ichthyoses. CONCLUSION: When genetic testing became available, it was offered primarily to patients with severe forms of ichthyosis. During the study period next-generation sequencing became the genetic testing method of choice providing new opportunities in diagnostics.

Exploring the Co-occurrence of dermatophyte infection and ichthyosis: A report of 3 cases.

Dermatophyte infections frequently pose diagnostic challenges, especially when occurring alongside ichthyosis, a genetic skin disorder characterized by dry, thickened, scaly skin. This case series outlines three cases where dermatophyte infections overlapped with ichthyosis, emphasizing the complexities in clinical identification and differential diagnosis. Atypical clinical presentations in these cases led to initial misdiagnoses. Ichthyosis, a genetic skin disorder characterized by thickened and scaly skin, creates an environment conducive to dermatophyte settlement, complicating the diagnostic process. The cases highlight the importance of considering fungal infections, even when clinical features deviate from the expected course. A vigilant diagnostic approach, including mycological examinations, is crucial for accurate identification and timely management.

Genetic analysis of seven patients with inherited ichthyosis and Nagashima­type palmoplantar keratoderma.

Inherited ichthyosis comprises a series of heterogeneous dermal conditions; it mainly manifests as widespread hyperkeratosis, xerosis and scaling of the skin. At times, overlapping symptoms require differential diagnosis between ichthyosis and several other similar disorders. The present study reports seven patients with confirmed or suspected to be associated with ichthyosis by conducting a thorough clinical and genetic investigation. Genetic testing was conducted using whole­exome sequencing, with Sanger sequencing as the validation method. The MEGA7 program was used to analyze the conservation of amino acid residues affected by the detected missense variants. The enrolled patients exhibited ichthyosis­like but distinct clinical manifestations. Genetic analysis identified diagnostic variations in the FLG, STS, KRT10 and SERPINB7 genes and clarified the carrying status of each variant in the respective family members. The two residues affected by the detected missense variants remained conserved across multiple species. Of note, the two variants, namely STS: c.452C>T(p.P151L) and c.647_650del(p.L216fs) are novel. In conclusion, a clear genetic differential diagnosis was made for the enrolled ichthyosis­associated patients; the study findings also extended the mutation spectrum of ichthyosis and provided solid evidence for the counseling of the affected families.

Waxy papules, infiltrated alopecic plaques, and shin ichthyosis.

A 38-year-old male presented with waxy papules, plaques over the neck and extremities, and ichthyotic scales over the lower limbs. Skin biopsy revealed a dense medium-sized lymphocytic infiltrate in the dermis, with perifollicular accentuation and focal exocytosis into the follicular epithelium with strong positivity for CD 3, 4, and 5. Considering the clinicopathological correlation, a diagnosis of follicular mycosis fungoides (FMF) was made. It is a variant of classic mycosis fungoides (MF) where atypical cells invade the follicular epithelium.

French national protocol for the management of congenital ichthyosis.

Congenital ichthyoses (CI) comprise a heterogeneous group of monogenic genetic skin diseases characterized by diffuse scaling, often associated with skin inflammation. Diagnosis of the individual form of ichthyosis is complex and is guided by clinical expertise. CI usually has a major impact on quality of life (QOL) and thus requires lifelong treatment. To date, there are no curative therapies, although various symptomatic treatment options exist. The present protocol for the management of CI has been drawn up in accordance with the recommendations published in 2012 by the French National Authority for Health, based on a literature review, with the help and validation of members of the French network for rare skin diseases (FIMARAD). It provides a summary of evidence and expert-based recommendations and is intended to help clinicians with the management of these rare and often complex diseases.

Congenital Ichthyosis: Current Approaches to Prenatal Diagnoses.

INTRODUCTION: Congenital ichthyosis represents a wide spectrum of diseases. This article reviews prenatal testing for ichthyosis. METHODS: We used pubmed.ncbi.nlm.nih.gov to search for 38 types of congenital ichthyosis combined with 17 words related to prenatal testing. RESULTS: Search resulted in 408 publications covering 13 types of ichthyoses and four types of tests. DISCUSSION: Biochemical testing is diagnostic in trichothiodystrophy, but nonspecific in X-linked ichthyosis and Refsum syndrome. Except in X-linked ichthyosis, biochemical testing requires invasive procedures to obtain fetal skin biopsy, amniocytes, or chorionic villus samples. It is superior to histological and cytological examination of fetal skin biopsy or amniocytes because keratinization occurs later in pregnancy and microscopy cannot differentiate between ichthyosis types. Imaging is more acceptable due to noninvasiveness and routine use, although ultrasonography is operator-dependent, nonspecific, and captures abnormalities at late stage. Molecular tests are described in at-risk pregnancies but testing of free fetal DNA was not described.

In-person validation of the Ichthyosis Scoring System.

BACKGROUND: Ichthyoses are a heterogeneous group of skin disorders characterized by scaling and erythema. Recognizing the variability of scale and erythema by region and ichthyosis subtype, we developed the Ichthyosis Scoring System (ISS) to quantify severity. We previously found ISS to have high inter- and intrarater reliability in evaluating photographic images. To confirm ISS clinical utility, we examined its performance at the 2022 Foundation for Ichthyosis and Related Skin Types conference. METHODS: Sixty-five participants were evaluated by 3 of 9 medical professionals trained to score ichthyosis scale and erythema using ISS. Intrarater and interrater intraclass correlation coefficients (ICC) were analyzed using one-way and two-way random effects models, respectively. RESULTS: Intrarater reliability was excellent (ICC = 0.931, 95% CI, 0.921-0.940) for scale and good (ICC = 0.876, 95% CI, 0.853-0.899) for erythema scoring. Compared to photo validation with excellent intrarater reliability ratings for both scale (ICC = 0.956, 95% CI, 0.925-0.974) and erythema (ICC = 0.913, 95% CI, 0.855-0.949), ISS demonstrated equivalent reliability for live use. Overall interrater reliability for 10 body sites showed excellent (ICC >0.9) and good (ICC >0.75) agreement and consistency for both scale and erythema. Palms were an exception, demonstrating moderate (ICC >0.5) interrater agreement and consistency for erythema evaluation. CONCLUSIONS: ISS is a reliable measure of global and regional ichthyosis severity during in-person evaluations. Ease-of-use, accessibility, and content validity in both live and photographic evaluation endorse ISS as a standard for ichthyosis severity analysis.

Ocular phenotype and therapeutic interventions in keratitis-ichthyosis-deafness (KID) syndrome.

BACKGROUND: To report ocular manifestations, clinical course, and therapeutic management of patients with molecular genetically confirmed keratitis-ichthyosis-deafness syndrome. METHODS: Four patients, aged 19 to 46, with keratitis-ichthyosis-deafness syndrome from across the UK were recruited for a general and ocular examination and GJB2 (Cx26) mutational analysis. The ocular examination included best-corrected visual acuity, slit-lamp bio-microscopy, and ocular surface assessment. Mutational analysis of the coding region of GJB2 (Cx26) was performed by bidirectional Sanger sequencing. RESULTS: All four individuals had the characteristic systemic features of keratitis-ichthyosis-deafness syndrome. Each patient was found to have a missense mutation, resulting in the substitution of aspartic acid with asparagine at codon 50 (p.D50N). Main ophthalmic features were vascularizing keratopathy, ocular surface disease, hyperkeratotic lid lesions, recurrent epithelial defects, and corneal stromal scarring. One patient had multiple surgical procedures, including superficial keratectomies and lamellar keratoplasty, which failed to prevent severe visual loss. In contrast, oral therapy with ketoconazole stabilized the corneal and skin disease in two other patients with keratitis-ichthyosis-deafness syndrome. The patient who underwent intracorneal bevacizumab injection showed a marked reduction in corneal vascularization following a single application. CONCLUSIONS: Keratitis-ichthyosis-deafness syndrome is a rare ectodermal dysplasia caused by heterozygous mutations in GJB2 (Cx26) with a severe, progressive vascularizing keratopathy. Oral ketoconazole therapy may offer benefit in stabilizing the corneal and skin disease.

Two novel heterozygous exonic deletions lead to Chanarin-Dorfman syndrome in a patient with congenital ichthyosis, sensorineural hearing loss, and liver dysfunction.

Chanarin-Dorfman syndrome is an autosomal recessively inherited disorder characterized by ichthyosis, sensorineural hearing loss, and hepatic dysfunction. We report on a 60-year-old female of Venezuelan descent who presented with congenital ichthyosis, progressive sensorineural hearing loss, and liver cirrhosis. We identify a heterozygous copy number deletion involving exon 1 and another heterozygous deletion involving exon 3 of the ABHD5 gene. Exon 2 is preserved. Both deletions were confirmed with RT-PCR. RNAseq from peripheral blood shows a reduction of ABHD5 expression overall and an absence of exon 3 expression, confirming the deleterious effects of the identified deletions. We present exonic deletions as a potentially common type of ABHD5 variation.

Ictiosis epidermolítica en un recién nacido: reporte de un caso / Epidermolytic ichthyosis in newborns: clinical case study / Ictiose epidermolítica em recém-nascido: relato de caso

La ictiosis epidermolítica es una genodermatosis de herencia autosómica dominante poco frecuente que requiere un diagnóstico oportuno, idealmente prenatal, para así brindar una asistencia neonatal adecuada, iniciar un tratamiento precoz y de esta manera disminuir su morbimortalidad. Se caracteriza por la formación de ampollas, múltiples erosiones y descamación con eritrodermia desde el nacimiento. Todos los tipos de ictiosis queratinopáticas son causadas por mutaciones en los genes de la familia de queratina KRT1, KRT2 y KRT10. Se presenta el caso clínico de un neonato de 9 días de vida, nacido en el interior del país, con diagnóstico de ictiosis epidermolítica y antecedente familiar de primer grado con la misma enfermedad. El interés de esta publicación radica en la descripción de una genodermatosis de baja frecuencia, reconocer la importancia del diagnóstico precoz, conocer el manejo, las complicaciones y destacar la importancia de la atención por un equipo multidisciplinario conformado por neonatólogo, dermatólogos, genetistas y pediatras.

Epidermolytic ichthyosis is a rare genodermatosis with autosomal dominant inheritance, which requires timely diagnosis, ideally prenatal diagnosis, in order to provide adequate neonatal care, start early treatment and thus reduce morbidity and mortality. It is characterized by the formation of blisters, multiple erosions and scaling with erythroderma from birth. All types of keratinopathic ichthyoses are caused by mutations in the genes of the keratin family KRT1, KRT2 and KRT10. We present the clinical case of a 9-day-old newborn from the interior of the country, with diagnosis and family history of epidermolytic ichthyosis. The interest of this publication lies in the description of a low-frequency genodermatosis, recognizing the importance of early diagnosis, understanding the management, complications and highlighting the importance of a multidisciplinary care team integrated by a neonatologist, dermatologists, geneticists and pediatricians.

A ictiose epidermolítica é uma genodermatose autossômica dominante rara que requer diagnóstico oportuno, idealmente pré-natal, para fornecer cuidados neonatais adequados, iniciar o tratamento precoce e, assim, reduzir sua morbidade e mortalidade. Caracteriza-se pela formação de bolhas, múltiplas erosões e descamação com eritrodermia desde o nascimento. Todos os tipos de ictioses queratinopáticas são causados por mutações nos genes da família da queratina KRT1, KRT2 e KRT10. É apresentado o caso clínico de um recém-nascido de 9 dias, nascido no interior do país, com diagnóstico de ictiose epidermolítica e história familiar de primeiro grau com a mesma doença. O interesse desta publicação reside na descrição de uma genodermatose de baixa frequência, reconhecendo a importância do diagnóstico precoce, conhecendo o manejo, as complicações e destacando a importância do atendimento por uma equipe multidisciplinar composta por neonatologistas, dermatologistas, geneticistas e pediatras.

Whole exome sequencing identifies novel pathogenic variants in TGM1 and ALOX12B in patients with hereditary ichthyosis.

BACKGROUND: Hereditary ichthyosis is a clinically and genetically heterogeneous disorder associated with more than 50 genes with TGM1, ALOX12B, and ALOXE3 being the most prevalent. Establishing an accurate diagnosis is important for effective genetic counseling and optimal patient management. OBJECTIVE: We studied the diagnostic value of whole exome sequencing (WES) in a small case series with hereditary ichthyosis. METHODS: During a 1-year period, index cases of 5 unrelated families clinically diagnosed with hereditary ichthyosis went through WES, followed by extensive segregation analysis. Prenatal diagnosis (PND) was conducted where indicated. RESULTS: We identified 4 homozygous variants-2 in TGM1 (c.655A > G and c.797A > G) and 2 in ALOX12B (c.527 + 2 T > G and c.1654G > T)-alongside a heterozygous variant in TGM1 (c.428G > A) in 5 families. The variants were all pathogenic/likely pathogenic according to the ACMG classification and segregation analysis, except for c.797A > G in TGM1 which remained a variant of unknown clinical significance. Four variants were novel. All families were referred either during pregnancy or before reproductive planning; 4 benefited from WES as it identified the mutation in the probands and enabled carrier detection in at-risk relatives; PND was conducted in 2 families. CONCLUSION: Our findings further support WES is a powerful tool for the comprehensive, accurate, and rapid molecular diagnosis of hereditary ichthyosis and can offer opportunities for reproductive planning, carrier screening and prenatal diagnosis to at-risk families.

Neu Laxova syndrome and megacystis in the first trimester: Broadening the fetal phenotype.

Neu Laxova syndrome (NLS) is a rare and lethal congenital disorder characterized by severe intra-uterine growth retardation (IUGR), ichthyosis, abnormal facial features, limb abnormalities with arthrogryposis and a wide spectrum of severe malformations of the central nervous system (CNS). NLS is due to biallelic variants in three genes previously involved in serine-deficiency disorders (PHGDH, PSAT1 and PSPH), extending the phenotypic spectrum of these disorders.

Acquired Ichthyosis Revealing Lymphocytic Colitis.

A 69-year-old patient with no personal or family history of ichthyosis consulted our dermatology department for diffused cutaneous xerosis with intense pruritus evolving for 3 weeks. Physical examination revealed diffused ichthyosis of large polygonal fine scales on the skin without erythema (Figure 1). The lesions spared the face. Examination of the mucous membranes, hair, and nails revealed no abnormalities. There was no fever or adenomegaly. A skin biopsy revealed an orthokeratotic hyperkeratosis with thinning of granular layer (Figure 2). The initial diagnosis of acquired ichthyosis was maintained. The patient also reported a change in bowel habits since 2 weeks with watery, non-bloody diarrhea and mild steatorrhea. His laboratory investigations presented low serum vitamin B12 level, mild anemia, hypoalbuminemia, and fecal leukocytes; however, antinuclear antibodies, perinuclear anti-neutrophil cytoplasmic antibodies (pANCA), rheumatoid factor, and complement components C3 and C4 were normal. A colonoscopy performed was also normal without any abnormalities. Colon biopsies revealed histologic aspects of lymphocytic colitis with more than 20% increase in lymphocytes in the surface epithelium of colorectal mucosa. Laboratory investigations excluded neoplasia, hemopathies, or autoimmune-associated diseases. The patient was treated with salazopyrin with a remarkable lessening of diarrhea and cutaneous manifestations within 4 weeks (Figure 3).

Case report of self-improving collodion ichthyosis in the newborn.

Self-improving collodion ichthyosis (SICI) is a relatively rare subtype of autosomal recessive congenital ichthyosis (ARCI) that is often characterized by a collodion baby (CB) phenotype at birth. A newborn girl, just 1 hour old, presented with taut, shiny, thick yellow crusts, like parchment, and scales on her trunk and upper limbs. The tightening effect had caused both upper eyelids to appear everted, and her lips and auricles were deformed. Based on whole-exome sequencing and examination of the clinical phenotype, the patient was diagnosed with ARCI. After admission, the exposed mucosa was covered with a sterile Vaseline gauze dressing, and she was placed in an incubator set to a temperature of 32°C with a humidity level of 75%. One week later, the parchment-like scales had begun to flake off, and at the age of 3 weeks, all bodily skin appeared normal. SICI was diagnosed. After discharge, the patient was followed up to 3 months of age, at which time her growth and development were comparable to those of her peers. Clinicians should consider SICI as a possible diagnosis when analyzing the prognosis of patients with CB. Reducing water loss and maintaining the electrolyte balance are particularly important for SICI treatment.

Otological problems in ichthyosis: A literature review.

BACKGROUND: Ichthyoses are a rare group of keratinization disorders characterized by scaling of the skin due to an impaired barrier function. Few studies have addressed ear involvement in patients with ichthyosis, although it is a probably underestimated aspect of the disease. OBJECTIVE: This study aims to provide an overview of the otological manifestations in ichthyosis and propose specific treatment options. METHODS: Articles were collected using PubMed, EMBASE, and Web of Science. A total of 53 articles were included in this literature review. RESULTS: The most common ear problem in patients with ichthyosis is scale accumulation in the ear canals, which can lead to conductive hearing loss and increases the risk of ear infections. Furthermore, some types of ichthyosis are associated with outer ear malformations. Lastly, sensorineural hearing loss is common in syndromic forms of ichthyosis. CONCLUSIONS: Otological problems are present in all types of ichthyoses and their treatment is challenging. The involvement of ear, nose, and throat specialists in the routine care of ichthyosis patients is essential for early identification and treatment of these manifestations. More research is needed to provide more insight into the otological problems in ichthyosis and to ameliorate treatment options.