Meta-Analysis of Mutations in ALOX12B or ALOXE3 Identified in a Large Cohort of 224 Patients

Genetic analysis of seven patients with inherited ichthyosis and Nagashima‑type 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 whole‑exome 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 ichthyosis‑like 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 ichthyosis‑associated patients; the study findings also extended the mutation spectrum of ichthyosis and provided solid evidence for the counseling of the affected families.

Human genetic defects of sphingolipid synthesis

Sphingolipids are ubiquitous lipids, present in the membranes of all cell types, the stratum corneum and the circulating lipoproteins. Autosomal recessive as well as dominant diseases due to disturbed sphingolipid biosynthesis have been identified, including defects in the synthesis of ceramides, sphingomyelins and glycosphingolipids. In many instances, these gene variants result in the loss of catalytic function of the mutated enzymes. Additional gene defects implicate the subcellular localization of the sphingolipid-synthesizing enzyme, the regulation of its activity, or even the function of a sphingolipid-transporter protein. The resulting metabolic alterations lead to two major, non-exclusive types of clinical manifestations: a neurological disease, more or less rapidly progressive, associated or not with intellectual disability, and an ichthyotic-type skin disorder. These phenotypes highlight the critical importance of sphingolipids in brain and skin development and homeostasis. The present article reviews the clinical symptoms, genetic and biochemical alterations, pathophysiological mechanisms and therapeutic options of this relatively novel group of metabolic diseases.

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.

Lipoxygenases at the Intersection of Infection and Carcinogenesis

The persisting presence of opportunistic pathogens like Pseudomonas aeruginosa poses a significant threat to many immunocompromised cancer patients with pulmonary infections. This review highlights the complexity of interactions in the host's defensive eicosanoid signaling network and its hijacking by pathogenic bacteria to their own advantage. Human lipoxygenases (ALOXs) and their mouse counterparts are integral elements of the innate immune system, mostly operating in the pro-inflammatory mode. Taking into account the indispensable role of inflammation in carcinogenesis, lipoxygenases have counteracting roles in this process. In addition to describing the structure-function of lipoxygenases in this review, we discuss their roles in such critical processes as cancer cell signaling, metastases, death of cancer and immune cells through ferroptosis, as well as the roles of ALOXs in carcinogenesis promoted by pathogenic infections. Finally, we discuss perspectives of novel oncotherapeutic approaches to harness lipoxygenase signaling in tumors.

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).

High TGM1 Allelic Heterogeneity causing Lamellar ichthyosis in a small geographic area in South Mexico: Another Example of the "Réunion Paradox"

Lamellar ichthyosis (LI) is an autosomal recessive congenital ichthyosis characterized by generalized dry skin and severe scaling. It is caused by biallelic mutations in the TGM1 gene, however molecular data from non-Caucasian populations are limited. Results of genetic-molecular analysis of a group of LI pedigrees originating from two close small populations from south Mexico are presented. LI affected individuals belonging to 9 apparently unrelated families were studied. Exome sequencing or Sanger sequencing in probands from each family was carried out. Furthermore, DNA from 294 unaffected subjects from one of the communities were Sanger sequenced to determine the carrier frequency of the c.427C > T TGM1 variant. Five different TGM1 pathogenic variants, either in homozygous or in compound heterozygous state, were demonstrated in affected subjects. The two most common variants were c.427C > T (p.Arg143Cys) and c.1159+1G > T. A novel c.1645+1G > T TGM1 pathogenic allele was recognized. Carrier frequency analysis identified a total of 23 individuals heterozygous for the c.427C > T variant, predicting a prevalence of 78 carriers per 1000 inhabitants in the community. A high TGM1 allelic heterogeneity with 5 different LI-causing alleles in a limited geographic area was demonstrated. While the occurrence of homozygosity for a founder mutation is expected in small populations with high frequency of a particular autosomal recessive disorder, the occurrence of multiple pathogenic alleles has been previously described, a situation known as the Reúnion paradox. Our results expand the current knowledge of the mutational spectrum of TGM1-linked LI.

Ichthyosis: presentation and management

PURPOSE OF REVIEW

This review focuses on the presentation and management of ichthyoses and highlights recent advances in treatment that hold promise for better targeted therapy.

RECENT FINDINGS

The ichthyoses are a group of rare genetic diseases with a wide phenotypic spectrum, characterized most often by generalized hyperkeratosis and scaling with variable erythema. The highly visible scaling and frequent itch contribute to decreased quality of life. Management for ichthyosis focuses on symptomatic relief and scale reduction with emollients, keratolytics, and retinoids. Recent advances in immune profiling and genotype-phenotype mapping have increased understanding of ichthyosis and shifted focus to pathogenesis-based targeted therapies with emerging biologics, small molecular inhibitors, and gene therapy.

SUMMARY

This article discusses clinical assessment and genotyping to make the diagnosis of specific forms of ichthyosis, provides guidance for management, and reviews new treatment options with systemic agents.

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.

Synthesis and Significance of Arachidonic Acid, a Substrate for Cyclooxygenases, Lipoxygenases, and Cytochrome P450 Pathways in the Tumorigenesis of Glioblastoma Multiforme, Including a Pan-Cancer Comparative Analysis

Glioblastoma multiforme (GBM) is one of the most aggressive gliomas. New and more effective therapeutic approaches are being sought based on studies of the various mechanisms of GBM tumorigenesis, including the synthesis and metabolism of arachidonic acid (ARA), an omega-6 polyunsaturated fatty acid (PUFA). PubMed, GEPIA, and the transcriptomics analysis carried out by Seifert et al. were used in writing this paper. In this paper, we discuss in detail the biosynthesis of this acid in GBM tumors, with a special focus on certain enzymes: fatty acid desaturase (FADS)1, FADS2, and elongation of long-chain fatty acids family member 5 (ELOVL5). We also discuss ARA metabolism, particularly its release from cell membrane phospholipids by phospholipase A₂ (cPLA₂, iPLA₂, and sPLA₂) and its processing by cyclooxygenases (COX-1 and COX-2), lipoxygenases (5-LOX, 12-LOX, 15-LOX-1, and 15-LOX-2), and cytochrome P450. Next, we discuss the significance of lipid mediators synthesized from ARA in GBM cancer processes, including prostaglandins (PGE₂, PGD₂, and 15-deoxy-Δ^12,14-PGJ₂ (15d-PGJ₂)), thromboxane A₂ (TxA₂), oxo-eicosatetraenoic acids, leukotrienes (LTB₄, LTC₄, LTD₄, and LTE₄), lipoxins, and many others. These lipid mediators can increase the proliferation of GBM cancer cells, cause angiogenesis, inhibit the anti-tumor response of the immune system, and be responsible for resistance to treatment.

Congenital Ichthyosis: Clinical and Genetic Characteristics of the Disease

Congenital ichthyosis is a group (almost 100 clinical variants) of rare genetic skin diseases caused by pathogenic changes in more than 50 genes. Clinical features of ichthyosis, regardless of its genotype, are dry skin, peeling, hyperkeratosis frequently accompanied with erythroderma. These patients have extremely low quality of life due to changes in appearance, discomfort due to itching and functional limitations (pain during walking, impaired hands motor skills and functions due to hyperkeratosis foci in functionally relevant areas), as well as impaired functions of various organs and systems in syndromic forms of disease. Patients need daily skin care and systemic medications. By now, there is no definitive treatment for ichthyosis. Diagnostic difficulties in determining the clinical forms of congenital ichthyosis are associated with their clinical heterogeneity and with similarity in external manifestations. Difficulties in differential diagnosis with other dermatoses are particularly crucial in case of syndromic forms of disease. This review presents the modern classification of ichthyoses, provides data on disease clinical and genetic variants, diagnostic algorithms, treatment methods for patients with this severe disease.

Randbetonte erythematöse Plaques bei einem Patienten mit kongenitaler Ichthyose: von häufigen und seltenen Dermatosen

Nicht-syndromale autosomal-rezessive kongenitale Ichthyosen (ARCI) sind seltene hereditäre Verhornungsstörungen mit einem heterogenen Spektrum an Phänotypen von einer nahezu erscheinungsfreien Haut über eine milde bis schwere Erythrodermie bis hin zu Panzer-artigen Schuppen. Zu den Hauptvertretern zählen die lamelläre Ichthyose, die kongenitale ichthyosiforme Erythrodermie, die Harlekin-Ichythose, die „bathing suit ichthyosis“ und die „self-improving congenital ichthyosis“ (SICI), die sich im Laufe des ersten Lebensjahres bessert und im späteren Leben nur noch durch eine Xerosis cutis mit diskreten, feinen weißen Schuppen äußert.

Wir berichten über einen 38-jährigen Patienten, der sich mit einer milden kongenitalen Ichthyose unbekannter genetischer Ursache und einem seit einem Monat erheblich verschlechterten Hautbefund vorstellte. Anhand des klinischen Befundes mit anulären, randbetonten, schuppenden erythematösen Plaques, der Histologie und einer Schuppenpilzkultur konnte eine durch Trichophyton rubrum hervorgerufene Tinea corporis als Ursache für die Exazerbation identifiziert werden. Diese heilte nach 4-wöchiger systemischer Therapie mit Terbinafin komplett ab. Zurück blieb nur eine Xerosis cutis mit einer feinen weißen Schuppung. Passend zur klinischen Verdachtsdiagnose einer SICI erbrachte die molekulargenetische Untersuchung zwei mutmaßlich compound-heterozygote, wahrscheinlich pathogene Varianten im ALOXE3-Gen, eine Spleiß-Variante (c.1392+2T>A;p.?) und ein komplexes Rearrangement. ALOXE3 kodiert für die Lipooxygenase E3, die für die epidermale Differenzierung und für den Aufbau des „cornified envelope“ bedeutsam ist. Varianten in diesem Gen sind eine der Hauptursachen für SICI.

Patienten mit Ichthyosen weisen aufgrund des verdickten Stratum corneum, einer verzögerten Desquamation, einer gestörten epidermalen Barrierefunktion und einer Störung der Talg- und Schweißproduktion ein erhöhtes Risiko für Dermatophytosen auf. Diese präsentieren sich oft atypisch und können daher leicht verkannt werden. Insbesondere bei schweren kongenitalen Ichthyosen sind chronische Verläufe und Rezidive häufig. Unser Fall zeigt, dass auch und gerade bei Patienten mit seltenen Verhornungsstörungen an häufige infektiöse Dermatosen wie Tinea corporis gedacht werden muss.

Identification of the first congenital ichthyosis case caused by a homozygous deletion in the ALOX12B gene due to chromosome 17 mixed uniparental disomy

Uniparental disomy (UPD) is a rare genetic event caused by errors during gametogenesis and fertilization leading to two copies of a chromosome or chromosomal region inherited from one parent. MixUPD is one type of UPD that contains isodisomic and heterodisomic parts because of meiotic recombination. Using whole-exome sequencing (WES), we identified the first case of ichthyosis due to a maternal mixUPD on chromosome 17, which results in a homozygous deletion of partial intron 8 to exon 10 in ALOX12B, being predicted to lead to an internal protein deletion of 97 amino acids. We also performed a retrospective analysis of 198 patients with ALOX12B mutations. The results suggested that the exon 9 and 10 are located in the mutational hotspots of ALOX12B. In addition, our patient has microtia and congenital stenosis of the external auditory canals, which is very rare in patients with ALOX12B mutations. Our study reports the first case of autosomal recessive congenital ichthyosis (ARCI) due to a mixUPD of chromosome 17 and expands the spectrum of clinical manifestations of ARCI caused by mutations in the ALOX12B gene.

Genetic Etiology of Ichthyosis in Turkish Patients: Nextgeneration Sequencing Identified Seven Novel Mutations

Objective:

Ichthyosis is a clinically heterogeneous group of genodermatoses characterized by widespread drying and scaling of the skin. It is also a genetically heterogeneous disorder, and 67 genes associated with the disease have been identified to date. However, there are still undiscovered genes causing the disease.

Methods:

We investigated 19 Turkish patients from 17 unrelated families using clinical exome sequencing or multigene panel screening.

Results:

Sixteen likely pathogenic or pathogenic variants were detected in 13 unrelated patients. We identified “variant of unknown significance” alteration in only one patient. Seven novel variants were identified in ABCA12, ALOX12B, and ALOXE3. The most commonly mutated gene was TGM1, followed by ABCA12 and ALOX12B.

Conclusions:

Because of the wide genetic variability of ichthyosis, it is difficult to diagnose the disease quickly and definitively. The clinical use of next-generation sequencing (NGS) methodologies is beneficial in the diagnostic approach to ichthyosis and genetic counseling. This study highlights the underlying molecular cause of ichthyosis by determining the mutational spectrum in a cohort of 19 patients. This study is the first and largest research from Turkey using NGS that highlights all ichthyosis subtypes.

Quality of life and clinical characteristics of self-improving congenital ichthyosis within the disease spectrum of autosomal recessive congenital ichthyosis

BACKGROUND

Autosomal recessive congenital ichthyosis (ARCI) is a heterogeneous group of ichthyoses presenting at birth. Self-improving congenital ichthyosis (SICI) is a subtype of ARCI and is diagnosed when skin condition improves remarkably (within years) after birth. So far, there is sparse data on SICI and quality of life (QoL) in this ARCI subtype. This study aims to further delineate the clinical spectrum of SICI as a rather unique subtype of ARCI.

OBJECTIVES

This prospective study included 78 patients (median age: 15 years) with ARCI who were subdivided in SICI (n=18) and non-SICI patients (nSICI, n=60) by their ARCI phenotype.

METHODS

Quality of life (QoL) was assessed using the (Children's) Dermatology Life Quality Index. Statistical analysis was performed with Chi-square- and t-tests.

RESULTS

The genetically confirmed SICI patients presented causative mutations in the following genes: ALOXE3 (8/16; 50.0%), ALOX12B (6/16; 37.5%), PNPLA1 (1/16; 6.3%) and CYP4F22 (1/16; 6.3%). Hypo-/anhidrosis and insufficient Vitamin D levels (< 30 ng/ml) were often seen in SICI patients. Brachydactyly (a shortening of the 4^th and 5^th finger) was statistically more frequent in SICI (p=0.023) than nSICI patients. A kink of the ear's helix was seen in half of the SICI patients and tends to occur more frequently in patients with ALOX12B mutations (p=0.005). QoL was less impaired in patients under the age of 16, regardless of ARCI type.

CONCLUSIONS

SICI is an underestimated, milder clinical variant of ARCI including distinct features such as brachydactyly and kinking of the ears. Clinical experts should be aware of these features when seeing neonates with a collodion membrane. SICI patients should be regularly checked for clinical parameters such as hypo-/anhidrosis or vitamin D levels and monitored for changes in quality of life.

Vitamin D Status in Distinct Types of Ichthyosis: Importance of Genetic Type and Severity of Scaling

Data on vitamin D status of patients with inherited ichthyosis in Europe is scarce and unspecific concerning the genetic subtype. This study determined serum levels of 25-hydroxyvitamin D3 (25(OH)D3) in 87 patients with ichthyosis; 69 patients were additionally analysed for parathyroid hormone. Vitamin D deficiency was pronounced in keratinopathic ichthyosis (n = 17; median 25(OH)D3: 10.5 ng/ml), harlequin ichthyosis (n = 2;7.0 ng/ml) and rare syndromic subtypes (n = 3; 7.0 ng/ml). Vitamin D levels were reduced in TG1-proficient lamellar ichthyosis (n = 15; 8.9 ng/ml), TG1-deficient lamellar ichthyosis (n = 12; 11.7 ng/ml), congenital ichthyosiform erythroderma (n = 13; 12.4 ng/ml), Netherton syndrome (n = 7; 10.7 ng/ml) and X-linked ichthyosis (n = 8; 13.9 ng/ml). In ichthyosis vulgaris 25(OH)D3 levels were higher (n = 10; 19.7 ng/ml). Parathyroid hormone was elevated in 12 patients. Low 25(OH)D3 levels were associated with high severity of scaling (p = 0.03) implicating scaling as a risk factor for vitamin D deficiency. Thus, this study supports our recent guidelines for ichthyoses, which recommend screening for and substituting of vitamin D deficiency.

Alterations of Ultra Long-Chain Fatty Acids in Hereditary Skin Diseases-Review Article

The skin is a flexible organ that forms a barrier between the environment and the body's interior; it is involved in the immune response, in protection and regulation, and is a dynamic environment in which skin lipids play an important role in maintaining homeostasis. The different layers of the skin differ in both the composition and amount of lipids. The epidermis displays the best characteristics in this respect. The main lipids in this layer are cholesterol, fatty acids (FAs) and ceramides. FAs can occur in free form and as components of complex molecules. The most poorly characterized FAs are very long-chain fatty acids (VLCFAs) and ultra long-chain fatty acids (ULCFAs). VLCFAs and ULCFAs are among the main components of ceramides and are part of the free fatty acid (FFA) fraction. They are most abundant in the brain, liver, kidneys, and skin. VLCFAs and ULCFAs are responsible for the rigidity and impermeability of membranes, forming the mechanically and chemically strong outer layer of cell membranes. Any changes in the composition and length of the carbon chains of FAs result in a change in their melting point and therefore a change in membrane permeability. One of the factors causing a decrease in the amount of VLCFAs and ULCFAs is an improper diet. Another much more important factor is mutations in the genes which code proteins involved in the metabolism of VLCFAs and ULCFAs—regarding their elongation, their attachment to ceramides and their transformation. These mutations have their clinical consequences in the form of inborn errors in metabolism and neurodegenerative disorders, among others. Some of them are accompanied by skin symptoms such as ichthyosis and ichthyosiform erythroderma. In the following review, the structure of the skin is briefly characterized and the most important lipid components of the skin are presented. The focus is also on providing an overview of selected proteins involved in the metabolism of VLCFAs and ULCFAs in the skin.

High rate of self-improving phenotypes in children with non-syndromic congenital ichthyosis: case series from south-western Germany

BACKGROUND

Non-syndromic congenital ichthyosis describes a heterogeneous group of hereditary skin disorders associated with erythroderma and scaling at birth. Although both severe and mild courses are known, the prediction of the natural history in clinical practice may be challenging.

OBJECTIVES

To determine clinical course and genotype-phenotype correlations in children affected by non-syndromic congenital ichthyosis in a case series from south-western Germany.

METHODS

We performed a retrospective observational study of 32 children affected by non-syndromic congenital ichthyoses seen in our genodermatosis clinic between 2011 and 2020. Follow-ups included assessment of weight and severity of skin involvement utilizing a modified Ichthyosis Area Severity Index (mIASI). mIASI was calculated as a sum comprising the previously published IASI score and an additional novel score to evaluate palmoplantar involvement. Linear regression was assessed using Pearson correlation, and statistical analysis was performed using the Wilcoxon-Mann-Whitney test.

RESULTS

This study included 23 patients with autosomal recessive congenital ichthyosis, seven with keratinopathic ichthyosis and two with harlequin ichthyosis. Cutaneous manifestations improved in more than 70% of the children during the follow-up. Especially in patients with mutations in ALOXE3 and ALOX12B, mIASI scores dropped significantly. The most common phenotype observed in this study was designated 'mild fine scaling ichthyosis'. Severe palmoplantar involvement occurred in patients with KRT1 and ABCA12 mutations; most patients demonstrated hyperlinearity as a sign of dryness and scaling. Weight was mainly in the normal range and negatively correlated with the severity of skin involvement.

CONCLUSIONS

Congenital ichthyosis that self-improves and evolves with mild fine scaling ichthyosis was the most common phenotype observed in our patients. This type might be underdiagnosed if the genetic diagnosis is not performed in the first year of life. mIASI is an easy and fast instrument for scoring disease severity and adding additional points for palmoplantar involvement might be valuable.

Report of a Novel ALOX12B Mutation in Self-Improving Collodion Ichthyosis with an Overview of the Genetic Background of the Collodion Baby Phenotype

Collodion baby is a congenital, transient phenotype encountered in approximately 70–90% of autosomal recessive congenital ichthyosis and is an important entity of neonatal erythroderma. The clinical outcome after this severe condition is variable. Genetic mutations of components of the epidermal lipoxygenase pathway have been implicated in the majority of self-improving collodion ichthyosis (SICI). In SICI, the shedding of the collodion membrane reveals clear skin or only mild residual manifestation of ichthyosis. Here we report the case of a girl born with a severe form of collodion baby phenotype, whose skin almost completely cleared within the first month of life. At the age of 3 years, only mild symptoms of a keratinization disorder remained. However, the severity of erythema and scaling showed mild fluctuations over time. To objectively evaluate the skin changes of the patient, we assessed the ichthyosis severity index. Upon sequencing of the ALOX12B gene, we identified a previously unreported heterozygous nonsense mutation, c.1607G>A (p.Trp536Ter) with the recurrent, heterozygous mutation c.1562A>G (p.Tyr521Cys). Thereby, our findings expand the genotypic spectrum of SICI. In addition, we summarize the spectrum of further genetic diseases that can present at birth as collodion baby, in particular the SICI.

Ichthyoses-A Clinical and Pathological Spectrum from Heterogeneous Cornification Disorders to Inflammation

Ichthyoses are inborn keratinization disorders affecting the skin only (non-syndromic) or are associated with diseases of internal organs (syndromic). In newborns, they can be life-threatening. The identification of the gene defects resulted in reclassification and a better understanding of the pathophysiology. Histopathologic patterns include orthohyperkeratosis with a reduced or well-developed stratum granulosum, hyperkeratosis with ortho- and parakeratosis with preserved or prominent stratum granulosum, and epidermolytic ichthyosis. Another pattern features “perinuclear vacuoles and binucleated keratinocytes”, which is associated with keratin mutations. Some ichthyoses are histologically defined by psoriasis-like features, and distinct subtypes show follicular hyperkeratosis. In addition to histological and immunohistochemical methods, these patterns allow a better histopathologic diagnosis.