Lamellar Ichthyosis Research Articles

ABCA12 mutations and autosomal recessive congenital ichthyosis: A review of genotype/phenotype correlations and of pathogenetic conceptsa

Mutations in ABCA12 have been described in autosomal recessive congenital ichthyoses (ARCI) including harlequin ichthyosis (HI), congenital ichthyosiform erythroderma (CIE), and lamellar ichthyosis (LI). HI shows the most severe phenotype. CIE and LI are clinically characterized by fine, whitish scales on a background of erythematous skin, and large, thick, dark scales over the entire body without serious background erythroderma, respectively. To date, a total of 56 ABCA12 mutations have been reported in 66 ARCI families including 48 HI, 10 LI, and 8 CIE families of African, European, Pakistani/Indian, and Japanese origin (online database: http://www.derm-hokudai.jp/ABCA12/). A total of 62.5% of reported ABCA12 mutations are expected to lead to truncated proteins. Most mutations in HI are truncation mutations and homozygous or compound heterozygous truncation mutations always results in HI phenotype. In CIE families, at least one mutation on each allele is typically a missense mutation. Combinations of missense mutations in the first ATP-binding cassette of ABCA12 underlie the LI phenotype. ABCA12 is a keratinocyte lipid transporter associated with lipid transport in lamellar granules, and loss of ABCA12 function leads to a defective lipid barrier in the stratum corneum, resulting in an ichthyotic phenotype. Recent work using mouse models confirmed ABCA12 roles in skin barrier formation.

Phenotype, genotype and ultrastructural findings in a pedigree with autosomal recessive congenital ichthyosis

Objective To investigate the clinical phenotype, genotype and ultrastructural features in a pedigree with autosomal recessive congenital ichthyosis. Methods Patients were examined for clinical manifestation. PCR was carried out to amplify all the 15 exons and adjacent splice sites of TGM1 gene followed by bidirectional sequencing. Skin samples were taken by biopsy from the back of the proband, fixed in 3% glu-taraldehyde for transmission electron microscopy. Results The proband presented an intermediate clinical phenotype between lamellar ichthyosis (LI) and non-bullous congenital ichthyosiform erythroderma (NCIE), while his brother manifested as a collodion baby. A C551T heterozygous mutation which located in the third exon of TGM1 gene and resulted in a substitution of arginine by cysteine at codon 143 (R143C), was detected in the proband, his brother and father. Meanwhile, another heterozygous C-to-T transition at position 759 causing a substitution of serine by phenylalanine at codon 212 (S212F), was noted in the proband, his brother and mother. Electron microscopy revealed not only features of ichthyosis congenital type Ⅲ but also those of ichthyosis congenital type Ⅱ in lesions of the proband. Conclusions The patients in this pedigree carry compound heterozygous mutations, i.e. R143C, a hot missense mutation, as well as a de novo mutation S212F. The proband, who harbors mutations in the TGM1 gene, shows electron microscopic features characteristic not only of ichthyosis congenital type Ⅱ but also of ichthyosis congenital type Ⅲ. Key words: Ichthyosis; Chromosome disorders; Phenotype; Genotype; Microscopy, electron

Revised nomenclature and classification of inherited ichthyoses: Results of the First Ichthyosis Consensus Conference in Sorèze 2009

Inherited ichthyoses belong to a large, clinically and etiologically heterogeneous group of mendelian disorders of cornification, typically involving the entire integument. Over the recent years, much progress has been made defining their molecular causes. However, there is no internationally accepted classification and terminology. We sought to establish a consensus for the nomenclature and classification of inherited ichthyoses. The classification project started at the First World Conference on Ichthyosis in 2007. A large international network of expert clinicians, skin pathologists, and geneticists entertained an interactive dialogue over 2 years, eventually leading to the First Ichthyosis Consensus Conference held in Sorèze, France, on January 23 and 24, 2009, where subcommittees on different issues proposed terminology that was debated until consensus was reached. It was agreed that currently the nosology should remain clinically based. "Syndromic" versus "nonsyndromic" forms provide a useful major subdivision. Several clinical terms and controversial disease names have been redefined: eg, the group caused by keratin mutations is referred to by the umbrella term, "keratinopathic ichthyosis"-under which are included epidermolytic ichthyosis, superficial epidermolytic ichthyosis, and ichthyosis Curth-Macklin. "Autosomal recessive congenital ichthyosis" is proposed as an umbrella term for the harlequin ichthyosis, lamellar ichthyosis, and the congenital ichthyosiform erythroderma group. As more becomes known about these diseases in the future, modifications will be needed. We have achieved an international consensus for the classification of inherited ichthyosis that should be useful for all clinicians and can serve as reference point for future research.

Bathing suit ichthyosis

Bathing suit ichthyosis (BSI) is a rare variant of autosomal recessive lamellar ichthyosis due to transglutaminase-1 (TGase-1) gene mutations leading to a temperature sensitive phenotype. It is characterized by dark-grey or brownish scaling restricted to the 'bathing suit' areas, whereas the extremities and central face are almost completely spared. We report a 2-year-old African girl with BSI with ultrastructural and biochemical demonstration of TGase-1 deficiency over the affected skin. TGase-1 gene analysis disclosed the homozygous p.R315L mutation, which may lead to a temperature sensitive dysfunction of the enzyme.

Quality of life in Swedish children with congenital ichthyosis

Congenital ichthyosis encompasses a large group of keratinizing disorders with widespread scaling and a variable degree of erythema. Little is known about the quality of life in children with congenital ichthyosis and the impact of the disease on their family. Fifteen children aged 5–16 years with lamellar ichthyosis, Netherton’s syndrome, epidermolytic hyperkeratosis or Harlequin ichthyosis, were investigated concerning the effect of their ichthyosis on their quality of life. This was measured with the established Children’s Dermatology Life Quality Index (CDLQI), and the Dermatitis Family Impact questionnaire (DFI) modified by substituting the word ichthyosis for eczema. The questionnaires covered the preceding seven days and each had a maximum score of 30: the higher the score, the greater the Quality of Life impairment. The median score was 9.0 (range 2–19) for the CDLQI and 9.0 (range 3–21) for DFI. There was a significant correlation between the DFI and the CDLQI scores. The item in the CDLQI questionnaire that showed the highest score was “itchy, scratchy, sore or painful skin” and the most highly scored item in the DFI questionnaire was effect on “housework, e.g. washing, cleaning”; both items related to the children’s symptoms. The results of the study clearly establish that congenital ichthyosis impairs the quality of life of the affected children and their families.

Interleukin-1 alpha blockade prevents hyperkeratosis in an in vitro model of lamellar ichthyosis

The autosomal recessive congenital ichthyoses are a family of related diseases, causing a severe defect in the barrier function of the epidermis. Neonates are usually born as collodion babies, but later form scales characteristic of the disease, due to a combination of thickening of the cornified layer and an increase in the production of non-polar lipids. Current treatments of choice are exfoliative creams and moisturizing agents and the use of oral retinoids. The skin condition and treatment impact significantly on quality of life and, with oral retinoids, there are potential complications associated with long-term use. A greater understanding of the mechanisms that result in scaling should lead to better directed therapies, not only for the inherited ichthyoses, but also other hyperkeratotic disorders. Using siRNA knockdown of the principle gene mutated in lamellar ichthyosis (LI), transglutaminase-1, in rat keratinocytes, we created an in vitro organotypic culture model that closely mimics the disease. Interleukin-1 alpha (IL1A) expression was increased and there was a lack of loricrin cross-linking. All LI patients tested had an increased IL1A and treatment of wild-type organotypic cultures with IL1A was sufficient to induce hyperkeratosis. Treatment of disease mimic organotypic cultures with IL-1 receptor antagonist led to a dose-dependent decrease in hyperkeratosis without a reduction in non-polar lipids in the cornified layer, which has the potential to reduce scaling without the requirement to constantly apply emollients.

Transglutaminase1 Preferred Substrate Peptide K5 Is an Efficient Tool in Diagnosis of Lamellar Ichthyosis

Lamellar ichthyosis (LI) is a genetically heterogeneous, severe genodermatosis showing widespread hyperkeratosis of the skin. Transglutaminase 1 (TGase1) deficiency by TGase1 gene (TGM1) mutations is the most prevalent cause of LI. Screening of TGase1 deficiency in skin is essential to facilitate the molecular diagnosis of LI. However, cadaverine, the most widely used substrate for TGase activity assay, is not isozyme specific. Recently, a human TGase1-specific highly preferred substrate peptide K5 (pepK5) was generated. To evaluate its potential as a diagnostic tool for LI, we performed pepK5 labeling of TGase1 activity in normal human and LI skin. Ca(2+)-dependent labeling of FITC-pepK5 was clearly seen in the upper spinous and granular layers of normal human skin where it precisely overlapped with TGase1 immunostaining. Both specificity and sensitivity of FITC-pepK5 labeling for TGase1 activity were higher than those of FITC-cadaverine labeling. FITC-pepK5 labeling colocalized with involucrin and loricrin immunostaining at cornified cell envelope forming sites. FITC-pepK5 labeling was negative in LI patients carrying TGM1 truncation mutations and partially abolished in the other LI patients harboring missense mutations. The present results clearly indicate that pepK5 is a powerful tool for screening LI patient TGase1 deficiency when we make molecular diagnosis of LI.

Two cases of collodion baby treated with acitretin

Objective To evaluate the therapeutic efficacy, side effects, influences on infantile growth and development, and safety of acitretin in the treatment of collodion baby.Metbods Two cases of collodion baby were treated with acitretin of 0.8 mg/kg per day. Patients were followed up monthly for 9 to 10 months. Body weight and height were monitored to evaluate the influence of acitretin on infantile growth and development. Results Both the two collodion babies experienced a nearly complete subsidence of lesions after treatment with acitretin for 2 to 5 weeks. Neither severe side effect nor influence on infantile growth and development was observed during the follow-up. Conclusion Acitretin is an effective treatment option for collodion baby. Key words: Infant; Collodion; Acitretin; Therapy

Surgical approach of ectropion in lamellar ichthyosis

Surgical approach of ectropion in lamellar ichthyosis

Genotypic and Clinical Spectrum of Self-Improving Collodion Ichthyosis: ALOX12B, ALOXE3, and TGM1 Mutations in Scandinavian Patients

Infants born with autosomal recessive congenital ichthyosis (ARCI) are often encapsulated in a collodion membrane, which shows a lamellar or erythrodermic type of ichthyosis upon shedding. However, some babies show a nearly normal underlying skin after several weeks, a phenotype called "self-healing collodion baby" (SHCB). Mutations in two genes, TGM1 and ALOX12B, have previously been implicated in the etiology of SHCB, but the full genotypic spectrum remains to be determined. DNA sequencing in 11 Swedish and 4 Danish SHCB patients showed ALOX12B mutations in eight cases, ALOXE3 mutations in three cases, and TGM1 mutations in one case. In three patients, we could not find mutations in any of the known ARCI genes. In all cases, a spontaneous shedding of the collodion membrane occurred 2-4 weeks after birth. When re-examined at 2-37 years of age, the patients showed skin xerosis, a mild or focal scaling, palmar hyperlinearity with keratoderma, and a frequent appearance of red cheeks and anhidrosis. Thus, we propose replacing SHCB with the term "self-improving collodion ichthyosis" (SICI). In conclusion, ALOX12B mutations are the leading cause of SICI in Scandinavia, followed by ALOXE3 mutations, which have not been previously associated with this variant of ARCI.

Genital Squamous Cell Carcinoma in a Congenital Ichthyosis

It is well known that patients with heritable cutaneous disease have an increased risk of developing tumors during their lifetime. This relationship has been proven for conditions such as xeroderma pigmentosum, Basal cell nevus syndrome, and Blooms syndrome. Multiple cutaneous tumors with Lamellar Ichthyosis had been reported in people with sun exposed skin. This article describes a case of genital squamous cell carcinoma in a patient with Lamellar Ichthyosis, which in our knowledge, described for the first time. During the long standing follow-up of patients with Lamellar Ichthyosis, careful attention should be paid to the occurrence of skin cancers in both, sun exposed and sun protected skin.

Pleomorphic Ichthyosis: Proposed Name for a Heterogeneous Group of Congenital Ichthyoses with Phenotypic Shifting and Mild Residual Scaling

Congenital ichthyosis is often associated with typical neonatal phenotypes, "Collodion baby" and "Harlequin foetus", later transforming into severe lamellar or erythrodermic ichthyosis. However, in a minority of cases the skin condition will improve spontaneously after birth, although slight scaling, xerosis, hypohidrosis and keratoderma usually persist. Some of these patients will eventually be diagnosed as suffering from self-improving collodion ichthyosis, ichthyosis prematurity syndrome, or other, even rarer, forms of ichthyosis also characterized by a phenotypic shift in early childhood. This paper summarizes newly described aetiologies for some of these diseases and discusses difficulties encountered when trying to distinguish them clinically from other types of autosomal recessive congenital ichthyosis. To remind health providers about this heterogeneous group of partially transient disorders of cornification, a new umbrella term, "pleomorphic ichthyosis", is proposed.

Case report: Prolonged collodion membrane causing constrictive bands of the digits and treatment

Collodion babies present unique diagnostic and management challenges. We describe a 2-month-old female with lamellar ichthyosis and prolonged collodion membrane with two constrictive bands of the fingers causing significant erythema, edema, and pain. We suggest prompt release of these constrictive bands with an 11-blade and closely follow up of collodion babies until their membrane has fully desquamated.

NIPAL4/Ichthyin Is Expressed in the Granular Layer of Human Epidermis and Mutated in Two Pakistani Families with Autosomal Recessive Ichthyosis

Background: Autosomal recessive congenital ichthyosis (ARCI) can be divided into 3 types including lamellar ichthyosis (OMIM 242304), nonbullous congenital ichthyosiform erythroderma (OMIM 242100) and harlequin ichthyosis (OMIM 242500). The last type is uncommon since newborns with harlequin ichthyosis usually die shortly after birth. Several genes have been linked to ARCI, but these represent only 60% of the known genetic causes of this condition. Methods: After having performed a linkage analysis, we analyzed the DNA of 2 consanguineous Pakistani families with ARCI for NIPAL4 mutations and performed in situ hybridization (ISH) for NIPAL4 mRNA in the epidermis. Results: The haplotype analysis revealed a linkage to chromosome 5, and we identified a recurrent missense mutation, p.A176D, in affected individuals from both families. We also determined by ISH that NIPAL4 mRNA is highly expressed in the granular cell layer of the epidermis, consistent with the ARCI phenotype. Conclusion: Our results expand the spectrum of the clinical manifestations of the NIPAL4 gene and further extend our understanding of its molecular function.

Ichthyosis

Ichthyoses constitute a large group of cornification disorders that affect the entire integument. The skin is characterized by visible scaling and in many cases by inflammation, for example, in bullous/keratinopathic ichthyosis or Netherton syndrome. From the viewpoint of classification it is useful to distinguish non-syndromic from syndromic types of ichthyosis. Ichthyosis vulgaris and recessive X-linked ichthyosis are common disorders - often of delayed onset, in contrast to congenital ichthyoses, which belong to the group of rare diseases and present at birth with either the features of collodion membrane or congenital ichthyosiform erythroderma. The diagnostic steps are based on clinical data, analyses such as the steroid sulfatase activity test, skin biopsies, and genetic results. However, the dramatic increase in knowledge about the pathophysiology of these conditions has not led to a curative therapy so far. The therapeutic management is multidisciplinary and involves ichthyosis patient organizations in many countries. The mainstay of treatment remains with moisturizing creams containing, for example, urea, lactic acid and other humectants and keratolytics, regular bathing, and mechanical scale removal. Patients with lamellar ichthyosis or ichthyosiform erythroderma in particular profit from oral therapy with retinoids or retinoic acid metabolism-blocking agents.

LC–MS/MS analysis of epoxyalcohols and epoxides of arachidonic acid and their oxygenation by recombinant CYP4F8 and CYP4F22

CYP4F22 and CYP4F8 are expressed in epidermis, and mutations of CYP4F22 are associated with lamellar ichthyosis. Epoxyalcohols (HEETs) and epoxides (EETs) of 20:4 n−6 appear to be important for the water permeability barrier of skin. Our aim was to study the MS/MS spectra and fragmentation of these compounds and to determine whether they were oxidized by CYP4F22 or CYP4F8 expressed in yeast. HEETs were prepared from 15-hydroperoxyeicosatetraenoic acid (15-HPETE), 12-HPETE, and their [ 2H 8]labeled isotopomers, and separated by normal phase-HPLC with MS/MS analysis. CYP4F22 oxygenated 20:4 n−6 at C-18, whereas metabolites of HEETs could not be identified. CYP4F8 formed ω3 hydroxy metabolites of HEETs derived from 12 R-HPETE with 11,12-epoxy-10-hydroxy configuration, but not HEETs derived from 15 S-HPETE. 8,9-EET and 11,12-EET were also subject to ω3 hydroxylation by CYP4F8. We conclude that CYP4F8 and CYP4F22 oxidize 20:4 n−6 and that CYP4F8 selectively oxidizes 8,9-EET, 11,12-EET, and 10,11 R,12 R-HEET at the ω3 position.

Spontaneous corneal perforation in a patient with lamellar ichthyosis and dry eye

We report spontaneous corneal perforation in a patient with lamellar ichthyosis. The patient presented with complaints of pain, redness, diminished vision, and discharge in her right eye for 15 days. Visual acuities were light perception in the right and 20/400 in the left eye. Cicatricial ectropion in both lower eyelids and 2 mm perforation site in the center of the right cornea were observed. Lamellar ichthyosis was suspected because of scaling and excessive dryness of entire body skin and was confirmed by skin biopsy. Amniotic membrane transplantation and transient tarsorraphy was performed and systemic anti-ichthyosis therapy was started. The follow-up visits were not possible because of patient inconsistency. In patients with cicatricial ectropion secondary to ichthyosis, corneal health should be closely monitored because of the perforation risk.

Sjogren-Larsson Syndrome

Sjogren-Larsson syndrome (SLS) is characterized by the triad of ichthyosis, mental retardation, and spastic diplegia or quadriplegia. The hallmark of SLS is ichthyosis. We report a case and review the major differential diagnosis of SLS. A 21-year-old woman presented with seizures, mental retardation, spastic diplegia, and ichthyosis since birth. Computed tomography scan revealed hypodense areas in the periventricular white matter. Skin biopsy demonstrated a lamellar ichthyosis. These findings were compatible with SLS. When ichthyosis is associated with spasticity and mental retardation, one should consider SLS. If hypogonadism, ataxia, retinitis, cardiomyopathy, or dwarfism is present, other diagnosis rather than SLS should be investigated.

Genotype-phenotype correlations with TGM1 : clustering of mutations in the bathing suit ichthyosis and self-healing collodion baby variants of lamellar ichthyosis

Genotype-phenotype correlations with <i>TGM1</i> : clustering of mutations in the bathing suit ichthyosis and self-healing collodion baby variants of lamellar ichthyosis

Lamellar ichthyosis with a novel homozygous C‐terminal mutation in the transglutaminase‐1 gene

The majority of cases of Lamellar ichthyosis (LI) are caused by mutations in the transglutaminase-1 (TGM1) gene. The mutations in the beta-barrel domains of the TGM1 gene are found very infrequently and several authors have suggested that these domains are not essential for the function of the enzyme. Other authors have postulated that mutations in these loci are pathogenic but they imply a less severe clinical picture of LI. We report a patient with a severe phenotype of LI who had a homozygous mutation affecting the beta-barrel 2 domain of the TGM1. This finding indicates that the integrity of beta-barrel domains is important for the correct function of the enzyme and that we are still far away from a consistent genotype-phenotype correlation.