A novel pathogenic variant in the corneodesmosin gene causing generalized inflammatory peeling skin syndrome with marked eosinophilia and trichorrhexis invaginata.

Generalized inflammatory peeling skin syndrome (PSS) is a rare autosomal recessive genodermatosis caused by loss-of-function disease-causing variants of the corneodesmosin gene (CDSN), resulting in excessive shedding of the superficial layers of the epidermis. We describe a case of generalized inflammatory PSS in an infant, presenting at day two of life with ichthyosiform erythroderma and superficial peeling of the skin. Hair microscopy showed trichorrhexis invaginata. Normal amounts of skin LEKT1, a product of SPINK5 on immunohistochemical staining excluded a diagnosis of Netherton syndrome. Genetic analysis revealed a homozygous novel complete CDSN deletion, estimated 4.6 kb in size, supporting the diagnosis of generalized inflammatory PSS.

Deep Phenotyping of Superficial Epidermolytic Ichthyosis due to a Recurrent Mutation in KRT2.

Superficial epidermolytic ichthyosis (SEI) is an autosomal dominant inherited ichthyosis. SEI is caused by mutations in KRT2 and frequently shows erythroderma and widespread blistering at birth. We report the clinical manifestations of two patients from a Japanese family with SEI caused by a hotspot mutation, p.Glu487Lys, in KRT2. In addition, we summarize previous reports on SEI patients with the identical mutation. One of the two patients had disease onset at the age of 7 months. The other patient's age of onset is unknown, but it was in childhood. Neither of the two patients showed erythroderma. To perform deep phenotyping, we studied the age of onset and the frequency of erythroderma in 34 reported SEI cases with the p.Glu487Lys mutation, including the present cases. Among the cases with sufficient clinical information, 44.4% of the cases that were due to p.Glu487Lys in KRT2 occurred at birth. Erythroderma was observed in 11.1% of the cases with p.Glu487Lys in KRT2.

PLACK syndrome is potentially treatable with intralipids.

We describe an 11-year-old girl with PLACK Syndrome (peeling skin, leukonychia, acral punctate keratosis, cheilitis, and knuckle pads), who was found to have a novel homozygous variant in CAST, the pathogenicity of which was confirmed using blood-derived RNA. There is no established treatment for PLACK syndrome. However, we demonstrate for the first time that this condition is associated with low levels of vitamin A and essential fatty acids, which prompted us to consider a potential treatment strategy. Indeed, we initiated this patient on intravenous lipid infusion (Vitalipid®; an emulsion of fat-soluble vitamins and lipofundin-MCT/LCT 20%) and the response was dramatic. Following the fourth monthly course of treatment, pruritis disappeared and the skin lesions showed remarkable objective improvement. PLACK syndrome is a very rare genodermatosis and only six families have been described to date with pathogenic CAST variants. This is the first report of an objective response to a therapeutic agent, which suggests that PLACK is a potentially treatable condition. The remarkable response we report and the relative safety of the intervention should prompt healthcare providers who care for PLACK syndrome patients to explore this as a potential treatment strategy in future studies.

Phenotypic suppression of acral peeling skin syndrome in a patient with autosomal recessive congenital ichthyosis.

Autosomal recessive congenital ichthyosis (ARCI) manifests with generalized scaling often associated with generalized erythema. Mutations in at least 13 different genes have been reported to cause ARCI. Acral peeling skin syndrome (APSS) is a rare autosomal recessive disorder manifesting with peeling over the distal limbs and dorsal surfaces of hands and feet. APSS is mostly due to mutations in TGM5, encoding transglutaminase 5. Both ARCI and APSS are fully penetrant genetic traits. Here, we describe a consanguineous family in which one patient with mild ARCI was found to carry a homozygous mutation in ALOXE3 (c.1238G > A; p.Gly413Asp). The patient was also found to carry a known pathogenic homozygous mutation in TGM5 (c.1335G > C; p.Lys445Asn) but did not display acral peeling skin. Her uncle carried the same homozygous mutation in TGM5 but carried the ALOXE3 mutation in a heterozygous state and showed clinical features typical of APSS. Taken collectively, these observations suggested that the ALOXE3 mutation suppresses the clinical expression of the TGM5 variant. We hypothesized that ALOXE3 deficiency may affect the expression of a protein capable of compensating for the lack of TGM5 expression. Downregulation of ALOXE3 in primary human keratinocytes resulted in increased levels of corneodesmosin, which plays a critical role in the maintenance of cell-cell adhesion in the upper epidermal layers. Accordingly, ectopic corneodesmosin expression rescued the cell-cell adhesion defect caused by TGM5 deficiency in keratinocytes as ascertained by the dispase dissociation assay. The present data thus provide evidence for phenotypic suppression in a human hereditary skin disorder.

A case report of severe dermatitis, allergies, and metabolic wasting (SAM syndrome).

The presence of eczema and elevated IgE in pediatric patients does not always indicate atopic dermatitis. Rare genodermatoses may share this clinical presentation and should be considered in the differential diagnosis for patients with congenital immunodeficiency and severe refractory dermatitis. We describe a case of severe dermatitis, allergies, and metabolic wasting syndrome, due to a novel mutation in DSG1 gene, an additional example of this uncommon genetic disorder of desmosome function.

A novel homozygous nonsense mutation in CAST associated with PLACK syndrome.

Peeling skin syndrome is a heterogeneous group of rare disorders. Peeling skin, leukonychia, acral punctate keratoses, cheilitis and knuckle pads (PLACK syndrome, OMIM616295) is a newly described form of PSS with an autosomal recessive mode of inheritance. We report a 5.5-year-old boy with features of PLACK syndrome. Additionally, he had mild cerebral atrophy and mild muscle involvements. Whole exome sequencing was performed in genomic DNA of this individual and subsequent analysis revealed a homozygous c.544G > T (p.Glu182*) nonsense mutation in the CAST gene encoding calpastatin. Sanger sequencing confirmed this variant and demonstrated that his affected aunt was also homozygous. Real-time qRT-PCR and immunoblot analysis showed reduced calpastatin expression in skin fibroblasts derived from both affected individuals compared to heterozygous family members. In vitro calpastatin activity assays also showed decreased activity in affected individuals. This study further supports a key role for calpastatin in the tight regulation of proteolytic pathways within the skin.

P63-related disorders: Dermatological characteristics in 22 patients.

In P63-related ectodermal dysplasias (ED), the clinical characteristics focus on extra-cutaneous manifestations. The dermatological phenotype remains incompletely characterized. We report the dermatological features of 22 patients carrying a TP63 mutation. Erosions, erythroderma and pigmentary anomalies are characteristics of P63-related ED. Our data suggest that patients might be classified into two major P63-related disorders: AEC and EEC. RHS and ADULT represent mild AEC and EEC forms, respectively.

Novel DSP Spectrin 6 Region Variant Causes Neonatal Erythroderma, Failure to Thrive, Severe Herpes Simplex Infections and Brain Lesions.

Desmoplakin (DSP) and Desmoglein 1 (DSG1) variants result in skin barrier defects leading to erythroderma, palmoplantar keratoderma and variable [AQ4] other features. Some DSG1 variant carriers present with SAM syndrome (Severe dermatitis, multiple Allergies, Metabolic wasting) and a SAM-like phenotype has been reported in 4 subjects with different heterozygous DSP variants. We report here a patient with a novel DSP spectrin region (SR) 6 variant c.1756C>T, p.(His586Tyr), novel features of brain lesions and severe recurrent mucocutaneous herpes simplex virus infections, with a favourable response to ustekinumab. Through a review of reported cases of heterozygous variants in DSP SR6 (n = 15) and homozygous or compound heterozygous variants in DSG1 (n = 12) and SAM-like phenotype, we highlight phenotypic variability. Woolly hair, nail abnormalities and cardiomyopathy characterize patients with DSP variants, while elevated immunoglobulin E and food allergies are frequent in patients with DSG1 variants. Clinicians should be aware of the diverse manifestations of desmosomopathies.

The spectrum of manifestations in desmoplakin gene (DSP) spectrin repeat 6 domain mutations: Immunophenotyping and response to ustekinumab.

BACKGROUND: The immune abnormalities underlying the ichthyoses are poorly understood. OBJECTIVE: To determine the immunophenotype of an ichthyosis resulting from mutations in the spectrin repeat 6 (SR6) domain of desmoplakin gene (DSP) and target therapy on the basis of molecular pathogenesis. METHODS: Immunophenotyping was performed by using the blood and skin of a girl with SR6 region DSP mutations causing erythroderma/ichthyosis and cardiomyopathy. RESULTS: On the basis of the discovery of T helper 1 and T helper 17/interleukin 23 skewing in the skin and T helper 17/interleukin 22 skewing in blood, ustekinumab therapy was initiated. Ustekinumab was also administered to a boy with an SR6 region DSP mutation and ichthyosis without cardiomyopathy. Both children responded despite previous poor responses to immunosuppressants and retinoids. LIMITATIONS: Small number of patients and immunophenotyping in only 1 patient. CONCLUSION: An understanding of the molecular basis of inflammation in rare cutaneous disorders can lead to targeted therapy, which promises to be more beneficial than broad immunosuppressants.

[Role of intercellular slit-like contacts (connexins) in the pathogenesis of erythroderma]. / Rol' mezhkletochnykh shchelevidnykh kontaktov (konneksinov) v patogeneze éritrodermii.

Erythroderma is a skin lesion characterized by redness, swelling, infiltration, and desquamation of greater than 90% of the skin. The etiology of erythroderma is not completely clear and the lesion can be manifestations of various chronic dermatoses, including atopic dermatitis, psoriasis, eczema, and toxicodermia, and be represented by erythrodermic mycosis fungoides. The pathogenesis of erythroderma especially at the genetic level remains little studied. Thus, one disease (erythroderma) can be a manifestation of different dermatoses and have similar clinical and histological signs. This paper gives a review of modern literature on the study of erythroderma in terms of morphology and genetic aspects.

The glycan-specific sulfotransferase (R77W)GalNAc-4-ST1 putatively responsible for peeling skin syndrome has normal properties consistent with a simple sequence polymorphisim.

Expanded access to DNA sequencing now fosters ready detection of site-specific human genome alterations whose actual significance requires in-depth functional study to rule in or out disease-causing mutations. This is a particular concern for genomic sequence differences in glycosyltransferases, whose implications are often difficult to assess. A recent whole-exome sequencing study identifies (c.229 C > T) in the GalNAc-4-ST1 glycosyltransferase (CHST8) as a disease-causing missense R77W mutation yielding the genodermatosis peeling skin syndrome (PSS) when homozygous. Cabral et al. (Genomics. 2012;99:202-208) cite this sequence change as reducing keratinocyte GalNAc-4-ST1 activity, thus decreasing glycosaminoglycan sulfation, as the mechanism for this blistering disorder. Such an identification could point toward potential clinical and/or prenatal diagnosis of a harmful medical condition. However, GalNAc-4-ST1 has minimal activity toward glycosaminoglycans, instead modifying terminal ß1,4-linked GalNAc on N- and O-linked oligosaccharides on specific glycoproteins. We find expression, processing and catalytic activity of GalNAc-4-ST1 completely equivalent between wild type and (R77W) sulfotransferases. Moreover, keratinocytes have little or no GalNAc-4-ST1 mRNA, indicating that they do not express GalNAc-4-ST1. In addition, loss-of-function of GalNAc-4-ST1 primarily presents as reproductive system aberrations rather than skin effects. These findings, an allele frequency of 0.004357, and a 10-fold difference in prevalence of CHST8 (c.299 C > T, R77W) across different ethnic groups, suggest that this sequence represents a "passenger" distributed polymorphism, a simple sequence variant form of the enzyme having normal activity, rather than a "driver" disease-causing mutation that accounts for PSS. This study presents an example for guiding biomedical research initiatives, as well as medical and personal/family perspectives, regarding newly-identified genomic sequence differences.

Peeling skin syndrome associated with novel variant in FLG2 gene.

Peeling skin syndrome is a rare genodermatosis characterized by variably pruritic superficial generalized peeling of the skin with several genes involved until now little is known about the association between FLG2 and peeling skin syndrome. We describe multiple family members from a consanguineous Saudi family with peeling skin syndrome. Next Generation Sequencing identifies a cosegregating novel variant in FLG2 c.632C>G (p.Ser211*) as a likely etiology in this family. Here, we reported on the clinical manifestation of homozygous loss of function variant in FLG2 as a disease-causing gene for peeling skin syndrome and expand the dermatology findings.

Omenn Syndrome Presenting with Striking Erythroderma and Extreme Lymphocytosis in a Newborn.

Omenn syndrome is an autosomal recessive form of "leaky" severe combined immune deficiency resulting in distinct phenotypic features. The patient described herein had an atypical presentation of Omenn syndrome, with conspicuous erythroderma and extreme lymphocytosis at birth, in contrast to the typical evolution of rash seen during the first few weeks of life. In addition, the skin findings were secondary to infiltration of CD8+ (cytotoxic) T-cells in contrast to the CD4+ (helper) T-cells typically seen, which broadens the Omenn syndrome phenotype.

Alu-mediated large deletion of the CDSN gene as a cause of peeling skin disease.

Peeling skin disease (PSD) is an autosomal recessive skin disorder caused by mutations in CDSN and is characterized by superficial peeling of the upper epidermis. Corneodesmosin (CDSN) is a major component of corneodesmosomes that plays an important role in maintaining epidermis integrity. Herein, we report a patient with PSD caused by a novel homozygous large deletion in the 6p21.3 region encompassing the CDSN gene, which abrogates CDSN expression. Several genes including C6orf15, PSORS1C1, PSORS1C2, CCHCR1, and TCF19 were also deleted, however, the patient showed only clinical features typical of PSD. The deletion size was 59.1 kb. Analysis of the sequence surrounding the breakpoint showed that both telomeric and centromeric breakpoints existed within Alu-S sequences that were oriented in opposite directions. These results suggest an Alu-mediated recombination event as the mechanism underlying the deletion in our patient.

Inflammatory peeling skin syndrome caused by homozygous genomic deletion in the PSORS1 region encompassing the CDSN gene.

Peeling skin syndrome (PSS) type B is a rare recessive genodermatosis characterized by lifelong widespread, reddish peeling of the skin with pruritus. The disease is caused by small-scale mutations in the Corneodesmosin gene (CDSN) leading to premature termination codons. We report for the first time a Japanese case resulting from complete deletion of CDSN. Corneodesmosin was undetectable in the epidermis, and CDSN was unamplifiable by PCR. QMPSF analysis demonstrated deletion of CDSN exons inherited from each parent. Deletion mapping using microsatellite haplotyping, CGH array and PCR analysis established that the genomic deletion spanned 49-72 kb between HCG22 and TCF19, removing CDSN as well as five other genes within the psoriasis susceptibility region 1 (PSORS1) on 6p21.33. This observation widens the spectrum of molecular defects underlying PSS type B and shows that loss of these five genes from the PSORS1 region does not result in an additional cutaneous phenotype.