Kazumitsu Sugiura

Autoinflammatory keratinization diseases

Among the genetic causes/predisposing factors for inflammatory keratinization disorders, several factors are associated with autoinflammatory mechanisms. Here we review these inflammatory keratinization disorders with autoinflammatory pathogenic mechanisms and advocate the novel and unique concept of autoinflammatory keratinization diseases (AIKDs). We propose the following definition of AIKD. First, the primary and main inflammation sites are the epidermis and the upper dermis. Second, inflammation in the epidermis and upper dermis leads to hyperkeratosis, which is the main and characteristic phenotype of AIKDs. Third, AIKDs have primary genetic causative factors associated with the hyperactivation of innate immunity (autoinflammation), mainly in the epidermis and upper dermis. Finally, the concept of AIKDs encompasses diseases with mixed pathomechanisms of autoinflammation and autoimmunity. AIKDs have genetic abnormalities as causative factors, and hyperactivation of the innate immune system resulting from those genetic defects plays an important role in the pathogenesis. Recently, a number of CARD14 gain-of-function variants/mutations have been reported as predisposing factors for psoriasis vulgaris (plaque-type psoriasis) and psoriatic arthritis. Jordan et al found a rare de novo gain-of-function variant in CARD14, p.Glu138Ala, in a sporadic case of severe early-onset generalized pustular psoriasis (GPP). Sugiura et al reported a rare variant in CARD14, p.Asp176His, to be a significant predisposing factor for GPP with preceding or concurrent psoriasis vulgaris lesions, and this variant underlies approximately 20% of patients with GPP with psoriasis vulgaris in the Japanese population. CARD14 variants are also disease susceptibility factors for European palmoplantar pustular psoriasis (palmoplantar pustulosis). Caspase recruitment domain-containing protein 14 (CARD14) encoded by CARD14 is expressed and localized mainly in the skin, especially in keratinocytes. Psoriasis-causative CARD14 mutations enhance nuclear factor kB activation and upregulate

Biallelic Mutations in KDSR Disrupt Ceramide Synthesis and Result in a Spectrum of Keratinization Disorders Associated with Thrombocytopenia.

Mutations in ceramide biosynthesis pathways have been implicated in a few Mendelian disorders of keratinization, although ceramides are known to have key roles in several biological processes in skin and other tissues. Using whole-exome sequencing in four probands with undiagnosed skin hyperkeratosis/ichthyosis, we identified compound heterozygosity for mutations in KDSR, encoding an enzyme in the de novo synthesis pathway of ceramides. Two individuals had hyperkeratosis confined to palms, soles, and anogenital skin, whereas the other two had more severe, generalized harlequin ichthyosis-like skin. Thrombocytopenia was present in all patients. The mutations in KDSR were associated with reduced ceramide levels in skin and impaired platelet function. KDSR enzymatic activity was variably reduced in all patients, resulting in defective acylceramide synthesis. Mutations in KDSR have recently been reported in inherited recessive forms of progressive symmetric erythrokeratoderma, but our study shows that biallelic mutations in KDSR are implicated in an extended spectrum of disorders of keratinization in which thrombocytopenia is also part of the phenotype. Mutations in KDSR cause defective ceramide biosynthesis, underscoring the importance of ceramide and sphingosine synthesis pathways in skin and platelet biology.

Autosomal dominant familial generalized pustular psoriasis caused by a CARD14 mutation

DEAR EDITOR, In 2012, gain-of-function mutations in CARD14, which encodes caspase recruitment domain family member 14, were identified as the cause of familial psoriasis vulgaris (PV) and familial pityriasis rubra pilaris (PRP). We and another group reported that CARD14 variants are associated with generalized pustular psoriasis (GPP) and palmoplantar pustular psoriasis. Other reports mentioned CARD14 mutations in individuals with GPP and erythrodermic PRP. Very recently, we described PRP type V as an autoinflammatory disease caused by CARD14 mutations. To date, two individuals with GPP caused by heterozygous CARD14 mutations have been reported. One patient was a member of a familial psoriasis pedigree, but no other member was affected by GPP. The other patient was a sporadic case caused by a de novo CARD14 mutation. Thus far, there have been no reports of familial GPP caused by a CARD14 mutation. Here we describe an autosomal dominant pedigree of GPP (among three generations) associated with CARD14 mutations. Our findings expand the phenotypic spectrum in CARD14-related autoinflammatory keratinization diseases. The proband was a 30-year-old woman (individual III-2, Fig. 1d) with a history of GPP from 6 months of age. She

Deficient stratum corneum intercellular lipid in a Japanese patient with lamellar ichthyosis by a homozygous deletion mutation in SDR9C7

Autosomal recessive congenital ichthyosis (ARCI) is an umbrella term for inherited non-syndromic ichthyosis, which includes harlequin ichthyosis, lamellar ichthyosis (LI), congenital ichthyosiform erythroderma and pleomorphic ichthyosis (also called self-healing/self-improving collodion baby).1 The clinical diversity is matched by genetic heterogeneity, with 11 genes currently implicated in the pathobiology of ARCI,2,3 including the most recent discovery of two missense mutations in SDR9C7 in three consanguineous Lebanese families.4 Here, we describe a case of ARCI (LI phenotype) that has a previously unreported homozygous deletion mutation in SDR9C7. We extend the spectrum of clinical features associated with SDR9C7 mutations, and identify deficient intercellular lipid and malformation of intercellular lipid layers in the stratum corneum. This article is protected by copyright. All rights reserved.

Granulocyte and monocyte apheresis can control juvenile generalized pustular psoriasis with mutation of IL36RN

Patients with deficiency of interleukin‐36 receptor antagonist (DITRA), due to mutation of IL36RN, exhibit psoriatic phenotypes, typically generalized pustular psoriasis (GPP). We report a paediatric patient with DITRA, whose cutaneous lesions varied from psoriasis vulgaris in infancy to annular pustular psoriasis with acute exacerbation to GPP at 13 years of age. Conventional systemic treatments for GPP, which include oral retinoids, ciclosporin and methotrexate, are controversial in paediatric cases, because of their adverse effects and uncertain long‐term consequences. Granulocyte monocyte apheresis, a process associated with few adverse events, promptly controlled the GPP of our paediatric patient, and has potential as a suitable alternative treatment for paediatric patients with DITRA.

A novel IFIH1 mutation in the pincer domain underlies the clinical features of both Aicardi-Goutières and Singleton-Merten syndromes in a single patient

DEAR EDITOR, Gain-of-function mutations in IFIH1 encoding interferon-induced helicase C domain-containing protein 1 were identified in a spectrum of human disease phenotypes including the overlap between Aicardi–Gouti eres syndrome (AGS) and Singleton–Merten syndrome (SMS). Here we describe a case with a novel IFIH1 missense mutation in the pincer domain. Our patient, a Japanese girl, first seen at 7 years of age, is the younger of two siblings born to nonrelated parents with no family history of any similar disorder. At the age of 6 months, she was noticed as having dry skin with mild erythema. She demonstrated erythematous cheeks and ichthyosis on the extremities (Fig. 1a). Since then, she has shown the following clinical features: low height (SD –2 8) and low weight (SD –1 7), osteopenia (Fig. 1d), poor dentition (Fig. 1e), myopia of the right eye and amblyopia of the left eye, and bilateral calcification of the deep frontal lobes and the globus pallidi on computed tomography (Fig. 1f). She has moderate motor and mental retardation. She can walk with another person’s assistance or by using a handrail. At the age of 8 years, she was able to run 30 metres. She can feed herself by using dentures. She can almost use the toilet by herself. She is not always spastic, but she does have a febrile seizure every year. She showed low IgA and IgM, and high IgE and IgG levels. Her ichthyotic skin was improved by bathing with baking soda. Following ethical approval, informed written consent was obtained in compliance with the Declaration of Helsinki guidelines. Whole-exome capture was performed (peripheral blood genomic DNA from the patient and both parents) by in-solution hybridization using SureSelect All Exon 50 Mb Version 5 0 (Agilent, Santa Clara, CA, U.S.A.) followed by massively parallel sequencing (HiSeq2500; Illumina, San Diego, CA, U.S.A.) with 150-bp paired-end reads. In total, 24 717 single-nucleotide substitutions were identified in this patient: 10 031 homozygous and 14 686 heterozygous. After filtering, 14 previously unreported heterozygous variants were found de novo. Within these variants, a nonsynonymous heterozygous mutation was identified in IFIH1 (c.2561T>A; p.Met854Lys), which was confirmed by Sanger sequencing. The mutation had not been described in our in-house database (data for 777 Japanese exomes), nor in the gnomAD Database (http://gnomad.broadinstitute.org/), which includes data for 123 136 whole exomes and 15 496 whole genomes. We confirmed paternity/maternity by single-nucleotide polymorphisms on exome data. In silico analysis with PolyPhen-2 (http://genetics.bwh.harvard.edu/pph2/) and the SIFT (http://sift.jcvi.org/) predict the mutation to be ‘damaging’. We did not identify potentially pathogenic mutations in genes implicated in inherited ichthyoses. A skin biopsy specimen from the right lower leg showed compact hyperkeratosis, parakeratosis with hypogranulosis, a few dyskeratotic cells and mild vacuolar degeneration in the epidermis. A number of facts support the pathogenicity of the present mutation (p.Met854Lys). Firstly, the mutation was absent in both parents, suggesting a de novo condition. Secondly, the mutation affects a residue that is highly conserved among different species (Fig. 1b). The corresponding methionine is a highly conserved amino acid residue that shows homology not only within the IFIH1, but also to human RIG-I and LGP2, which also encode the other antiviral RNA helicase proteins. Thirdly, the mutation lies on the pincer domain, which connects helicase domain 2 (Hel2) and the C-terminal domain (CTD), and is composed of two a helices (aP1–aP2) that emerge from the last b-strand of Hel2. p.Met854Lys is located at the first helix, aP1. Although the pincer is neither an ATPase core domain nor a direct RNA-binding site, it transmits information between Hel2 and CTD, regulating the behaviour of IFIH1, which is essential for RNA sensing of IFIH1. Immunohistochemical stainings revealed that p-STAT3 was strongly expressed in the nuclei of keratinocytes in the patient (Fig. 1h), although there were no significant changes in the staining of IFIH1. The interferon (IFN)-a receptor, the receptor of type I IFN, activates Janus kinase 1 and tyrosine kinase 2. Phosphorylation of the receptor by these kinases results in the recruitment of STAT proteins, phosphorylation, dimerization and nuclear translocation. The three predominant STAT complexes (STAT1, STAT2 and STAT3) that form in response to type I IFN control distinct gene expression programmes. Our observations suggest the possibility that type I IFN signalling is activated in the patient’s epidermis. All 11 previously reported pathogenic mutations in IFIH1 were located in the Hel1 or Hel2 domains and were associated with upregulated type I interferon signalling (a summary of the data is available from the authors. The present proband shows characteristic clinical features of AGS (intracranial

Enhancement of individual differences in proliferation and differentiation potentials of aged human adipose-derived stem cells

Background Adipose-derived stem cells (ASCs) are a robust, multipotent cell source. They are easily obtained and hold promise in many regenerative applications. It is generally considered that the function of somatic stem cells declines with age. Although several studies have examined the effects of donor age on proliferation potential and pluripotency of ASCs, the results of these studies were not consistent. Objective This study tested whether the donor age affects the yield of ASCs from adipose tissue, as well as the proliferation and differentiation potentials of ASCs. Methods This study used ASCs obtained from adipose tissues of 260 donors (ages 5–97 years). ASCs were examined for individual differences in proliferation, and adipogenic, osteogenic and chondrogenic differentiation potentials in vitro. Characteristics of ASCs from each donor were evaluated by the principal component analysis (PCA) using their potential parameters. Results Analyses on ASCs demonstrated that adipogenic potentials declined with age, but proliferation, osteogenic and chondrogenic potentials were not correlated with age. Interestingly, in all ASC potentials, including adipogenesis, individual differences were observed. Principal component analysis (PCA) revealed that individual differences became evident in the elderly, and those variations were more prominent in females than in males. Conclusions This study demonstrated age-related changes in the potentials of ASCs and revealed that the individual differences of ASCs become significant in people over 60 years of age (for females over 60, and for males over 80). We believe that it is important to carefully observe ASC potentials in order to achieve effective regenerative medicine treatments using ASCs.

Successful treatment of continuous intra-arterial administration of prostaglandin E1, urokinase and heparin for intractable digital ulcers by upper extremity arterial occlusion in diffuse cutaneous systemic sclerosis patient

Dear Editor, We present a case of diffuse cutaneous systemic sclerosis (dcSSc) with arterial occlusion in the upper extremities, in which a positive outcome was obtained after continuous intraarterial infusion (CIAI) of prostaglandin E1 (PGE1), urokinase and heparin. A 38-year-old Japanese man with anti-topoisomerase Ipositive dcSSc had been treated for digital ulcers (DU) with oral antibiotics, vasodilators or i.v. infusion of PGE1 for 20 years. However, 2 months before visiting our hospital, he developed severe pain and swelling in his left forearm and hand, which developed into marked edema and pain in his entire left hand. In addition, his left hand was colder than the right, and DU appeared worse on his left fingers (Fig. 1a). He had no medical history of smoking, trauma or hyperlipidemia. Antiphospholipid antibody, prothrombin time, activated partial thromboplastin time, thrombin time, serum cholesterol, triglycerides and cryoglobulin were all within normal limits. The occlusion of radial and ulnar arteries revealed by contrast-enhanced computed tomography (CT) and angiography (Fig. 1b,c). We began treating with i.v. injection of PGE1 (20 lg/day) for 1 week; however, it was ineffective. Next, we performed CIAI therapy with PGE1 (20 lg/day), urokinase (60 000 U/day) and heparin (5000 U/day) via the left brachial artery. Surprisingly, his symptoms went into remission after two courses of therapy (each 2 weeks). Recanalization of arteries was confirmed by CT angiography (Fig. 1d–f). He had no recurrence of ulcers for 12 months after treatment. Microvascular disease is one of the hallmarks of SSc and macrovascular involvement is generally rare, although is observed in some patients. The angiographic evaluation of eight SSc patients with DU were reported, seven of whom had

Roles of aberrant hemichannel activities due to mutant connexin26 in the pathogenesis of KID syndrome

Germline missense mutations in GJB2 encoding connexin (Cx) 26 have been found in keratitis, ichthyosis and deafness (KID) syndrome. We explored the effects of three mouse Cx26 mutants (Cx26-G12R, -G45E and -D50N) corresponding to KID syndrome-causative human mutants on hemichannel activities leading to cell death and the expression of immune response-associated genes. We analyzed the 3D images of cells expressing wild-type (WT) or mutant Cx26 molecules to demonstrate clearly the intracellular localization of Cx26 mutants and hemichannel formation. High extracellular Ca2+ conditions lead to the closure of gap junction hemichannels in Cx26-G12R or Cx26-G45E expressing cells, resulting in prohibition of the Cx26 mutant-induced cell death. Fluorescent dye uptake assays revealed that cells with Cx26-D50N had aberrantly high hemichannel activities, which were abolished by a hemichannel blocker, carbenoxolone and 18α-Glycyrrhetinic acid. These results further support the idea that abnormal hemichannel activities play important roles in the pathogenesis of KID syndrome. Furthermore, we revealed that the expressions of IL15, CCL5, IL1A, IL23R and TLR5 are down-regulated in keratinocytes expressing Cx26-D50N, suggesting that immune deficiency in KID syndrome expressing Cx26-D50N might be associated not only with skin barrier defects, but also with the down-regulated expression of immune response-related genes.

Trichothiodystrophy, complementation group A complicated with squamous cell carcinoma

Editor There are three related, clinically defined disorders of DNA repair: xeroderma pigmentosum (XP), trichothiodystrophy (TTD) and Cockayne syndrome (CS). Photosensitivity, neurological/developmental abnormalities and skin cancer are important pathological features that can be used to distinguish between these three archetypes. TTD is a rare, autosomal recessive disease characterized by brittle, sulphur-deficient hair and multisystem abnormalities. The general TFIIH subunit 5 (GTF2H5) gene, GTF2H5, is known to be a causative gene of TTD, complementation group A (TTDA, OMIM#616395). None of five patients with mutations in TTDA showed skin cancers (Table 1). Here, we describe a recurrent mutation in GTF2H5 in a Japanese male suffering from TTDA complicated with squamous cell carcinoma (SCC). The proband is a 44-year-old Japanese man, the oldest of four siblings born to related parents. At the age of 15 years, left sensorineural deafness was noted. On examination, he had short and somewhat brittle hair, with no hypotrichosis (Fig. 1a). He was found to have generalized scaling on the face, trunk and extremities, and palmoplantar keratoderma (Fig. 1b). A lesional skin biopsy revealed hyperkeratosis, acanthosis and thinned granular layers (Fig. 1g). Light microscopy and scanning electron microscopy demonstrated abnormal, irregular hair surfaces (Fig. 1d, e). He has short stature ( 4.2 standard deviations) with normal weight. Other normal or negative findings include the absence of all of the following: photosensitivity, teeth or visual abnormalities, micrognathia, developmental delay, recurrent infections and abnormalities in maternal pregnancy and fetal development. Oral administration of etretinate (0.3 mg/kg/day) effectively resolved the ichthyosis eruptions. When he was 42 years old, an ulcerated nodule with a fissure developed on the right neck (Fig. 1c). A biopsy specimen from the nodule showed the proliferation of atypical keratinocytes in the epidermis, and the invasion of these cells to the upper dermis was observed (Fig. 1h). The nodule was diagnosed as moderately differentiated SCC and was surgically excised. Ethical approval was obtained, and all research was performed in accordance with the Declaration of Helsinki principles. Genomic DNA from the patient’s peripheral blood leucocytes was used for whole-exome sequencing analysis. Analysis of the data revealed a homozygous non sense mutation in GTF2H5, c.163G>T (p.Glu55*) (Fig. 1f). We did not identify any potentially pathogenic mutations in specific genes such as MPLKIP nor in other genes associated with trichothiodystrophy/photosensitivity. The mutation p.Glu55* identified in GTF2H5 has been reported previously as a pathogenic mutation in a Japanese individual with TTDA. In addition, a non sense mutation of the adjacent arginine, p.Arg56*, has been reported in TTDA. Taken together, these pathogenic mutations potentially underscore the functional importance of the C-terminus. The reported Japanese boy with the identical GTF2H5 mutation c.163G>T had photosensitivity, but no skin cancer. There are phenotypic disparities between the two Japanese subjects with the homozygous mutation p.Glu55*, although we cannot exclude the possibility that skin cancer may develop later in the reported boy’s life. Our case has SCC, but no photosensitive dermatoses. We speculate that his cumulative sun exposure might have affected the development of SCC, as the neck region is continuously exposed to sunlight, potentially resulting in DNA damage. In XP patients, the median age of first non-melanoma skin