Yohya Shigehara

Mutations in SDR9C7 gene encoding an enzyme for vitamin A metabolism underlie autosomal recessive congenital ichthyosis.

Autosomal recessive congenital ichthyosis (ARCI) is a heterogeneous group of hereditary skin disorder characterized by an aberrant cornification of the epidermis. ARCI is classified into a total of 11 subtypes (ARCI1-ARCI11) based on their causative genes or loci. Of these, the causative gene for only ARCI7 has not been identified, while it was previously mapped on chromosome 12p11.2-q13.1. In this study, we performed genetic analyses for three Lebanese families with ARCI, and successfully determined the linkage interval to 9.47 Mb region on chromosome 12q13.13-q14.1, which was unexpectedly outside of the ARCI7 locus. Whole-exome sequencing and the subsequent Sanger sequencing led to the identification of missense mutations in short chain dehydrogenase/reductase family 9C, member 7 (SDR9C7) gene on chromosome 12q13.3, i.e. two families shared an identical homozygous mutation c.599T > C (p.Ile200Thr) and one family had another homozygous mutation c.214C > T (p.Arg72Trp). In cultured cells, expression of both the mutant SDR9C7 proteins was markedly reduced as compared to wild-type protein, suggesting that the mutations severely affected a stability of the protein. In normal human skin, the SDR9C7 was abundantly expressed in granular and cornified layers of the epidermis. By contrast, in a patient’s skin, its expression in the cornified layer was significantly decreased. It has previously been reported that SDR9C7 is an enzyme to convert retinal into retinol. Therefore, our study not only adds a new gene responsible for ARCI, but also further suggests a potential role of vitamin A metabolism in terminal differentiation of the epidermis in humans.

A novel heterozygous mutation in desmoplakin gene in a Lebanese patient with Carvajal syndrome and tooth agenesis.

K.L. Nufer, S. Tomihara, N.A. Prow, H.P. Soyer, T.W. Prow,* M. Ardigo Dermatology Research Centre, The University of Queensland, School of Medicine, Translational Research Institute (The University of Queensland), Brisbane, Australia, QIMR Berghofer Medical Research Institute, Herston, Qld, Australia, Dermatology Department, Princess Alexandra Hospital, Brisbane, Qld, Australia, San Gallicano Dermatological Institute, IRCCS, IFO, Rome, Italy *Correspondence: T.W. Prow. E-mail: t.prow@uq.edu.au

Case of pemphigus herpetiformis with immunoglobulin G autoantibodies against desmocollin-3

Dear Editor, Pemphigus herpetiformis (PH) is one of the less common forms of pemphigus, which is recognized as a distinct variant of pemphigus characterized by its pruritus, rarity of mucosal involvement and good response to sulfones. Ishii et al. reported that the major antigens of PH were desmoglein (DSG)1 and DSG3, both of which are well-known autoantigens for pemphigus foliaceus and pemphigus vulgaris, respectively. However, it is known that several cases of PH have autoantibodies against desmocollins (DSC), which can be also detected in paraneoplastic pemphigus (PNP) and pemphigus vegetans. We herein report a case of PH with immunoglobulin (Ig)G autoantibodies against DSC3, but without anti-DSGs autoantibodies. A 63-year-old Japanese woman visited our hospital because of itchy edematous erythemas and vesicles on the face, trunk and extremities. She had no particular medical history. On physical examination, there were pruritic annular edematous erythemas on her face, trunk and extremities, some of which were accompanied by vesicles and small tense bullae at the peripheral area (Fig. 1a–c). No mucosal involvement of oral cavity was present. Laboratory tests showed mild eosinophilia, and computed tomography did not suggest internal malignancies. Enzyme-linked immunosorbent assays for IgG antibodies against DSG1, DSG3 and BP180-NC16a were all negative. Biopsy specimen from her left thigh revealed spongiosis with numerous eosinophils in the dermis, but without apparent acantholysis (Fig. 1d,e). Direct immunofluorescence showed deposition of IgG (Fig. 1f) and C3 (data not shown) at the intercellular portion of the epidermis (Fig. 1f). Indirect immunofluorescence using normal skin and the patient’s serum also showed IgG deposition on the cell surface of the epidermis at a titer of 1:64. In order to identify the target molecule(s) of autoantibodies generated in the patient, we performed a series of in vitro experiments (Supporting Information) and found that the patient’s serum specifically reacted with the extracellular domain of DSC3 (Figs S1,1g). Therefore, we diagnosed our

A novel splice site mutation in the ADAR gene leading to exon skipping and dyschromatosis symmetrica hereditaria in a Japanese patient

Dyschromatosis symmetrica hereditaria (DSH) (MIM 127400) is an autosomal dominantly inherited genodermatosis, characterized by a mixture of hyperpigmented and hypopigmented macules on the dorsal hands and feet. The disease is known to be caused by mutations in the adenosine deaminase, RNA-specific (ADAR) gene. Although over 100 ADAR mutations have been reported to date, splice-site mutations are relatively rare. We report a Japanese patient with DSH, who had a novel heterozygous splice site mutation in the ADAR gene. The patient was a 17-year-old Japanese boy, who showed the typical clinical and histological features of DSH (Fig. 1a,b). His father and elder brother also had similar skin symptoms. To disclose the molecular basis of DSH in the patient, we conducted a series of genetic analyses (detailed methods are available in Data S1 online). The study was approved by institutional review board of Niigata University and the patient provided written informed consent. Using peripheral blood-derived genomic DNA of the patient as a template, PCR and direct sequencing analysis of the ADAR gene were performed as described previously, and revealed a heterozygous mutation c.2271– 1G>T in intron 6 of the ADAR gene (Fig. 2a). To our knowledge, this mutation has not previously been reported. Screening assay with the restriction enzyme EcoNI excluded the mutation from 100 healthy Japanese control individuals (Fig. 2b). We then performed reverse transcription (RT)-PCR using total RNA derived from skin samples from the patient and a healthy control individual. PCR for the ADAR-cDNA amplified a 151-bp product only from the patient’s sample (Fig. 2c), rather than the expected size (377 bp) of a normal transcript. Direct sequencing of this PCR product revealed that it lacked the entire sequence of exon 7 (Fig. 2d), showing that the mutation c.2271–1G>T resulted in skipping of exon 7 at the mRNA level, which was predicted to cause a frameshift at codon 757 and generate a premature termination codon (PTC) (p.Lys757Asnfs*13) (Fig. 2d). The small size of the transcript (Fig. 2c) indicated that it was largely degraded via nonsense-mediated mRNA decay. Nevertheless, there is a possibility that a truncated ADAR protein could be generated in the patient to some degree. The ADAR protein is composed of two adenosine deaminase Z-alpha domains, three double-stranded (ds) RNA-binding domains and a dsRNA adenosine deaminase domain, which are encoded by exons 2, 2–7 and 9–15, respectively, of the ADAR gene. It is noteworthy that the majority of ADAR mutations are predicted to abolish expression and/or function of the C-terminal deaminase domain. Consistent with previous studies, the mutant ADAR protein in our patient (p.Lys757Asnfs*13) completely lacks the deaminase domain, which further suggests the crucial role of this domain in the function of the ADAR protein. We conclude that c.2271–1G>T (p.Lys757Asnfs*13) is a pathogenic mutation for DSH in our patient, although further analyses will be required to disclose the definite mechanisms of how the mutation affects the differentiation of melanocytes and causes the disease.

Hailey-Hailey disease patient with a novel missense mutation in ATP2C1 successfully treated with minocycline hydrochloride

fingers starting immediately after birth. His growth and development were normal. The patient was suspected to be a product of underage brother–sister incest and was adopted by his foster parents. His biological parents did not have any apparent bullous disorders. The blister formation was refractory and new blisters had developed on his legs. There were blisters on the intertriginous regions including the maniphalanx (Fig. 1a), legs (Fig. 1b), toes and lower back. Milia were seen on the left auricle, forehead and lower legs (Fig. 1b). Histological analysis of a biopsied specimen of the skin adjacent to the bullous lesion did not show apparent epidermolysis but did show poor cell infiltration. Immunofluorescent study using an anti-type VII collagen mouse monoclonal antibody (LH7.2) did not demonstrate marked decrease of the expression levels of type VII collagen at the basement membrane zone (Fig. 1c,d). Electron microscopy of the skin specimen showed signs of splitting beneath the lamina densa suggesting DEB, whereas the anchoring fibrils kept their loop structure (Fig. 1e). Furthermore, the density of anchoring fibrils per every 10 lm lamina densa in the present case was significantly lower than that of healthy controls (n = 6, 15.2 5.6 vs 44.7 8.8, P = 0.000041). The direct sequencing analysis of amplified the COL7A1 gene with polymerase chain reaction revealed a c.6216+5G>T homozygous mutation in COL7A1, intron 74 (Fig. 1f), and thus confirmed the diagnosis of RDEB. The present case with a homozygous c.6216+5G>T mutation that induces PTC showed a mild phenotype. This mutation produces three transcripts, one of which is a wild type. Consistently, our immunofluorescent and electron microscopy studies of the perilesional skin showed the expression of type VII collagen at the basement membrane zone and anchoring fibrils with loop structure beneath the basement membrane whereas the number of anchoring fibrils was decreased. This may be a reason for the mild phenotype associated with this mutation, although we are aware of the limitation of the analysis using clinical specimens from a single case in this study. In conclusion, a case of RDEB associated with homozygous c.6216+5G>T mutation in COL7A showed a mild phenotype, with an ultrastructurally decreased number of anchoring fibrils.

Two cases of hypohidrotic ectodermal dysplasia caused by novel deletion mutations in the EDA gene

Dear Editor, Hypohidrotic ectodermal dysplasia (HED) is one of 200 different genetic conditions of ectodermal dysplasia (ED) characterized by hypotrichosis, hypodontia and hypohidrosis. Most cases of HED show X-linked recessive inheritance and are caused by mutations in the ectodysplasin (EDA) gene (Online Mendelian Inheritance in Man #305100). We herein report two Japanese patients with X-linked HED caused by novel deletion mutations. Patient 1 was a 12-year-old Japanese boy admitted to hospital because of decreased sweating with idiopathic fever since birth. His scalp hair was sparse and he had a saddle nose and hypodontia (Fig. 1a–c). Patient 2 was a 3-month-old boy admitted to a hospital because of dry skin and hypotrichosis. He also showed low-set ears and a saddle nose (Fig. 1e,f). Patient 1 had typical symptoms of HED. In patient 2, facial abnormalities, including low-set ears and saddle nose, were suspected as ED. We were unable to clearly determine

A case of non-episodic angioedema with eosinophilia induced by influenza vaccine

Angioedema with eosinophilia (AE) is characterized by hypereosinophilia in peripheral blood, angioedema, fever, and weight gain [1-3]. AE is triggered by various factors, including infection and drugs [1-3]. It is classified as nonepisodic AE (NE-AE) or episodic AE (E-AE) [1, 2]. We report a rare case of NE-AE induced by influenza vaccination. A 52-year-old Japanese woman developed fever (37.5◦C) and mild oedema over her whole body two hours after receiving vaccination against influenza virus. She had been receiving the same vaccination for the last 10 years, with no side effect. Although she was treated with an antipyretic/analgesic drug, mild fever persisted and the oedema gradually worsened. Therefore, she was admitted to our hospital seven days after the vaccination. Physical examination revealed oedema all over her body (figure 1A), which was more pronounced on her extremities. Laboratory work-up revealed significantly elevated white blood cell (WBC) count (21,880/ L) and mild liver dysfunction. Histopathological examination at the first medical examination revealed mild dermal oedema and a perivascular