Takuya Takeichi

Inherited ichthyoses are a group of genetic disorders characterized by generalized dry skin, scaling and hyperkeratosis, and often associated with erythroderma. These manifestations are due to mutations in genes mostly involved in skin barrier formation. Inherited ichthyoses consist of non-syndromic ichthyoses and ichthyosis syndromes. Non-syndromic ichthyoses are characterized by the phenotypic expression of the disorder being seen only in the skin. Non-syndromic ichthyoses include ichthyosis v

With appropriate diagnostic platforms and bioinformatics support, WES is likely to increase mutation detection in cases of EB and improve EB diagnostic services, although skin biopsy remains an important diagnostic investigation in current clinical practice.

The corneocyte lipid envelope, composed of covalently bound ceramides and fatty acids, is important to the integrity of the permeability barrier in the stratum corneum, and its absence is a prime structural defect in various skin diseases associated with defective skin barrier function. SDR9C7 encodes a short-chain dehydrogenase/reductase family 9C member 7 (SDR9C7) recently found mutated in ichthyosis. In a patient with SDR9C7 mutation and a mouse Sdr9c7-KO model, we show loss of covalent bindi

<h3>Importance</h3> We found<i>CARD14</i>mutations (2 de novo novel mutations and another previously reported mutation) in 3 of 3 patients with pityriasis rubra pilaris (PRP) type V, but not in patients with PRP of other types. Our findings, combined with the published literature, suggest that type V PRP, both familial and sporadic, can be caused by<i>CARD14</i>mutations. Detailed clinical observation revealed that all 3 patients displayed unique patchy macular brown hyperpigmentation. <h3>Objec

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

Individuals with inherited skin diseases often pose one of the most difficult diagnostic challenges in dermatology. The hunt for the underlying molecular pathology may involve candidate gene screening or linkage analysis, which is usually determined by the initial history, the physical findings and laboratory tests. Recent technical advances in DNA sequencing, however, are shifting the diagnostic paradigm. Notably, next-generation sequencing allows a more comprehensive approach to diagnosing inh

Heterozygous mutations in <i>JAK1</i> which result in JAK-STAT hyperactivity have been implicated in an autosomal dominant disorder that features multi-organ immune dysregulation. This study identifies another previously unreported heterozygous missense <i>JAK1</i> mutation, H596D, in an individual with a unique autoinflammatory keratinization disease associated with early-onset liver dysfunction and autism. Using CRISPR-Cas9 gene targeting, we generated mice with an identical <i>Jak1</i> knock-

Only two homozygous nonsense mutations in the epidermal isoform of the dystonin gene, DST-e, have been reported previously in autosomal recessive epidermolysis bullosa simplex (EBS); the affected pedigrees were Kuwaiti and Iranian. This subtype of EBS is therefore considered to be a rare clinicopathological entity. In this study, we identified four seemingly unrelated Kuwaiti families in which a total of seven individuals had predominantly acral trauma-induced blistering since infancy. All affec

The physiology of human skin pigmentation is varied and complex, with an extensive melanogenic paracrine network involving mesenchymal and epithelial cells, contributing to the regulation of melanocyte survival and proliferation and melanogenesis. Mutations in several genes, involving predominantly the KIT ligand/c-Kit and Ras/mitogen-activated protein kinase signalling pathways, have been implicated in a spectrum of diseases in which there is hyperpigmentation, hypopigmentation or both. Here, w