These data clearly provide further evidence that NPPK is caused by loss-of-function mutations in SERPINB7.

Nagashima-type palmoplantar keratosis (NPPK) is an autosomal recessive skin disorder with a high, unmet medical need that is caused by mutations in SERPINB7. Almost all NPPK patients carry the founder nonsense mutation c.796C>T (p.Arg266Ter) in the last exon of SERPINB7. Here we sought to determine whether topical nonsense-suppression (readthrough) therapy using gentamicin is applicable to NPPK. First, we demonstrated that gentamicin enhanced readthrough activity in cells transfected with SERPINB7 cDNA carrying the mutation and promoted full-length SERPINB7 protein synthesis in NPPK keratinocytes. We next conducted an investigator-blinded, randomized, bilaterally controlled compassionate use study of topical gentamicin in which five NPPK patients with c.796C>T were enrolled. Patients' self-reported improvement of hyperkeratosis was significantly greater on the gentamicin side than the control side (P = 0.0349). In two patients, hyperkeratosis was improved on the gentamicin side, as determined by a blinded-investigator assessment. These results indicate the therapeutic potential of topical gentamicin for NPPK. Unexpectedly, we also found that mutant SERPINB7 mRNAs harboring r.796c>u were degraded by nonsense-mediated mRNA decay. Furthermore, the truncated SERPINB7 protein was degraded via a proteasome-mediated pathway. These findings provide important insights into the mRNA/protein quality-control system in humans, which could be a potential therapeutic target for genetic diseases.

A novel splice site mutation, c.582+1delG, in NCSTN was identified in the familial patients with HS. We also reveal for the first time that a γ-secretase gene mutation is not linked to the development of nonfamilial HS. These results would further pave the way to a better understanding of the contribution of γ-secretase and other genes to the pathogenesis of HS and to the development of a new therapeutic strategy for HS.

Mutations in FLG coding profilaggrin cause ichthyosis vulgaris and are an important predisposing factor for atopic dermatitis. Until now, most case-control studies and population-based screenings have been performed only for prevalent mutations. In this study, we established a high-throughput FLG mutation detection system by real-time PCR with a set of two double-dye probes and conducted comprehensive screening for almost all of the Japanese-population-specific FLG mutations (ten FLG mutations). The present comprehensive screening for all ten FLG mutations provided a more precise prevalence rate for FLG mutations (11.1%, n = 820), which seemed high compared with data of previous reports based on screening for limited numbers of FLG mutations. Our comprehensive screening suggested that population-specific FLG mutations may be a significant predisposing factor for hay fever (odds ratio = 2.01 [95% CI: 1.027-3.936, P < 0.05]), although the sample sizes of this study were too small for reliable subphenotype analysis on the association between FLG mutations and hay fever in the eczema patients and the noneczema individuals, and it is not clear whether the association between FLG mutations and hay fever is due to the close association between FLG mutations and hay fever patients with eczema.

No abstract