A new objective histological scale for studying human photoaged skin.

BACKGROUND: A quantitative understanding of the histological alteration of the skin is important for assessing the severity of photoaging. METHODS: We performed Elastica-van Gieson staining and immunohistochemistry for decorin on 34 facial skin sections. We evaluated the alteration of collagen fibers and decorin (a modulator for collagen fibrillogenesis), according to the 5 grades of morphological change in elastic fibers that was established by Kligman (1969). The objectivity of a stage (Stages I-VI), which was established in this study, was evaluated using weighted kappa statistical analysis based on the degree of agreement in stage determination by 11 observers using a blind procedure. Correlation between the crow's-feet-area wrinkles grades of another 26 women and stages was also analyzed. RESULTS: The initial alteration of elastic fibers was observed in the deep dermis. Decorin was not detected in very severely altered skin. Based on the combination of changes in the elastic fibers, collagenic fibers, and decorin, skin tissues were categorized into 6 stages according to severity. The statistical analysis showed almost perfect agreement between observers. Significant positive correlation between stages and wrinkle scores was found. CONCLUSIONS: We propose a new objective histological scale that is useful for assessing the severity of photoaging.

Diffuse and focal palmoplantar keratoderma can be caused by a keratin 6c mutation.

The palmoplantar keratodermas (PPKs) are a large group of genodermatoses comprising nearly 60 genetically distinct diseases. They are characterized by hyperkeratosis on the palms and soles with or without extrapalmoplantar hyperkeratotic lesions. Focal PPK is one of the hallmarks of pachyonychia congenita, a rare autosomal dominant disorder resulting from mutations in the keratin genes KRT6A, KRT6B, KRT16 or KRT17. Recently, in-frame deletion mutations of KRT6C have been identified in three families with focal PPK with slight or no nail changes. We report here a novel KRT6C mutation identified in a Japanese family with PPK with phenotypic heterogeneity, presenting with not only focal but also diffuse hyperkeratosis. The proband had diffuse hyperkeratosis on the soles and small focal hyperkeratoses on the palms, while the two other affected individuals showed focal hyperkeratoses on the soles. All three patients were heterozygotes for c.1414G>A in KRT6C, predicted to result in p.Glu472Lys. These findings strongly suggest that screening of patients with nonepidermolytic diffuse PPK, in whom the pathogenic mutations are yet to be determined, might identify mutations in KRT6C.