A novel telomerase activity and microRNA-21 upregulation identified in a family with palmoplantar keratoderma

Palmoplantar keratoderma is a set of skin diseases with hyperkeratotic thickening of palms and soles which are characteristic of these heterogeneous group of keratinization disorders. Various genetic mutations, autosomal dominant or recessive, have been identified which may triggerpalmoplantar keratoderma, as KRT9 (Keratin 9), KRT1 (Keratin1), AQP5 (Aquaporin), SERPINB 7 (serine protease inhibitor). The identification of causal mutations is extremely important for the correct diagnosis. Here, we report the case of a family affected from Palmoplantar keratoderma caused by autosomal dominant KRT1 mutations (Unna-Thost disease). Telomerase activation and hTERT expression take a part in the process of cell proliferation and inflammation and microRNAs, as microRNA-21, are emerging as drivers in the regulation of telomerase activity. Here, the patients underwent KRT1 analysis genetic sequence, telomerase activity and miR-21 expression. Beside histopathology assay was performed. The patients presented thickening of the skin on soles of the feet and the palms of the hands, KRT1mutations and showed high expression levels of hTERT and hTR, the gene encoding for the telomeric subunits, and miR-21 (fold change > 1.5 and p value = 0.043), explicating the aberrant proliferation of epidermal layer and the inflammatory state characterizing palmoplantar keratoderma.

Automated summary

Palmoplantar keratoderma is a group of skin diseases characterized by thickening of the palms and soles. Various genetic mutations, such as KRT9, KRT1, AQP5 and SERPINB 7, have been identified as triggers for palmoplantar keratoderma. In this study, a family with palmoplantar keratoderma caused by autosomal dominant KRT1 mutations was analyzed for KRT1 genetic sequence, telomerase activity, and miR-21 expression. The patients showed thickening of the skin on their hands and feet, KRT1 mutations, and high expression levels of hTERT, hTR, and miR-21, indicating aberrant proliferation and inflammation.