White sponge nevus presenting as genital lesions in a 28-year-old female

A novel keratin 13 variant in a four-generation family with white sponge nevus

We report a novel KRT13 germ line variant that causes white sponge nevus (WSN) with mucosal dysplasia. Genital, vaginal, and cervical WSN were observed in four female patients, of whom two had premalignant cervical lesions at young age. Two of the 12 patients with oral WSN developed oral squamous cell carcinoma.

Expression profiling of white sponge nevus by RNA sequencing revealed pathological pathways

BACKGROUND

White sponge nevus (WSN) is a rare periodontal hereditary disease. To date, almost all WSN studies have focused on case reports or mutation reports. Thus, the mechanism behind WSN is still unclear. We investigated the pathogenesis of WSN using expression profiling.

METHODS

Sequence analysis of samples from a WSN Chinese family revealed a mutation (332 T > C) in the KRT13 gene that resulted in the amino acid change Leu111Pro. The pathological pathway behind the WSN expression profile was investigated by RNA sequencing (RNA-seq).

RESULTS

Construction of a heatmap revealed 24 activated genes and 57 reduced genes in the WSN patients. The ribosome structure was damaged in the WSN patients. Moreover, the translation rate was limited in the WSN patients, whereas ubiquitin-mediated proteolysis was enhanced.

CONCLUSIONS

Our results suggest that the abnormal degradation of the KRT13 protein in WSN patients may be associated with keratin 7 (KRT7) and an abnormal ubiquitination process.

Current approaches to the diagnosis and treatment of white sponge nevus

White sponge nevus (WSN) in the oral mucosa is a rare autosomal dominant genetic disease. The involved mucosa is white or greyish, thickened, folded and spongy. The genes associated with WSN include mutant cytokeratin keratin 4 (KRT4) and keratin 13 (KRT13). In recent years, new cases of WSN and associated mutations have been reported. Here, we summarise the recent progress in our understanding of WSN, including clinical reports, genetics, animal models, treatment, pathogenic mechanisms and future directions. Gene-based diagnosis and gene therapy for WSN may become available in the near future and could provide a reference and instruction for treating other KRT-associated diseases.