Natural Course of Epidermolysis Bullosa Simplex with Mottled Pigmentation in a Japanese Family with the p.P25L Mutation in KRT5

The document reports on a Japanese family with a history of epidermolysis bullosa simplex with mottled pigmentation (EBS-MP), a rare subtype of EBS, caused by the p.P25L mutation in the KRT5 gene. The study followed a 3-year-old boy with EBS-MP for 6 years, observing the development of reticulate hyperpigmentation, keratotic warty papules, and a tendency to blister with minor trauma, but no alopecia. His 42-year-old father exhibited similar symptoms, including diffuse non-cicatricial alopecia that began in young adulthood, distinct from androgenic alopecia. Genetic testing confirmed the p.P25L mutation in both the boy and his father. Over time, the boy's hyperpigmentation and warty hyperkeratosis lesions increased, matching the father's intensity. The study suggests that late-onset non-cicatricial alopecia could be a feature of EBS-MP with the p.P25L mutation. The research was supported by various grants and there was no conflict of interest declared.