1. ^*Department of Dermatology, Osaka Red Cross Hospital, Osaka, Japan;
2. ^†Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan;
3. ^‡Department of Dermatology, Kyoto University Graduate School of Medicine, Kyoto, Japan

Correspondence: Yuji Horiguchi, MD, PhD, Department of Dermatology, Osaka Red Cross Hospital, Fudegasaki-cho 5-30, Ten'noji-ku, 543-8555 Osaka, Japan. Email: horiguch@fa2.so-net.ne.jp

Received 10 December 2004; Revised 23 February 2005; Accepted 28 February 2005.

Abstract

Twenty-five- and 22-y-old Japanese women, who are cousins, presented with distal skin fragility, widespread small, pigmented macules, and toenail deformity. Blisters occurred between the epidermis and the dermis with degeneration of the basal cells, suggesting epidermolysis bullosa simplex with mottled pigmentation (EBS-MP). Electron microscopy of the pigmented spots demonstrated vacuolization of basal cells as well as disturbed junctional structures and incontinence of pigmentation. Gene analysis resulted in detection of a heterozygous deletion of a guanine nucleotide in exon 9 at position 1649. P25L mutation was not detected in either case. It is possible that EBS-MP occurs not only based on the P25L mutation of the keratin 5 molecule, but also because of other types of mutations of epidermal keratin genes.