Abstract: 【Abstract】 A 23-year-old male patient presented with repeated painful erosion on the soles of both feet for 10 years, and with walking difficulties for half a month. Skin examination showed thick dark-brown finger and toe nails with distal protuberance, and hard keratinous materials under the nails. Obvious hyperkeratosis and maceration occurred on the soles of both feet, which appeared milky-white in color; diffuse papulovesicles were observed on the soles and lateral margins of both feet with scattered erosions. Vesicles were observed on the wrist and forehead. Follicular papules and fine scales were scattered on the extensor aspect of the forearm and elbow, and diffuse white patches were observed on the surface of the tongue. The above clinical manifestations were consistent with pachyonychia congenita. Peripheral blood samples were obtained from the patient, his parents and grandmother, and subjected to whole-exome sequencing. Sequencing showed two mutations in both the patient and his father, including base deletions at position 516 - 518 （c.516-518 del CAA） in exon 1 of the KRT6A gene, which caused pachyonychia congenita-K6a, and a base substitution at position 3 970 （c.3970 C>T） in exon 27 of the PLEC gene, which may cause epidermolysis bullosa simplex Ogna. The same mutation in the PLEC gene was found in the patient′s grandmother. The patient was diagnosed with pachyonychia congenita complicated by suspected epidermolysis bullosa simplex Ogna. After 9-month treatment with acitretin, the nails became lighter in color, plantar skin lesions were obviously relieved, and scattered millet-like vesicles in the wrist completely subsided. The patient was followed up at present.

Key words: Pachyonychia congenita, Epidermolysis bullosa simplex, Acitretin, Keratin-6A gene, PLEC gene