Abstract: The proband, a 30-year-old Chinese male presented with skin rashes for 12 years, especially on the armpit, periumbilical area and inner upper arm and which gradually increased. The rashes was accompanied by mild itching, which was aggravated by heat and sweating. Pathologic examination showed that the acanthocyte layer of the epidermis was partially shrunk, the epidermal process was extended, horn cyst structures were seen, and a few mononuclear cells were infiltrated around the blood vessels in the superficial dermis. A total of 5 cases in the family, including 4 males and 1 female, sufferred from similar symptoms. All 5 patients carried the nonsense heterozygotic mutation of KRT5 gene (c.14C>A; p. Ser5*). The diagnosis of Dowling-Degos disease was made according to the genetic testing, clinical and histopathological findings.

Key words: Dowling-Degos disease, family, genetic diagnosis