A 50-year-old man presented with congenital scaling and hyperkeratosis on his palms, the soles of his feet and the extensor areas of his joints. The flexural areas were unaffected. His maternal grandmother, questionably his maternal uncle, his mother, all three brothers, one of his two sisters as well as two nephews and three nieces have or had similar skin changes. A punch biopsy was taken from the left palm. Clinical and histological signs led to the diagnosis of erythrodermia congenitalis ichthyosiformis bullosa of Brocq. We confirmed this genetically and found a heterozygous duplication (c.1752dupT) in the keratin 1 gene (KRT-1). To our knowledge, this is the first case of this skin condition reported in the literature with a heterozygous duplication (c.1752dupT) in KRT-1.