Keratosis linearis with ichthyosis congenita and sclerosing keratoderma (KLICK-syndrome): a rare, autosomal recessive disorder of keratohyaline formation?

We report a 32-year-old man with an unusual combination of congenital ichthyosis, sclerosing palmoplantar keratoderma with pseudoainhum, and bizarre striate hyperkeratosis in the fixtures, but no systemic involvement. The condition, which improved on oral etretinate therapy, had not appeared previously in the family. On light microscopy the involved epidermis showed marked acanthosis with hypergranulosis and hyperkeratosis. Electron microscopy disclosed numerous large keratohyaline granules in superficial keratinocytes. The clinical picture and histology are virtually identical to those of a Spanish family suffering from an autosomally recessive skin disease of unknown etiology. We hypothesize that the condition is due to a genetic defect in the formation of keratohyaline granules.