Genodermatoses.

This article describes some of the genodermatoses encountered in the black populations in Africa, starting with ainhum, which appears to be genetically determined. Palmoplantar keratodermas are common in Africa but are difficult to classify and their hereditary nature is not always recognized. Of the ichthyoses, the lamellar type is commonest, with the so-called bathing-suit distribution apparently unique to Africans. Albinism and xeroderma pigmentosum are important causes of cutaneous malignancy in the tropics. Neurofibromatosis and tuberous sclerosis are relatively common, whereas hypermelanosis of Ito is rare but easy to recognize in dark skin.