A case of dyskeratosis congenita is reported. This rare hereditary disease usually has the following progression: ectodermal dystrophy (reticular skin pigmentation, nail dystrophy, leukokeratosis of mucosal membranes), appearing in the first decade, followed in about 50% of these patients by a hematopoietic disorder resembling Fanconi's anemia, usually developing in the second or third decade. Carcinomas may occur in leukokeratotic areas in the third, fourth, or fifth decade. This patient's clinical course is interesting because the thrombocytopenia developed as an isolated symptom at the age of 5 years and preceded the skin anomalies by three years. The diagnosis of dyskeratosis congenita was made only after an evolution of five years. The diagnosis of dyskeratosis congenita--although it is a rare disease--should be considered in every child first seen with aplastic anemia or thrombocytopenia.