Two siblings, a 12-year-old girl and a 7-year-old boy, had recurrent episodes of haemolytic-uraemic syndrome/thrombotic thrombocytopenic purpura, manifested mainly by thrombocytopenia and micro-angiopathic haemolytic anaemia. During 11 years of follow up the girl responded only to steroids, whereas many other therapeutic modalities were ineffective. Following treatment with low dose danazol relapses became fewer and of diminished severity and completely subsided after 6 months. The boy started his illness with signs of haemolytic uraemic syndrome and later developed neurological manifestations. During a 6 year follow up he responded only to plasma exchange. Although chronic thrombocytopenia persisted during the past 3 years, the boy's clinical condition improved.
Conclusion: A family with two children with recurrent episodes of thrombotic thrombocytopenic purpura is described. In one child danazol could have had a beneficial effect.