Hemolytic uremic syndrome in families-an Argentinian experience.

Six hundred and thirty-one patients with hemolytic uremic syndrome (HUS) were treated from 1960 to 1992; 19 (3%) were familial cases, of which 9 were classified as concomitant (including twins), 6 as non-concomitant, and 4 as recurrent. In the recurrent group there were 15 HUS episodes, 10 being concomitant in 2 patients. Prodromal diarrhea was present only in concomitant and non-concomitant cases. Patients with recurrences were sisters from a single family. Concomitant and non-concomitant cases had clinical features, course, and age similar to typical endemoepidemic forms of HUS, in which an association with verocytotoxin-producing Escherichia coli has been reported. There may be a genetic determinant in concomitant cases; these occurred outside the season during which endemoepidemic forms are typically detected. In patients with recurrent disease a genetic factor which may lead to the development of the disease when triggered by viral infections is likely.