[Bloom's syndrome. Discussion of the diagnosis concerning two cases of terminal leukemia in a sibship (author's transl)].

Two brothers developed acute leukemia, one at the age of 7 months and the other at the age of 14 months. Both suffered from a staturoponderal retardation and the same malformation syndrome. The karyotype carried out only on the second child revealed breaks and chromatid changes. A diagnosis of Fanconi's anaemia can be discarbed since no blood cytopenia preceded the leukemia. Finally, the diagnosis of Bloom's syndrome prevailed despite the absence of telangiectatic erythema and the atypical chromosomal anomalies.