[Chromosome 1 abnormalities at band 1p32 in two atomic bomb survivors with myelodysplastic syndrome].

We reported on 2 atomic bomb survivors(a 60-year-old man and 63-year-old woman)suffering myelodysplastic syndrome(MDS) associated with 1p32 chromosomal abnormalities. They were exposed to atomic bomb radiation at distances of 1.2 and 1.1 km, respectively, and were given a diagnosis of MDS 44 and 46 years after the bombing, respectively. The male patient had refractory anemia(RA) and a bone marrow cell karyotype of 46, XY, del(1)(p22p32), t(8;11)(p11;p15). The female patient had RA with excess of blasts (RAEB) and a karyotype of 45, X, -X, t(1;11)(p32;q23), +del(1)(p32), inv(3) (p21q27), del(5)(q15), -6, -9, -19, +mar 1, +mar 2. Multi-separated nuclear megakaryocytes were observed in both patients. These findings suggested that they had been exposed to radiation near the atomic explosion despite the fact that their symptoms of MDS developed more than 40 years after the bombing. 1p32 is known to be the locus of the TAL1 gene. However, Southern blot analysis did not reveal rearrangement of the TAL1 gene in the male patient.