Gain of an isochromosome 5p: a rare recurrent abnormality in acute myeloid leukemia.

Chromosomal abnormalities characterize the biological behavior of acute myeloid leukemia (AML), also facilitating the identification of genes responsible for its development and/or progression. Isochromosome 5p, i(5p), represents a rare chromosomal abnormality described, to date, in only a few AML cases. In almost all the cases reported, the i(5p) was accompanied by other abnormalities. Here, a new case of AML, evolved from a myelodysplastic syndrome (MDS) with a clonal trisomy 8, is reported. The case presented the following karyotype: 46, XY[15]/47, XY, +8[4]/47,XY, +1(5) (p10)[3]/ 48,XY,+i(5)(p10)+8[3]. To our knowledge, this is the first reported case of AML to present a clone with an isolated i(5p). The cytogenetic findings supported the hypothesis that i(5p) may represent a primary abnormality, which characterizes a small subset of AML cases.