Bone marrow karyotype of 86-year-old woman with myelofibrosis evolution from essential thrombocythemia showed unbalanced translocation involving chromosome 1 and acrocentric chromosomes 14, 15 and 22 (Figure 1), configuring the phenomenon of Jumping translocation (JT). Twenty metaphases showed: 46,XX,der(14)t(1;14)(q12;p11.2)[11]/46,XX,der(22)t(1;22)(q12;p11.2)[3]/46,XX,der(15)t(1;15)(q12;p11.2)[2]/46,XX[4].
A-G- banding Karyotype, showing ideogram of 1q in blue, 14q in yellow, 15q in red and 22q in green. B-Partial Karyotype with normal chromosome 14, der(14)t(1;14)(q12;p11.2) and schematic model blue/yellow of der(14). C- Partial Karyotype with normal chromosome 15, der(15)t(1;15)(q12;p11.2) and schematic model blue/red of der(15). D- Partial Karyotype with normal chromosome 22, der(22)t(1;22)(q12;p11.2) and schematic model blue/green of der(22).
JT is a rare cytogenetic aberration that occurs when a donor segment chromosome breaks off and merges into two or more receptor chromosomes, resulting in an unbalanced translocation with gain of the donor chromosome segment.1 This phenomenon shows genetic instability, despite not being associated with other chromosomal abnormalities and is associated with an unfavorable prognosis in myeloid neoplasms.2 Among the chromosomal gains, the most frequent is the partial trisomy 1q, as in the case described.
