Karyotype evolution in the bone marrow of a patient with Fanconi anemia: breakpoints in clonal anomalies of this disease

A 21-year-old Fanconi anemia patient developed refractory anemia. Laboratory studies revealed a transitory increased platelet count and a typical del(5q). Bone marrow karyotyping showed a -6, +der(6)t(1;6)(q12;p25) rearrangement and, two years later, a mosaic -6, +der(6),t(1:6)(q12;p25)/-2, +der 2), t(1;2)(q12;q37) constitution. The chromosome mechanism operating in this patient is discussed.