A 7-month-old girl was diagnosed with acute megakaryoblastic leukemia and, at the time of diagnosis, the karyotype was 48-50,XX,+4,+5,del(5)(p13),del(6)(q14), +8,inv(8)(p23.1q13),der(13) t(13;?;?),+19,-20,+21,+22,+mar [cp20]. At relapse, there was clear evidence of her constitutional status as a carrier of the pericentric inversion (8)(p23.1q13). It was a familial inversion affecting the patient's maternal lineage; a history of cancer and bleeding anomalies in carriers of the inversion led us to consider their nonrandom association with these pathologies.