Myelodysplastic syndrome, juvenile myelomonocytic leukemia, and acute myeloid leukemia associated with complete or partial monosomy 7

We reviewed the clinical features, treatment, and outcome of inn children w ith myelodysplastic syndrome (MDS), juvenile myelomonocytic leukemia (JMML) , and acute myeloid leukemia (AML) associated with complete monosomy 7 (-7) or deletion of the long arm of chromosome 7 (7q-). Patients with therapy-i nduced disease were excluded. The morphologic diagnoses according to modifi ed FAB criteria were: MDS in 72 (refractory anemia (RA) in fl, RA with exce ss of blasts (RAEB) in eight, RAEB in transformation (RAEB-T) in 10, JMML i n 43), and AML in 28. The median age st presentation was 2.8 years (range 2 months to 15 years), being lowest in JMML (1.1 year). Loss of chromosome 7 as the sole cytogenetic abnormality was observed in 75% of those with MDS compared with 32% of those with AML. Predisposing conditions (including fam ilial MDS/AML) were found in 20%. Three-year survival was 82% in RA, 63% in RAEB, 45% in JMML, 34% in AML, and 8% in RAEB-T. Children with -7 alone ha d a superior survival than those with other cytogenetic abnormalities: this was sorely due to a better survival in MDS (3-year survival 56 vs 24%). Th e reverse was found in AML (3-year survival 13% in -7 atone vs 44% in other cytogenetic groups). Stable disease for several years was documented in mo re than half the patients with RA or RAEB. Patients with RA, RAEB or JMML t reated with bone marrow transplantation (BMT) without prior chemotherapy ha d a 3-year survival of 73%. The morphologic diagnosis was the strongest pro gnostic factor. Only patients with a diagnosis of JMML fitted what has prev iously been referred to as the monosomy 7 syndrome. Our data give no suppor t to the concept of monosomy 7 as a distinct syndrome.