Parental origins of chromosome 7 loss in childhood monosomy 7 syndrome.

Bone marrow monosomy 7 (Mo 7) is associated with childhood preleukemic myeloproliferative and myelodysplastic syndromes (MPS and MDS). We used a series of polymorphic markers to investigate the parental origins of chromosomes lost from the bone marrows of 12 children with MPS/MDS and Mo 7. Eight Mo 7 bone marrows lost a maternal chromosome 7 and four cases lost the paternal homologue. Our data and the results of previous laboratory and clinical observations in the familial and sporadic forms of childhood Mo 7 suggest that chromosome 7 deletions contribute to leukemogenesis by gene dosage.