title: Dicentric chromosome in the bone marrow of a child with megakaryoblastic leukaemia and Down's syndrome.
abstract: A two year old girl with Down's syndrome (constitutional karyotype: 47 + 21), presenting with pancytopenia, developed acute megakaryoblastic leukaemia (AMKL). Her bone marrow contained an abnormal clone with a novel dicentric chromosome derived from chromosomes 5 and 7 (karyotype 46, XX, -5, -7, +dic (5;7) (p 13; p 11.2), +21. This case provides further evidence for a connection between chromosome 21 and this unusual form of childhood leukaemia, and raises questions about the loss of short arm material from chromosomes 5 and 7 compared with the more usual monosomy or long arm loss.
authors.affiliation: Department of Paediatric Oncology, Bristol Children's Hospital.
authors.forename: A O
authors.initials: AO
authors.lastname: Wilkie
authors.forename: C
authors.initials: C
authors.lastname: Kitchen
authors.forename: A
authors.initials: A
authors.lastname: Oakhill
authors.forename: R T
authors.initials: RT
authors.lastname: Howell
authors.forename: P J
authors.initials: PJ
authors.lastname: Berry
mesh_terms: D001853:Bone Marrow / Q000648:ultrastructure; D002675:Child, Preschool; D002891:Chromosomes, Human, Pair 21; D002895:Chromosomes, Human, Pair 5 / Q000648:ultrastructure*; D002897:Chromosomes, Human, Pair 7 / Q000648:ultrastructure*; D004314:Down Syndrome / Q000150:complications / Q000235:genetics / Q000473:pathology*; D005260:Female; D006801:Humans; D007621:Karyotyping; D007947:Leukemia, Megakaryoblastic, Acute / Q000150:complications / Q000235:genetics / Q000473:pathology*; D014178:Translocation, Genetic