title: Down syndrome with low hypodiploidy in precursor B-cell acute lymphoblastic leukemia.
abstract: We describe the rare finding of a 33-month-old child neonatally diagnosed with Down syndrome, who presented with pre-B acute lymphoblastic leukemia (ALL) with a pretreatment bone marrow karyotype in which a low hypodiploid cell line (38 chromosomes) was identified in 17/19 cells studied. The abnormal cell line retained the extra constitutional chromosome 21. Hypodiploidy (loss of one or more chromosomes) is seen in approximately 5% of all childhood pre-B ALL cases and in approximately 2.2% cases of individuals with a constitutional trisomy 21. Low hypodiploidy, associated with a high risk of relapse, is rare in pediatric ALL cases in the general population, and, to our knowledge, is previously unreported in patients with trisomy 21.
authors.affiliation: Department of Pathology and Laboratory Medicine, Section of Cytogenetics, Drexel University College of Medicine, St. Christopher's Hospital for Children, Philadelphia, PA 19134, USA. Jennifer.Morrissette@tenethealth.com
authors.forename: Jennifer J D
authors.initials: JJ
authors.lastname: Morrissette
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Halligan
authors.forename: Hope H
authors.initials: HH
authors.lastname: Punnett
authors.forename: Ann Shoemaker
authors.initials: AS
authors.lastname: McKenzie
authors.forename: Felicula
authors.initials: F
authors.lastname: Guerrero
authors.forename: J P
authors.initials: JP
authors.lastname: de Chadarévian
mesh_terms: D002051:Burkitt Lymphoma / Q000150:complications / Q000235:genetics*; D002675:Child, Preschool; D004171:Diploidy; D004314:Down Syndrome / Q000150:complications / Q000235:genetics*; D005260:Female; D006801:Humans; D007621:Karyotyping; D008297:Male