title: Cryptic deletions and inversions of chromosome 21 in a phenotypically normal infant with transient abnormal myelopoiesis: a molecular cytogenetic study.
abstract: A case of transient abnormal myelopoiesis in a normal newborn without features of Down syndrome is described. The majority of bone marrow cells analysed belonged to a chromosomally abnormal clone with trisomy for chromosomes 18 and 21. Complex intrachromosomal rearrangements of one chromosome 21, demonstrated by fluorescence in situ hybridization using locus-specific probes, were found in a minor population of the clonal cells. These rearrangements involved loci previously shown to be rearranged in the leukaemic cells from patients with Down syndrome and leukaemia. However, the child's myeloproliferation resolved rapidly, with disappearance of the abnormal clone, and 3.5 years later she remains well.
authors.affiliation: LRF Centre for Childhood Leukaemia, Department of Molecular Haematology, Institute of Child Health, London.
authors.forename: H M
authors.initials: HM
authors.lastname: Kempski
authors.forename: J L
authors.initials: JL
authors.lastname: Craze
authors.forename: J M
authors.initials: JM
authors.lastname: Chessells
authors.forename: B R
authors.initials: BR
authors.lastname: Reeves
mesh_terms: D002869:Chromosome Aberrations; D002891:Chromosomes, Human, Pair 21; D004314:Down Syndrome / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007231:Infant, Newborn; D019891:Leukopoiesis; D009196:Myeloproliferative Disorders / Q000235:genetics*; D010641:Phenotype