title: [Transitory leukemoid reaction with regressive clonal course in a mongoloid newborn infant].
abstract: A neonate with Down's syndrome presented with partial blast infiltration that spontaneously regressed without relapse at age 6 months. Sequential cytogenetic studies of cells in blood and bone marrow initially showed presence of a clone with 46 chromosomes and reciprocal translocation of chromosomes 5 and 7. This clone and the hematologic abnormality later disappeared simultaneously. Two explanations may be suggested: a defect in the maturation of normal blasts due to abnormal environment in the bone marrow, or an intrinsic abnormality of hematopoietic cells. The case reported would favor the second hypothesis.
mesh_terms: D002905:Chromosomes, Human, 4-5; D002906:Chromosomes, Human, 6-12 and X; D002999:Clone Cells; D004314:Down Syndrome / Q000097:blood* / Q000235:genetics; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007621:Karyotyping; D007955:Leukemoid Reaction / Q000235:genetics*; D014178:Translocation, Genetic
vernacular_title: Réaction leucémoïde transitoire avec évolution clonale régressive chez un nouveau-né mongolien.