title: A case of mosaic Down's syndrome with two Robertsonian translocations.
abstract: A baby with stigmata of Down's syndrome was found to be a mosaic with two different cell lines: 45,XX,der(14q;21q)/46,XX,der(21q;21q)+21. The chromosome rearrangements appeared to have risen de novo. Four mechanisms are discussed for the origin of the mosaicism: dissociation of a translocation (14q;21q) chromosome already present in the 45,XX, der(14q;21q) zygote; two translocation events occurring sequentially at the first and second zygote (46,XX) divisions; a chromatid translocation in a 47,XX,+21 zygote; and an independent origin of the two cell lines.
authors.affiliation: Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey N.L. México.
authors.forename: C H
authors.initials: CH
authors.lastname: Leal-Garza
authors.forename: E I
authors.initials: EI
authors.lastname: Cortés-Gutiérrez
authors.forename: R
authors.initials: R
authors.lastname: Ortiz-Jalomo
authors.forename: R
authors.initials: R
authors.lastname: García-Cavazos
mesh_terms: D002883:Chromosomes, Human, Pair 14 / Q000235:genetics*; D002891:Chromosomes, Human, Pair 21 / Q000235:genetics*; D004314:Down Syndrome / Q000235:genetics*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007621:Karyotyping; D009030:Mosaicism / Q000235:genetics*; D014178:Translocation, Genetic / Q000235:genetics*