title: Cytogenetic investigations in trisomy 21 with reciprocal 4/9 translocation: report of a case.
abstract: A 3-month-old male infant with Down's syndrome resulting from de novo trisomy 21 had an additional reciprocal translocation between the long arms of chromosomes 4 and 9: 47,XY,+21,rcp t(4;9)(q35;q22.3). Both C- and Ag-NOR bandings showed that the extra chromosome 21 was maternal in origin, but that the translocated chromosome 9 was from the father. To evaluate the nature of the translocation, fluorescence in situ hybridization (FISH) with whole chromosome painting probes (Coatasomes 4 & 9), followed by an enzymatic precipitation (HRP-DAB) assay was used. Whole chromosome FISH demonstrated the origin of the translocated region and clarified the karyotype. Enzymatic methods achieved the same result and were kept as a permanent record.
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital, Taipei, R.O.C.
authors.forename: J W
authors.initials: JW
authors.lastname: Hou
authors.forename: T R
authors.initials: TR
authors.lastname: Wang
mesh_terms: D002894:Chromosomes, Human, Pair 4; D002899:Chromosomes, Human, Pair 9; D004314:Down Syndrome / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D008297:Male; D014178:Translocation, Genetic