title: Isochromosome 12p mosaicism (Pallister-Killian syndrome): newborn diagnosis by direct bone marrow analysis.
abstract: A patient who exhibited the phenotype of the Pallister mosaic aneuploid syndrome was cytogenetically diagnosed in the newborn period by bone marrow analysis. A 47,XY,i(12p) karyotype was observed in 100% of the metaphases from direct bone marrow preparations, while phytohemagglutinin (PHA)-stimulated bone marrow was 23% isochromosome positive. Initially, 10% of metaphases from a peripheral blood culture were isochromosome positive, but at 2 months of age all metaphases examined were cytogenetically normal. Serial fibroblast cultures were 75%, 100%, and 28% positive, respectively. The isochromosome was also present in all metaphases examined from lung tissue and testes. This karyotypic pattern supports a theory that tissue-limited mosaicism may result from selection due to differing developmental potentials of certain karyotypes in various tissues.
authors.affiliation: Department of Pediatrics, University of Colorado Health Sciences Center, Denver 80262.
authors.forename: B E
authors.initials: BE
authors.lastname: Ward
authors.forename: M W
authors.initials: MW
authors.lastname: Hayden
authors.forename: A
authors.initials: A
authors.lastname: Robinson
mesh_terms: D000015:Abnormalities, Multiple / Q000235:genetics; D000782:Aneuploidy; D001856:Bone Marrow Examination; D002675:Child, Preschool; D002869:Chromosome Aberrations; D025063:Chromosome Disorders; D002881:Chromosomes, Human, Pair 12; D006801:Humans; D007621:Karyotyping; D008297:Male; D009030:Mosaicism