Tetrasomy 18p de novo: parental origin and different mechanisms of formation.

Abstract

We have used eight PCR-based DNA polymorphisms to determine the parental origin and mechanisms of formation in 9 patients with de novo nonmosaic tetrasomy 18p. The 9 patients, 4 girls and 5 boys, had clinical features characteristic of i(18p) syndrome. The supernumerary marker chromosome was identified by fluorescence in situ hybridization (FISH) analysis using centromeric probes and a flow-sorted 18p-specific library. The isochromosome was of maternal origin in all 9 cases. The formation of tetrasomy 18p cannot be explained by a single model. In 6 cases, meiosis II nondisjunction, followed by subsequent postzygotic misdivsion, and in 1 case postzygotic nondisjunction and postzygotic misdivision were the most likely mechanisms of formation. Alternative mechanisms are suggested in the remaining 2 cases.

• Authors: M Bugge, E Blennow, U Friedrich, M B Petersen, F Pedeutour, A Tsezou, A Orum, S Hermann, T Lyngbye, C Sarri, D Avramopoulos, S Kitsiou, J C Lambert, M Guzda, N Tommerup, K Brøndum-Nielsen
• Journal: European journal of human genetics : EJHG (Eur J Hum Genet) Vol. 4 Issue 3 Pg. 160-7 ( 1996) ISSN: 1018-4813 [Print] England
• PMID: 8840116 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Topics

• Adolescent
• Adult
• Aneuploidy
• Child
• Child, Preschool
• Chromosome Mapping
• Chromosomes, Human, Pair 18
• Female
• Humans
• In Situ Hybridization, Fluorescence
• Infant
• Male