Characterization of the first supernumerary tricentric ring chromosome 1 mosaicism by conventional and molecular cytogenetic techniques

Item Type:	Article
Title:	Characterization of the first supernumerary tricentric ring chromosome 1 mosaicism by conventional and molecular cytogenetic techniques
Creators Name:	Toennies, H. and Hennies, H.C. and Spohr, H.L. and Neitzel, H.
Abstract:	We report on the conventional cytogenetic and fluorescence in situ hybridization (FISH) results obtained for a 3.5-year-old girl with developmental and language delay and a supernumerary ring chromosome mosaicism in 8% of T-lymphocytes analyzed. Using different conventional and molecular cytogenetic techniques as YAC hybridization and comparative genomic hybridization, we could show that the extra tricentric ring chromosome consists of three heterochromatic blocks with inserted euchromatic material. Additionally, chromosome microdissection followed by FISH analysis demonstrated that the small tricentric ring chromosome consisted of material from the pericentromeric region of chromosome 1q21. Thus, the patient has a mosaic of normal cells and cells with partial pentasomy of the pericentromeric region of chromosome 1. So far, 19 cases with single supernumerary marker chromosome 1 have been published, but no tricentric ring chromosome 1 is, to our knowledge, reviewed in the literature. In this study, we compare the clinical features of our patient with cytogenetically comparable cases described in the literature. We introduce a hypothesis for the formation of a tricentric ring chromosome: starting with a monocentric ring, sister chromatid exchange leading to the formation of a tetracentric ring, which underwent intrastrand recombination generating the tricentric ring.
Keywords:	Chromosome Banding, Cytogenetic Analysis, Fluorescence In Situ Hybridization, Human Pair 1 Chromosomes, Language Development Disorders, Mosaicism, Motor Skills Disorders, Nucleic Acid Hybridization, Ring Chromosomes
Source:	Cytogenetic and Genome Research
ISSN:	1424-8581
Publisher:	Karger
Volume:	103
Number:	1-2
Page Range:	28-33
Date:	2003
Official Publication:	https://doi.org/10.1159/000076285
PubMed:	View item in PubMed

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