Topic
Ring chromosome
About: Ring chromosome is a research topic. Over the lifetime, 1546 publications have been published within this topic receiving 31061 citations. The topic is also known as: supernumerary circular chromosome.
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TL;DR: A 10-year-old mentally and physically retarded girl has a mosaic ring-4 chromosome that has increased from 9% to 72% in the past seven years.
Abstract: A 10-year-old mentally and physically retarded girl has a mosaic ring-4 chromosome. The number of ring chromosomes in her peripheral blood preparations has increased from 9% to 72% in the past seven years. The child had a low birth weight and has had several phenotypic changes.
11 citations
Journal Article•
TL;DR: A literature review of cases of r(11) shows that the clinical features of these patients, although showing different frequencies, are similar to those of the del(11q) syndrome.
Abstract: A female infant with severe growth-weight retardation and with a ring chromosome 11, associated with trisomy X in 15% of metaphases, has been reported. A literature review of cases of r(11) shows that the clinical features of these patients, although showing different frequencies, are similar to those of the del(11q) syndrome. It has been suggested that the variability of the mental retardation in r(11) patients is attributable to the unstability of the ring and to the different break points in these two chromosomal rearrangements. The origin of the r(11) was also addressed by studying fragile sites of the parents at 11p15 and 11q25.
11 citations
TL;DR: Using different conventional and molecular cytogenetic techniques as YAC hybridization and comparative genomic hybridization, it is shown that the extra tricentric ring chromosome consists of three heterochromatic blocks with inserted euchromatic material.
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.
11 citations
TL;DR: Cells from cancer effusion (breast cancer) were analyzed by G banding techniques and the origin of three marker chromosomes could be traced accurately by this banding technique.
11 citations
TL;DR: An infant with ring 15 is discussed, a product of the second pregnancy for her mother, who was 161cm tall and 27 years of age at that time and the father was 168 cm tall and 35 years ofAge.
Abstract: Ring chromosomes are rare in man. Friedrich and Nielson1could not find one ring in the compiled data of the cytogenetic screening of 31,801 consecutive live-born children. Hecht and Vlietinck,2as well as Zdansky et al,3claim that the phenotypic and cytogenetic differences among even "identical rings" do not permit an accurate delineation of an identifiable syndrome. On the other hand, certain ring chromosome syndromes (ring 1, 6, 9,13, 15, 21, and 22) appear already in textbooks4as separate clinical entities. To solve the controversy, more case reports seem warranted. Therefore, we discuss an infant with ring 15. Report of a Case.—This girl was a product of the second pregnancy for her mother, who was 161 cm tall and 27 years of age at that time. The father was 168 cm tall and 35 years of age. Illness, exposure to drugs, and roentgenograms during the pregnancy were
11 citations