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: Proximal chromosome 4q therefore is a candidate region for disease genes for both HIES and autism and identification of genes disrupted or lost during the formation of the marker chromosome as well as linkage studies in kindreds with HIES or autism may help understand the etiology of these complex phenotypes.
33 citations
TL;DR: The clinical expression of patients with 18 long and short arm deletions are contrasted and compared with the findings in this patient and other patients with ring 18 chromosomes.
Abstract: Ring chromosomes, long of interest in cytogenetics, have been intensively studied in corn and Drosophila (McClintock, 1932, 1938; Morgan, 1933; Battacharya, 1950) and also described in Crepis, Tulipa, Tradescantia, and other species. In the past few years, a number of reports of ring chromosomes in man have appeared (Table I). We recently encountered a mentally retarded patient with multiple congenital anomalies, in a high proportion of whose cells we found a ring chromosome 18. The clinical expression of patients with 18 long (Lejeune, Berger, Lafourcade, and Rethore, 1966) and short arm deletions (Grouchy, Bonnette, and Salmon, 1966) are contrasted and compared with the findings in our patient and other patients with ring 18 chromosomes. The variability in size and frequency of ring chromosomes in human subjects and in this patient are discussed.
33 citations
TL;DR: The formation of a neocentromere in a previously undescribed chromosomal region at 1p32→p36.1 in an oligospermic patient is described and evidence suggests that neocentromeres formation constitutes a viable mechanism for the mitotic stabilisation of acentric ring chromosomes.
Abstract: Neocentromeres are functional centromeres formed in chromosome regions outside the normal centromere domains and are found in an increasing number of mitotically stable human marker chromosomes in both neoplastic and non-neoplastic cells. We describe here the formation of a neocentromere in a previously undescribed chromosomal region at 1p32→p36.1 in an oligospermic patient. Cytogenetic GTL banding analysis and the absence of detectable fluorescence in situ hybridisation (FISH) signals using telomeric probes indicate the marker to be a ring chromosome. The chromosome is negative for CBG banding and is devoid of detectable centromeric α satellite and its associated centromere protein CENP-B, suggesting activation of a neocentromere within the 1p32-36.1 region. Functional activity of the neocentromere is shown by the retention of the ring chromosome in 97% of the patient's lymphocytes and 100% of his cultured fibroblasts, as well as by the presence of key centromere binding proteins CENP-E, CENP-F, and INCENP. These results indicate that in addition to CENP-A, CENP-C, and CENP-E described in earlier studies, neocentromere activity can further be defined by CENP-F and INCENP binding. Our evidence suggests that neocentromere formation constitutes a viable mechanism for the mitotic stabilisation of acentric ring chromosomes.
Keywords: neocentromere; centromere proteins; α satellite DNA; chromosome 1
33 citations
TL;DR: A ring chromosome derived from group 17–18 was found in a mentally retarded girl and there are cytological indications of two simultaneous mechanisms: lagging and destruction of complex unstable structures.
Abstract: A ring chromosome derived from group 17–18 was found in a mentally retarded girl. The ring shows considerable variability. With respect to the size the ring is enlarged in 9% of the cells. In 19% of the cells the ring is eliminated; in these cells the chromosome number is only 45. The elimination of the ring has been studied. There are cytological indications of two simultaneous mechanisms: lagging and destruction of complex unstable structures.
33 citations
TL;DR: Morphological, cellular and molecular evidences reveal that complete or partial chromosome elimination from inducer HZI1 controls the maize in vivo haploid induction.
33 citations