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: It is proposed that the cutaneous hyperpigmentation and café au lait spots in the proband represent effects of the r(15) chromosome but are not caused by the deletion of specific gene(s) on distal 15q.
Abstract: Ring chromosome 15 [r(15)] syndrome is characterised by specific facial features, cafe au lait spots, failure to thrive, mental retardation and typically with a terminal deletion of the long arm of chromosome 15. We report a 2.5 year old girl showing normal growth and development, large hyperpigmented skin changes showing hypopigmentated areas inside, multiple cafe au lait spots and premature graying-like hypopigmentation of scalp hair. She had a karyotype of r(15) in peripheral lymphocytes and fibroblasts. By FISH analysis the breakpoint was located distal to locus D15S936 (15q26.3) and within 300 kb of the end of the chromosome, indicating no deletion of functional genes on 15q. Hyperpigmentation and cafe au lait spots are rare signs in ring chromosome syndromes, but with r(15) syndrome, cafe au lait spots have been described in about 30% of patients and have been considered to result from the deletion of gene(s) on distal 15q. Based on the frequent observation of patchy hyperpigmentation with the r(15) syndrome, absent hyperpigmentation in cases of distal 15q deletion without a ring chromosome, and the telomeric breakpoint location in our patient indicating no significant deletion, we propose that the cutaneous hyperpigmentation and cafe au lait spots in our proband represent effects of the r(15) chromosome but are not caused by the deletion of specific gene(s) on distal 15q. Patchy skin hypopigmentation is a well known nonspecific sign in cytogenetic mosaicism which is commonly seen in ring syndrome.
10 citations
TL;DR: Cytogenetic investigation of a recurrent leiomyosarcoma of the small bowel from a 45-year-old woman revealed a r(13)(p11q34) as the sole abnormality in a majority of the cells analyzed, suggesting alteration of genes on this chromosome could have played a role in the pathogenesis of this tumor.
10 citations
TL;DR: A new continuous cell line derived from an untreated human retinoblastoma, FMC-RB1, is strongly positive for common acute lymphoblastic leukemia antigen and shows a number of ring chromosomes and two marker chromosomes considered to be derivations of chromosome #17, making it suitable for a variety of biological studies.
10 citations
TL;DR: In peripheral blood cultures of a phenotypically abnormal Caucasian girl, a ring-shaped chromosome was observed in place of an E group member, and it is suggested that this ring chromosome has become a permanent part of the complement of the patient.
Abstract: In peripheral blood cultures of a phenotypically abnormal Caucasian girl, a ring-shaped chromosome was observed in place of an E group member. The rest of the chromosomes of the complement did not show any obvious structural anomaly. The ring chromosome was noted in 100% of the recorded cells, and its size in individual metaphases remained fairly constant. It is suggested that this ring chromosome has become a permanent part of the complement of the patient.
10 citations
TL;DR: This case demonstrates that an increased nuchal translucency thickness detected by early ultrasonography should preferably lead to not only QF-PCR for the diagnosis of Down syndrome but also karyotyping, and seems to be no need for a "ring syndrome" concept.
Abstract: Background
Ring chromosome 10 is a rare cytogenetic finding. Of the less than 10 reported cases we have found in the literature, none was characterized using high-resolution microarray analysis. Ring chromosomes are frequently unstable due to sister chromatid exchanges and mitotic failures. When mosaicism is present, the interpretation of genotype-phenotype correlations becomes extremely difficult.
10 citations