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High-resolution cytogenetic characterization of telomeric associations in ring chromosome 19

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High-resolution cytogenetic studies of a normal individual with ring chromosome 19 indicate that, at the late-to-mid prophase level of band resolution, no apparent chromosomal material is missing, and that telomeric fusion/association, not deletion, is the cause of the ring chromosome formation. Sub-band analysis of the telomeric fusion shows thin chromatin filaments between the telomeres of some of the very elongated ring chromosomes, which cannot be resolved by metaphase chromosme analysis. The ring chromosome found in this individual shows evidence of the characteristic instability associated with ring chromosomes, including duplicated segments, double rings, and subsequent loss of the ring resulting in cells with monosomy 19. The lack of phenotypic effect and the unstable ring behavior, unlike previously reported patients with ring 19, support the formation of this ring by telomeric association.

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  1. Arrighi FE, Hsu TC (1971) Localization of heterochromatin in human chromosomes. Cytogenetics 10:81–86

  2. Gardner RJM, Monk NA, Clarkson JE, Allen GJ (1986) Ring 21 chromosome: the mild end of the phenotypic spectrum. Clin Genet 30:466–470

  3. Gillessen-Kaesbach G, Ngo NTK (1990) Ring 19 mosaicism detected during prenatal diagnosis. Prenat Diagn 10:683–687

  4. Goodpasture C, Bloom SE (1975) Visualization of nucleolar organizer regions. III. Mammalian chromosomes using silver staining. Chromosome 53:37–50

  5. Heim S, Mandahl N, Kristoffersson U, Mitelman F, Rooser B, Rydholm A, Willen H (1987) Marker ring chromosome: a new cytogenetic abnormality characterizing lipogenetic tumors. Cytogenet Cell Genet 24:319–326

  6. Hoo JJ, Obermann Y, Cramer H (1974) The r(20) syndrome. J Med Genet 24:161–171

  7. Jacobs PA, Matsura JS, Mayer M, Newlands IM (1978) A cytogenetic survey of an institution for the mentally retarded. I. Chromosome abnormalities. Clin Genet 13:37–60

  8. Kosztolanyi G (1987) Does “ring syndrome” exist? An analysis of 207 case reports on patients with ring autosome. Hum Genet 75:174–179

  9. Leung AKC, Rudd NL (1988) A case of ring (9)/del(9p) mosaicism associated with gastroesophageal reflux. Am J Gent 29:43–48

  10. Niikawa N, Tamura T (1980) 13q-/r(13) mosaicism. J Med Genet 17:316–319

  11. Sawyer JR, Thomas EL, Roloson GJ, Chadduck WM, Boop FA (1992) Telomeric associations evolving to ring chromosomes in a recurrent pleomorphic xanthoastrocytoma. Cancer Genet Cytogenet 60:152–157

  12. Schwartz Hs, Allen GA, Butler MG (1990) Telomeric association. Appl Cytogenet 16:133–137

  13. Seabright M (1971) A rapid banding technique for human chromosomes. Lancet 11:971–972

  14. Streekantaiah C, Leong SPL, Davis JR, Sandberg AA (1990) Intratumoral cytogenetic heterogeneity in a benign neoplasm. Cancer 67:3100–3116

  15. Sybert VP, Bradley CM, Salk D (1988) Mosaicism for ring 19: a case report. Clin Genet 34:382–385

  16. Uchida IA, Lin CC (1972) Ring formation of chromosomes nos. 19 and 20. Cytogenetics 11:208–215

  17. Yung JF, Sobel DB, Hoo JJ (1990) Origin of 46, XX/46, XY, r(19) mosaicism. Am J Med Genet 36:391–393

  18. Yunis JJ (1981) Mid-prophase human chromosomes: the attainment of 2000 bands. Hum Genet 56:293–298

  19. Yunis JJ, Sawyer JR, Ball DW (1978) The characterization of the high-resolution G-banded chromosomes of man. Chromosoma 67:293–307

  20. Yunis JJ, Ball DW, Sawyer JR (1979) G-banding patterns of high-resolution human chromosomes 6–22,X and Y. Hum Genet 49:291–306

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Correspondence to Jeffrey R. Sawyer.

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Sawyer, J.R., Rowe, R.A., Hassed, S.J. et al. High-resolution cytogenetic characterization of telomeric associations in ring chromosome 19. Hum Genet 91, 42–44 (1993). https://doi.org/10.1007/BF00230220

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  • Normal Individual
  • Phenotypic Effect
  • Cytogenetic Study
  • Double Ring
  • Subsequent Loss