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.

Ring 21 chromosome presenting with epilepsy and intellectual disability: clinical report and review of the literature.

Abstract: Ring 21 Chromosome Presenting With Epilepsy and Intellectual Disability: Clinical Report and Review of the Literature Nicola Specchio,* Antonio Carotenuto, Marina Trivisano, Simona Cappelletti, Cristina Digilio, Rossella Capolino, Matteo Di Capua, Lucia Fusco, and Federico Vigevano Division of Neurology, Bambino Gesù Children’s Hospital IRCCS, Rome, Italy Medical School, University of Naples, Naples, Italy Clinic for Nervous System Diseases, University of Foggia, Foggia, Italy Unit of Clinical Psychology, Bambino Gesù Children’s Hospital IRCCS, Rome, Italy Division of Medical Genetics, Bambino Gesù Children’s Hospital IRCCS, Rome, Italy

Origin of 46,XY/46,XY,r(19) mosaicism

Abstract: We report on a case of 46,XY/46,XY,r(19) mosaicism. The patient shows minimal clinical abnormality and the terminal deletions prerequisite for the ring formation are not microscopically discernible. The origin of the mosaicism is discussed. Firstly, the mosaicism may represent chimerism with a prezygotic origin of the ring chromosome; secondly, the ring chromosome could have arisen postzygotically; and thirdly, the ring could have been of a prezygotic origin with the apparently normal cells actually containing reopened rings. The consequences of these hypothesis on genetic counselling are discussed.

Ring XY bivalent: a new phenomenon at metaphase I of meiosis in man.

Abstract: The unusual appearance of a ring XY bivalent at metaphase I of meiosis is reported in some cells of an oligospermic human male. Higher than usual frequencies of ring configuration in the XY pair were also observed during prophase I. The defect could be attributable to loss of some DNA sequences from the distal heterochromatic tip of the Y chromosome long arm.

Deletion mapping of 39 random isolated Y-chromosome DNA fragments

Abstract: Thirty-nine recombinants isolated from a Y chromosome-specific library were deletion mapped. Seven deletion intervals were defined by hybridization of probes to DNA of eight individuals with aberrant Y chromosomes. Extreme cytogenetic limits of the deletion intervals were determined by in situ hybridization of one probe per deletion interval. Five intervals, with a total of twenty-five probes, were allocated to the longarm euchromatic region. The probes described will be useful for characterization of aberrant Y chromosomes, in searching for expressed sequences on the Y chromosome, and for further study of the evolutionary relationship between the Y chromosome and other chromosomes.

The terminal 760 kb region on 4p16 is unlikely to be the critical interval for growth delay in Wolf–Hirschhorn syndrome

Abstract: In a recent issue of the journal, Concolino et al 1 describe a patient with severe growth retardation and a ring chromosome 4, in which a 760 kb deletion within the terminal 4p16.3 region was detected by array comparative genomic hybridisation (CGH). Severe growth delay is one of the most striking features in Wolf–Hirschhorn syndrome (WHS), a multiple congenital anomalies/mental retardation condition caused by partial 4p deletion. The association of growth delay, the typical “Greek warrior helmet” profile, mental retardation and seizures defines the core WHS phenotype. All these signs are related to haploinsufficiency of genes residing within the terminal 1.9 Mb region on 4p16.3.2 Precise …