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Ring chromosome 20 with loss of telomeric sequences detected by multicolour PRINS
Author(s) -
Brandt Carsten A.,
Kierkegaard Ole,
Hindkjær Johnny,
Jensen Peter K. A.,
Pedersen Søren,
Therkelsen Aage J.
Publication year - 1993
Publication title -
clinical genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 102
eISSN - 1399-0004
pISSN - 0009-9163
DOI - 10.1111/j.1399-0004.1993.tb03837.x
Subject(s) - ring chromosome , karyotype , biology , genetics , chromosome , cytogenetics , ring (chemistry) , chromosome 22 , somatic cell , microbiology and biotechnology , in situ hybridisation , fluorescence in situ hybridization , proband , mutation , gene , chemistry , organic chemistry
Brandt CA, Kierkegaard O, Hindkjær J, Jensen PKA, Pedersen S. Ring chromosome 20 with loss of telomeric sequences detected by multicolour PRINS. Clin Genet 1993: 44: 26–31. © Munksgaard, 1993 A ring chromosome 20 in a male infant with epileptic seizures, mental and somatic growth retardation, and behavioural disturbances is described. Conventional cytogenetics revealed the karyotype to be 46,XY,r(20)(pter→qter) and no signs of mosaicism were found. Fluorescence in situ hybridisation using the clone p20Z1 identified the ring to be derived from chromosome 20. By counting 111 metaphases, only 7% were found to be missing the ring. The absence of telomeric sequences in the ring chromosome was demonstrated by multicolour PRINS: a three‐step PRimed IN Situ labelling technique, using unlabelled primers. A terminal deletion of both arms thus seems to be the cause of the ring formation in the proband. Bivariate flow‐analysis of chromosomes verified a deletion of the ring chromosome. The clinical and cytogenetic findings are compared with previous cases. A specific ring 20 syndrome seems justified.