A jumping Robertsonian translocation : a molecular and cytogenetic study

• Published in: Human genetics Vol. 98; no. 3; pp. 291 - 296
• Main Authors: GROSS, S. J, THARAPEL, A. T, PHILLIPS, O. P, SHULMAN, L. P, PIVNICK, E. K, PARK, V. M
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-09-1996; Berlin; New York, NY
• Subjects: Adult; Biological and medical sciences; Child; Chromosome aberrations; Chromosomes, Human, Pair 21; Chromosomes, Human, Pair 22; Down Syndrome - genetics; Female; Humans; In Situ Hybridization, Fluorescence; Infant; Karyotyping; Male; Medical genetics; Medical sciences; Mosaicism; Pedigree; Translocation, Genetic; Chromosomal aberration; Case study; Human; Uniparental disomy; Cytogenetics; Abnormal chromosome; Abnormal chromosome G21; Mosaicism; Down syndrome; Chromosome translocation
• ISSN: 0340-6717; 1432-1203
• DOI: 10.1007/s004390050209

We report a patient with mosaicism for two different Robertsonian translocations, both involving chromosome 21. She carries an unbalanced cell line with an i(21q) and a balanced cell line with a rob(21q22q). She is phenotypically normal but has two children who inherited the i(21q) and have Down syndrome. We demonstrate that both abnormal chromosomes are dicentric and that the proband's 21/21 rearrangement is an isochromosome formed from a maternally derived chromosome 21. We propose a model in which the i(21q) is the progenitor rearrangement in the proband, which subsequently participated in a nonreciprocal rearrangement characteristic of a jumping translocation. In addition, we review other cases of constitutional mosaicism involving jumping translocations.