Multiple supernumerary ring chromosomes of different origin in a patient: A clinical report and review of the literature

We describe a patient with multiple congenital abnormalities exhibiting 2-5 supernumerary chromosomes per cells. A variety of FISH techniques were used to demonstrate that the markers are probably rings, lack detectable telomere sequences, and originate from different non-acrocentric chromosomes, namely 6, 7, 10, 12, and 19. Such cases are extremely rare and this is only the 8th published report of an individual presenting three or more supernumerary chromosomes. We reviewed all available cases of multiple supernumerary chromosomes and the collective data indicate that multiple markers seem always to be rings of different origin. These results provide evidence that such multiple ring markers cannot possibly represent duplication or recurrence of an original structural rearrangement but must be derived with a common causality from different chromosomes. Possible mechanisms for the simultaneous production of multiple rings from different chromosomes are proposed, including the breakdown and rearrangement of a haploid complement shortly after fertilization in a triploid zygote. (C) 2003 Wiley-Liss, Inc.