De Novo Three-Way Chromosome Translocation [46,XX,t(1;20;4) (p32;q12;q32)] in a Patient with Developmental Delay: A Case Report

Abstract

INtRoductIoN Reciprocal de novo translocations occur in about 1 in 2,000 newborns (1). Although balanced translocations are not often associated with abnormal phenotypes, unbalanced translocations resulting in deleted or altered gene sequences usually cause appreciable clinical features (2,3). Unbalanced translocations even more unusual are complex chromosome rearrangements (CCRs). CCRs are structural abnormalities that involve more than two break points and exchange of genetic material between two or more chromosomes (4,5). Almost all the carriers of the balanced reciprocal translocations are believed to be normal by phenotype. Moreover, it is known that the modification or inactivation of specific disease genes at chromosomal breakpoints have been very phenomenal in identifying genes that are associated with a variety of disorders, mostly early-onset disorders (6). The most common CCRs involve three chromosomes with breakpoints on each chromosome.