A Rare Case of Mosaic Unbalanced Non-Robertsonian Translocation Involving Chromosomes 15 and 22 with Congenital Abnormalities in Monozygotic Twins.

Balanced de novo non-robertsonian translocations (non-RTs), which involve acrocentric chromosomes, are rare findings in clinical cytogenetics and may be associated with an abnormal phenotype. These translocations, detected by conventional karyotyping, are found in approximately 1:1,000 neonates. In most of these cases, one of the parents carries the same translocation. In this study, we report a rare non-RT involving chromosomes 15 and 22 defined as 45, XX, -22,der(15;22)t(15;22)/46, XX, der(15)t(15;22),der(22). To our knowledge, this is the first report of a non-RT t(15;22) with these breakpoints.