Fig. 2

Proposed multi-step mechanism for the formation of the discordant structural chromosomal aberrations in the chorionic villi and amniotic fluid. a Firstly, the derivate chromosome, der(21)t(10;21)(p11.21;q10), occurred during early zygote divisions. b In order to rescue the chromosomal imbalance, the der(21)t(10;21)(p11.21;q10) participated in additional rearrangements in some of the cells. This led to the formation of an isochromosome 21 containing two long arms of chromosome 21, i(21q), and an isochromosome 10 containing two short arms of chromosome 10, i(10p), that was subsequently lost. c Lastly, the remaining chromosome aberrations were distributed into the different fetoplacental cell lines