Combined FISH and PRINS sperm analysis of complex chromosome rearrangement t(1;19;13): an approach facilitating PGD

Abstract

Complex chromosome rearrangements (CCRs) are structural aberrations involving three or more breakpoints on two or more chromosomes. These CCRs result in a high rate of chromosome imbalances potentially leading to subfertility and congenital abnormality. In this study, we analysed meiotic segregation in the sperm of a patient with a familial CCR 46, XY,t(1;19;13)(p31;q13.2;q31)mat included in an intracytoplasmic sperm injection program because of oligoasthenozoospermia. The rearrangement was first identified using conventional and molecular cytogenetic methods. Primed in situ labelling (PRINS) and fluorescence in situ hybridization (FISH) techniques were then combined allowing the simultaneous use of five fluorochromes on the same sperm preparation, for the segregation analysis and the evaluation of the reproductive options for this patient. Segregation analysis was performed in a total of 1822 sperm nuclei from the translocation carrier. The percentage of unbalanced sperm was 75.9%, including 34.1% from 3:3 segregation, 38.2% from 4:2 segregation, 3.5% from 5:1 segregation and 0.05% from 6:0 segregation. Only 14.8% of sperm nuclei were consistent with a normal or balanced chromosome complement. In conclusion, chromosome segregation analysis combining FISH and PRINS was performed in sperm from a CCR carrier using five fluorochromes. These results advance our understanding of the mechanisms of meiotic segregation, and facilitate the assessment of the usefulness of preimplantation genetic diagnosis procedures in CCR couples.

Meiotic outcomes of three-way translocations ascertained in cleavage-stage embryos: refinement of reproductive risks and implications for PGD

“…18,23,24 In our study and the sperm study of Pellestor et al 18 the proportions of the products were similar, and unbalanced products reflecting 3:3 adjacent-2 segregation and those consistent with 4:2 nondisjunction were much higher than the proportions consistent with 2:2 adjacent-2 and 3:1 in sperm and embryo studies of two-way reciprocal translocations. 16,25 We are aware of two other published reports that included PGD for threeway translocations.…”

Meiotic segregation and interchromosomal effects in a rare (1:2:10) complex chromosomal rearrangement

“…To date, a few studies have examined segregation in a CCR, a t(2;11;22) [8] , a t(5;13;14) [9], and a t(1;19;13) [10], and these have found much higher frequencies of unbalanced chromosome complements (86.5%, 69.4%, 75.9% respectively). However, a study, similar to this one, that examined chromosome specific frequency of unbalanced complements in a t(2;4;8), found rates lower than those reported here, 3.3% in chromosome 4 and 4.8% chromosomes in chromosome 8 [11].…”

Sequential FISH allows the determination of the segregation outcome and the presence of numerical anomalies in spermatozoa from a t(1;8;2)(q42;p21;p15) carrier

“…This fact clearly increases the complexity of the analysis, first due to the lack of commercial probes labelled with five different fluorochromes, second because of the difficulty of analysing five probes in the small area of a sperm nucleus. As a consequence, other strategies have been used including sperm karyotyping [3], multi-colour banding [16], primed in situ labelling [12], or aneuploidy screening of the chromosomes involved in the three-way rearrangement [9,13].…”