First clinical application of SNP microarray based 24 chromosome aneuploidy screening of human blastocysts

DNA Microarray Reveals That High Proportions of Human Blastocysts from Women of Advanced Maternal Age Are Aneuploid and Mosaic1

“…However, when single and multiple chromosome errors were analyzed together, as shown in Figure 1B, we found that chromosome errors could occur in any of the 23 pairs of chromosomes, but errors in chromosome 21 (11.3%) were the most frequent chromosome anomaly, followed by chromosomes 22 (10.8%), 16 (7.7%), 7 (6.2%), and 15 (5.7%). When we analyzed chromosomes 13, 18, 21, and XY, which are the most common chromosomes examined by FISH, we found that only 12.7% of the blastocysts had these chromosome errors, and the rate increased to 29.5% if 12 chromosomes were analyzed (8,9,13,14,15,16,17,18,21,22, and XY). However, if all chromosomes were examined with microarray, 56.6% of the blastocysts had chromosome errors (Table 1).…”

“…Comparative genomic hybridization (CGH) and whole-genome arrays can accurately measure DNA copy number in a sample [10]. Because CGH and arraybased CGH can be used to detect DNA copies in a few cells or a single cell, such technologies have been recently applied to PGD in human embryos produced by IVF [11][12][13][14][15][16][17], and there is an increased tendency for them to be used more commonly in infertility clinics. It has been found that transfer of arrayscreened normal blastocysts could significantly increase implantation of embryos [16].…”

“…Recently, more clinicians and laboratory scientists have tended to perform microarray by using trophectoderm (TE) cells biopsied from blastocysts instead of blastomere biopsy from Day 3 cleavage embryos [16]. Because more than one cell can be biopsied from a blastocyst, it is expected that more accurate information can be obtained with blastocyst biopsy compared with one-cell biopsy from Day 3 embryos [16,18,19].…”

“…Because more than one cell can be biopsied from a blastocyst, it is expected that more accurate information can be obtained with blastocyst biopsy compared with one-cell biopsy from Day 3 embryos [16,18,19]. Due to its accuracy, the array-based PGD has been used not only in patients with advanced ages, but also in young patients [16,19], and a higher pregnancy rate was obtained in the patients who underwent transfer of array-screened embryos than in those without screened embryos [19].…”

“…Currently, use of a TE cell biopsy from a blastocyst is encouraged in IVF laboratories [16,19]. However, due to mosaicism of human embryos, it is possible that chromosomes are different among TE cells or between TE cells and inner cell mass (ICM) cells.…”