Prospective, randomized, blinded, and paired analysis of 24 chromosome microarray PGD (mPGD) vs 9 chromosome fish PGD (fPGD) in dispersed cleavage stage human embryos: mPGD has superior consistency

Abstract

OBJECTIVE: Compare the prevalence of cytogenetic abnormality and mosaicism found with two different PGD techniques. DESIGN: Prospective, randomized, and blinded. MATERIALS AND METHODS: Population: 8 arrested cleavage stage embryos were studied. Each was biopsied into individual cells. The cells from each embryo were randomized into even groups. Those destined for fPGD (n=51) were fixed 1 cell/slide. Cells for mPGD (n=52) were put into individual tubes. Analysis: fPGD and mPGD was performed as previously described. Statistics: For each method, results were evaluated for mosaicism, number of unique chromosomal compliments, and number of individual chromosomes with abnormal copy numbers via paired analyses. RESULTS: 1 cell from the mPGD group did not amplify. 4 cells from the fPGD had uninterpretable results. Mosaicism was less common with mPGD (2/8) than fPGD (8/8) (P<0.05). When mosaicism was found, the number of distinct diagnoses was greater with fPGD (2-6) than mPGD (2-3) (P<0.01). In 2 embryos where mosaicism was found with mPGD, the mosaicism made sense. In embryo 7, 3 cells were 46,XY, 1 was 45,XY-13, and 2 were 47,XY+13. In embryo 8, 4 cells were 45,X and 1 was 47,XXX. In each case, a single chromosome was involved. fPGD results showed a 100% mosaicism rate. Only 1 embryos' fPGD results potentially made sense; 3 cells were 45,X and 1 was 44,X-13 (monosomy X - meiotic error; monosomy 13 - mitotic error). The fPGD results in the other 7 embryos varied significantly and were not physiologically logical. More chromosomes were called aneuploid with fPGD (33-55%; 3 to 5 of 9) than with mPGD (0-4%; 0 to 1 of 24) (P<0.05).Tabled 1Cells Analyzed (n)Different Genetic Dx (n)Abnormal Chromosomes (n)Genetic DiagnosisEmbryofPGDmPGDfPGDmPGDfPGDmPGDmPGD166515/90/2446,XX276614/90/2446,XY346313/90/2446,XY458313/90/2446,XY567415/90/2447,XX+18676413/90/2445,X746233/91/2445,XY-13; 46,XY; 47,XY+13845221/91/2445,x; 47,XXXTotal / P value4350P<0.05P<0.05 Open table in a new tab CONCLUSIONS: This is the first prospective, randomized, blinded, and paired comparison between mPGD and fPGD. Mosaicism was less common and made physiologic sense with mPGD. In contrast, fPGD, evaluated a smaller number of chromosomes with a proportionally smaller opportunity for finding mosaicism, still had a dramatically higher level of inter-cell variation in diagnosis. Within a single embryo, there was no overall consistency in the abnormalities found with fPGD. mPGD provides more complete and consistent results than fPGD.