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Table 3 Summary of the present study and previous studies that used BoBs™ and other diagnostic techniques

From: Combined use of bacterial artificial chromosomes-on-beads with karyotype detection improves prenatal diagnosis

Study Results
Present Study Prenatal BoBs™: Normal (4708, 97.03%); abnormal (144, 2.97%)
Conventional karyotyping: Normal (4656, 95.96%); abnormal (196, 4.04%)
Combined use of BoBs™ and karyotyping: Normal (4633, 95.49%); abnormal (219, 4.51%)
Combined use of BoBs™ and karyotyping detected more abnormalities (4.51%) than BoBs™ alone (2.97%) or karyotyping alone (4.04%)
Leung et al. [21] Traditional karyotyping and BoBs™: 2053 prenatal cases (1421 uncultured chorionic villus samples, 616 amniotic fluid samples, 16 other clinical samples)
Traditional karyotyping: 100% concordance with BoBs™ for all non-mosaic cases involving trisomy 21, 18, and 13
Saldarriaga et al. [24] BAC aCGH plus karyotyping vs. karyotyping or BAC aCGH alone: 9974 pregnant patients
aCGH: higher sensitivity (94.5% vs. 67.3%) and lower false-negative rate (4.5% vs. 33%) than karyotyping
No significant difference in false positives for aCGH and karyotyping (1.3% vs. 1%)
Perez-Duran et al. [25] BoBs™: 50 samples from spontaneous abortions before 20 weeks gestation
32% of samples had chromosomal abnormalities, 50% of which were the most common chromosomal abnormalities (Down syndrome, Turner syndrome, and trisomy 13)
Vialard et al. [11, 26] BoBs™ (first study [11]): 408 samples and prospective testing of 212 consecutive samples: no false-positive results; no triploids; mosaic conditions at 20–30%; high predictive value (1 of 1700); high sensitivity (> 98%) and specificity (> 99%); false-negative rate below 2%
BoBs™ (second study [25]): 1653 prenatal samples: failure rate of 3.3%; overall detection rate of approximately 1 in 10. Detected abnormalities: 85% common aneuploidies; 11 duplications and microdeletions, with overall microdeletion and microduplication rate of 1 in 145
Choy et al. [9] BoBs™ and karyotyping: 2153 samples
BoBs™ found 6 microdeletion syndromes, including DiGeorge syndrome, that karyotyping did not detect
BoBs™ sensitivity was 96.7% and specificity was 100%
Karyotyping detected 15 (0.7%) cases with major chromosomal abnormalities; BoBs™ detected only 8 (53.3%) of these 15 cases
Garcia-Herraro et al. [28] BoBs™ combined with karyotyping: 364 prenatal samples; 309 amniotic fluid samples and 35 chorionic villus samples were normal
Concordance rate of 98.51% between BoBs™ and conventional karyotyping
3 of 5 samples without agreement had chromosomal abnormalities not detected by BoBs™ (2 Robertsonian translocations, 1 reciprocal translocation and 2 with polymorphisms)
Grati et al. [15] BoBs™ plus karyotyping: 9648 samples
Overall incidence rate of 0.7% for cryptic imbalances
BoBs™ had low a priori risk of approximately 0.3%
Rosenfeld et al. [19] BoBs™ and karyotyping: 2940 samples
7.9% aneuploidies and 0.45% partial chromosomal abnormalities
Combined with karyotyping, additional detection of 1 in 745 for low risk cases (e.g. normal ultrasound and isolated ultrasound marker and increased nuchal measurements), and 1 in 165 for fetal structural or growth abnormalities
Rosenfeld et al. [29] aCGH compared with other traditional analyses: 535 fetal demise samples
aCGH detected significant clinical abnormalities in 12.8% of samples characterized as normal or unknown karyotypes
Normal karyotype subset: significant clinical abnormalities in 6.9% (20 of 288); 107 samples examined by aCGH and SNP: SNP detected significant clinical abnormalities in 7 cases (7.5%)
aCGH did not provide fetal results for 8.3% (20 cases) because of poor DNA quality and maternal cell contamination