Table 1.

Allelic ratios of trisomy 21 and normal CVS samples.

n1Allelic ratios
Replication 12Replication 2
MeanRange3MeanRange
DSCR2
 Control CVS6(Reference interval,4 0.757–1.509)
 Unknown CVSNormal5111.0730.869–1.1610.8590.657–1.032
T21-H620.3210.114–0.5280.3470.304–0.391
T21-L0
PRDM15
 Control CVS4(Reference interval, 0.838–1.070)
 Unknown CVSNormal180.9590.872–1.0240.9170.795–0.992
T21-H71.6181.563–1.7021.5811.472–1.780
T21-L0
UBE2G2
 Control CVS7(Reference interval, 0.645–1.149)
 Unknown CVSNormal140.9870.846–1.0760.9550.823–1.027
T21-H41.7211.575–1.9161.5661.425–1.654
T21-L0
HS21C101
 Control CVS6(Reference interval, 0.840–1.152)
 Unknown CVSNormal210.9700.832–1.0630.9480.850–1.066
T21-H21.6091.390–1.8281.5711.404–1.738
T21-L20.5460.503–0.5880.5300.502–0.558
COL6A2
 Control CVS6(Reference interval, 0.844–1.294)
 Unknown CVSNormal221.1761.056–1.4141.2101.043–1.450
T21-H51.8801.809–2.0372.0031.924–2.249
T21-L20.6960.694–0.6980.6920.651–0.734
  • 1 Number of heterozygous cases.

  • 2 Samples were assayed in 2 independent replicate reactions.

  • 3 Highest and lowest values of the sample group.

  • 4 Reference interval (mean ± 2 SD) of the SNP assay. The allelic ratios of the heterozygous control CVS were determined for replication 1 and replication 2 individually. The highest and lowest (mean ± 2 SD) values of the 2 replications were assigned as the reference limits.

  • 5 CVS samples from pregnant women carrying a euploid fetus.

  • 6 CVS samples from pregnant women carrying a trisomy 21 fetus. T21-H, samples with the higher-mass allele overrepresented. T21-L, samples with the lower-mass allele overrepresented.