Poster session V Academic issues, antepartum fetal assessment, genetics, hypertension, medical-surgical-disease: Abstracts 687 – 838| Volume 206, ISSUE 1, SUPPLEMENT , S367, January 01, 2012

837: LBA1 genome wide fetal aneuploidy detection by sequencing of maternal plasma DNA: diagnostic accuracy in a prospective, blinded, multicenter study


      The ability to detect fetal aneuploidies across the genome must be demonstrated if massively parallel sequencing (MPS) of maternal plasma DNA is to be widely incorporated into prenatal care. We prospectively determined the diagnostic accuracy of MPS to detect whole chromosome fetal aneuploidy.

      Study Design

      Blood samples were collected in a prospective, blinded study from 2,882 women undergoing prenatal diagnostic procedures at 60 United States sites. All singleton pregnancies with any abnormal karyotype and a balance of subjects with euploid karyotypes (∼1:4 ratio) were randomly selected by an independent biostatistician. Sample lists were submitted to the laboratory for sequencing. Six independent classifications for chromosomes 21, 18, 13, male, female and monosomy X were made for each sample and compared to fetal karyotype.


      Within an analysis cohort of 532 samples, 89/89 trisomy 21 cases, (sensitivity 100% (95% CI 95.9-100)), 35/36 trisomy 18 cases (sensitivity 97.2%, (95% CI 85.5-99.9)), 11/14 trisomy 13 cases (sensitivity 78.6%, (95% CI 49.2-99.9)), 232/233 females (sensitivity 99.6%, (95% CI 97.6->99.9)), 184/184 males (sensitivity 100%, (95% CI 98.0-100)), and 15/16 monosomy X cases (sensitivity 93.8%, (95% CI 69.8-99.8)) were classified (Table 1, Figure 1). There were no false positives for autosomal aneuploidies in unaffected subjects (100% specificity). In addition, fetuses with mosaicism for trisomy 21 (3/3), trisomy 18 (1/1), and monosomy X (2/7), as well as three cases of translocation trisomy, two cases of other autosomal trisomy (T20 and T16) and other sex chromosome aneuploidies (XXX, XXY and XYY) were correctly classified.
      Tabled 1
      Table thumbnail grt52


      This is the first prospective study to demonstrate the efficacy of MPS of maternal plasma DNA with optimized normalization to detect aneuploidy across the genome. MPS provides superior sensitivity and specificity to diagnose trisomies 21 and 18, compared to screening by serum analytes and ultrasound, and is capable of detecting trisomy 13 and monosomy X. This approach would require far fewer invasive procedures to diagnose fetal aneuploidy.