Prenatal aneupioidy detection by fluorencence in situ hybridization (FISH) in 1,068 second trimester pregnancies with fetal ultrasound abnormalities
- Integrated Genetics, Framingham, MA (United States)
One indication for rapid prenatal aneuploidy detection in uncultured amniocytes by FISH is the identification of fetal abnormalities by ultrasound. We analyzed 1,068 consecutive specimens from second trimester pregnancies with fetal ultrasound abnormalities referred for FISH plus cytogenetics. These specimens are a subset (14.7%) of the most recent 7,240 clinical referrals for these combined analyses. Hybridization with specific probes for chromosomes 21, 18, 13, X and Y were used to detect common aneuploidies. As defined by previously described criteria, specimens were reported as informative disomic, informative trisomic, or uninformative within two days of receipt. The rate of informative results from acceptable specimens was 90.1%. The vast majority of uninformative results was due to maternal cell contamination which precluded analysis. Within the informative group there were no false positives, false negatives nor reports of incorrect gender. Of the 1,068 tested specimens with ultrasound abnormalities, 135 (12.5%) were cytogenetically diagnosed as aneuploid. Prior to the cytogenetic analysis, a total of 107 aneuploidies were correctly identified by FISH. The remaining 26 aneuploidies generated an uninformative FISH result. The overall FISH detection rate for aneuploidy (including informative and uninformative results) was 79%. Other unbalanced chromosome abnormalities were present in 2.1% of specimens and 0.7% had balanced chromosome abnormalities. The inclusive total cytogenetic abnormality rate was 15.4%, of which 85% were potentially detectable by our FISH protocol. This clinical experience demonstrates that aneuploidy detection by FISH on uncultured amniocytes can provide accurate and rapid identification of aneuploidies, especially when such abnormalities are suspected following the diagnosis of fetal anomalies by ultrasound examination.
- OSTI ID:
- 134509
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-1243
- Journal Information:
- American Journal of Human Genetics, Vol. 55, Issue Suppl.3; Conference: 44. annual meeting of the American Society of Human Genetics, Montreal (Canada), 18-22 Oct 1994; Other Information: PBD: Sep 1994
- Country of Publication:
- United States
- Language:
- English
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