FISH of uncultured amniocytes for prenatal diagnosis: Experience in 24 cases using commercially available probes

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · American Journal of Human Genetics

OSTI ID:134510

Weremowicz, S; Sandstrom, M McH; Walsh, K A ^[1]

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1. Harvard Medical School, Boston, MA (United States); and others

Rapid prenatal diagnosis of chromosomal aneuploidies is being requested increasingly by physicians at our institution. We report our experience in providing rapid diagnoses in prenatal samples referred following an abnormal ultrasound examination (n=22) and for confirmation of trisomy 21 prior to selective termination in a twin gestation (n=22). Uncultured amniocytes (46,XY) and cultured lymphocytes (46,SY) were used as control cells and a DXZ1 probe was hybridized separately from the test probes as a control probe. In 23 cases our FISH interpretation was concordant with the cytogenetic analysis. In one case referred to rule out trisomy 21 in which cystic hygroma was detected on ultrasound exam in a 35 y.o. G2 P1, a FISH interpretation of disomy 21 was based on 18% of cells with 1 signal, 65% with 2, 15% with 3, and 2% with 4; the large percentage of 3 signals was also reported. Cytogenetic analysis was 47,XX,+21 in 63 metaphases. Subsequent FISH analysis of metaphases revealed a large number of chromosomes 21 with only one site of hybridization that might have contributed to the discordant interpretation. Whether this result reflects population polymorphism in hybridization of this cosmid remains to be elucidated. Our findings confirm use of FISH as an invaluable adjunct to conventional cytogenetics; however, results must be interpreted cautiously until larger numbers of cases have been analyzed to detect potentially rare events.

• OSTI ID: 134510
• Report Number(s): CONF-941009--
• Journal Information: American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
ACCURACY
CHROMOSOMAL ABERRATIONS
DETECTION
DNA HYBRIDIZATION
EFFICIENCY
EMBRYONIC CELLS
FLUORESCENCE
HUMAN Y CHROMOSOME
PROBES
ULTRASONOGRAPHY