False-positive prenatal diagnosis of trisomy 18 by interphase FISH: hybridization of chromosome 18 alpha-satellite probe (D18Z1) to chromosome 2.

摘要

Amniocentesis was done on a 39-year-old woman at 16 weeks of gestation for rapid prenatal screen (chromosomes 13, 18, 21) and chromosome analysis. The indication was an increased risk of trisomy based on a first trimester combined fetal ultrasound biometry and maternal blood serum screening.Spreads for interphase fluorescence in situ hybridization (FISH) were directly prepared from uncultured amniocytes. Spreads for conventional cytogenetic analysis and metaphase FISH analysis were prepared from in situ cultured amniocytes and from parental blood lymphocytes.