title: Prenatal detection of structural abnormalities of chromosome 18: associations with interphase fluorescence in situ hybridization (FISH) and maternal serum screening.
abstract: We describe two cases of prenatally ascertained isochromosome 18. Case 1 included both an isochromosome 18p and an isochromosome 18q, while Case 2 involved only an isochromosome 18q. Both of these cases were associated with a positive maternal serum triple screen trisomy 18 risk (greater than 1 in 100 risk). In addition, fluorescence in situ hybridization (FISH) was performed on uncultured amniotic fluid interphase cells in both cases looking for aneuploidy for chromosomes 13, 18, 21, X and Y. The results of the interphase analyses support the common knowledge that careful interpretation of interphase FISH analysis is necessary and that results should be followed by full cytogenetic analysis. To our knowledge these are the first reported cases of structurally abnormal chromosomes 18 being associated with a positive maternal serum triple screen for trisomy 18.
authors.affiliation: Department of Genetics and Center for Human Genetics Laboratory, Case Western Reserve University and University Hospitals of Cleveland, Cleveland, OH 44106, USA. michael.graf@uhhs.com
authors.forename: Michael D
authors.initials: MD
authors.lastname: Graf
authors.forename: Prabhcharan
authors.initials: P
authors.lastname: Gill
authors.forename: Michael
authors.initials: M
authors.lastname: Krew
authors.forename: Stuart
authors.initials: S
authors.lastname: Schwartz
mesh_terms: D000328:Adult; D000649:Amniocentesis; D000653:Amniotic Fluid / Q000737:chemistry / Q000166:cytology; D006063:Chorionic Gonadotropin / Q000097:blood; D002869:Chromosome Aberrations; D002887:Chromosomes, Human, Pair 18; D004964:Estriol / Q000097:blood; D005260:Female; D005865:Gestational Age; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007399:Interphase; D018404:Isochromosomes; D008297:Male; D011296:Prenatal Diagnosis; D014314:Trisomy; D000509:alpha-Fetoproteins / Q000032:analysis
chemical_list: D006063:Chorionic Gonadotropin; D000509:alpha-Fetoproteins; D004964:Estriol