Down syndrome with pure partial trisomy 21q22 due to a paternal insertion (4;21) uncovered by uncultured amniotic fluid interphase FISH.
OBJECTIVE
To emphasize the usefulness and reliability of fluorescence in situ hybridization (FISH) on uncultured amniotic fluid cells in the prenatal diagnosis of common chromosomal aneuploidies.


METHODS
FISH analyses utilizing centromeric, locus-specific or whole chromosome paint DNA probes specific for chromosomes X, Y, 13, 18, 21, and 4 were performed on uncultured amniotic fluid cells or the peripheral blood specimen from the father. Routine chromosome analysis was carried out as well.


RESULTS
A prenatal case with partial trisomy 21 due to a paternal cryptic insertion (4;21) was ascertained by a rapid overnight FISH on uncultured amniotic fluid cells. The fetus was delivered at term and had classical features of Down syndrome.


CONCLUSIONS
Our results stress the importance of FISH on uncultured amniotic fluid cells to supplement routine cytogenetics, especially in cases with abnormal ultrasound findings.
Lee
J
J
Department of Pediatrics, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
Stanley
J R
JR
Vaz
S A
SA
Mulvihill
J J
JJ
Wilson
P
P
Hopcus-Niccum
D
D
Li
Shibo
S
D000328:Adult; D000649:Amniocentesis; D000653:Amniotic Fluid; D002869:Chromosome Aberrations; D002889:Chromosomes, Human, Pair 2 / Q000235:genetics*; D002891:Chromosomes, Human, Pair 21 / Q000235:genetics*; D004314:Down Syndrome / Q000235:genetics* / Q000473:pathology; D005220:Fathers; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D007399:Interphase / Q000235:genetics; D007621:Karyotyping; D008297:Male; D011247:Pregnancy; D014314:Trisomy