The role of FISH in prenatal diagnosis
- Univ. of California, Los Angeles (United States)
FISH provides a cytogenetic technique which is useful in defining de novo translocations, deletions, insertions, and marker chromosomes in prenatal diagnosis. While the cytogenetic interpretation may be improved with FISH, it may not resolve questions concerning prognosis and options which are genetic counseling issues. Two recent cases illustrate this. Case 1 involved a 45,X/46,X,+mar karyotype from amniocentesis. 22/50 cells had 46,X/46,X+mar; 28/50 cells had 45,X. The marker was smaller than a G. C banding did not confirm this as a Y. The father`s peripheral blood study was normal and his Y did not resemble the marker. It appeared likely that the marker was a structurally abnormal Y since male external genitalia were detected by fetal ultrasound. FISH using alpha- and classical (DYZ1/DYZ3) satellite Y-specific probes did not identify the marker as a Y. Case 2 was a fetus which had a de novo translocation 46,XX,t(3;11)(q26.3;q21) by amniocentesis and confirmed by UBS. FISH for the number 3 and 11 chromosomes confirmed this rearrangement. The parents were advised of the risk associated with a de novo balanced translocation. The possible prognosis for these two different fetuses was not changed by the FISH analysis. FISH, while helpful, is only one aspect of the studies done to provide more accurate genetic counseling to parents; the pregnancy/family history, fetal ultrasound, other possible prenatal studies and pregnancy outcome from perspective studies compose other important aspects that are not mutually exclusive.
- OSTI ID:
- 134648
- 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
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