title: Improved prenatal detection of fra(X)(q27.3): methods for prevention of false negatives in chorionic villus and amniotic fluid cell cultures.
abstract: The reliable detection of fra(X)(q27.3) in prenatal samples is important for providing genetic counseling. We have identified 5 new cases of prenatal fragile X [fra(X)] detection in 3 chorionic villus sample (CVS) and 2 amniotic fluid (AF) cell cultures. In 4 of the 5 cases, either excess thymidine (THY) or a combination of THY and 5-fluorodeoxyuridine (FUdR) was clearly superior to FUdR alone as fra(X) inducers. Amniocytes from one case were cultured only in RPMI-1640 and later exposed to FUdR or THY separately. They showed only 2% fra(X) while parallel cultures initiated in Chang medium and incubated in RPMI for at least 7 days (recovery) before fra(X) induction exhibited strikingly increased fra(X) frequencies. Chang medium alone will not allow fra(X) induction in AF (Jenkins EC, Brown WT [1986]: "Genetic Disorders and the Fetus: Diagnosis, Prevention and Treatment." New York: Plenum Press, pp 185-204). Now, using CVS cells, we report that only 1% and 0% fra(X) were detected using FUdR or THY in cells cultured in RPMI for 4 days after removal from Chang medium. Cells with 7 days "recovery" in RPMI exhibited increases from 2 to 6%. Therefore, we have found that Chang medium is very helpful when the appropriate recovery time in another medium is allowed before fra(X) induction. Some false negative reports can be attributed to: induction in Chang medium alone; lack of sufficient recovery time after initiating cells in Chang before induction; and unavailability of the excess THY fra(X) induction system.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Genetics, New York State Institute for Basic Research in Developmental Disabilities, Staten Island 10314.
authors.forename: E C
authors.initials: EC
authors.lastname: Jenkins
authors.forename: M S
authors.initials: MS
authors.lastname: Krawczun
authors.forename: S L
authors.initials: SL
authors.lastname: Stark-Houck
authors.forename: C J
authors.initials: CJ
authors.lastname: Duncan
authors.forename: S
authors.initials: S
authors.lastname: Kunaporn
authors.forename: H
authors.initials: H
authors.lastname: Gu
authors.forename: C
authors.initials: C
authors.lastname: Schwartz-Richstein
authors.forename: P N
authors.initials: PN
authors.lastname: Howard-Peebles
authors.forename: A
authors.initials: A
authors.lastname: Gross
authors.forename: S L
authors.initials: SL
authors.lastname: Sherman
mesh_terms: D000649:Amniocentesis; D000653:Amniotic Fluid / Q000166:cytology; D002478:Cells, Cultured; D002824:Chorionic Villi / Q000648:ultrastructure; D015193:Chorionic Villi Sampling; D003470:Culture Media / Q000494:pharmacology; D005069:Evaluation Studies as Topic; D005188:False Negative Reactions; D005260:Female; D005467:Floxuridine / Q000494:pharmacology; D005600:Fragile X Syndrome / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology; D006801:Humans; D008297:Male; D011247:Pregnancy; D013936:Thymidine / Q000494:pharmacology; D014960:X Chromosome / Q000187:drug effects
chemical_list: D003470:Culture Media; D005467:Floxuridine; D013936:Thymidine