title: The role of cordocentesis in assessment of mosaicism found in amniotic fluid cell culture.
abstract: Chromosomal mosaicism presents one of the most difficult problems in prenatal cytogenetic diagnosis, requiring the differentiation of true mosaicism from pseudomosaicism. To overcome associated problems and to prevent termination of normal pregnancies, we investigated 23 pregnancies in which true mosaicism has been found in amniotic fluid cell culture. A fetal blood sample was obtained by cordocentesis for rapid karyotyping, and meticulous sonographic examinations were carried out for detecting fetal abnormalities. The 23 cases in which mosaicisms were found in amniocytes involved five cases with sex chromosomal abnormalities, twelve with autosomal trisomy, four with autosomal structural defects, one with a supernumerary marker and one with tetraploidy. The karyotype from fetal leukocytes confirmed the diagnosis of mosaicism in only three out of 23 cases. These three included: two autosomal trisomies (47,XY + 13/47,XY + 21 and 46,XY/47,XY + 21) and one sex chromosome mosaicism (45,X/46,XY). These were all selected for elective termination of pregnancies by the parents' request. Post abortion karyotype re-confirmed previous karyotype. The other twenty lymphocyte karyotypes were normal, and of these, 19 patients gave birth at term, and one delivered prematurely due to premature rupture of membranes. All 20 born infants were found normal by both neonatal examination and re-karyotypes. We conclude that finding of mosaicism in amniotic fluid culture requires further investigation. Furthermore, in the presence of amniotic fluid cell true mosaicism and normal karyotype in fetal blood, continuation of the pregnancy is safe and to be recommended.
authors.affiliation: Obstetrics and Gynecology Department, Central Emek Hospital, Afula, Israel.
authors.forename: E
authors.initials: E
authors.lastname: Shalev
authors.forename: Y
authors.initials: Y
authors.lastname: Zalel
authors.forename: E
authors.initials: E
authors.lastname: Weiner
authors.forename: H
authors.initials: H
authors.lastname: Cohen
authors.forename: Y
authors.initials: Y
authors.lastname: Shneur
mesh_terms: D000032:Abortion, Therapeutic; D000328:Adult; D000653:Amniotic Fluid / Q000166:cytology*; D002869:Chromosome Aberrations / Q000175:diagnosis / Q000235:genetics; D025063:Chromosome Disorders; D017218:Cordocentesis; D005260:Female; D005312:Fetal Blood / Q000166:cytology; D005315:Fetal Diseases / Q000175:diagnosis* / Q000235:genetics; D006801:Humans; D007621:Karyotyping; D008423:Maternal Age; D009030:Mosaicism; D011123:Polyploidy; D011247:Pregnancy; D011256:Pregnancy Outcome; D011262:Pregnancy Trimester, Second; D018566:Pregnancy, High-Risk; D012729:Sex Chromosome Aberrations / Q000175:diagnosis / Q000235:genetics; D014314:Trisomy; D016216:Ultrasonography, Prenatal