ISOLATED FETAL CHOROID-PLEXUS CYSTS AND KARYOTYPE ANALYSIS - IS IT NECESSARY

The purpose of this study was to evaluate the risk of fetal aneuploidy in the presence of isolated choroid plexus cysts and to evaluate the results obtained from our institution and those reported previously in the English literature. All patients with fetal choroid plexus cysts on prenatal ultrasonography were offered genetic counseling and amnioc entesis for fetal karyotyping. Seven of 274 fetuses, 2.6% (95% confide nce interval = 1.0 to 5.2%), with isolated choroid plexus cysts were a neuploid. Literature analysis located 23 other reports of 1537 fetuses with isolated choroid plexus cysts; 26 were karyotypically abnormal, 1.7% (95% confidence interval = 1.0 to 2.4%). When evaluating only tho se patients whose indication for amniocentesis was choroid plexus cyst s (i.e., eliminating those patients with advanced maternal age or abno rmal serum screening) the risk of having a fetus with trisomy 18 chang ed little, 1.9% (95% confidence interval = 0.4 to 5.5%). Our data, com bined with those of the literature, suggest that the risk of finding a n abnormal fetal karyotype in the presence of isolated choroid plexus cysts is at least 1% and may be as high as 2.4%. On the basis of these results, genetic counseling and prenatal diagnosis should be offered to these patients.