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Case of non‐mosaic trisomy 20 in amniotic fluid cultures without anomalies in the fetus: Cytogenetic discrepancy between amniocytes and fetal blood
Author(s) -
Maeda Kazuhisa,
Imoto Issei,
Kaji Takashi,
Yoshida Yukiko,
Nakayama Soichiro,
Irahara Minoru
Publication year - 2015
Publication title -
journal of obstetrics and gynaecology research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 50
eISSN - 1447-0756
pISSN - 1341-8076
DOI - 10.1111/jog.12488
Subject(s) - amniocentesis , fetus , karyotype , trisomy , amniotic fluid , medicine , aneuploidy , prenatal diagnosis , placenta , obstetrics , gestational age , chorionic villus sampling , andrology , pregnancy , pathology , biology , chromosome , genetics , gene
We report a case of non‐mosaic trisomy 20 detected prenatally by amniocentesis during the 16th week of pregnancy. Fetal blood sampling showed a normal karyotype and no fetal, neonatal or infant abnormalities were observed. Amniotic fluid cell karyotyping revealed a trisomy 20 (47, XY ,+20) with 100% trisomic cells (38/38); however, a subsequent cordocentesis revealed a normal male karyotype. Moreover, a follow‐up ultrasonographic examination did not reveal any major congenital malformations, and a healthy male infant was delivered subsequently at an appropriate gestational age without obvious anomalies. Cytogenetic analysis of blood lymphocytes from the infant revealed a normal karyotype, but cultured cells from the term placenta showed a mosaic karyotype 47, XY ,+20/46, XY with 88% trisomic cells (44 of 50). Furthermore, no anomalies or developmental delays were observed in the neonatal period, thus suggesting two possibilities: confined placental mosaicism with the presence of normal and abnormal cell lineages, or generalized mosaicism affecting a limited number of tissues in both the placenta and fetus.