ABSTRACT
We present two fetuses who were prenatally diagnosed by amniocentesis as having chromosomal mosaicism but who had a normal karyotype in the fetal blood by cordocentesis. One of the both fetuses had Turner and the other had trisomy 20 mosaicism. The prognosis for Turner mosaicism and trisomy 20 mosaicism diagnosed prenatally has yet to be established. The pregnancy with 45,X/46,XX mosaicism was terminated at 23+3 weeks' gestation. Autopsy findings showed no features of Turner's syndrome. Postnatal cytogenetic analysis revealed 45,X[4]/46,XX[52] mosaicism in skin and 46,XX in the lung tissue. The other fetus had amniocytes with trisomy 20 mosaicism and fetal cord blood cells with a normal karyotype. The baby was delivered at 38+2 weeks' gestation. At birth and 3 months after birth, no apparent abnormal findings were found. These cases with chromosomal discrepancy among various fetal tissues are rare. Two cases were discussed with the review of literature.