626
LETTERS TO THE EDITOR
Table 1. Summary of six patients undergoing early twin amniocentesis
Patient 1 2 3
4 5 6
Indication Maternal age 38 One fetus with cystic hygroma Maternal age 41 Maternal age 36 One fetus with cystic hygroma; maternal age 37 Maternal age 36
Gestational age (weeks)
No. of needle insertions
10.4
2
11.7 12.4 13.6
3 2 2
11.3 12.2
2 2
within theconfines of an Institutional Review Ward, R.H., Petrou, M., Modell, B.M., Knott, P.D., Maxwell, D., Hooker, J.G. (1988). Board protocol. However, for those patients Chorionic villus sampling in a high-risk desiring first-trimester prenatal cytogenetic p o p u l a t i o n 4 years’ experience, Br. J. Obstet. analysis of twin pregnancies, early twin Gynaecol.,95,103(r1035. amniocentesis warrants consideration as an applicable prenatal diagnostic procedure. SHERMAN ELIAS, LEEP. SHULMAN, OWEN P. PHILLIPS, JEFFREY S. DUNGAN, Confirmation of CVS mosaicism CHRISG R E V E N C ~ AND ~ DJOELEIGHSIMPSON Department of Obstetrics and Gynecology, We read with interest the report of Kalousek University of Tennessee, Memphis; et al. (1991) of a series of 34 chorionic villus Memphis. Tennessee, U.S.A. sampling (CVS) cases with confined placental mosaicism (CPM) in cultured cells. They found evidence of similar mosaicism in 17 of REFERENCES the 34 term placentae. In these confirmed Elias, S., Gerbie, A.B., Simpson, J.L., Nadler, H.L., Sabbagha, R.E., Shkolnik, A. (1980). cases, a high percentage of cells analysed Genetic amniocentesis in twin gestations, Am. J . from CVS material was abnormal, and it was only within this group of cases that Obstet. Gynecol., 138, 169-113. King, C.R., Cox, G., Arthur, T. (1990). Successful intrauterine growth retardation (IUGR) was chorionic villus sampling of a triplet pregnancy. observed. A case report, J. Reprod. Med., 3 5 , 4 4 1 4 3 . We have studied term placentae from four Pergament, E., Wapner, R., Jackson, L., cases of CPM detected in direct and/or longSchulman, J.D., Fine, B., Copeland, K., Black, term cultures offirst-trimester chorionic villi. S.H., Ginsberg, N., Verlinsky, Y.(1990). Risk All cases had a normal karyotype in both and efficacy of chorionic villus sampling in multiple gestations (Abstract), Am. J . Hum. Genel., amniotic fluid and cord blood follow-up studies. We cultured amnion, chorion, and 41, A282. multiple areas of villi from term placentae Pijpers, L., Kleijer, W.J., Reuss, A., Jahoda, M.G., and were able to confirm the presence of an Los, F.J.,Sachs,E.S., Wladimiroff, J.W.(1990). Transabdominal chorionic villus sampling in a abnormal cell line in only one of the four multiple pregnancy at risk for arginosuccinic cases (see Table 1, p. 627). We found two aciduria: a case report, Am. J. Med. Genet., 36, abnormal cell lines in both the direct prep449450. aration and the long-term cultures in case 1 Shulman, L.P., Simpson, J.L., Elias, S. (1992). (May et al. 1990). The 18 cell line, but not Invasive prenatal genetic techniques. In: Sciarra, J. (Ed.). Gynecology and Obstetrics, the +22 line, was present in term placenta. The 18 and 22 lines composed 2 1 and 57 Philadelphia: Lippincott, in press. Svigos, J., Rudzki, Z., Morris, D. (1990). Selective per cent, respectively, of cells analysed from feticide in twin pregnancy: a case report, Med. J. the direct preparation, and 60 and 7 per cent, Aust., 152,492494. respectively, of those from the cultures.
+
+
+
627
LETTERS TO THE EDITOR
Table 1. Number and per cent (in parentheses) of abnormal cells observed in CVS and term placentae
cvs Case
Abnormality
Direct
Term Placentae
Culture
Amnion
Chorion
Villi*
~
1 2 3 4
+ 18 +22 + 13 453 f 3
11/53 (21) 30/53(57)
0130
6/23 (26) 22/43 (5 1)
27/45 (60) 3/45(7)
0/30 0130
9/30 (30)
0/30
0130 0/30 -
0130 0130
0/30 0130
0/33
5/35 (14) 0135 0/58 0164 0/60
*Villus samples from two or more sites.
REFERENCES Additionally, in our case 4,51 per cent of the direct preparation cells were +3, while Kalousek, D.K., Howard-Peebles, P.N., Olson, long-term cultures and term placenta were S.B., Barrett, I.J., Dorfmann, A., Black, S.H., Schulman, J.D., Wilson, R.D. (1991). Connormal. Thus, these data suggest that it is the firmation of CVS mosaicism in term placentae proportion of abnormal cells in CVS cultures and high frequency o f intrauterine growth and not so much that proportion in direct retardation association with confined placental preparations which is correlated with conmosaicism, Prenuf.Diugn., 11,743-750. firmation of mosaicism in term placenta. May, K.M.,Marion, J.P., Hassold, T.J., Priest, Furthermore, our cases fit Kalousek’s rule J.H. (1990). Analysis of triple cell line mosaicism that in general, levels of mosaicism for involving trisomies 18 and 22 in first trimester aneuploidy less than 35 per cent in CVS and term placental villi, Am. J . Hum. Genet.,47, cultures cannot be detected in term placenta. A28 1 . Our four cases of CPM, including the one confirmed in term placenta, were not associated with IUGR. These findings are Maternal serum hCG levels in triploidy: consistent with the report of Kalousek et al. variability and need to consider molar tissue (1991), who found IUGR in less than half (6 of 17) of their CPM cases confirmed in term Kohn et al. (1991) have raised the interesting placenta and in none of the unconfirmed possibility that a finding of low maternal cases. serum human chorionic gonadotropin Our small series of CPM cases suggests (MShCG) in second-trimester screening for that a high proportion of aneuploid cells in fetal Down’s syndrome may be associated cultured first-trimester chorionic villi may with fetal triploidy. In the two cases that they represent a line that will persist to birth. studied, both the MShCG and the maternal Although we have not confirmed IUGR in serum unconjugated oestriol (MSuE3) values such pregnancies, we agree that evidence were very low. Their finding of low MShCG from the larger series of Kalousek et al. in triploidy is surprising since 86 per cent (1991) would indicate a need to monitor of triploid conceptuses are associated with them for possible IUGR. partial hydatidiform mole (Szulman et al., M. MAY*, 1981), a condition which might be expected KRISTIN DEBRA F. SAXE*, to result in elevated rather than low MShCG AND JEAN H . PRIEST? levels. The findings of Kohn et al. prompted us to *Emory Genetics Laboratory, Department of Pediatrics, review six patients who had triploid products Emory University, of conception in which both MShCG values Atlanta, Georgia, U.S.A. and histopathological information were tDepartment of Medical Genetics, available (Table 1, p. 628). Cases 1-3 had Shodair Children k Hospital. Helena, maternal serum samples drawn at gestaMontana, U.S.A. tional ages appropriate for prenatal Down’s
LETTERS TO THE EDITOR
Table 1. Summary of six patients undergoing early twin amniocentesis
Patient 1 2 3
4 5 6
Indication Maternal age 38 One fetus with cystic hygroma Maternal age 41 Maternal age 36 One fetus with cystic hygroma; maternal age 37 Maternal age 36
Gestational age (weeks)
No. of needle insertions
10.4
2
11.7 12.4 13.6
3 2 2
11.3 12.2
2 2
within theconfines of an Institutional Review Ward, R.H., Petrou, M., Modell, B.M., Knott, P.D., Maxwell, D., Hooker, J.G. (1988). Board protocol. However, for those patients Chorionic villus sampling in a high-risk desiring first-trimester prenatal cytogenetic p o p u l a t i o n 4 years’ experience, Br. J. Obstet. analysis of twin pregnancies, early twin Gynaecol.,95,103(r1035. amniocentesis warrants consideration as an applicable prenatal diagnostic procedure. SHERMAN ELIAS, LEEP. SHULMAN, OWEN P. PHILLIPS, JEFFREY S. DUNGAN, Confirmation of CVS mosaicism CHRISG R E V E N C ~ AND ~ DJOELEIGHSIMPSON Department of Obstetrics and Gynecology, We read with interest the report of Kalousek University of Tennessee, Memphis; et al. (1991) of a series of 34 chorionic villus Memphis. Tennessee, U.S.A. sampling (CVS) cases with confined placental mosaicism (CPM) in cultured cells. They found evidence of similar mosaicism in 17 of REFERENCES the 34 term placentae. In these confirmed Elias, S., Gerbie, A.B., Simpson, J.L., Nadler, H.L., Sabbagha, R.E., Shkolnik, A. (1980). cases, a high percentage of cells analysed Genetic amniocentesis in twin gestations, Am. J . from CVS material was abnormal, and it was only within this group of cases that Obstet. Gynecol., 138, 169-113. King, C.R., Cox, G., Arthur, T. (1990). Successful intrauterine growth retardation (IUGR) was chorionic villus sampling of a triplet pregnancy. observed. A case report, J. Reprod. Med., 3 5 , 4 4 1 4 3 . We have studied term placentae from four Pergament, E., Wapner, R., Jackson, L., cases of CPM detected in direct and/or longSchulman, J.D., Fine, B., Copeland, K., Black, term cultures offirst-trimester chorionic villi. S.H., Ginsberg, N., Verlinsky, Y.(1990). Risk All cases had a normal karyotype in both and efficacy of chorionic villus sampling in multiple gestations (Abstract), Am. J . Hum. Genel., amniotic fluid and cord blood follow-up studies. We cultured amnion, chorion, and 41, A282. multiple areas of villi from term placentae Pijpers, L., Kleijer, W.J., Reuss, A., Jahoda, M.G., and were able to confirm the presence of an Los, F.J.,Sachs,E.S., Wladimiroff, J.W.(1990). Transabdominal chorionic villus sampling in a abnormal cell line in only one of the four multiple pregnancy at risk for arginosuccinic cases (see Table 1, p. 627). We found two aciduria: a case report, Am. J. Med. Genet., 36, abnormal cell lines in both the direct prep449450. aration and the long-term cultures in case 1 Shulman, L.P., Simpson, J.L., Elias, S. (1992). (May et al. 1990). The 18 cell line, but not Invasive prenatal genetic techniques. In: Sciarra, J. (Ed.). Gynecology and Obstetrics, the +22 line, was present in term placenta. The 18 and 22 lines composed 2 1 and 57 Philadelphia: Lippincott, in press. Svigos, J., Rudzki, Z., Morris, D. (1990). Selective per cent, respectively, of cells analysed from feticide in twin pregnancy: a case report, Med. J. the direct preparation, and 60 and 7 per cent, Aust., 152,492494. respectively, of those from the cultures.
+
+
+
627
LETTERS TO THE EDITOR
Table 1. Number and per cent (in parentheses) of abnormal cells observed in CVS and term placentae
cvs Case
Abnormality
Direct
Term Placentae
Culture
Amnion
Chorion
Villi*
~
1 2 3 4
+ 18 +22 + 13 453 f 3
11/53 (21) 30/53(57)
0130
6/23 (26) 22/43 (5 1)
27/45 (60) 3/45(7)
0/30 0130
9/30 (30)
0/30
0130 0/30 -
0130 0130
0/30 0130
0/33
5/35 (14) 0135 0/58 0164 0/60
*Villus samples from two or more sites.
REFERENCES Additionally, in our case 4,51 per cent of the direct preparation cells were +3, while Kalousek, D.K., Howard-Peebles, P.N., Olson, long-term cultures and term placenta were S.B., Barrett, I.J., Dorfmann, A., Black, S.H., Schulman, J.D., Wilson, R.D. (1991). Connormal. Thus, these data suggest that it is the firmation of CVS mosaicism in term placentae proportion of abnormal cells in CVS cultures and high frequency o f intrauterine growth and not so much that proportion in direct retardation association with confined placental preparations which is correlated with conmosaicism, Prenuf.Diugn., 11,743-750. firmation of mosaicism in term placenta. May, K.M.,Marion, J.P., Hassold, T.J., Priest, Furthermore, our cases fit Kalousek’s rule J.H. (1990). Analysis of triple cell line mosaicism that in general, levels of mosaicism for involving trisomies 18 and 22 in first trimester aneuploidy less than 35 per cent in CVS and term placental villi, Am. J . Hum. Genet.,47, cultures cannot be detected in term placenta. A28 1 . Our four cases of CPM, including the one confirmed in term placenta, were not associated with IUGR. These findings are Maternal serum hCG levels in triploidy: consistent with the report of Kalousek et al. variability and need to consider molar tissue (1991), who found IUGR in less than half (6 of 17) of their CPM cases confirmed in term Kohn et al. (1991) have raised the interesting placenta and in none of the unconfirmed possibility that a finding of low maternal cases. serum human chorionic gonadotropin Our small series of CPM cases suggests (MShCG) in second-trimester screening for that a high proportion of aneuploid cells in fetal Down’s syndrome may be associated cultured first-trimester chorionic villi may with fetal triploidy. In the two cases that they represent a line that will persist to birth. studied, both the MShCG and the maternal Although we have not confirmed IUGR in serum unconjugated oestriol (MSuE3) values such pregnancies, we agree that evidence were very low. Their finding of low MShCG from the larger series of Kalousek et al. in triploidy is surprising since 86 per cent (1991) would indicate a need to monitor of triploid conceptuses are associated with them for possible IUGR. partial hydatidiform mole (Szulman et al., M. MAY*, 1981), a condition which might be expected KRISTIN DEBRA F. SAXE*, to result in elevated rather than low MShCG AND JEAN H . PRIEST? levels. The findings of Kohn et al. prompted us to *Emory Genetics Laboratory, Department of Pediatrics, review six patients who had triploid products Emory University, of conception in which both MShCG values Atlanta, Georgia, U.S.A. and histopathological information were tDepartment of Medical Genetics, available (Table 1, p. 628). Cases 1-3 had Shodair Children k Hospital. Helena, maternal serum samples drawn at gestaMontana, U.S.A. tional ages appropriate for prenatal Down’s
