Routine chromosome analysis on fetal blood microaliquots obtained at fetoscopy

A routine study of the fetal karyotype was performed on samples obtained at 64 fetoscopic procedures. In 13 cases only pure amniotic fluid was available for the cultures, while in the remaining 51 cases the chromosome analysis was carried out on PHA-stimulated lymphocyte microcultures set up with any excess fetal blood above the requirements for globin-chain synthesis. Karyotype could be determined on fetal lymphocytes in 44 cases (86 per cent). All the fetuses were chromosomally normal. This experience shows that cytogenetic analysis using microaliquots of fetal blood is a relatively simple technique which should be introduced into routine prenatal diagnosis by fetoscopy.     

Sampling pure fetal blood in twin pregnancies by fetoscopy using a single uterine puncture

A technique for sampling pure fetal blood in twin pregnancies using a single uterine entry with a fetoscope is described. The fetoscope was inserted into one sac and after blood had been obtained from that, twin, the fetus in the other sac was sampled by trans-septal passage of the blood-sampling needle. This was done in six out of seven patients, the first in the series having two separate insertions of the fetoscope, one into each sac. Pure fetal blood was taken from all 14 fetuses, either from the placental insertion of the umbilical cord or the umbilicus, and the volume of the samples ranged from 200 μl to 1200 μl. In six patients the fetuses were at risk of β-thalassaemia and in one of haemophilia A. Some observations are made relating zygosity to the ultrasonic and fetoscopic appearance of the septum between the sacs.     

Prenatal confirmation of trisomy 12 mosaicism by fetal skin biopsy

Trisomy 12 mosaicism diagnosed at 16 weeks' amniocentesis in a 42-year-old woman was not confirmed at 18 weeks' gestational age in amniotic fluid or fetal blood. Fetal skin biopsy performed at the same time did, however, allow the detection of trisomy 12 in 1 of 14 fibroblasts analysed. Fetal skin biopsy can be included within the diagnostic procedures to be performed when a level III mosaicism is found in the amniotic fluid.     

Fetal skin biopsy in prenatal diagnosis of some genodermatoses

Various methods of obtaining fetal skin for prenatal diagnosis of certain autosomal-recessive congenital genodermatoses have been assessed. An attempt was made to obtain fetal skin by fetoscopy in 15 patients prior to pregnancy termination for a variety of medical reasons at 18–26 weeks. Specimens were obtained only in five cases (8 successful attempts out of 48). In twelve cases, of which five had a history of a child with junctional (Herlitz type) or dystrophic (Hallopeau-Siemens type) epidermolysis bullosa or non-bullous congenital ichthyosiform erythroderma at 16–25 weeks of pregnancy, fetal skin was obtained without fetoscopy under direct ultrasonic control. Specimens were obtained in all cases (33 successful attempts out of 39). In three cases, fetal pathology was diagnosed by the method of semi-thin and ultra-thin skin sections, and the respective pregnancies were terminated.     

Prenatal diagnosis of harlequin ichthyosis by fetal skin biopsy; Report of two cases

Two cases of harlequin ichthyosis were successfully diagnosed prenatally by fetal skin biopsy. The aborted fetuses were later confirmed to be afflicted with this very unusual skin disease. Both families had a previous history of harlequin ichthyosis. In performing the biopsy, it was found that amniotic fluid cytology can also be very helpful in the diagnosis of this kind of severe ichthyosis. With regard to these families, the disease may have been transmitted in an autosomal dominant fashion, and not in a recessive manner as is commonly believed.     

The safety of fetoscopy: (I). Effect of umbilical vessel puncture on the fetal heart rate and cord histology

The fetal heart rate (FHR) was continuously monitored during 42 umbilical vessel punctures performed at the placental insertion of the cord in 24 diagnostic fetoscopies in which pure fetal blood was obtained. In only one patient did a deceleration first appear during puncture and aspiration of fetal blood. In two patients decelerations preceded fetoscopy and in two others they began during the fetoscopy but before puncture of an umbilical vessel. In 19 patients, the FHR did not change at all during the procedure. Fetal haemorrhage after sampling was either absent or minimal. Six pregnancies were terminated because a positive diagnosis had been made and 18 healthy babies were born. Umbilical cords were examined after 7 terminations of pregnancy and after 6 deliveries. In the former group the puncture could just be seen with the naked eye and the needle track was demonstrated histologically in 6. No traces of the puncture or other abnormalities were found in the cords after delivery. Fetal blood sampling from umbilical cord vessels, particularly at the placental insertion of the cord, is the technique of choice since pure fetal blood can be obtained without increasing the risk of fetoscopy.     

Creatine kinase estimation in pure fetal blood samples for the prenatal diagnosis of duchenne muscular dystrophy

This paper compares the results of a survey of plasma creatine kinase (CK) activity measured in fetuses at-risk for Duchenne muscular dystrophy (DMD) with a reliable control series. Only pure fetal blood samples obtained by fetoscopy at between 17–24 weeks gestational age were used. Of the at-risk group 19 male pregnancies, mostly at low risk for DMD, proceeded to term with a normal outcome; there was no significant difference between their fetal plasma CK activities and the control group. Another 21 male pregnancies were terminated. This group included the highest risk mothers and hence was expected to contain a significant proportion of affected fetuses. The fetal plasma CK activity range was overlapping but significantly higher than the control group. No grossly elevated CK value was obtained. We conclude that, on average, DMD fetuses at this gestational age have higher plasma CK activity than controls. The problems of applying this finding to the prenatal diagnosis of DMD are discussed.     

Prenatal ultrasound diagnosis of fetal scoliosis with termination of the pregnancy: Case report

Gross scoliosis of the fetal thoracic spine was diagnosed at 18 weeks gestation. The pregnancy was terminated and the fetus found to have webbing of the neck and an imperforate anus in addition to vertebral defects.     

Cytogenetic analysis of 1375 amniotic fluid specimens from pregnancies with gestational age less than 14 weeks

Our laboratory has received 1375 early amniotic fluid (EA) specimens during the past 5-year period for cytogenetics analysis. The gestational ages of the EA specimens were less than 14 weeks as estimated by ultrasound. The average volume of specimen received was 16 ml. Specimens were typically received in two collection tubes and cultured in Chang A and in supplemented MEM media using the in situ technique. Of the 1375 EA specimens received, 1356 were successfully cultured and yielded results. Abnormal results were found in 67 (4.9 per cent) of the cases. Nineteen specimens (1.4 per cent) failed to yield a result. The mean turn-around time (TAT) for all EA specimens was 8.28 days. In 1991, the average TAT for the EA specimens was 8.00 days compared with a TAT of 6.59 days for all specimens received over 14 weeks gestational age. The number of EA specimens received has increased from 1.5 per month in 1986 to 57 per month in 1991. In summary, our experience with EA specimens for cytogenetic analysis has demonstrated that the success rate is 98.6 per cent and that an increasing number of obstetricians are performing early amniocentesis as they seek to provide their patients with earlier results and an alternative to chorionic villus sampling.     

Prenatal diagnosis of thalassemia major by fetal blood analysis: Experience with 1000 cases

In this report we have summarized our experience with the prenatal diagnosis of β-thalassemia in 1000 pregnancies followed at least until 12 months after birth. In the majority of these cases, the thalassemia lesion was the nonsense mutation at the codon corresponding to amino acid 39, which produces the hematological phenotype of β-thalassemia. Fetal blood sampling was carried out by placental aspiration, by which a sufficient amount of fetal blood for analysis was obtained in the majority of cases (99 per cent). The fetal mortality associated with fetal blood sampling was 6·3 per cent. Those placental samples contaminated by maternal cells were successfully purified by Ørskov lysis. Fetal blood was analysed by globin chain synthesis on CM–52 columns, which gave reliable results. Two misdiagnoses (0·2 per cent) have been made of which one was due to a non-globin protein co-migrating with the β-chains while the other resulted from a misclassification of the type of thalassemia segregating in the family.     

Activity and multiple forms of α-L-fucosidase and hexosaminidase in chorion biopsy specimens and some fetal organs

It was shown that activities and isoenzyme patterns of x-L-fucosidase and hexosaminidase were similar in biopsy specimens of chorion obtained immediately before induced abortion in normal pregnancy and in chorion tissue itself. A comparative study of isoenzyme patterns of these glycosidases showed their similarity in chorion and human fetal kidney, liver and lungs. The data obtained may be applied to the investigation of the multiple forms of α-L-fucosidase and hexosaminidase in chorion biopsy specimens for the prenatal diagnosis of fucosidosis (α-L-fucosidase deficiency). Tay-Sachs diseases (hexosaminidase A deficiency) and Sandhoff disease (deficiency of hexosaminidase A and B).     

Prenatal diagnosis of tyrosinase-negative oculocutaneous albinism by an electron microscopic dopa reaction test of fetal skin

An electron microscopic DOPA reaction test of fetal skin was used for the prenatal diagnosis of tyrosinase-negative oculocutaneous albinism (OCA). The subject was a 34-year-old Japanese woman in her second pregnancy. Her first child, born in 1982, had been previously examined and confirmed to have tyrosinase-negative OCA. The parents requested a prenatal diagnosis and we sampled skin from the upper trunk of the fetus. On conventional electron microscopy, the development of melanosomes in interfollicular melanocytes had progressed no further than stage II. Fetal skin samples incubated with L-DOPA solution indicated a lack of tyrosinase activity and showed that the melanosomes had not progressed beyond stage II. In skin samples from the trunks of three Japanese fetuses aborted for other reasons at 19–20 weeks of gestation, most premature melanosomes were further melanized to stage IV after incubation with L-DOPA solution. A prenatal diagnosis of tyrosinase-negative OCA was made. The parents requested a termination and skin biopsies of the abortus confirmed the diagnosis. This study shows that tyrosinase is normally present in melanocytes of the fetal epidermis at 20 weeks' gestation, and that the electron microscopic DOPA reaction test of a fetal skin biopsy specimen is safe and practical, and provides reliable information for making a prenatal diagnosis of tyrosinase-negative OCA in the second trimester.     

Prenatal diagnosis,fetal pathology and cytogenetic analysis of A 46,XX/47,XX, + 15 mosaic

Mosaic trisomy 15 was prenatally diagnosed on amniotic fluid cells from two consecutive amniocenteses and was confirmed on cells from five different fetal tissues. The proportion of normal versus trisomic cells was consistently higher in the amniotic cell cultures and-with one exception-in the fetal tissues, while serial subcultures gave different results. The slightly atypical external features and internal malformations of the affected fetus as compared to the only clinical observation from the literature are not unusual enough to allow the delineation of a specific malformation pattern.     

Attitudes toward abortion for fetal anomaly in the second vs. the third trimester: A survey of Parisian obstetricians

Cross-cultural differences exist in prenatal diagnosis and abortion for fetal anomaly, stemming from variations in laws, reimbursement policies, litigation, physicians' decision-making authority, and attitudes toward the prevention of handicaps. The first part of this paper discusses such differences in France and the U.S. The second part describes a survey of practising obstetricians in Paris, designed to assess (1) their attitudes toward pregnancy termination for various conditions, (2) their concern about fetal viability, (3) their desire for diagnostic certainty before justifying a late abortion, and (4) their perceived role in such decision-making. Among the 64.8 per cent (N = 217) who responded, the majority supported third-trimester termination (TTT) for diseases such as spina bifida, trisomy 21 , microcephaly, and Duchenne muscular dystrophy; 30–59 per cent supported TTT for cystic fibrosis and sickle cell disease; and 22–29 per cent supported TTT for haemophilia, tetralogy of Fallot, limb amputation, and Turner and Klinefelter syndromes. Obstetricians who approved of abortion across trimesters were less concerned with the certainty of diagnosis than its severity, more likely to think that abortion ought to be the parents' choice, but more likely to report making a recommendation to the parents about whether to abort a fetus. Such permissive abortion attitudes might imply more permissive prenatal diagnosis and abortion practice among Parisian obstetricians, which might lead to increased migration of patients from other E.C. countries. Cross-cultural variation in obstetric practice suggests that an international registry of pregnancies terminated for medical reasons, enabling further study of this issue, would be valuable.     

Normal ultrasonic size and characteristics of the fetal adrenal glands

Utilizing real-time ultrasound we define the normal fetal adrenal glands from the 20th week of gestational age. The normal acoustic characteristics of the adrenals are described. Potential applications of the nomogram derived from this study are suggested.     

Chorion biopsy in early pregnancy: A method of early prenatal diagnosis for inherited disorders

Chorion biopsy was performed in 165 cases at 6–12 weeks of pregnancy, following an ultrasonic or embryo-fetoscopic chorion frondosum localization. One hundred patients had their biopsies taken immediately before induced abortion. In 39 cases abortion was carried out 5–10 days after biopsy. In 26 pregnant patients biopsy was performed for genetic reasons. Fetal sex was determined in ‘native’ smears from biopsy specimens for cytological investigation, using X- and Y-chromatin assays. Fetal sex diagnosis proved correct in all the cases. In 40 observations, the origin of the biopsy specimen was histologically checked. In 16 biopsy specimens, a number of enzymes were simultaneously assayed: β-D-ghcosidase, β-D-galacto-sidase, β-D-hexosaminidase, β-D-glucuronidase, α-L-fucosidase, β-D-mannosidase, sphingo-myelinase and arylsulphatase A. The levels of the above enzymes were compared to those observed in tissue cultures of amniotic cells obtained through amniocentesis at 16–18 weeks of pregnancy. The amniotic sac remained intact in all cases of chorion biopsy. If the pregnancy was maintained after the biopsy, no spontaneous abortions were recorded, and pregnancies resulted in the timely delivery of full-term healthy infants. Therefore, the method described is a valuable means of diagnosing inherited disorders, with promising applications in prenatal medicine.     

Transvaginal sonography—detection of findings suggestive of fetal chromosomal anomalies in the first and early second trimesters

Over a 4-year period, 14 dyskaryotic fetuses were diagnosed by amniocentesis, performed after early detection of malformations using transvaginal sonography (TVS). These 14 dyskaryotic fetuses were detected out of 4878 sonographic screenings performed by TVS between 9 and 16 weeks' gestation. Twenty-eight per cent of the referrals were at high risk and 72 per cent were at low risk for fetal malformations. Two hundred and twenty-nine fetuses (4.7 per cent) of the screened population had 265 anomalies, 39 per cent of them being transient. In 7 of the 14 dyskaryotic fetuses (50 per cent), the sonographically detected anomalies were transient, being undetected by follow-up sonographic screenings at later gestational ages (⩾18 weeks). Postponing the first sonographic scan aimed at malformation detection to a later gestational age may lead to transient anomalies and their associated dyskaryosis being missed.     

Detection and isolation of fetal cells from maternal blood using the flourescence-activated cell sorter (FACS)

The presence of fetal cells in the maternal circulation during pregnancy has been suggested by repeated observations of small numbers of cells containing Y chromatin or a Y chromosome in the blood of pregnant women. With the fluorescence-activitated cell sorter (FACS), we have used antibodies to a paternal cell surface (HLA) antigen, not present in the mother, to select fetal cells from the lymphocyte fractions of a series of maternal blood samples, collected as early as 15 weeks of gestation. These sorted cells have been examined for a second paternal genetic marker, Y chromatin. Y chromatin-containing cells were found among the sorted cells from prenatal maternal blood specimens in 8 pregnancies subsequently producing male infants whose lymphocytes reacted with the same antibodies to paternal antigen used for sorting with the FACS. In each of 17 pregnancies resulting in male infants who failed to inherit the antigen detected by the antibodies used for cell sorting, Y chromatin-containing cells were not found prenatally. The use of two paternal genetic markers, a cell surface antigen and nuclear Y chromatin, to identify fetal cells in maternal blood permits us to conclude that these cells are present in the mother's circulation, as early as 15 weeks gestation. Further development of the techniques reported here could lead to widespread screening of maternal blood samples during pregnancy for detection of fetal genetic abnormalities.     

Prenatal diagnosis of fetal anomalies during the second trimester of pregnancy: Their characterization and delineation of defects in pregnancies at risk

During a follow-up study of 19 790 pregnancies at risk for a genetic disease, from 1968 to 1989, 1083 fetuses were found to have an anomaly during the second trimester, leading to 977 terminations of pregnancy. Neural tube defects (31.4 per cent), chromosomal disorders (27.1 per cent), and Mendelian or multifactorial diseases (10.6 per cent) were the main causes of fetal anomaly. More than half (52.9 per cent) of the fetal anomalies were detected by routine ultrasound examination. Forty-two per cent of cystic hygromas were secondary to a chromosomal defect. We stress the importance of a comprehensive fetal and newborn examination to ensure an accurate diagnosis so that subsequently accurate counselling can be provided.