Prenatal diagnosis of genetic diseases using chorionic villi

Chorionic villi biopsy allows first trimester prenatal diagnosis of some genetic diseases. In this study the results of 163 diagnoses are presented, and among these, 59 diagnoses of autosomal recessive metabolic diseases with 8 observations of congenital adrenal hyperplasia due to 21 OH deficiency and 6 observations of Fanconi anemia.     

Prenatal diagnosis of triploidy by transabdominal aspiration of chorionic villi

A case of triploidy identified in second trimester fetal diagnosis is presented. Cytogenetic study was undertaken in chorionic willi obtained by transabdominal placentocentesis. The diagnosis was confirmed by cytogenetic analysis of cultured amniotic fluid cells. The observation was revealed within a programme of combined ultrasound and cytogenetic prenatal monitoring, in association with maternal age. The fetus aborted at 23 weeks of pregnancy was abnormal, including congenital malformations and hypoplasia of internal organs and placenta.     

First-trimester diagnosis on chorionic villi obtained by direct vision technique

Summary An improved technique for direct vision chrionic biopsy that gives a clear view of the amniotic sac was developed. With this technique, used in 48 women prior to vacuum aspiration and in six cases for diagnosis (karyotyping or enzyme analysis), it was possible to obtain chorionic villi free from contamination by maternal tissue. It was also possible to pick out villi (rich in blood vessels and with abundant buds on their surface) found to be most capable of growing in vitro. In the diagnostic cases, the pregnancies have continued uneventfully since the sampling; one pregnancy is now in the 32nd week.     

Prenatal enzymatic diagnosis of Krabbe disease (globoid-cell leukodystrophy) using chorionic villi

Summary Sixteen pregnancies in families with children enzymatically diagnosed as having Krabbe disease (KD) were monitored for prenatal KD using the assay of galactosyl ceramide -galactosidase (GCG) in uncultured chorionic villi (CV), cultured CV, or cultured amniotic fluid cells (AFC). Prenatal KD diagnoses were made for 5 pregnancies on the basis of lower than 10% normal GCG activity in cultured CV or AFC. Uncultured CV were studied in 3 out of the 5 KD embryos, although the GCG activities of 14%–23% as compared with control villi were diagnostically inconclusive; the relatively high activities were considered to be caused by maternal GCG contamination of these very small villus samples. Although the villi from 6 of the other pregnancies yielded more conclusive results, the use of uncultured CV alone is not recommended for prenatal KD diagnosis, this material being subject to possible uncontrolled contamination with maternal enzyme.     

Somatic stability in chorionic villi samples and other Huntington fetal tissues

We have studied different tissues from two affected fetuses with Huntington's disease (HD). In the first case the analysis was performed at 11 weeks of pregnancy; CAG repeats from seven different tissues were compared with the results obtained in the chorionic villi sample (CVS). We found 42 CAG repeats in all samples. In the second case the study was done at 12 weeks; eight tissues (including brain) were studied and compared with the CVS; in all of them, 44 CAG repeats were obtained. Our results show a somatic stability in the different analyzed tissues and suggest that mitotic instability can be a secondary consequence of neuronal degeneration and gliosis. Likewise, our data show great viability in the prenatal diagnosis (PD) of Huntington's disease using samples from any tissue.     

Prenatal enzymatic diagnosis and exclusion of Krabbe's disease (globoid-cell leukodystrophy) using chorionic villi in five risk pregnancies

Summary Galactosyl ceramide -galactosidase activity was determined in chorionic villi (CV) samples obtained between the 9th and 11th weeks of gestation from 5 women with pregnancies at risk for Krabbe's disease (globoid-cell leukodystrophy, KD). These enzyme activities were compared with those in controls, as well as with those in cultured amniotic fluid cells (AFC) from one of the five at-risk pregnancies and from 29 KD-risk pregnancies studied previously. The results of these CV enzyme analyses were such that one case of fetal KD was clearly diagnosable, one fetal genotype heterozygous for KD was presumed, and three normal fetal genotypes were suggested. The use of both uncultured and cultered CV can be recommended for prenatal KD testing, but AFC may continue to play an important role, too. Of the 58 prenatal KD tests we have evaluated since 1974, a positive diagnosis of Krabbe's disease was made (and confirmed after termination of pregnancy when feasible) in 23 which is significantly more than 25% of 58.This paper is dedicated to Professor Jürgen Peiffer (Director, Institut für Hirnforschung, University of Tübingen) on the occasion of his 65th birthday     

Origin of mitotic cells of the chorionic villi in direct chromosome analysis

Summary The origin of mitotic cells was investigated histologically in chorionic tissue, metaphase plates of which were used for direct cytogenetic study. Mitotic figures were often observed in the Langhans' cell layers, but absolutely none were seen in the syncytium and stromal cells.     

Chromosome abnormalities in early pregnancy analyzed by direct chromosome preparation of chorionic villi

Summary Chorionic villi chromosome analysis was performed on 1,186 cases of induced abortion between the 5th and 11th week of gestation. The total incidence of major chromosome abnormalitites, including numerical and structural chromosomal changes as well as mosaics and polyploids, was 4.5% (53 cases). The most common abnormalities were trisomy 21 (5 cases), trisomy 16 (4 cases), and monosomy X (4 cases). The incidence of chromosome abnormalities increased with the advancing age of the mother.     

Health-related quality-of-life assessment of prenatal diagnosis: chorionic villi sampling and amniocentesis

This study assesses the health-related quality-of-life (HRQL) effects of chorionic villi sampling (CVS) and genetic amniocentesis (GA), including both process and outcomes of prenatal diagnosis. The HRQL of 126 women participating in a randomized controlled clinical trial of CVS versus GA in Toronto and Hamilton, Ontario, was assessed in four interviews at weeks 8, 13, 18, and 22 of pregnancy. Statistical analyses included analysis of variance, repeated measures analysis of covariance, chi-square, Fisher's exact test, Student's t-tests, and paired t-tests. Utility scores for patients undergoing CVS exceeded those for GA patients at week 18 (p = 0.04). Utility scores for hypothetical health states did not differ significantly by trial arm. CVS results in slightly improved HRQL during prenatal diagnosis. This advantage needs to be weighed against the high disutility patients attach to infrequent outcomes associated with pregnancy losses, equivocal diagnoses, and diagnostic inaccuracy.     

Cell cycle studies in chorionic villi

Summary We have studied the cell cycle of cells obtained from chorionic villi in direct and culture preparations by incorporation of the thymidine analogue BrdU to produce latelabelling or sister chromatid differentiation patterns. We have, therefore, been able to estimate the duration of the cell cycle and, more specifically, the length of some of its phases. While results for chorionic villus sample cells in culture resembled those obtained for fibroblasts, data for the spontaneously dividing trophoblastic cells in direct preparations were different. Villi exposed to BrdU immediately after sampling showed a slight delay in the incorporation of the analogue and a lower percentage of labelled cells compared to villi treated after an overnight incubation, probably due to a temporary effect of the sampling technique. Results from semi-direct protocols suggest that cells have a G2 of no more than 4h, and a mid-S phase of 10–16h. The G1 period is very variable. After 48 h incubation with BrdU, only 4% of cells reach their second generation, whereas this percentage increases up to 70% after 72h, indicating that under these experimental conditions most cells have a cell cycle of approximately 36 h. The average number of sister chromatid exchanges was similar in both direct preparations and cultures: 5.2±2.1 SCE per cell.     

Pyruvate carboxylase activity in chorionic villi: possibility of application to prenatal diagnosis

Pyruvate carboxylase (PC) activity was assayed in 27 chorionic villi samples (CVS) obtained at 9-12 weeks of gestation. The kinetic properties of the CVS enzyme were similar to those of liver PC; more than 75% of PC activity was recovered in the mitochondrial fraction of CVS. Apparent Km for pyruvate, ATP, acetyl CoA and HCO3- in the presence of saturation concentrations of the other reactants, were 0.3, 0.44, 0.015 and 6.0 mmol/l, respectively. The optimum pH was 7.5-8.0. The activity of PC in CVS was 3.2 +/- 0.3 nmol/min/mg protein, which is severalfold higher than that of amniotic fluid fibroblasts.     

Prenatal diagnosis and significance of fetal infections.

Viruses like rubella, cytomegalovirus, varicella-zoster virus and parasites like Toxoplasma gondii can be transmitted from a pregnant woman to her fetus and can affect fetal development. Several factors determine the likelihood of fetal infection and the risk of consequences for the fetus, such as the timing of transmission during gestation or the immunologic status of the mother. No single diagnostic modality can be applied to all infections. Knowledge of the diagnostic methods available is essential for accurate counseling and treatment of affected pregnant women.     

Cytogenetic analysis of chorionic villi: a technical assessment

Summary Eighty-five samples of chorionic villi from women undergoing prenatal diagnosis at 8 to 12 weeks' gestation were subjected to cytogenetic analysis. Samples were prepared by a direct technique that permits limited analysis within two hours and by a short-term culture technique that permits detailed structural analysis within one week. An adequate number of cell divisions for cytogenetic analysis was obtained from 96% of living fetuses. Using both the direct technique and short-term culture, satisfactory banded chromosomal preparations were made in 93% of cases. Eleven of 12 pregnancies (92%) shown by ultrasound to be dead shortly before sampling, had cytogenetic abnormalities. Further studies are needed to develop banding definition equivalent to that available on cultured amniocytes.     

Alkaline phosphatase expression in human chorionic villi

The physicochemical properties and electrophoretic mobility of different isoforms of alkaline phosphatase were studied in chorionic villi. Based on selective inactivation and inhibition studies (thermal stability, inactivation by urea, EDTA and L(+)ascorbic acid and L-amino acid inhibition), evidence was obtained for the existence of two distinct types of alkaline phosphatase in trophoblast cells. One type is peculiar to chorionic villi while the other is also found in term placenta. Both show two isoforms. These two isoforms were observed with polyacrylamide gel electrophoresis, carried out at pH 6.0 and 9.5. It is suggested that the qualitative and quantitative methods of alkaline phosphatase analysis could be used for first trimester fetal diagnosis of severe infantile hypophosphatasia and for understanding genetic control during early fetal development.     

Efficient direct chromosome analyses and enzyme determinations from chorionic villi samples in the first trimester of pregnancy

Chorionic villi were obtained by an aspiration technique which proved to be the best of four alternative procedures. We report in detail the series of experiments which led to (1) successful, rapidly growing cell cultures practically free of maternal cell contamination (the use of hormone-supplemented Chang medium greatly increased the growth rate); (2) an efficient direct method to obtain high quality metaphases from the Langhans cells of the cytotrophoblast tissue and with which the fetal karyotype is defined within a few hours of chorionic villi sampling; and (3) successful testing for the activity of eight enzymes directly from the villi samples, thus showing that this material is suitable for a rapid, direct diagnosis of the related metabolic diseases.     

Identification of trophoblast in chorionic villi biopsy samples

Summary Genetic linkage studies were carried out in families with X-linked hypohidrotic ectodermal dysplasia (C-S-T syndrome). A DNA probe DXYS1 (pDP34), which maps both to the proximal part of the long arm of the X chromosome, Xq13-Xq21, and proximally on Yp, was used to detect a TaqI restriction fragment length polymorphism of the X-chromosomal locus in the DNA samples from 11 families. This locus was found to be closely linked to the X-linked hypohidrotic ectodermal dysplasia locus, with a lod score of 2.66 at recombination fraction () of 0.06 (90% confidence limits 0.01–0.26). Only one crossover was observed in nineteen meioses. This indicates that the probe DXYS1 is closely linked to the X-linked hypohidrotic ectodermal dysplasia locus and is likely to facilitate carrier detection and prenatal diagnosis tests.     

Ultrastructural study of chorionic villi in maternal-fetal isoimmunity

The Authors studied the Human normal full term placenta and in the feto-maternal Rh and ABO incompatibilities. In the Human normal full term placenta the sincitium trophoblastum coat shows the usual microvillosity and the normal cytoplasmatic organules; in the placenta of ABO isoimmunized subjects the sincitium trophoblastum coat is intensely vacuolyzated; in the placenta of Rh isoimmunized subjects the lamina sincitiale vacuolyzation is more evident in the basal side. Discussion on the morphology related to the placenta barrier function.