A null mutation in HLA-G is not associated with preeclampsia or intrauterine growth retardation.

Modulation of the expression of genes of the major histocompatibility complex (MHC) in tissues at the maternal-fetal interface almost certainly plays a role in successful development of the semi-allogeneic fetus. While expression of the classical class I genes (HLA-A, B, C) is low to non-existent at this site, the non-classical molecule, HLA-G, is expressed uniquely in fetal cells at the maternal-fetal interface. The recent demonstration that homozygotes for a deletion mutation in exon 3 (1597DeltaC) of HLA-G do not express the full-length HLA-G1 isoforms indicates a potential reduction in expression of this isoform in heterozygotes. If the full-length isoform of HLA-G (i.e. HLA-G1) contributes to proper invasion of maternal spiral arteries by extravillous cytotrophoblast, then 1597DeltaC heterozygotes could be at increased risk for disorders of trophoblast invasion. Two populations, infants with intrauterine growth retardation (IUGR) and infants of preeclamptic (PE) mothers, were genotyped for the 1597DeltaC polymorphism. The frequency of 1597DeltaC in these samples was not significantly different from healthy controls, suggesting that heterozygotes for this deletion mutation are not at significantly increased risk for PE or IUGR (P = 0.727 and 0.803, respectively).

Cellular response in rabbit eyes after human fetal RPE cell transplantation.

BACKGROUND: This study was carried out to study inflammatory and proliferative cellular responses in the rabbit eye after subretinal transplantation of human fetal retinal pigment epithelial (HFRPE) cells. METHODS: 5-Bromo-2-deoxyuridine (BrdU)-labeled HFRPE cells were injected subretinally into rabbit eyes at three different concentrations. Macrophage, glial, and proliferative responses of the eye tissues were studied by immunohistochemistry and light microscopy at different times after the surgery. RESULTS: In transplanted eyes, the HFRPE cells were distributed irregularly either as multilayers or monolayers. In eyes receiving high-density cell suspensions, retinal breaks were seen. No retinal breaks were noted in the eyes receiving low-density HFRPE cell suspensions. The highest intensity of inflammatory response was seen at 4-14 days after surgery, with greater expression in transplanted eyes receiving high-density cell suspensions. The host cellular response was characterized initially by local infiltration of the retina and subretinal space by macrophages and glial cells. After day 14, a decline in the number of donor cells was noted in all eyes. At later stages the host cellular response was characterized mainly by local choroidal thickening and infiltration by inflammatory cells. Proliferative response was expressed mainly by retinal cells. CONCLUSION: Initial inflammatory and proliferative responses after the xenogenic human to rabbit HFRPE cell transplantation were expressed by retinal cells with later involvement of the choroid. Our results showed a decline in the number of donor cells starting from day 14 after the transplantation. This may suggest a possibility of rejection. The initial quantity of injected cells may be critical for the intensity of the immune and inflammatory responses.

Growth of human fetal retinal pigment epithelium as microspheres.

BACKGROUND: The aim was to develop a three-dimensional cell culture system for human fetal retinal pigment epithelial (HFRPE) cells for in vitro cellular studies and for possible application in subretinal transplantation. METHODS: Pieces of freshly isolated HFRPE monolayer tissue were grown on crosslinked fibrinogen (CLF) films. The growth pattern and morphologic characteristics of the implanted tissue were studied using phase-contrast microscopy, photography, and light and electron microscopy. The cells were screened immunohistochemically for HLA-ABC, HLA-DR, ICAM-1, B7, and Cytokeratin. Cell proliferation was studied using 5-bromo-2-deoxyuridine incorporation. RESULTS: After attachment to CLF, HFRPE monolayer tissue formed small tumor-like formations, i.e. microspheres. HFRPE microspheres survived and proliferated in a floating state for at least 4 months. After attachment of the microspheres to the culture dish floor, formation of a confluent HFRPE cell monolayer with high proliferative activity was noted around the microspheres. HFRPE cells stained positive for HLA-ABC, ICAM-1, and cytokeratin and negative for B7 and HLA-DR. The microspheres could be easily detached from the dish and they were able to initiate similar growth after reattachment. CONCLUSION: HFRPE grown on CLF resemble a three-dimensional culture system with high yield of pure cells that can be useful for a wide variety of in vitro studies. Because of their adjustable size, spherical shape, and ability to initiate growth of cells with a high proliferative potential, HFRPE microspheres may be successfully utilized as a source of donor cells for subretinal transplantation.

Patient or physician preferences for decision analysis: the prenatal genetic testing decision.

The choice between amniocentesis and chorionic villus sampling for prenatal genetic testing involves tradeoffs of the benefits and risks of the tests. Decision analysis is a method of explicitly weighing such tradeoffs. The authors examined the relationship between prenatal test choices made by patients and the choices prescribed by decision-analytic models based on their preferences, and separate models based on the preferences of their physicians. Preferences were assessed using written scenarios describing prenatal testing outcomes, and were recorded on linear rating scales. After adjustment for sociodemographic and obstetric confounders, test choice was significantly associated with the choice of decision models based on patient preferences (odds ratio 4.44; Cl, 2.53 to 7.78), but not with the choice of models based on the preferences of the physicians (odds ratio 1.60; Cl, 0.79 to 3.26). Agreement between decision analyses based on patient preferences and on physician preferences was little better than chance (kappa = 0.085+/-0.063). These results were robust both to changes in the decision-analytic probabilities and to changes in the model structure itself to simulate non-expected utility decision rules. The authors conclude that patient but not physician preferences, incorporated in decision models, correspond to the choice of amniocentesis or chorionic villus sampling made by the patient. Nevertheless, because patient preferences were assessed after referral for genetic testing, prospective preference-assessment studies will be necessary to confirm this association.

HLA-G1 protein expression is not essential for fetal survival.

HLA-G is a nonclassical, class I HLA gene that is primarily expressed by fetal cells at the maternal-fetal interface and is thought to play a key role in the induction of tolerance in pregnancy. This paper reports the identification of a single base pair deletion at position 1597 (1597delC) in exon 3 (encoding the alpha2-domain) of HLA-G on 20 of 272 (7.4 per cent) African American chromosomes, three of 102 (2.9 per cent) Hispanic chromosomes, and none of 134 Caucasian chromosomes. This relatively common frameshift mutation results in amino acid substitutions in all of the residues in the second half of exon 3 including the conserved cysteine at codon 164. An adult individual was identified who was homozygous for this 'null' allele, and a first trimester placenta that was homozygous for 1597delC had no detectable HLA-G1 protein. These data indicate that expression of HLA-G1 protein is not essential for fetal survival.

Genetic counseling: clinical and ethical challenges.

After explaining the origin, nature, and goals of genetic counseling, we consider the impact of the Human Genome Project on its practice. In light of the availability of presymptomatic tests for late-onset disorders and the possibility of preventive behavior or treatment, we examine the apparent conflict between nondirectiveness and directiveness in genetic counseling. We discuss views of genetic counselors, medical geneticists, and counselees on specific issues, and document gender differences in attitudes toward genetic ties to offspring. Because genetic discrimination and unequal access to genetic services are likely to increase with advances in genetics, we conclude that efforts of genetic counselors to adhere to the principle of justice or equity in their practice cannot be successful without governmental and public support, as well as support from researchers and colleagues in health care.

The role of physician preferences in the choice of amniocentesis or chorionic villus sampling for prenatal genetic testing.

Our objective was to determine the effect of physician preferences, as well as physician demographic, obstetric, and practice-related factors, on the choice of prenatal test made by their patients. We studied preferences for prenatal outcomes for 372 pregnant women who either chose amniocentesis (AMN) (n = 288) or chorionic villus sampling (CVS) (n = 84) for the indication of maternal age. We also studied preferences for these outcomes for the 92 physicians that referred them for testing. Preferences were assessed using written scenarios and were measured on linear rating scales. According to patients, the choice of prenatal test was made entirely or mostly by the physician in 14% of cases and was shared equally between patient and physician in 37% of cases. After adjustment for patient preferences, physician concern about spontaneous abortion of a normal fetus after CVS (odds ratio 0.71; CI, 0.48-1.05; p = 0.08), and a limb reduction (LRD) birth after CVS (odds ratio 0.85; CI, 0.68-1.05; p = 0.12), tended to decrease their patients' odds of choosing CVS, but the results were not statistically significant. No other physician preference, and no physician demographic, obstetric, or practice-related factor, influenced patient test choice. We conclude that after taking patient preferences into account, physician preferences and practice-related factors did not emerge as significant determinants of the choice of prenatal test made by their patients. It remains possible, however, that physician concern about spontaneous abortion and about LRD increase the likelihood of their patients choosing AMN over CVS.

Choroid plexus cysts: infant and early childhood developmental outcome.

OBJECTIVE: To determine the infant and early childhood developmental outcome associated with choroid plexus cysts diagnosed prenatally. METHODS: Between January 1990 and August 1995, 8270 women underwent second-trimester ultrasound examinations. All women whose fetuses were diagnosed as having choroid plexus cyst(s) underwent ultrasonographic detailed anatomy survey, were offered fetal karyotyping, and were followed with serial ultrasounds. Fetal karyotype, associated structural anomalies, maternal serum triple analyte screen, neonatal outcomes, and infant and early childhood developmental milestones were recorded. The children were followed subsequently, and developmental assessment was performed with a modified Denver II Developmental Screening Test. RESULTS: A diagnosis of choroid plexus cyst was made in 89 fetuses (1.1%). The mean (+/-standard deviation [SD]) gestational age at diagnosis was 18.2 +/- 1.9 weeks (range 15-22). The cysts varied in size and laterality, with a mean (+/-SD) size of 5.9 +/- 3.3 mm (range 1-23). Three of the 61 women who underwent testing for fetal karyotype (4.9%) had abnormal karyotypes identified. All three karyotypes were trisomy 18, and all three trisomy 18 fetuses had additional sonographic abnormalities. All 28 women who chose not to undergo fetal karyotypic analysis delivered phenotypically normal infants. Infant and childhood developmental follow-up was performed on 76 children with cysts diagnosed prenatally. The mean (+/-SD) length of childhood follow-up was 35.5 +/- 16.2 months (range 12-82). All 76 children were found to be developmentally normal by the Denver II Developmental Screening Test. CONCLUSION: These observations suggest that the finding of isolated choroid plexus cysts is not associated with delayed infant and early childhood development or an increased risk of abnormal karyotype. The presence of isolated choroid plexus cysts does not warrant intensive infant and early childhood follow-up.

Prenatal testing for limb reduction defects. How patients' views affect their choice of CVS.

OBJECTIVE: To determine the effect of reports and media coverage on chorionic villus sampling (CVS) and limb reduction defects (LRD) on patients' utilization of CVS for prenatal testing for advanced maternal age and to quantitate the relation of preferences for CVS and amniocentesis (AMN) outcomes to test utilization. STUDY DESIGN: We compared CVS and AMN utilization rates in two groups of women seen at one academic medical center before and after publicity concerning CVS and LRD. We measured preferences, in rating-scale units, for potential outcomes of prenatal testing in the after-publicity group. Relationships between preferences and CVS utilization were examined using multivariate methods. RESULTS: The proportion of women utilizing CVS for prenatal testing declined significantly for the after-publicity group (23%) as compared with the prepublicity group (47.4%, P = .0001). Belief that the birth of a child with LRD after CVS was worse than a similar birth after AMN significantly reduced the odds of choosing CVS. A decrement in preference for a child with LRD after CVS of 5 rating-scale units reduced the likelihood of CVS by 15% (confidence interval [CI], 1-28%); a decrement of 10 units reduced the likelihood of CVS by 28% (CI, 1-48%). This effect persisted after adjustment for demographic and obstetric covariates, prior prenatal testing, locus of decision making (patient versus physician or shared) and other maternal preferences for outcomes of prenatal testing. CONCLUSION: Lower patient preference for a child with LRD after CVS was an independent predictor of choosing AMN over CVS and was probably responsible for the significant decrease in CVS utilization at our hospital.

Analysis of parent of origin specific DNA methylation at SNRPN and PW71 in tissues: implication for prenatal diagnosis.

Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are distinct developmental disorders caused by absence of paternal or maternal contributions of the chromosome region 15q11-q13, resulting from deletions, uniparental disomy (UPD), or rare imprinting mutations. Molecular cytogenetic diagnosis is currently performed using a combination of fluorescence in situ hybridisation (FISH), DNA polymorphism analysis, and DNA methylation analysis. Only methylation analysis will detect all three categories of PWS abnormalities, but its reliability in tissues other than peripheral blood has not been examined extensively. Therefore, we examined the methylation status at the CpG island of the small nuclear ribonucleoprotein associated polypeptide N (SNRPN) gene and at the PW71 locus using normal and abnormal lymphoblast (LB) cell lines (n = 48), amniotic fluid (AF) cell cultures (n = 25), cultured chorionic villus samples (CVS, n = 17), and fetal tissues (n = 18) by Southern blot analysis with methylation sensitive enzymes. Of these samples, 20 LB cell lines, three AF cultures, one CVS, and 15 fetal tissues had been previously diagnosed as having deletions or UPD by other molecular methods. Methylation status at SNRPN showed consistent results when compared with FISH or DNA polymorphism analysis using all cell types tested. However, the methylation pattern for PW71 was inconsistent when compared with other tests and should therefore not be used on tissues other than peripheral blood. We conclude that SNRPN, but not PW71, methylation analysis may be useful for diagnosis of PWS/AS on LB cell lines, cultured amniotic fluid, or chorionic villus samples and will allow, for the first time, prenatal diagnosis for families known to carry imprinting centre defects.

Prenatal diagnosis of uniparental disomy 15 following trisomy 15 mosaicism.

Maternal uniparental disomy 15 (UPD15), responsible for approximately 25 per cent of Prader-Willi syndrome cases, is usually caused by maternal meiosis I non-disjunction associated with advanced maternal age. These cases may initially be detected as mosaic trisomy 15 during routine prenatal diagnostic studies. In such cases, PCR (polymerase chain reaction) microsatellite analysis of uncultured cells makes prospective prenatal diagnosis for UPD15 possible with results available in 2-4 days. We have performed molecular analyses on a series of seven cases of mosaic trisomy 15 identified in amniotic fluid (AF, n = 3) or chorionic villus samples (CVS, n = 4) from patients initially referred for advanced maternal age or abnormal triple screen. In all cases, the maternal ages were > or = 35 years and maternal meiosis I non-disjunction was documented as the cause of the trisomy in all informative cases (n = 5). Of the three case with mosaic trisomy 15 at amniocentesis, two showed the presence of the trisomy in the fetus. Molecular analysis showed one case with maternal UPD15 in the euploid cell line and one case with biparental inheritance. Both of these families elected to terminate the pregnancies based on the presence of true fetal mosaicism. In the third case, low-level trisomy 15 mosaicism in the amniotic fluid was not confirmed in a follow-up amniotic fluid sample and molecular analysis indicated biparental inheritance in the fetus. For the four trisomy 15 mosaics detected at CVS, molecular analysis was performed on direct amniotic fluid cell lysates for prospective diagnosis of UPD at 14-16 weeks' gestation. Follow-up cytogenetic analysis of the amniotic fluid in all four cases was normal, indicating confined placental mosaicism. Molecular analysis showed one of these four cases to have maternal heterodisomy 15. Based on the likelihood of Prader-Willi syndrome due to maternal UPD15, the couple chose to terminate the pregnancy. The total of two of seven cases of trisomy 15 mosaicism resulting in UPD15 is consistent with the theoretical expectation of one-third and indicates a high risk of UPD in such pregnancies. Therefore, UPD testing should be offered in all cases of mosaic trisomy 15 encountered in CVS or amniocentesis.

Use of decision analysis to evaluate patients' choices of diagnostic prenatal test.

Women with a family history of a chromosomal or genetic abnormality must weigh several factors in choosing between amniocentesis and chorionic villus sampling. We compared the prenatal test choices of three such women with those of decision analytic models that incorporated their preferences. Patient preferences were assessed using visual linear rating scales. Threshold analysis was used to determine preference ranges, and stochastic sensitivity analysis to provide confidence levels, for each choice of test. The test choices of patients and decision analytic models agreed in one case, and disagreed in two cases. In one of the latter two cases, stochastic and threshold analyses showed the disagreement to be slight; for small shifts in preference differences for first- vs. second-trimester diagnosis, or first- vs. second-trimester therapeutic abortion, patient and decision model would have agreed. In the other, stochastic analysis showed their differences to be large; there were no thresholds for early diagnosis, or for early therapeutic abortion, that would have led to agreement between patient and model. In the two cases in which patient and decision model agreed or slightly disagreed, the patients had made their own choice of prenatal test. In the case in which patient and decision model strongly disagreed, the patient's physician had shared in the choice of test. Decision analysis can be useful in analyzing prenatal test choices based on individual preferences for pregnancy outcomes. When choices of patients and decision models do not agree, examination of the locus of decision making (patient vs. physician) may help resolve apparent differences.

Developmental regulation of the catalytic subunit of the apolipoprotein B mRNA editing enzyme (APOBEC-1) in human small intestine.

Apolipoprotein (apo) B mRNA editing is a site-specific cytidine deamination reaction responsible for the production of apoB-48 in mammalian small intestine. This process is mediated by an enzyme complex that includes the catalytic subunit, APOBEC-1. In the present study, it is shown that the developmental regulation of apoB mRNA editing in fetal human small intestine is closely mirrored by accumulation of APOBEC-1 mRNA. Similar results were obtained using Caco-2 cells, the data further suggesting that culture of these cells under conditions previously shown to promote differentiation produce an earlier and more marked induction of APOBEC-1 mRNA abundance. Complementary analysis of APOBEC-1 protein accumulation using immunocytochemical localization reveals its appearance to be temporally coordinated with the accumulation of APOBEC-1 mRNA and its distribution to be confined to villus-associated enterocytes. Previous studies demonstrated a close temporal association between the development of triglyceride synthesis and apoB mRNA editing in the rat liver and small intestine. Analysis of fatty acid CoA ligase, monoacylglycerol acyltransferase, and diacylglycerol acyltransferase activity in preparations of human liver and small intestine demonstrates activity of all three enzymes in the late first and early second trimester, suggesting that certain aspects of complex lipid biosynthesis in the human fetal small intestine and liver are regulated developmentally. The cues that modulate the post-transcriptional regulation of fetal human small intestinal apoB gene expression may thus include both temporal programming and events related to the emergence of lipid transport capability.

Preferences of pregnant women for amniocentesis or chorionic villus sampling for prenatal testing: comparison of patients' choices and those of a decision-analytic model.

Decision analytic models have suggested that the choice of amniocentesis or chorionic villus sampling for prenatal genetic testing is a utility-driven decision. We compared preferences for prenatal testing among 156 pregnant women who had chosen either amniocentesis (n = 82) or chorionic villus sampling (n = 74) for the indication of maternal age. We also compared their choices with those of a decision-analytic model based on their preferences, and age-specific rates of spontaneous abortion and chromosomal abnormalities. Preferences were assessed using written scenarios describing potential outcomes of prenatal testing, and were recorded on linear rating scales. The differences in preference ratings for first- vs second-trimester prenatal diagnosis of a normal child (4.2 vs -1.6, p = 0.0004), and for first- vs second-trimester abortion of an abnormal fetus (4.4 vs -1.6, p = 0.01), were significantly greater among women choosing chorionic villus sampling than among women choosing amniocentesis. There were no significant differences between chorionic villus sampling and amniocentesis patients in their preference ratings for test-related miscarriage, disconfirmed results at pregnancy termination, or maternal morbidity from therapeutic abortion. After adjusting for demographic and obstetric factors, the difference in preferences for early vs late prenatal diagnosis was an independent predictor of the choice of chorionic villus sampling in a multivariate model. Among women whose decision analyses selected amniocentesis, 56.8% had chosen amniocentesis, and among women whose analyses selected chorionic villus sampling, 63.2% had chosen chorionic villus sampling (p = 0.05). We conclude that the preferences of pregnant women for the outcomes of prenatal testing were associated with their choice of amniocentesis or chorionic villus sampling. In addition, the choice of prenatal test made by the majority of women was concordant with that of a decision-analytic model that incorporated their preferences. Nevertheless, because many women made choices that were discordant with their decision-analytic results, further research into the bases for their choices is warranted.

A cost-effectiveness analysis of amniocentesis and chorionic villus sampling for prenatal genetic testing.

Amniocentesis and chorionic villus sampling are tests for the prenatal diagnosis of cytogenetic abnormalities. We calculated the incremental costs per abnormal birth averted, and the incremental costs per quality-adjusted outcome, of amniocentesis and chorionic villus sampling performed for the indication of maternal age. Probabilities were obtained from the literature, and direct medical costs from hospital charges deflated to reflect aggregated contracted care reimbursements. Utilities were used to quality-adjust prenatal testing outcomes. Based on costs per abnormal birth averted, at all maternal ages from 30 to 43 years, amniocentesis was more cost-effective than chorionic villus sampling; at ages 44 and 45, chorionic villus sampling was more cost-effective. However, if the anxiety reduction provided by first-trimester diagnosis was equivalent to a 0.2% risk of an abnormal child, chorionic villus sampling was more cost-effective than amniocentesis at all maternal ages. Based on data from the 1988 United States natality cohort, the current policy of testing women aged 35 and older would cost $103,329 and $111,184 per abnormal birth averted for amniocentesis and chorionic villus sampling, respectively. Testing women aged 30 and older would almost double these costs. For either prenatal test, targeting high risk women for testing, and striving for utilization rates of 50% or higher, appeared to be the most cost-effective policy.

Posterior urethral valves in successive generations.

Posterior urethral valves (PUV) are a frequent cause of urinary tract obstruction in infant males and may be diagnosed by antenatal ultrasound. PUV have been observed in siblings and in identical twins. However, genetic factors in PUV are poorly understood. In this article, we report the occurrence of PUV diagnosed antenatally in a fetus whose father and paternal uncle were both treated for PUV in childhood. This is the first reported case of PUV that we are aware of occurring in successive generations.

Cook obstetrics and gynecology catheter multicenter chorionic villus sampling trial: comparison of birth defects with expected rates.

OBJECTIVE: The null hypothesis was that offspring of women undergoing first-trimester chorionic villus sampling do not experience a rate of birth defects exceeding background rates. STUDY DESIGN: Follow-up information regarding major malformations was prospectively sought on offspring of 4105 women undergoing first-trimester chorionic villus sampling from nine centers participating in a collaborative study with the Cook obstetrics and gynecology catheter. These data were compared with data from the Collaborative Perinatal Project and other registries. RESULTS: A total of 84 offspring with major malformations was identified (2.36%). Compared with background rates, there was no increase in the incidence of total malformations or specific malformations (including limb reduction defects) in the subjects. One institution experienced all three limb reduction defects in this series; the probability of this occurring by chance alone is < 1%. CONCLUSION: Chorionic villus sampling was not found to result in an increase in major birth defects or in specific categories of birth defects in this series.

A prospective trial of prenatal screening for Down syndrome by means of maternal serum alpha-fetoprotein, human chorionic gonadotropin, and unconjugated estriol.

OBJECTIVE: Our purpose was to prospectively evaluate the effectiveness of prenatal screening for Down syndrome by means of multiple serum markers. STUDY DESIGN: alpha-Fetoprotein, human chorionic gonadotropin, and unconjugated estriol were measured in 8233 midtrimester serum samples, including 7492 from women < 35 years old and 741 from women > or = 35 years old. Down syndrome risks were computed by means of age and all three markers. Further testing was recommended for patients with a risk > or = 1:270. Testing for trisomy 18 was recommended for patients with an alpha-fetoprotein < or = 0.70 multiples of the median, human chorionic gonadotropin < or = 0.50 multiples of the median, and unconjugated estriol < or = 0.55 multiples of the median. RESULTS: Of women screened initially 10.4% had a Down syndrome risk > or = 1:270; 10 of 12 known cases of Down syndrome were identified. One abnormality was detected for every 33 amniocenteses performed in this group. Of 0.4% of patients at increased risk for trisomy 18, two cases of trisomy 18 and one of triploidy were found. CONCLUSION: Multiple marker screening is effective in identifying the majority of fetal chromosome anomalies.