Cell-free fetal DNA screening in the USA: a cost analysis of screening strategies.

OBJECTIVES: To determine whether implementation of primary cell-free fetal DNA (cffDNA) screening would be cost-effective in the USA and to evaluate potential lower-cost alternatives. METHODS: Three strategies to screen for trisomy 21 were evaluated using decision tree analysis: 1) a primary strategy in which cffDNA screening was offered to all patients, 2) a contingent strategy in which cffDNA screening was offered only to patients who were high risk on traditional first-trimester screening and 3) a hybrid strategy in which cffDNA screening was offered to all patients ≥ 35 years of age and only to patients < 35 years who were high risk after first-trimester screening. Four traditional screening protocols were evaluated, each assessing nuchal translucency (NT) and pregnancy-associated plasma protein-A (PAPP-A) along with either free or total beta-human chorionic gonadotropin (ß-hCG), with or without nasal bone (NB) assessment. RESULTS: Utilizing a primary cffDNA screening strategy, the cost per patient was 1017 US$. With a traditional screening protocol using free ß-hCG, PAPP-A and NT assessment as part of a hybrid screening strategy, a contingent strategy with a 1/300 cut-off and a contingent strategy with a 1/1000 cut-off, the cost per patient was 474, 430 and 409 US$, respectively. Findings were similar using the other traditional screening protocols. Marginal cost per viable case detected for the primary screening strategy as compared to the other strategies was 3-16 times greater than the cost of care for a missed case. CONCLUSIONS: Primary cffDNA screening is not currently a cost-effective strategy. The contingent strategy was the lowest-cost alternative, especially with a risk cut-off of 1/1000. The hybrid strategy, although less costly than primary cffDNA screening, was more costly than the contingent strategy.

Impact of nuchal translucency credentialing by the FMF, the NTQR or both on screening distributions and performance.

OBJECTIVE: In the USA, both The Fetal Medicine Foundation (FMF) and the Nuchal Translucency Quality Review Program (NTQR) have operated education, review and credentialing for physicians and sonographers for the measurement of nuchal translucency (NT). We sought to assess differences in the distribution of NT measurements based upon the system from which the operator obtained their education, review and credentialing. METHODS: 398 311 NT measurements by 1541 sonographers who had performed ≥ 50 exams from July 2008 to June 2010 were grouped by organization. Differences between grouped measurements were assessed using analysis of variance of log(10) NT multiples of the median (MoM), with sonographer and organization as factors. RESULTS: MoM values were significantly lower (P ≤ 0.001) and SD was significantly higher (P < 0.001) for the NTQR group compared with the FMF group or those sonographers credentialed by both. The percentage of individuals with negative bias ≥ 10% was greater for the NTQR group (P < 0.001). The difference was less but still significant (P = 0.009) when bias was adjusted for by the overall median for the organization. CONCLUSIONS: Although NT MoM measurements were significantly lower and had a wider variance when obtained by the NTQR group, our data cannot distinguish between bias in training or the attributes of the participating sonographers in each program. With these large numbers, it is unlikely that patient characteristics could explain the discrepancy in distributions. Ongoing efforts to monitor sonographer performance with remediation for poor performers may reduce discrepancies between organizations.

Chromatin structural transitions and the phenomenon of vitellogenin gene memory in chickens.

We have previously shown that the steroid hormone-mediated transcriptional activation of the chicken vitellogenin II gene (VTGII) in the liver is accompanied by a series of chromatin structural changes, including the formation of two sets of 5'-proximal nuclease-hypersensitive sites and the demethylation of a single 5'-flanking MspI site which lies within a region of DNA that recently has been shown by Jost and co-workers to specifically bind the estrogen receptor complex in vitro. To assay the stability and possible functional significance of these induced structural changes, we transiently activated the VTGII gene during embryonic development and then allowed the chickens to hatch and grow for various periods of time before analyzing their livers. By 7 weeks posthatching all of the induced 5'-flanking hypersensitive sites had decayed. Moreover, the loss of these sites occurred without consequence to the "memory effect," that is, these structural features did not need to be present in hormone withdrawn birds to allow this gene to be activated more rapidly in response to a secondary presentation of estradiol. Although the demethylation was more stable, it also appeared not to be the basis of the memory phenomenon. The birds that still exhibited memory after 25 weeks of hormone withdrawal were not more extensively demethylated within the receptor-binding site than were the birds which failed to show memory at this age. A similar uncoupling of these two parameters was also observed when embryos were first injected with submaximal doses of estradiol and then assayed 1 week after hatching; the chickens which acquired memory were not demethylated to any greater extent than those which did not acquire memory. Other parameters that may be relevant to memory are discussed.

Two functional estrogen response elements are located upstream of the major chicken vitellogenin gene.

We used a transient-expression assay to identify two estrogen response elements (EREs) associated with the major chicken vitellogenin gene (VTGII). Each element was characterized by its ability to confer estrogen responsiveness when cloned in either orientation next to a chimeric reporter gene consisting of the herpes simplex virus thymidine kinase promoter and the chloramphenicol acetyl transferase-coding region. Deletion analyses indicated that sequences necessary for the distal ERE resided within the region from -626 to -613 (nucleotide positions relative to the VTGII start site) whereas those necessary for the proximal ERE were within the region from -358 to -335. These distal and proximal elements contain, respectively, a perfect copy and an imperfect copy of the 13-base-pair sequence that is an essential feature of the EREs associated with two frog vitellogenin genes. These chicken VTGII EREs mapped near regions that were restructured at the chromatin level when the endogenous VTGII gene was expressed in the liver in response to estradiol. These data suggest a model for the tissue-specific expression of this estrogen-responsive gene.

Estrogen-dependent transcriptional activation and vitellogenin gene memory.

The concept of hepatic memory suggests that a gene responds more rapidly to a second exposure of an inducer than it does during the initial activation. To determine how soon estrogen-dependent DNA/protein interactions occur during the primary response, in vivo dimethylsulfate footprinting was carried out using genomic DNA amplified by ligation-mediated PCR. When estrogen was added to disrupted cells from a hormone-naive liver, changes within and around the estrogen response elements occurred within seconds, indicating a direct and rapid effect on this estrogen-responsive promoter that had never before been activated. Because this effect was so rapid relative to the delayed onset of mRNA accumulation during the primary response, run-on transcription assays were used to determine the transcription profiles for four of the yolk protein genes during the primary and secondary responses to estrogen. As with the accumulation of mRNA, the onset of transcription was delayed for all of these genes after a primary exposure to estrogen. Interestingly, after the secondary exposure to estrogen, the vitellogenin I, vitellogenin II, and very low density apolipoprotein II genes displayed a more rapid onset of transcription, whereas the primary and secondary profiles of apolipoprotein B transcription in response to estrogen were identical. Because the apoB gene is constitutively expressed in the absence of estrogen, and the vitellogenins are quiescent before the administration of the hormone, hepatic memory most likely represents a relatively stable event in the transition to an active state of a gene that is committed for tissue-specific expression.

Insulin inhibits the estrogen-dependent expression of the chicken very low density apolipoprotein II gene in Leghorn male hepatoma cells.

Expression of the very low density apolipoprotein II (apoVLDLII) gene in the chicken is absolutely dependent on estrogen. ApoVLDLII mRNA is expressed in the Leghorn male hepatoma (LMH) cell line in response to estrogen in completely defined medium. Addition of serum to these cultures results in a decrease in apoVLDLII mRNA. Data in this report demonstrate that 1 nM insulin has the same inhibitory effect as 10% serum. Insulin inhibits apoVLDLII mRNA in a dose-dependent manner; 100 fM insulin inhibits the estrogen-dependent response by 76%. After transfection of LMH cells with apoVLDLII sequences from an 8.9-kilobase (kb) genomic clone (pApo107) that contains the entire 2.9-kb coding sequence along with approximately 3 kb each of 5'- and 3'-flanking DNA, the estrogen-dependent expression of apoVLDLII mRNA from both the endogenous gene and transfected DNA is reduced by insulin. Furthermore, insulin reduces by more than 90% the estrogen-dependent expression from a chimeric construct, pApoCAT, which contains apoVLDLII sequences -900/+1455 cloned 5' of the bacterial chloramphenicol acetyltransferase (CAT) reporter gene. To determine the specificity of the response, expression of the pApoCAT construct was tested with insulin-like growth factor-I and insulin. Three hundred picomolar insulin inhibits the estrogen-mediated CAT activity by 50%. Insulin-like growth factor-I at this concentration has no effect or slightly increases the estrogen-dependent expression of pApoCAT, suggesting that the observed inhibitory action is mediated by the insulin receptor. Consequently, the LMH cells provide an excellent model system in which to study the molecular mechanism of insulin and estrogen interaction in the regulation of gene expression.

Regulation of the ovalbumin gene: effects of insulin, adenosine 3',5'-monophosphate, and estrogen.

Induction of the ovalbumin gene in chicken oviduct explant cultures requires the presence of a serum component in addition to estrogen. Previous studies have demonstrated that either insulin or related peptides, such as proinsulin or insulin-like growth factor, can eliminate the requirement for serum. In the present study, we determined that half-maximal binding of [125I]iodoinsulin to oviduct cell membranes occurs with 5 X 10(-10) M insulin, and proinsulin is 10-fold less effective than insulin as a competitor. Induction of the ovalbumin gene is half-maximal with 10(-9) M insulin, and both proinsulin and insulin-like growth factor are 10-fold less potent. These results suggest that insulin is the physiological hormone that is required in addition to estrogen to stimulate transcription of the ovalbumin gene. In an effort to understand the mechanism by which insulin regulates the steroid response in this system, we searched for agents that could substitute for insulin. We found that cyclic nucleotide derivatives, such as 8-bromo-cAMP, can mimic the effect of insulin on ovalbumin gene expression and that the phosphodiesterase inhibitor isobutylmethylxanthine can potentiate this response to 8-bromo-cAMP. Activation of oviduct adenylate cyclase with either forskolin or cholera toxin also allows the estrogen-mediated induction of mRNA, and both of these agents produce a dramatic rise in intracellular cAMP. Although these results suggest that the effect of insulin on gene regulation might depend on a cAMP-mediated mechanism, we are unable to detect any change in cellular cAMP levels in response to insulin. We conclude that insulin and cAMP are producing their effects on activation of the ovalbumin gene via convergent pathways. The involvement of an activator of protein kinase, cAMP, strongly suggests that protein phosphorylation events play a regulatory role in the expression of the ovalbumin gene.

Characterization of a gonadotropin-releasing hormone receptor site in term placenta and chorionic villi.

The properties of GnRH receptor sites in the human placenta were analyzed by binding studies performed in particulate and solubilized receptor preparations. The binding affinities (Ka) of the membrane receptor of term placenta for the GnRH superagonists [D-Lys6]- and [D-Ala6]des-Gly10- GnRH-N-ethylamide were 1.6 X 10(6) and 5.4 X 10(5) M-1, respectively. The binding affinities of native GnRH and a potent GnRH antagonist were similar to those of the superagonists (1.1 and 2.0 X 10(6) M-1, respectively). The placental sites could be solubilized by extraction with the detergent 3-[(3-cholamidopropyl) dimethylammonio] 1-propane sulfonate, with retention of 40-45% of the specific binding activity, though with a significant decrease in binding affinity. The sites were also solubilized with sodium dodecyl sulfate after covalent labeling with a photoreactive 125I-labeled [D-Lys6] GnRH agonist derivative. Analysis of the solubilized hormone-receptor complex on polyacrylamide gradient gels showed a single band of 53,700 mol wt, similar to the mol wt of the pituitary GnRH receptor in other species. It is clear that the placental receptor differs markedly from the GnRH receptor of the pituitary gland in its low binding affinity and lack of selectivity for GnRH analogs. However, it is possible that the human placental receptor for GnRH could serve as a low affinity regulatory site for locally formed GnRH or related low affinity regulatory site for locally formed GnRH or related peptides within the placenta, and that the placental GnRH system has a significant role in the maintenance of pregnancy.

Expression and regulation of vascular endothelial growth factor in a first trimester trophoblast cell line.

Embryo implantation and development are critically dependent upon the spatial and temporal regulation of angiogenesis and localized vascular permeability. A key mediator of these effects is the endothelial cell mitogen vascular endothelial growth factor (VEGF). VEGF has been shown to promote endometrial vascular permeability, fetal vasculogenesis and placental, fetal and maternal angiogenesis. However, the mechanism through which this regulation occurs in the placenta is poorly understood. This study was conducted to determine if the pro-angiogenic cytokines, TNF-alpha and TGF-beta1, affect VEGF expression in human first trimester trophoblasts. Culture of a first trimester trophoblast cell line (HTR-8/SVneo), in the presence of either TNF-alpha or TGF-beta1, resulted in the expression of significant levels of VEGF in culture. The trophoblast cell line also showed a time-dependent and a dose-dependent increase in VEGF mRNA levels when cultured in the presence of either TNF-alpha or TGF-beta1. These results suggest that both TNF-alpha and TGF-beta1 may regulate the production of VEGF in early gestational trophoblasts and may therefore serve to modulate placental vascular permeability and angiogenesis that are necessary for embryo implantation and placentation.

Ultrasound screening for fetal chromosome anomalies.

Ultrasound evidence for aneuploidy may be found in almost every organ of the fetus and can be used to modify the risk of aneuploidy. The diagnosis of these minor anomalies on second-trimester ultrasonography will increase the risk of an abnormal karyotype whereas the absence of these findings may reduce this danger. The most specific and most ominous isolated markers for fetal aneuploidy are nuchal findings (edema or cysts), indicating the need to obtain a fetal karyotype in all cases irrespective of maternal age or results of biochemical serum screening. Hyperechoic fetal bowel is apparently also a strong indicator of fetal aneuploidy. Other isolated sonographic markers may increase the risk of an abnormal karyotype three- to ninefold. Most sonographic markers for aneuploidy specify an increased risk for Down syndrome, but choroid plexus cysts are apparently more specific for trisomy 18. Along with other screening methods, ultrasound screening for fetal aneuploidy should be used routinely to identify additional pregnancies at need for evaluation of fetal karyotype.

In utero fetal muscle biopsy for the diagnosis of Duchenne muscular dystrophy in a female fetus "suddenly at risk".

DNA methods to diagnose Duchenne muscular dystrophy (DMD) are not always informative, and we have published previously the first instance of in utero muscle biopsy to assess dystrophin in a male fetus having the same "X" as an affected sib. We present here a female fetus with a de novo X,1 translocation with breakpoint at Xp21, detected on amniocentesis for advanced maternal age. The translocation breakpoint placed her at high risk for DMD. In utero muscle biopsy at 20 weeks of gestation produced a specimen positive for dystrophin immunofluorescence indicating a likely normal fetus. The pregnancy was continued, and at term the baby girl was found to have normal serum creatine kinase levels, and was therefore unaffected with DMD. Our experiences add de novo Xp21 translocation to the indications for in utero muscle biopsy for diagnosis of DMD.

Prenatal diagnosis of nonrhizomelic chondrodysplasia punctata (Conradi-Hünermann syndrome).

Chondrodysplasia punctata has been classified into two major types including the rare autosomal recessive "rhizomelic type" and a more common but genetically heterogenous nonrhizomelic type (referred to by some authors as "Conradi-Hünermann (CH) type"). The former is typically lethal, manifesting serious anomalies, and allowing several instances of confident prenatal diagnosis. The latter being milder has more subtle anomalies and prenatal diagnosis has been uncommonly reported (confined to cases diagnosed incidentally by flat-plate X-ray examination of the mother in late third trimester, and a case found by directed ultrasound performed in a Mendelian affected mother). Cases included 1) a young primigravida thought to be affected with Conradi-Hünermann syndrome presented at 16 weeks gestation for prenatal diagnosis and counseling. Ultrasound examination of the fetus detected assymetric limb shortness allowing the presumptive diagnosis of an affected fetus which was confirmed after delivery near term. 2) A normal 38-year-old multipara with unremarkable family history underwent routine fetal ultrasound evaluation at 18 weeks gestation. Disorganization of the spine, premature echogenicity of femoral epipheses, and frontal bossing with depressed nasal bridge were described. Neonatal examination confirmed suspicion of CH. Case 1 demonstrates the importance of solid clinical diagnosis in Mendelian malformation-affected parents for directing prenatal diagnostic efforts. Case 2 represents the first index case of CH diagnosed antenatally by ultrasound. Diagnostic clues which must be considered in establishing these diagnoses are discussed, as are some of the difficulties and limitations in antenatal counseling such cases.

Microscopic neuroblastoma in a fetus with a de novo unbalanced translocation 3;10.

We report on a fetus with a de novo unbalanced translocation 3;10 and a microscopic neuroblastoma. The fetus had the karyotypic and phenotypic manifestations of partial dup (3q). The finding of a constitutional chromosomal abnormality and a microscopic neuroblastoma, although possibly coincidental, supports Knudson's two hit hypothesis for development of neuroblastomas and other embryonal tumors. In this case the first mutation is represented by the constitutional abnormality, possibly resulting in the microscopic neuroblastoma. A second mutation affecting the abnormal cells, which may be more prone to mutagenesis, may trigger a neuroblastoma.

Ultrasonographic prenatal diagnosis and fetal pathology of Langer mesomelic dwarfism.

In a family at risk for Langer mesomelic dwarfism, we document the onset of disproportionate growth in the second trimester by sonographic biometry. Midtrimester pathologic correlation of this condition demonstrates primary changes in the growthplate in the regions of proliferating cartilage and hypertrophic and degenerative chondrocytes.

Two consecutive hydrolethalus syndrome-affected pregnancies in a nonconsanguinous black couple: discussion of problems in prenatal differential diagnosis of midline malformation syndromes.

Hydrolethalus syndrome is a rare autosomal recessive (AR) disorder characterized by polyhydramnios, CNS abnormalities, cleft lip/palate, micrognathia, and polydactyly. Its molecular basis is unknown and prenatal diagnosis is challenging due to phenotypic overlap with several other midline malformation syndromes. A 34-year-old G3P2, nonconsanguinous, married, African-American woman was referred at 19 weeks of gestation after ultrasound findings of "multiple congenital anomalies." A previous pregnancy had been terminated following ultrasound findings of polyhydramnios, cleft lip/palate, polydactyly, severe hydrocephalus, and a Dandy-Walker malformation (DWM). Level II ultrasound evaluation of the current pregnancy demonstrated all of the anomalies which had been present in her previous pregnancy. Karyotype of amniocytes was 46,XX. Autopsy following pregnancy termination confirmed ultrasound findings. The pedigree, sonographic, and autopsy findings in this case were most consistent with hydrolethalus syndrome, although other AR multiple midline malformation syndromes were considered. Our case was detected by 19 weeks. Confident differential diagnosis is difficult for the geneticist and even more so for the sonologist given the technical limitations of ultrasound. It is uncertain whether these mendelian midline malformation syndromes represent slightly different phenotypic expressions of a common genetic defect or are manifestations of allelic and or locus heterogeneity. We suggest that for prenatal diagnostic purposes, in the absence of knowledge of the molecular basis of these disorders, the fine distinctions are not crucial as long as their mendelian inheritance is recognized and presence or absence of manifestations which make them severe are ascertained.

Familial omphalocele: considerations in genetic counseling.

Nonsyndromal omphalocele is generally regarded as a sporadic malformation. Recurrence risk is considered negligible. We report on a patient in whom 5 consecutive pregnancies (by 2 separate nonconsanguineous partners) were complicated by omphalocele as an isolated defect. Neither the patient nor her partners had history of relatives with omphalocele, although the patient's brother and his son had large umbilical hernias requiring repair in infancy. Some familial cases of nonsyndromal omphalocele have been previously reported; most such pedigrees suggest vertical transmission, although there are a few cases with only a single generation involved. In our case, the multigenerational finding of ventral wall hernias makes an autosomal dominant mechanism with variable expressivity a tenable explanation. The collected instances of familial nonsyndromal omphalocele emphasize omphalocele heterogeneity and caution in counseling recurrence risks.

Triply discordant triplets: probability, management options, and risks.

The spontaneous occurrence of triplets is rare. With increased utilization of "assisted reproductive technologies," multifetal gestations have become more common. The empiric fetal risk for major malformation is approximately 3%. In a triplet pregnancy each fetus independently carries this risk so that the probability of having at least one malformed fetus is approximately 9%. It is much less likely to have 2 or 3 simultaneously but discordantly malformed fetuses in a multizygotic triplet gestation (.09% and .0027% risk, respectively). We report on the first case, to our knowledge, of an ovulation-stimulated triplet pregnancy complicated by 3-way discordance for major malformations diagnosed in the late second trimester by ultrasound. Fetus A was affected by congenital diaphragmatic hernia and trisomy 21; fetus B had encephalocele, a midline facial defect, and a cleft palate; and fetus C had evidence of unilateral claw hand but an otherwise normal fetal survey. At 19 weeks of gestation, fetus A was found to have spontaneously died, and a selective termination of triplet B was performed. We conclude: (1) the finding of a single major malformation in one fetus should lead to extensive search for malformations in all members of the pregnancy, and (2) the simultaneous occurrence of major malformations in more than one member of a multifetal gestation is a circumstance under which multiple selective termination deserves consideration. In this article we discuss important issues and caveats in the performance of selective termination for abnormal members of multifetal gestations.

Fiscal impact of a potential legislative ban on second trimester elective terminations for prenatally diagnosed abnormalities.

This study was designed to determine the fiscal impact of a theoretical legislative ban on elective terminations for prenatally diagnosed abnormalities at Hutzel Hospital/Wayne State University. A fiscal comparison was completed for patients who had second trimester elective terminations for prenatally diagnosed abnormalities versus not allowing the procedure. An eight-year database of genetics cases and hospital and physician cost estimates for performing elective terminations for prenatally diagnosed abnormalities, and published reports of the average lifetime costs per selected birth defects, were used to calculate the net cost. The estimated lifetime cost for an average cohort year of a legislative ban on elective terminations for prenatally diagnosed abnormalities was found to be at least $8.5 million for patients treated at Hutzel Hospital. Extrapolated, a similar ban on second trimester elective terminations would have a net cost of $74 million in Michigan and $2 billion annually in the United States.

Psychosocial functioning in the Ehlers-Danlos syndrome.

Ehlers-Danlos Syndrome (EDS) is a group of related genetic disorders of connective tissue presenting with joint hypermobility, skin extensibility, and tissue fragility. Although the pathophysiology of EDS is increasingly understood, the psychosocial effects of having EDS have not been examined. We psychologically tested and interviewed 41 adults and 7 children with EDS. Anxiety, depression, anger, and interpersonal concerns were significantly elevated, varying from one-quarter to one-third of patients; over 70% had a history of some mental health care use. Psychological difficulties appear to result from chronic pain and disability, ostracism or avoidance of relationships and social activities, sexual difficulties and reproductive concerns, and frustration with the medical system. Specific types of EDS (e.g., EDS Type I) are associated with greater pain and psychological distress. Psychological intervention, prescribed with the recognition that psychiatric features are secondary to EDS, is recommended for some patients.

Prenatal evaluation of a de novo X;9 translocation.

A case of X-autosome translocation was diagnosed prenatally [46,X, t(X;9)(p21.3 approximately 22.1;q22]. We describe the use of fluorescence in situ hybridization (FISH) to estimate the integrity of the Duchenne muscular dystrophy (DMD) gene. X-inactivation studies were used as well to assess the probability of phenotypic abnormalities associated with functional partial disomy X and monosomy 9.