Application of risk score analysis to low-coverage whole genome sequencing data for the noninvasive detection of trisomy 21, trisomy 18, and trisomy 13.

OBJECTIVES: Clinical performance of a low coverage, low cost, massively parallel sequencing (MPS)-based assay to stratify risk of trisomy 21, 18, and 13 pregnancies was determined. METHODS: The study included 1100 samples with birth outcome or karyotype results, comprising low-risk patients (84.2%) negative for risk indications from maternal age, serum screening, ultrasound, or family history, and high-risk patients (15.8%) with at least one of the aforementioned indications. Cell free DNA (cfDNA) was extracted from maternal plasma. Library preparation incorporated 96 index barcodes to enable sequencing on a HiSeq 2000 or 2500. Risk scores were calculated using chromosomal representation, fetal fraction, and maternal age at the estimated date of delivery. A risk score greater than or equal to 1 in 100 was used to stratify samples as high risk for trisomy 21, trisomy 18, or trisomy 13. RESULTS: Sensitivity and specificity were calculated based on risk group stratification. Trisomy 21, trisomy 18, and trisomy 13 were detected with greater than 99% sensitivity and 99.9% specificity. Fetal sex classification accuracy was 99.3%. CONCLUSIONS: We conclude that simplified MPS can be used to stratify the risk of pregnancies for trisomy 21, trisomy 18, and trisomy 13 and accurately determine fetal sex. © 2015 John Wiley & Sons, Ltd.

Circulating cell free DNA testing: are some test failures informative?

OBJECTIVE: The proportion of circulating cell free DNA derived from the feto-placental unit (fetal fraction or FF) correlates with test success and interpretation reliability. Some fetal disorders are associated with systematically lower FF, sometimes resulting in noninformative results. METHODS: We analyzed results from pregnancies tested in a nested case/control study derived from a cohort of 4664 high-risk pregnancies. Low FF was defined before and after adjusting for maternal weight and gestational age. RESULTS: Compared with euploid pregnancies, the median FF was significantly higher in Down syndrome pregnancies (ratio 1.17) and significantly lower in trisomy 18 and triploid pregnancies (ratios 0.71 and 0.19, respectively). Among 2157 pregnancies tested, 13 (0.6%) had FF <3.0% (all noninformative), including three trisomy 18 and three triploidy fetuses. After adjustment, 16 pregnancies (0.7%) had FF <0.3 multiples of the median (six informative), including one trisomy 18 and three triploidy fetuses. Modeled positive predictive values for low and high-risk populations were 7% and 30%, respectively. CONCLUSION: Among women with noninformative results attributable to low FF, trisomy 18 and/or triploidy risk are sufficiently high to warrant offering additional assessments (e.g. ultrasound). If the testing indication is ultrasound abnormality, amniocentesis and karyotype/microarray should be considered. © 2014 John Wiley & Sons, Ltd.

Anti-inflammatory drugs in experimental atherosclerosis. Part 5. Influence of cortisone acetate on short-term and long-term cholesterol fluxes in atherosclerotic aorta.

Previous studies in this series have shown that cortisone and other anti-inflammatory drugs inhibit atherosclerotic plaque development in cholesterol-fed rabbits. The present study was designed to investigate the influence of cortisone on the processes of cholesterol influx and efflux in the aorta wall. Forty-seven New Zealand white rabbits were fed a 1% cholesterol diet for periods up to 12 weeks. In addition 23 of the animals were fed 5 mg cortisone acetate daily. At 0, 5 and 12 weeks, groups were fed a tracer dose of [3H]cholesterol. Plasma cholesterol specific radioactivity was measured at intervals during the next 10 days. Total aorta cholesterol and its specific activity were measured by killing groups of animals at 2 days and 10 days. Atherosclerotic plaque intensity at 12 weeks, measured planimetrically, averaged 68 +/- 12% in controls vs. only 6 +/- 3% in cortisone-treated animals. During the period between 5 and 12 weeks, net cholesterol accumulation by chemical analysis averaged only 11 micrograms/g aorta/day in cortisone-treated animals vs. 117 micrograms/g in controls. [3H]cholesterol influx (measured during a brief 2-day exposure) at 5 weeks averaged 206 and 199 micrograms/g tissue/day and at 12 weeks 586 micrograms and 281 micrograms/day in control and cortisone-treated animals, respectively. Measured over a longer 10-day period, however, the apparent influx of [3H]cholesterol was much less in cortisone-treated animals, averaging only 53 micrograms/day compared to 269 micrograms/day in controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Parental decision following prenatal diagnosis of fetal chromosome abnormality.

In the event of prenatal diagnosis of fetal chromosome abnormality, parents must choose between continuation and termination of the pregnancy. To determine whether parents are capable of understanding differences in severity among aneuploidy syndromes, we examined the outcome chosen for all pregnancies in which a fetal chromosome disorder was diagnosed at Northwestern Memorial Hospital between January, 1977 and June, 1986. Among amniocentesis cases, 88% with autosomal aneuploidy were terminated, but only 41% with sex chromosome abnormalities and none with de novo structural rearrangements were terminated. Among a smaller group of chorionic villus sampling cases, all with abnormal results were terminated. Similar patterns of parental behavior were noted in other prenatal diagnosis units. We conclude that parents do distinguish among, and respond specifically to, fetal chromosome disorders of differing severity, at least in the second trimester of pregnancy. However, parents appear more inclined to terminate all pregnancies with chromosome abnormalities when the diagnosis has been made in the first trimester.

Noninvasive first-trimester screening for fetal aneuploidy.

We reviewed all studies concerning noninvasive first trimester screening for fetal aneuploidy obtained from a MEDLINE search through June 1996 with additional sources identified through cross-referencing. Three screening and diagnostic modalities are of potential application in noninvasive first trimester testing for fetal aneuploidy: ultrasound, maternal biochemical markers, and analysis of fetal cells retrieved from maternal sources. Sensitivities of the sonographic finding of nuchal translucency thickness in combination with maternal age for trisomy 21, performed between 10 and 14 weeks of gestation in experienced hands, and maternal biochemical markers independently may be as high as 86 percent and 60 percent, respectively. Sensitivity, specificity, and predictive values of these diagnostic modalities alone, in combination with each other, or in conjunction with other predisposing factors such as maternal age, in large low risk populations have not currently been established. Analysis of fetal cells retrieved from maternal sources, although more complex, may offer definitive noninvasive prenatal diagnosis yet is not currently available in clinical practice. We conclude that noninvasive first trimester screening for fetal aneuploidy modalities including sonographic examination for nuchal translucency thickness and maternal biochemical markers, is feasible. Clinical feasibility; and all-encompassing clinical management paradigms of these and other early noninvasive first trimester screening methods for fetal aneuploidy, are not yet available.

Screening for the aneuploid fetus.

Advances in ultrasound technology have dramatically improved the detection of fetal defects. Although only an invasive test can provide a diagnosis, the incorporation of sonography into current biochemically based screening programs should significantly improve the detection of a host of other physically based fetal abnormalities. This article provides an overview and discussion of the prenatal sonographic features that may suggest the presence of a significant chromosomal abnormality.

Reproductive genetics for couples older than 40 years of age.

The counseling process, which involves genetic screening and prenatal diagnosis, is presented. Also addressed are the recent advances in assisted reproductive technologies, which may prove to be particularly useful for these patients.

Unexplained positive/elevated maternal serum alpha-fetoprotein associated with placenta increta. A case report.

Maternal serum alpha-fetoprotein (MSAFP) is a regularly utilized antenatal screening test for the identification of pregnancies at increased risk for a variety of genetic and nongenetic abnormalities. Complete mid-trimester evaluation of the patient with a positive screening test may fail to reveal an etiology for a positive MSAFP value. This case report concerns an unexplained positive/elevated MSAFP screening test for a patient found at delivery to have abnormal placentation.

Molecular analysis and chorionic villus sampling (CVS): opportunities for rapid prenatal diagnosis in the military.

Prior to recent advances in the field of molecular biology, prenatal diagnosis of hemoglobinopathies was accomplished by direct analysis of the gene product(s) in samples obtained by fetoscopy or, more recently, percutaneous umbilical blood sampling. The use of the polymerase chain reaction enables quicker diagnosis than with indirect or cumbersome Southern blot techniques. This case, reporting a couple at risk for fetal sickle cell disease, is a model for rapid prenatal diagnosis and demonstrates the capabilities which exist in the military health care referral system. Within 24 hours of a couple's presentation for consultation and accomplishment of chorionic villus sampling (CVS), preliminary results of both cytogenetic and sickle cell status of an at-risk fetus were determined. Final analysis was accomplished by 48 hours. The combination of early referral, early sampling by CVS, and application of advances in DNA laboratory technologies offers tremendous improvements for care heretofore unavailable as a complete "package" in the military. The implications and limitations for prenatal testing for single gene disorders within the military medical health care system will be discussed.

Maternal serum alpha-fetoprotein (MSAFP) screening: the Keesler experience.

Maternal serum alpha-fetoprotein (MSAFP) screening is rapidly becoming a standard of practice in all regions of the United States and Canada. This paper will review the initial results of MSAFP screening in 761 patients at USAF Medical Center Keesler, and offer recommendations for Department of Defense hospitals offering such testing.

Management of immune thrombocytopenia purpura at a military medical center.

OBJECTIVE: To investigate whether fetal platelets in immune thrombocytopenia purpura (ITP) may be predicted by antepartum assessment. METHODS: A prospective analysis was conducted of 28 pregnant women with ITP out of 8,056 deliveries. Of the 28 patients, 13 were evaluted by fetal scalp sampling and 11 were evaluated by percutaneous umbilical blood sampling (PUBS). RESULTS: The mean fetal and maternal platelet counts prior to delivery were 146,000 and 176,000, respectively. The mean fetal and maternal platelet counts after delivery were 245,000 and 149,000, respectively. Fetal cord platelet counts could not be predicted by maternal platelet count, the presence/absence of maternal direct/indirect anti-platelet antibodies, steroid therapy, or history of splenectomy. PUBS for fetal platelet assessment correlated well with fetal postdelivery counts. CONCLUSIONS: Patients with ITP rarely exhibit complications. No antepartum characteristic enhances reliable prediction of neonatal outcome. Method of delivery should be based on obstetric guidelines.

Placental echolucencies: does their presence influence outcome following genetic amniocentesis?

Women undergoing genetic amniocentesis procedures were evaluated for the presence of ultrasonographic echolucencies within the placenta. Non-calcified sonolucencies < 4 to 5 cm were classified as subchorionic hematomas (SH). Of the 1,000 pregnancies evaluated, 153 (15%) pregnancies manifested SH prior to amniocentesis (study group). The indications for referral were similar in the study and control groups. There were 13 (1.3%) losses: 3 and 10 in the study and control groups, respectively, with no statistical difference in fetal losses between the groups: RR 1.52 (95% confidence interval 0.56-4.14; p = 0.32). Placental sonolucencies < 4 to 5 cm in diameter appear to be incidental ultrasound findings not associated with increased fetal loss following genetic amniocentesis. Complications following invasive prenatal diagnosis cannot be attributed to the presence of these common ultrasound findings.