Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0013080 (Down syndrome)
 14,180 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

With the aid of two commercially available analysis programmes we effected non-invasive assessment of the risk for Down's syndrome in 597 pregnancies with healthy fetuses and in 22 pregnancies with trisomie 21-affected fetuses, maternal age ranging between 18 and 45 years. Based on the women's serum levels, hormone concentrations of AFP, free estriol and beta HCG were determined, a multiple of their median was combined with the age factor, and the result used as a parameter for overall risk estimation. A risk cut-off-level greater then 1:250 was considered to represent a positive risk. For patients younger than 35 years test sensitivity, at just over 50%, was found to be low. For those aged 35 years or greater, however, the Dermalog programme was able to detect 94.4% and the Alpha programme 88.2% of fetuses affected by trisomy 21, with a false-positive rate of 19.6 and 19.1%, respectively. If the test were to be applied to all pregnant women beyond 35 years of age the detection rate of Down's syndrome could be nearly doubled compared to today's figure (only 50%, of women in this age group undergo amniocentesis). By the same token the rate of amniocentesis-induced abortion (approx. 1%) could be reduced to about one third.
 ...
PMID:[Prenatal serum screening for Down's syndrome]. 137 69

The addition of two new markers in maternal serum, estriol and HCG, to those already known, namely the level of maternal serum alfa-fetoprotein and maternal age, considerably improves the expected results of a screening strategy for Down syndrome. The detection rate is slightly increased from 53.0% to 57.6%, but, more importantly, the false-positive rate decreases from 9.4% to 7.3%. It is our belief that, at least in women aged less than 35 years, a screening strategy based on a combination of maternal age and biochemical markers should be incorporated into antenatal care. For older women, the results of such a maternal serum test may refine counseling for genetic amniocentesis, as a much more explicit risk calculation can be performed than that based on age alone.
 ...
PMID:Maternal serum markers in screening for Down syndrome. 168 25

Serum samples from 320 women with chromosomally normal fetuses and from 50 women with fetuses affected by Down's syndrome were assayed retrospectively for human chorionic gonadotropin (hCG), pregnancy-specific beta 1 glycoprotein (SP1), alpha fetoprotein (AFP), and unconjugated estriol (uE3) between 14 and 21 weeks of gestation. Nonparametric discriminant analysis was applied to calculate Down syndrome risks on the basis of various combinations of serum parameters. At a risk threshold that falsely identifies 5% of controls as being affected, 46 to 48% of Down syndrome pregnancies were detected by combinations of hCG/AFP, hCG/AFP/uE3, and hCG/AFP/uE3/SP1 respectively. HCG, AFP, and uE3 were assayed in 652 serum samples from women who underwent amniocentesis because of maternal age (> or equal to 35 years in this prospective study). 49% of women with euploid fetal karyotype, 8 of 10 pregnancies with Down's syndrome, and 3 pregnancies with sex chromosomal anomalies were identified as being at an increased risk (> 1:380).
 ...
PMID:Risk of fetal Down's syndrome based on maternal age and varying combinations of maternal serum markers. 752 30

High levels of maternal serum alpha-1-fetoprotein (S-AFP) are associated with fetal structural abnormalities like neutral tube defects and congenital nephrosis. It has a very high detection rate when used for screening of these diseases. On the other hand, the low levels of maternal S-AFP act as a marker of many fetal chromosomal aberrations. The detection rate of S-AFP alone for the screening of Down's syndrome is low. Wald et al. have shown that the addition of the determination of maternal serum chorionic gonadotrophin (S-HCG-beta) to S-AFP analysis, and using a computer program for risk estimation increases the detection rate for Down's syndrome to about 57% with a false positive rate of 5%. In this study we present the results of our screening program for structural fetal defects and chromosomal aberrations in Eastern Finland, and describe the standardization and quality control of maternal serum AFP and HCG-beta analysis.
 ...
PMID:Quality specifications for S-AFP and S-HCG-beta determinations for screening of fetal abnormalities. 752 12

Two years after introduction of maternal serum screening for Down's syndrome in German-speaking Switzerland, based on measurements of alpha-fetoprotein, unconjugated estriol and total beta-HCG, results were analyzed of the two cytogenetic laboratories in Zurich and of a separate collective of the Department of Obstetrics at the University of Zurich. In a total of 489 cases with increased risk for Down's syndrome (> or = 1:380 at term) 19 (1:26; approximately 4%) had an abnormal fetal karyotype from which 16 had a trisomy 21. 13 out of these 16 mothers were aged below 35 years. Thus, after ultrasound, maternal serum screening detects the highest percentage of fetuses with chromosomal abnormalities. At the Department of Obstetrics 2962 serum screening tests were performed during a period of 2 1/2 years. 14.6% of the women were > or = 35 years old, 7.6% showed increased risk and 14 fetuses had an abnormal karyotype including 10 with Down's syndrome. 7 of these 10 were detected by the serum test. Nevertheless, the limited sensitivity of serum screening, its limitation predominantly to detection of fetuses with Down's syndrome and the rather late stage of screening, make effective first trimester screening mandatory.
 ...
PMID:[Trisomy-21 screening using AFPplus in the eastern part of Switzerland]. 754 52

Free beta-HCG is a new analyte that has been suggested to be superior to total HCG when used in combination with alpha-fetoprotein (AFP) for Down syndrome risk screening in early pregnancy. We have evaluated this claim on 21 samples collected from Down syndrome pregnancies and 180 samples from unaffected pregnancies. The detection rates for the combination of AFP with free beta-HCG or the combination of AFP with total HCG were identical (71 per cent) but the initial screen positive rate (equivalent to the false-positive rate) was 7.5 per cent for AFP + free beta-HCG screening compared with 3.5 per cent for AFP + total HCG screening. We conclude that the case for free beta-HCG is unproven and suggest that further data be collected before free beta-HCG becomes acceptable.
 ...
PMID:A comparison of total and free beta-HCG assays in Down syndrome screening. 769 Apr 82

Recent advances in our understanding of hCG/hCG beta synthesis by trophoblastic and nontrophoblastic tissues together with improved techniques for measuring hCG have helped to define the role of hCG as a clinical marker. HCG determination by sensitive immunometric assay enables detection of hCG immunoreactivity in normal men and women. It facilitates early detection of normal pregnancy and significantly contributes to the diagnosis of various pregnancy-related disorders, such as ectopic pregnancy, spontaneous abortion, hydatidiform mole, choriocarcinoma or Trisomy 21. Further, determination of this marker is immensely helpful to guide curative intervention in testicular cancer. For diagnosis and follow-up of patients with testicular cancer, a method measuring both hCG and hCG beta or separate methods for each component are recommended, because a significant portion of seminoma exclusively secrete free hCG beta. Also, hCG beta production by other than trophoblastic malignancies has been well recognized. A possible clinical use of hCG beta as a marker of cancers of the bladder, pancreas or biliary tract is currently debated.
 ...
PMID:Clinical use of HCG and hCG beta determinations. 769 Sep 85

Many recent studies have identified biometric parameters which can be used as screening factors in the diagnosis of chromosomic anomalies. This derives from the assertion that karyotype testing in over-35-year-old women alone only allows 20-30% of fetuses suffering from chromosomic anomalies to be diagnosed. The majority of these fetuses remain undiagnosed during the prenatal period given that a high percentage of younger women are excluded from screening. For a long time researchers have hoped to introduce the assay of clinical and instrumental parameters thus allowing anomalous fetuses to be diagnosed in under-35-year-old women. It is now possible to define a biochemical parameter in maternal sera which can identify women at risk and refer them for cytogenetic tests: AFP assay and still more recently the contemporary assay of AFP, estriol and beta-HCG allows greater diagnostic accuracy. However, even using this method only part of those fetuses with chromosomic alterations are identified. Since it is unlikely that screening could be performed without indications in the under 35-year-old age group, it is important to identify routine echographic parameters which can then serve as the indication for subsequent cytogenetic tests and a definitive diagnosis. In this way, by integrating ultrasonographic examination, using biometric and morphological tests, with a biochemical evaluation it will be possible to achieve a higher percentage of diagnosis. This paper examines the most common malformations including trisomy 13, trisomy 18 and trisomy 21 syndromes, Turner's syndrome and triploidy, together with the main echographic findings which accompany them.
 ...
PMID:[Echographic markers of chromosome abnormalities]. 785 67

Prenatal screening for Down's syndrome (DS) can be achieved by combining maternal age risks and maternal serum additional parameters (AFP, HCG, uE3) by computer assisted statistical analysis. Nevertheless this measure of risk is far from broad and practical application in Italy, due to cultural and organization difficulties. So we suggest a different technical approach, the age specific risk being multiplied by the HCG/AFP likelihood ratio. HCG and AFP can be tested by an automated Elisa assay, and calculations performed by a simple method, excluding computer and software package use. About 100 pregnancies were evaluated both by a modified version of the Wald test and the method described hereafter. Using the automated HCG and AFP Elisa Testing and Crossley statistical calculation a higher False Positive Rate was observed. On the other hand no different Detection Rate was observed for the two tests. On a retrospective study we found that 5 sera from affected pregnancies were correctly identified both by the modified Wald test and the other method. It is concluded that, despite different False Positive Rates, the choice of which test to use depends on evaluation of local resources, one test being easier-to-perform and more sensitive, the other one probably being more specific but more difficult to perform.
 ...
PMID:[Prenatal screening for Down's syndrome: a simplified method]. 825 99

Alpha-fetoprotein (AFP), unconjugated oestriol (UE3), intact human chorionic gonadotrophin (intHCG), and the free beta subunit of chorionic gonadotrophin (F beta HCG) were investigated in a series of 21 chromosomally abnormal and 14 open neural tube defect pregnancies ascertained from a series of 14,000 prospectively collected maternal serum samples at 6-14 weeks' gestation. In 16 cases of Down's syndrome, significant reductions were found for AFP (0.65 multiples of the normal median) and UE3 (0.67 MOM). IntHCG levels were unaltered (0.97 MOM) but a significant increase was found for F beta HCG (1.96 MOM). Significant correlations were found for AFP and UE3 in the controls and for intHCG and F beta HCG in both the control and the Down's syndrome pregnancies. In a group of five trisomy 18 pregnancies, median MOMs were for AFP 0.71, for UE3 0.34, for intHCG 0.27, and for F beta HCG 0.15. None of 13 pregnancies with open neural tube defects at 8-13 weeks gestation had elevated maternal serum AFP levels, whereas matched second-trimester samples from the same pregnancies at 16-18 weeks gestation all had significantly elevated AFP levels. Thus, biochemical screening for chromosome abnormalities may be practicable in the first trimester using free beta human chorionic gonadotrophin in combination with AFP and maternal age. However, a separate screening protocol using AFP at 15-18 weeks gestation would still be required for effective detection of neural tube defects.
 ...
PMID:First-trimester biochemical screening for fetal chromosome abnormalities and neural tube defects. 828 87


1 2 3 Next >>