The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
K H Nicolaides - One of the best experts on this subject based on the ideXlab platform.
-
first trimester screening for Trisomy 21 using alpha fetoprotein
Fetal Diagnosis and Therapy, 2011Co-Authors: Foteini E Bredaki, David Wright, Pedro Matos, Argyro Syngelaki, K H NicolaidesAbstract:Objective: To investigate the potential value of adding maternal serum alpha-fetoprotein (AFP) to free β-human chorionic gonadotropin (β-hCG) and PAPP-A and fetal nuchal translucency (NT) thickness in first-trimester screening for Trisomy 21. Methods: In this case control study, serum AFP was measured in 100 Trisomy 21 and 1,500 euploid pregnancies in which screening for Trisomy 21 had been performed by a combination of serum free β-hCG and PAPP-A and fetal NT at 11–13 weeks’ gestation. We examined the effect of adding AFP on the performance of screening by the combined test. Results: In the Trisomy 21 pregnancies, the median multiple of the normal median AFP, adjusted for gestational age, maternal weight, racial origin, smoking status and method of conception, was significantly reduced (0.7037, 95% CI: 0.6398–0.7739). Adding AFP to the combined test improved the performance of screening and for a risk cut-off of 1 in 100, the false-positive rate was reduced from 2.8 by 0.4% (95% CI: 0.13–0.77%) without a significant change in detection rate. Conclusions: Inclusion of serum AFP improves the performance of the first-trimester combined test in screening for Trisomy 21.
-
frontomaxillary facial angles in screening for Trisomy 21 at 14 23 weeks gestation
American Journal of Obstetrics and Gynecology, 2007Co-Authors: Jiri Sonek, Ran Neiger, David S Mckenna, Christopher S Croom, M Borenstein, Cathy Downing, Toby Genrich, K H NicolaidesAbstract:Objective The objective of the study was to investigate the potential value of the frontomaxillary facial (FMF) angle in second-trimester ultrasound screening for Trisomy 21. Methods We examined stored images of fetal profiles taken before amniocentesis at 14-24 weeks from 100 euploid fetuses and 34 with Trisomy 21. The FMF angles between the upper surface of the upper palate and the frontal bone (FMF bone ) and the skin over the forehead (FMF skin ) were measured. Results In the euploid group the FMF angles decreased with gestation. In the fetuses with Trisomy 21, the FMF bone and FMF skin angles were 79.4% and 87.9% above the 95th percentile for gestation of the respective values from the euploid group. In Trisomy 21 fetuses, there was no significant difference in FMF angles between those with nasal bone hypoplasia (n = 19) and those without (n = 15). Conclusion The FMF angle is substantially higher in Trisomy 21 than euploid fetuses. Measurement of the FMF angles is likely to prove a useful method in prenatal screening for Trisomy 21 in the second trimester.
-
nasal bone assessment in prenatal screening for Trisomy 21
American Journal of Obstetrics and Gynecology, 2006Co-Authors: Jiri Sonek, S Cicero, Ran Neiger, K H NicolaidesAbstract:A small nose is a common facial feature of individuals with Trisomy 21. Evidence based on radiologic, histomorphologic, and sonographic studies shows that nasal bone abnormalities are significantly more common in Trisomy 21 fetuses than in euploid fetuses. These abnormalities, which include both nasal bone absence and short nasal bone length, can be detected by prenatal ultrasound. In this article we review the evidence and discuss the potential value of assessment of the fetal nasal bone in screening for Trisomy 21.
-
prospective first trimester screening for Trisomy 21 in 30 564 pregnancies
American Journal of Obstetrics and Gynecology, 2005Co-Authors: K Avgidou, A T Papageorghiou, R Bindra, Kevin Spencer, K H NicolaidesAbstract:OBJECTIVE: This study was undertaken to evaluate the performance of a 1-stop clinic for first-trimester assessment of risk (OSCAR) for Trisomy 21 by a combination of maternal age, fetal nuchal translucency (NT) thickness, and maternal serum-free ss- human chorionic gonadotrophin (hCG) and pregnancy-associated plasma protein-A (PAPP-A). STUDY DESIGN: OSCAR was carried out in 30,564 pregnancies at 11 to 13 + 6 weeks. Patient-specific risks for Trisomy 21 and detection and false-positive rates were calculated. RESULTS: The median maternal age was 34 (range 15-49) years. Chromosomal abnormalities were identified in 330 pregnancies, including 196 cases of Trisomy 21. The estimated risk for Trisomy 21 was 1 in 300 or greater in 7.5% of the normal pregnancies, in 93.4% of those with Trisomy 21 and in 88.8% of those with other chromosomal defects. CONCLUSION: The most effective method of screening for chromosomal defects is by first-trimester fetal NT and maternal serum biochemistry.
-
nasal bone hypoplasia in Trisomy 21 at 15 22 weeks gestation
Ultrasound in Obstetrics & Gynecology, 2003Co-Authors: S Cicero, Jiri Sonek, David S Mckenna, Christopher S Croom, L Johnson, K H NicolaidesAbstract:Objective To investigate the potential value of ultrasound examination of the fetal profile for present/hypoplastic fetal nasal bone at 15-22 weeks' gestation as a marker for Trisomy 21. Methods This was an observational ultrasound study in 1046 singleton pregnancies undergoing amniocentesis for fetal karyotyping at 15-22 (median, 17) weeks' gestation. Immediately before amniocentesis the fetal profile was examined to determine if the nasal bone was present or hypoplastic (absent or shorter than 2.5 mm). The incidence of nasal hypoplasia in the Trisomy 21 and the chromosomally normal fetuses was determined and the likelihood ratio for Trisomy 21 for nasal hypoplasia was calculated. Results All fetuses were successfully examined for the presence of the nasal bone. The nasal bone was hypoplastic in 21/34 (61.8%) fetuses with Trisomy 21, in 12/982 (1.2%) chromosomally normal fetuses and in 1/30 (3.3%) fetuses with other chromosomal defects. In 3/21 (14.3%) Trisomy 21 fetuses with nasal hypoplasia there were no other abnormal ultrasound findings. In the chromosomally normal group hypoplastic nasal bone was found in 0.5% of Caucasians and in 8.8% of Afro-Caribbeans. The likelihood ratio for Trisomy 21 for hypoplastic nasal bone was 50.5 (95% CI 27.1-92.7) and for present nasal bone it was 0.38 (95% CI 0.24-0.56). Conclusion Nasal bone hypoplasia at the 15-22-week scan is associated with a high risk for Trisomy 21 and it is a highly sensitive and specific marker for this chromosomal abnormality.
Jiri Sonek - One of the best experts on this subject based on the ideXlab platform.
-
frontomaxillary facial angles in screening for Trisomy 21 at 14 23 weeks gestation
American Journal of Obstetrics and Gynecology, 2007Co-Authors: Jiri Sonek, Ran Neiger, David S Mckenna, Christopher S Croom, M Borenstein, Cathy Downing, Toby Genrich, K H NicolaidesAbstract:Objective The objective of the study was to investigate the potential value of the frontomaxillary facial (FMF) angle in second-trimester ultrasound screening for Trisomy 21. Methods We examined stored images of fetal profiles taken before amniocentesis at 14-24 weeks from 100 euploid fetuses and 34 with Trisomy 21. The FMF angles between the upper surface of the upper palate and the frontal bone (FMF bone ) and the skin over the forehead (FMF skin ) were measured. Results In the euploid group the FMF angles decreased with gestation. In the fetuses with Trisomy 21, the FMF bone and FMF skin angles were 79.4% and 87.9% above the 95th percentile for gestation of the respective values from the euploid group. In Trisomy 21 fetuses, there was no significant difference in FMF angles between those with nasal bone hypoplasia (n = 19) and those without (n = 15). Conclusion The FMF angle is substantially higher in Trisomy 21 than euploid fetuses. Measurement of the FMF angles is likely to prove a useful method in prenatal screening for Trisomy 21 in the second trimester.
-
nasal bone assessment in prenatal screening for Trisomy 21
American Journal of Obstetrics and Gynecology, 2006Co-Authors: Jiri Sonek, S Cicero, Ran Neiger, K H NicolaidesAbstract:A small nose is a common facial feature of individuals with Trisomy 21. Evidence based on radiologic, histomorphologic, and sonographic studies shows that nasal bone abnormalities are significantly more common in Trisomy 21 fetuses than in euploid fetuses. These abnormalities, which include both nasal bone absence and short nasal bone length, can be detected by prenatal ultrasound. In this article we review the evidence and discuss the potential value of assessment of the fetal nasal bone in screening for Trisomy 21.
-
nasal bone hypoplasia in Trisomy 21 at 15 22 weeks gestation
Ultrasound in Obstetrics & Gynecology, 2003Co-Authors: S Cicero, Jiri Sonek, David S Mckenna, Christopher S Croom, L Johnson, K H NicolaidesAbstract:Objective To investigate the potential value of ultrasound examination of the fetal profile for present/hypoplastic fetal nasal bone at 15-22 weeks' gestation as a marker for Trisomy 21. Methods This was an observational ultrasound study in 1046 singleton pregnancies undergoing amniocentesis for fetal karyotyping at 15-22 (median, 17) weeks' gestation. Immediately before amniocentesis the fetal profile was examined to determine if the nasal bone was present or hypoplastic (absent or shorter than 2.5 mm). The incidence of nasal hypoplasia in the Trisomy 21 and the chromosomally normal fetuses was determined and the likelihood ratio for Trisomy 21 for nasal hypoplasia was calculated. Results All fetuses were successfully examined for the presence of the nasal bone. The nasal bone was hypoplastic in 21/34 (61.8%) fetuses with Trisomy 21, in 12/982 (1.2%) chromosomally normal fetuses and in 1/30 (3.3%) fetuses with other chromosomal defects. In 3/21 (14.3%) Trisomy 21 fetuses with nasal hypoplasia there were no other abnormal ultrasound findings. In the chromosomally normal group hypoplastic nasal bone was found in 0.5% of Caucasians and in 8.8% of Afro-Caribbeans. The likelihood ratio for Trisomy 21 for hypoplastic nasal bone was 50.5 (95% CI 27.1-92.7) and for present nasal bone it was 0.38 (95% CI 0.24-0.56). Conclusion Nasal bone hypoplasia at the 15-22-week scan is associated with a high risk for Trisomy 21 and it is a highly sensitive and specific marker for this chromosomal abnormality.
Joseph M Cabral - One of the best experts on this subject based on the ideXlab platform.
-
Trisomy 21 consistently activates the interferon response
eLife, 2016Co-Authors: Kelly D Sullivan, Hannah C Lewis, Amanda A Hill, Ahwan Pandey, Leisa P Jackson, Joseph M CabralAbstract:Our genetic information is contained within structures called chromosomes. Down syndrome is caused by the genetic condition known as Trisomy 21, in which a person is born with an extra copy of chromosome 21. This extra chromosome affects human development in many ways, including causing neurological problems and stunted growth. Trisomy 21 makes individuals more susceptible to certain diseases, such as Alzheimer’s disease and autoimmune disorders – where the immune system attacks healthy cells in the body – while protecting them from tumors and some other conditions. Since cells with Trisomy 21 have an extra copy of every single gene on chromosome 21, it is expected that these genes should be more highly expressed – that is, the products of these genes should be present at higher levels inside cells. However, it was not clear which genes on other chromosomes are also affected by Trisomy 21. Sullivan et al. aimed to identify which genes are affected by Trisomy 21 by studying samples collected from a variety of individuals with, and without, this condition. Four genes in chromosome 21 encode proteins that recognize signal molecules called interferons, which are produced by cells in response to viral or bacterial infection. Interferons act on neighboring cells to regulate genes that prevent the spread of the infection, shut down the production of proteins and activate the immune system. Sullivan et al. show that cells with Trisomy 21 produce high levels of genes that are activated by interferons and lower levels of genes required for protein production. In other words, the cells of people with Down syndrome are constantly fighting a viral infection that does not exist. Constant activation of interferon signaling could explain many aspects of Down syndrome, including neurological problems and protection against tumors. The next steps are to fully define the role of interferon signaling in the development of Down syndrome, and to find out whether drugs that block the action of interferons could have therapeutic benefits.
Christopher S Croom - One of the best experts on this subject based on the ideXlab platform.
-
frontomaxillary facial angles in screening for Trisomy 21 at 14 23 weeks gestation
American Journal of Obstetrics and Gynecology, 2007Co-Authors: Jiri Sonek, Ran Neiger, David S Mckenna, Christopher S Croom, M Borenstein, Cathy Downing, Toby Genrich, K H NicolaidesAbstract:Objective The objective of the study was to investigate the potential value of the frontomaxillary facial (FMF) angle in second-trimester ultrasound screening for Trisomy 21. Methods We examined stored images of fetal profiles taken before amniocentesis at 14-24 weeks from 100 euploid fetuses and 34 with Trisomy 21. The FMF angles between the upper surface of the upper palate and the frontal bone (FMF bone ) and the skin over the forehead (FMF skin ) were measured. Results In the euploid group the FMF angles decreased with gestation. In the fetuses with Trisomy 21, the FMF bone and FMF skin angles were 79.4% and 87.9% above the 95th percentile for gestation of the respective values from the euploid group. In Trisomy 21 fetuses, there was no significant difference in FMF angles between those with nasal bone hypoplasia (n = 19) and those without (n = 15). Conclusion The FMF angle is substantially higher in Trisomy 21 than euploid fetuses. Measurement of the FMF angles is likely to prove a useful method in prenatal screening for Trisomy 21 in the second trimester.
-
nasal bone hypoplasia in Trisomy 21 at 15 22 weeks gestation
Ultrasound in Obstetrics & Gynecology, 2003Co-Authors: S Cicero, Jiri Sonek, David S Mckenna, Christopher S Croom, L Johnson, K H NicolaidesAbstract:Objective To investigate the potential value of ultrasound examination of the fetal profile for present/hypoplastic fetal nasal bone at 15-22 weeks' gestation as a marker for Trisomy 21. Methods This was an observational ultrasound study in 1046 singleton pregnancies undergoing amniocentesis for fetal karyotyping at 15-22 (median, 17) weeks' gestation. Immediately before amniocentesis the fetal profile was examined to determine if the nasal bone was present or hypoplastic (absent or shorter than 2.5 mm). The incidence of nasal hypoplasia in the Trisomy 21 and the chromosomally normal fetuses was determined and the likelihood ratio for Trisomy 21 for nasal hypoplasia was calculated. Results All fetuses were successfully examined for the presence of the nasal bone. The nasal bone was hypoplastic in 21/34 (61.8%) fetuses with Trisomy 21, in 12/982 (1.2%) chromosomally normal fetuses and in 1/30 (3.3%) fetuses with other chromosomal defects. In 3/21 (14.3%) Trisomy 21 fetuses with nasal hypoplasia there were no other abnormal ultrasound findings. In the chromosomally normal group hypoplastic nasal bone was found in 0.5% of Caucasians and in 8.8% of Afro-Caribbeans. The likelihood ratio for Trisomy 21 for hypoplastic nasal bone was 50.5 (95% CI 27.1-92.7) and for present nasal bone it was 0.38 (95% CI 0.24-0.56). Conclusion Nasal bone hypoplasia at the 15-22-week scan is associated with a high risk for Trisomy 21 and it is a highly sensitive and specific marker for this chromosomal abnormality.
David S Mckenna - One of the best experts on this subject based on the ideXlab platform.
-
frontomaxillary facial angles in screening for Trisomy 21 at 14 23 weeks gestation
American Journal of Obstetrics and Gynecology, 2007Co-Authors: Jiri Sonek, Ran Neiger, David S Mckenna, Christopher S Croom, M Borenstein, Cathy Downing, Toby Genrich, K H NicolaidesAbstract:Objective The objective of the study was to investigate the potential value of the frontomaxillary facial (FMF) angle in second-trimester ultrasound screening for Trisomy 21. Methods We examined stored images of fetal profiles taken before amniocentesis at 14-24 weeks from 100 euploid fetuses and 34 with Trisomy 21. The FMF angles between the upper surface of the upper palate and the frontal bone (FMF bone ) and the skin over the forehead (FMF skin ) were measured. Results In the euploid group the FMF angles decreased with gestation. In the fetuses with Trisomy 21, the FMF bone and FMF skin angles were 79.4% and 87.9% above the 95th percentile for gestation of the respective values from the euploid group. In Trisomy 21 fetuses, there was no significant difference in FMF angles between those with nasal bone hypoplasia (n = 19) and those without (n = 15). Conclusion The FMF angle is substantially higher in Trisomy 21 than euploid fetuses. Measurement of the FMF angles is likely to prove a useful method in prenatal screening for Trisomy 21 in the second trimester.
-
nasal bone hypoplasia in Trisomy 21 at 15 22 weeks gestation
Ultrasound in Obstetrics & Gynecology, 2003Co-Authors: S Cicero, Jiri Sonek, David S Mckenna, Christopher S Croom, L Johnson, K H NicolaidesAbstract:Objective To investigate the potential value of ultrasound examination of the fetal profile for present/hypoplastic fetal nasal bone at 15-22 weeks' gestation as a marker for Trisomy 21. Methods This was an observational ultrasound study in 1046 singleton pregnancies undergoing amniocentesis for fetal karyotyping at 15-22 (median, 17) weeks' gestation. Immediately before amniocentesis the fetal profile was examined to determine if the nasal bone was present or hypoplastic (absent or shorter than 2.5 mm). The incidence of nasal hypoplasia in the Trisomy 21 and the chromosomally normal fetuses was determined and the likelihood ratio for Trisomy 21 for nasal hypoplasia was calculated. Results All fetuses were successfully examined for the presence of the nasal bone. The nasal bone was hypoplastic in 21/34 (61.8%) fetuses with Trisomy 21, in 12/982 (1.2%) chromosomally normal fetuses and in 1/30 (3.3%) fetuses with other chromosomal defects. In 3/21 (14.3%) Trisomy 21 fetuses with nasal hypoplasia there were no other abnormal ultrasound findings. In the chromosomally normal group hypoplastic nasal bone was found in 0.5% of Caucasians and in 8.8% of Afro-Caribbeans. The likelihood ratio for Trisomy 21 for hypoplastic nasal bone was 50.5 (95% CI 27.1-92.7) and for present nasal bone it was 0.38 (95% CI 0.24-0.56). Conclusion Nasal bone hypoplasia at the 15-22-week scan is associated with a high risk for Trisomy 21 and it is a highly sensitive and specific marker for this chromosomal abnormality.
