OBJECTIVE To evaluate the clinical accuracy of the IONA® test for aneuploidy screening. METHODS This was a multicenter blinded study in which plasma samples from pregnant women at increased risk of trisomy 21 underwent cell-free DNA analysis utilizing the IONA test. For each sample, the IONA software generated a likelihood ratio and a maternal age-adjusted probability risk score for trisomies...

Liver failure in neonates is a rare but often fatal disease. Trisomy 21 is not usually associated with significant infantile liver disease. If present, hepatic dysfunction in an infant with Trisomy 21 is likely to be attributed to transient myeloproliferative disorder with hepatic infiltration by hematopoietic elements and may be associated with secondary hemosiderosis. A less commonly recogniz...

OBJECTIVE To establish an algorithm for first-trimester combined screening for trisomy 21 with biochemical testing from 7 to 14 weeks' gestation and ultrasound testing at 11-13 weeks. METHODS This was a multicenter study of 886 pregnancies with trisomy 21 and 222 475 unaffected pregnancies with measurements of free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein...

OBJECTIVE Trisomy 21 is associated with a flat face, which can now be quantified by measurement of the frontomaxillary facial (FMF) angle. The aim of this study was to examine whether in trisomy 21 fetuses fetal nuchal translucency (NT) thickness and maternal serum free ss-human chorionic gonadotropin (ss-hCG) and pregnancy-associated plasma protein-A (PAPP-A) are independent of the FMF angle, ...

OBJECTIVE To determine the reproducibility of diagnosing tricuspid regurgitation (TR) at 11 + 0 to 13 + 6 weeks' gestation, to examine further the relationship between TR and the presence of chromosomal defects and to calculate the likelihood ratios for trisomy 21 and trisomy 18 in fetuses with TR. METHODS Pulsed wave Doppler of flow across the tricuspid valve was carried out by 12 obstetrici...

This study aimed to verify the reliability of the 7 tissue differentially methylated regions used in the methylated DNA immunoprecipitation (MeDIP) real-time quantitative polymerase chain reaction (real-time qPCR) based approach of fetal DNA in maternal blood to diagnosis of fetal trisomy 21. Forty pregnant women with high risk pregnancy who were referred after first or second trimester screeni...

INTRODUCTION Free trisomy 21 is responsible for 95% of Down syndrome cases. Advanced maternal age and susceptible recombination patterns are recognized risk factors associated to Down syndrome. Maternal origin of trisomy occurs in approximately 90% of cases; paternal and mitotic origin share the remaining 10%. However, the recombination events that serve as a risk factors for trisomy 21 have no...

OBJECTIVE To determine possible differences in hepatic artery flow between trisomy 21 and euploid fetuses at 11-13 weeks' gestation. METHODS Hepatic artery pulsatility index (PI) and peak systolic velocity (PSV) were measured in fetuses at low risk of aneuploidies (n = 350) and another group at high risk, including 283 euploid and 47 with trisomy 21. The association of hepatic artery PI and P...

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 per...

A patient with Down's syndrome was found to have 47,XX,+18/47,XX,+21 mosaicism. Chromosome 18 trisomy was found only in 18% of lymphocytes and not in skin fibroblasts. A likely interpretation is double nondisjunction in a single lymphocyte precursor of a trisomy 21 embryo. A brief review of other cases of mitotic multiple nondisjunction and double aneuploid mosiacism is presented.