OBJECTIVE The study aimed to validate the efficacy of detection of fetal cell-free DNA in maternal plasma of trisomy 21, 18 and 13 in a clinical setting. METHODS A total of 2340 women at high risk for Down syndrome based on maternal age, prenatal history or a positive sesum or sonographic screening test were offered prenatal noninvasive aneuploidy test. According to the prenatal noninvasive a...

BACKGROUND Screening for fetal chromosome abnormalities in the first trimester includes analysis of the serological markers pregnancy-associated plasma protein A (PAPP-A) and free beta human choriogonadotropin (free beta hCG). The blood sample is traditionally taken around week 12 of gestation, but the performance of earlier blood sampling is not well documented. METHODS We studied 44,537 sin...

Trisomy 21 is a chromosomal condition caused by the presence of all or part of an extra 21st chromosome. There has been limited research into the DNA methylation status of CpG islands (CGIs) in trisomy 21, therefore, exploring the DNA methylation status of CGIs in 21q is essential for the development of a series of potential epigenetic biomarkers for prenatal screening of trisomy 21. First, DNA...

1. Edwards JH, Harnden DG, Cameron AH, Crosse VM, Wolff OH. A new trisomic syndrome. Lancet. 1960;1:787-90. 2. Warkany J, Passarge E, Smith LB. Congenital malformations in autosomal trisomy syndromes. Am J Dis Child. 1966;112:502-17. 3. Rasmussen SA, Wong LY, Yang Q, May KM, Friedman JM. Population-based analyses of mortality in trisomy 13 and trisomy 18. Pediatrics. 2003;111:777-84. 4. Carter ...

Serum concentrations of fetal antigen 2 (FA-2), the amino-propeptide of the alpha1 chain of collagen type I, were measured in peripheral blood from women with normal (n = 234) and trisomy 21 affected (n = 14) pregnancies between 9 and 11 weeks gestation. Serum FA-2 concentrations were seen to be stable throughout this period, and though raised FA-2 concentrations were seen at the 10th week of g...

This article reviews the performance of first trimester screening for chromosomal anomalies using various combinations of ultrasound and maternal serum biochemical modalities. Detection rates in excess of 90% can be routinely achieved for Trisomy 21, Trisomy 13, Trisomy 18 using a combination of fetal nuchal translucency (NT) thickness and maternal serum free ss-hCG and PAPP-A at 11 + 0 to 13 +...

Down syndrome is a collection of features that are caused by trisomy for human Chromosome 21. While elevated transcript levels of the more than 350 genes on the chromosome are primarily responsible, it is likely that multiple genetic mechanisms underlie the numerous ways in which development and function diverge in individuals with trisomy 21 compared to euploid individuals. We consider genotyp...

A case of Turner's syndrome, detected antenatally and complicated by the finding of trisomy 20 mosaicism in 50% of cells from each of two amniotic fluid cultures, is described. Cultures from seven fetal tissues in the subsequent abortus showed a predominance of 45,X cells, but nevertheless suggested the existence of a very low level of trisomy 20 mosaicism in three fetal tissues. The diagnostic...

Measurement of alpha-fetoprotein concentration and acetylcholinesterase activity in amniotic fluid can be used to identify chromosomal defects as well as neural tube defects. In seven cases of trisomy 21 and one case of partial trisomy 3, alpha-fetoprotein concentrations were below the reference range but values for acetylcholinesterase activity were normal for the appropriate gestational age. ...

Three patients, with constitutional trisomy 8 mosaicism (CT8M), who developed a malignancy are reported. The diagnoses were refractory anaemia, acute lymphoblastic leukaemia, and idiopathic myelofibrosis. In the child with acute leukaemia, the CT8M was diagnosed at birth due to severe dysmorphisms and malformations; the other two patients showed a milder phenotype, and the CT8M was diagnosed on...