نتایج جستجو برای: trisomy 9
تعداد نتایج: 487797 فیلتر نتایج به سال:
OBJECTIVE To assess the potential performance of screening for fetal trisomies 21, 18 and 13 by cell-free DNA (cfDNA) analysis of maternal blood using the IONA® test. METHODS This was a nested case-control study of cfDNA analysis of maternal plasma using the IONA test. Samples were obtained at 11-13 weeks' gestation, before chorionic villus sampling, from 201 euploid pregnancies, 35 with tris...
OBJECTIVE To assess the performance of chromosome-selective sequencing of maternal plasma cell-free DNA (cfDNA) in non-invasive prenatal testing for trisomy 13. METHODS Two-phase case-control study on a single plasma sample per case. The first phase was used to optimize the trisomy 13 algorithm, which was then applied to a second dataset to determine the risk score for trisomy 13 by laborator...
Marker chromosomes are very rare in Klinefelter patients and phenotypic findings are related to the affected chromosomal region. The phenotypic effects of small supernumerary marker chromosomes (sSMC) range from multiple malformations/mental retardation to no effect (ie a normal phenotype). This wide spectrum of phenotypes is due to the origin, structure and gene content of the marker chromosom...
Massively parallel sequencing of DNA molecules in the plasma of pregnant women has been shown to allow accurate and noninvasive prenatal detection of fetal trisomy 21. However, whether the sequencing approach is as accurate for the noninvasive prenatal diagnosis of trisomy 13 and 18 is unclear due to the lack of data from a large sample set. We studied 392 pregnancies, among which 25 involved a...
OBJECTIVE To determine the frequency of cytogenetic abnormalities in patients diagnosed as primary myelodysplastic syndrome (MDS) using conventional karyotyping. STUDY DESIGN Case series. PLACE AND DURATION OF STUDY The Clinical Laboratory, The Aga Khan University Hospital, Karachi, between January 2006 - June 2012. METHODOLOGY Patients of all ages and either gender who fulfilled WHO crit...
OBJECTIVE (1) To validate the mixture model in a single operator dataset and (2) to compare the detection rates for fetal chromosomal defects obtained from the mixture model with those obtained from either the delta nuchal translucency (NT) or log multiple of the median (MoM) approach. METHODS Database query, viable singletons [crown-rump length (CRL) 45-84 mm corresponding to 11-13(+6) weeks...
Non-invasive prenatal testing (NIPT) demonstrated a small chance for a false negative result. Since the "fetal" DNA in maternal blood originates from the cytotrophoblast of chorionic villi (CV), some false negative results will have a biological origin. Based on our experience with cytogenetic studies of CV, we tried to estimate this risk. 5967 CV samples of pregnancies at high risk for common ...
John Hilton Edwards [7] first described the symptoms of the genetic disorder known as Trisomy 18?one of the most common forms of human trisomy, which occurs when cells have an extra copy of a chromosome, in 1960. Trisomy 18 [5], also known as Edwards Syndrome [6], occurs approximately once per 6000 live births and is second in frequency only to Trisomy 21, or Down?s Syndrome, as an autosomal tr...
Trisomy 21 mosaicism in a woman with two children with trisomy 21 Down's syndrome* Summary. Trisomy 21 mosaicism was identified by fluorescent quinacrine banding in a phenotypically normal mother, who gave birth to two children with trisomy 21 Down's syndrome. Trisomy 21 Down's syndrome associated with maternal mosaicism was first described by Smith et al in 1962. Since then there have been at ...
Trisomy 21 is associated with high maternal serum concentrations of intact human chorionic gonadotrophin alpha(HCG) and free beta-HCG whereas these concentrations are markedly decreased in trisomy 18. In this study, we investigated the effect of trisomy 21 and 18 on endogenous HCG concentrations and luteinizing hormone (LH)/HCG receptor expression in placental villous tissue in eight trisomy 21...
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