نتایج جستجو برای: trisomy of 21
تعداد نتایج: 21198882 فیلتر نتایج به سال:
OBJECTIVES To derive a model and examine the performance of first-trimester screening for trisomy 18 by maternal age, fetal nuchal translucency (NT) thickness, and maternal serum free beta-human chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein-A (PAPP-A). METHODS Prospective combined screening for trisomy 21 was performed at 11 + 0 to 13 + 6 weeks in 56 893 singleton ...
OBJECTIVE.Our goal was to determine whether the third ventricle is significantly enlarged among neonates with trisomy 21, compared with infants without clinical signs of trisomy 21. This enlargement might be related to hypoplasia of the structures surrounding the third ventricle. These structures participate in cognitive development, and hypoplasia in this area may be responsible for some of th...
OBJECTIVE To provide estimates of maternal age- and gestational age-related risks for trisomy 21. METHODS The prevalence of trisomy 21 was examined in 57,614 women who had fetal karyotyping at 9-16 weeks of gestation for the sole indication of maternal age of 35 years or more. On the basis of the maternal age distribution and the reported maternal age-related risk for trisomy 21 at birth, the...
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...
Down syndrome is one of the most common causes of mental retardation observed in approximately 1/700 live birth. The use of two or more STR markers related to chromosome 21 facilitates the diagnosis of Down syndrome within about six hours from the collection of the samples. This is the first study has been performed in Iranian population to assess the diagnostic value of using small tandem repe...
BACKGROUND It has been suggested that an increase in oxidative stress in individuals with Down syndrome (DS) may cause adverse effects in the cell membranes through the oxidation of polyunsatured fatty acids. METHODS We examined erythrocyte malondialdehyde (MDA) levels in 100 individuals of both sexes (34 males and 66 females) with DS, aged from newborn to 29 years. The cytogenetic analysis r...
We evaluated performance characteristics of a laboratory-developed, non-invasive prenatal screening (NIPS) assay for fetal aneuploidies. This assay employs massively parallel shotgun sequencing with full automation. GC sequencing bias correction and statistical smoothing were performed to enhance discrimination of affected and unaffected pregnancies. Maternal plasma samples from pregnancies wit...
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