Abstract: Chromosomal abnormalities occur in 0.1% to 0.2% of live births; Trisomy 21 (Down syndrome) is the most common karyotype abnormality in live-born infants (1 per 800 live births. Trisomy 21 is the most common genetic cause of mental retardation and one of the few aneuploidies compatible with post-natal survival. The vast majority of meiotic errors leading to the trisomic condition occur in the egg, as nearly 90% of cases involve an additional maternal chromosome. The severity of each of the phenotypic features is highly variable among the patients. Besides mental retardation, present in every individual with Down syndrome (DS), Trisomy 21 is associated with more than 80 clinical traits including congenital heart disease, duodenal stenosis or atresia, imperforate anus, Hirschprung disease, muscle hypotonia, immune system deficiencies, increased risk of childhood leukemia and early onset Alzheimer's disease. The rapid changes in prenatal screening and diagnostic techniques bring new challenges Developments in Trisomy 21 (Down syndrome) screening have sought to increase sensitivity and specificity of screening tests.Various methods have been used to identify women at risk of carrying a fetus with Trisomy 21, including consideration of maternal age, biochemical markers, amniocentesis and prenatal ultrasound. This article reviews the literature on prenatal screening for Down’s syndrome which is evidence based and this extensive literature examines how appropriate widely-held understandings of Down’s syndrome are, and asks whether or not practitioners and prospective parents have access to the full range screening and diagnostic test and keeping in account moral, ethical, social &financial milieu of the region and from the point of view of a regional foetal medicine unit. From the point of view of the individual woman, this means that if she chooses to participate in screening, she will have a high chance of detection of Down syndrome, and a low chance that a subsequent invasive diagnostic test will be recommended when her baby is unaffected, since invasive testing carries a low but measurable risk of foetal death.
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Author Name: Dr. Vinita Singh.
URL: View PDF
Keywords: Down’s syndrome, Non- invasive prenatal screening, screening ultrasound.
ISSN: 2394-2746
EISSN: 2394-2754
EOI/DOI: 01/12/2014
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