This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetic Approach to Pediatric Medicine, Subject name: Pediatrics
[{'content': 'Prenatal diagnosis of Down Syndrome is by - \nSelect and explain. \nA. Karyo typing, B. Triple test, C. Fetal ultrasonography, D. All of above', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'D' i.e., All of above o Screening for Down syndrome in pregnancy can be done by number of option like - Karyotyping by - Chorionic villus sampling at 10-12 weeks. Amniocentesis at 16-18 wreeks. Cordocentasis after 18 weeks. Maternal serum marker - PAPP-A and free ji HCG in first trimester. a-feto protein, HCG and estradiol (Triple test) in second trimester. Fetal USG - done in 2nd trimester to look for - Increased nuchal fold thickness. Short femur and humerus. Duodenal atresia.", 'role': 'assistant'}]