This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetics And Genetic Disorders, Subject name: Pediatrics
[{'content': 'A Down syndrome patient is posted for surgery, the necessary preoperative investigation to be done is: \nSelect and explain. \nA. Echocardiography, B. CT brain, C. X-ray cervical spine, D. USG abdomen', 'role': 'user'}, {'content': "Answer: A \nExplanation: a. Echocardiography > c. X-ray cervical spine(Ref: Nelson's 20/e p 610-615, Ghai 8/e p 637-639)Congenital heart diseases are more common in Down syndrome (in 50%), than atlantoaxial instability (20%); so a preoperative echocardiogram is warranted, so that management of child can be planned accordingly.", 'role': 'assistant'}]