This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cytogenetic Disorders, Subject name: Pathology
[{'content': "Trisomy 21 is - \nSelect and explain. \nA. Down's syndrome, B. Turner syndrome, C. Kleinfelter syndrome, D. Edward syndrome", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Dow n's syndrome Trisomy 21 is synonymous with down's syndrome and is the most common of the chromosomal disorders o Down's syndrome - Trisomy 21 o Edwards syndrome - Trisomy 18 o Patau syndrome - Trisomy 13 o Kleinfelter syndrome - 47XXY o Turner syndrome - 45 XO", 'role': 'assistant'}]