This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Genetics of Common Disorders, Subject name: Pediatrics
[{'content': 'Male downs syndrome genotype- \nSelect and explain. \nA. 46 XY, B. 47 XY, C. 45 XY, D. 47 XXY', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., 47 XY o In 95% of cases of Down syndrome-trisomy of 21:-Extra chromosome is of maternal in origin.1% have mosaic with some all have 46 chromosome.4% have robertsonian translocation, n t(13 : 21)t(14 : 21)t(15 : 21)Very rarely long arm of chromosome 21 is triplicate (Partial trisomy).", 'role': 'assistant'}]