This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'A couple has two children affected with tuberous sclerosis. On detailed clinical and laboratory evaluation (including molecular studies) both parents are normal. Which one of the following explains the two affected children in this family ? \nSelect and explain. \nA. Non penetrance, B. Uniparental disomy, C. Genomic imprinting, D. Germline mosaicism', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Germline mosaicism is seen with osteogenesis imperfecta and tuberous sclerosis. For details, see text.', 'role': 'assistant'}]