This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Growth, Subject name: Pediatrics
[{'content': 'A 1 yr 5 month old boy was brought to the Pediatrics OPD by his mother. She complained that her son did not have any teeth till then. All of the following could be the underlying causes EXCEPT? \nSelect and explain. \nA. Rickets, B. Pierre Robin sequence, C. Cleidocranial dysostosis, D. Down syndrome', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Delayed dentition: - When no tooth has erupted by the age of 13 months. Answer is Pierre Robin sequence- cause of natal teeth', 'role': 'assistant'}]