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 child with a small head, minor anomalies of the face including a thin upper lip, growth delay, and developmental disability can have all of the following, except: \nSelect and explain. \nA. A chromosomal syndrome, B. A teratogenic syndrome, C. A Mendelian syndrome, D. A polygenic syndrome', 'role': 'user'}, {'content': "Answer: D \nExplanation: d. A polygenic syndrome(Ref: Nelson's 20/e p 618-619)The given child has microcephaly, thin upper lip & growth & developmental delay. These features can be seen in:a. A chromosomal syndrome like Tetrasomy 12p (Pallister-Killian syndrome)b. A teratogenic syndrome like fetal alcohol syndromec. Amendelian syndrome like Rubinstein-Taybi syndromeHence, a polygenic syndrome is least likely in the given scenarioIn a polygenic disease, multiple genes contribute to the disease like hypertension & diabetes", 'role': 'assistant'}]