This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous System, Subject name: Physiology
[{'content': "The over-expression of a trinucleotide repeat causes \nSelect and explain. \nA. Parkinson's disease, B. Caisson's disease, C. Addison's disease, D. Huntington's disease", 'role': 'user'}, {'content': "Answer: D \nExplanation: (D) Huntington's disease > Trinucleotide repeat expansions cause a number of chronic neuro degenerative disease.> Most of them are late onset and cell deaths is prominent in all of them.> The mutations occurs in open reading frames of the gene involved, with the expansions being smaller than those found in the fragile chromosome conditions.> Examples Huntington's disease. Fragile X syndrome. X-linked spino bulbar muscular atrophy. Myotonic dystrophy.", 'role': 'assistant'}]