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: Medicine
False about Fragile-x syndrome 
Select and explain. 
A. Mutation in DMPK gene, B. Second most common cause of mental retardation, C. Macro orchidism, D. High arched palate
A: Mutation in DMPK gene
Answer: A: Mutation in DMPK gene 
Explanation: Mutation in FMR-1 gene (Familial mental retardation-1 gene).