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: Pediatrics
[{'content': "A 4-year baby is having a large face, large jaw, large ear and macroorchidism is – \nSelect and explain. \nA. Mc Cuneal bright syndrome, B. Down's syndrome, C. Cri–du chat syndrome, D. Fragile X syndrome", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Fragile X syndrome\n\nFragile X syndrome is the prototype of diseases in which the mutation is characterized by a long repeating sequence of three nucleotides.\nNormally, a codon is triplet (trinucleotide).\nIn these type of disorders, this trinucleotide sequence undergoes amplification and the same sequence is repeated many times in the genome.\nIn most cases, the affected sequences share the nucleotide G and C.\n\n\nClinical features of fragile - X syndrome\n\nMental retardation\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0 \xa0\xa0\xa0 \xa0 \xa0 \xa0 \xa0\xa0\nLarge testis (macroorchidism)\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0\nLarge everted ears\nHyperextensible joint\xa0\nLong face with large mandible\nHigh arched palate \xa0\nMitral valve prolapse', 'role': 'assistant'}]