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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
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All of the following may occur in Down's syndrome, except:
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The correct answer is  Undescended testis has not been described as an association with Down's syndrome. Hypothyroidism, ventricular septal defect, Brushfield's spots are seen in Down's syndrome. Ref: Essential Pediatrics By O P Ghai, 6th Edition, Page 592; Down Syndrome By Mark Selikowitz, 2008, Preview.