All of the following may occur in Down's syndrome, except:
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.
Hypothyroidism
Undescended testis
Ventricular septal defect
Brushfield's spots