A 15-year-old girl with short stature, neck webbing, and sexual infantilism is found to have coarctation of the aorta. A chromosomal analysis likely would demonstrate which of the following?

Short stature, neck webbing, sexual infantilism, and a shield like chest with widely spaced nipples are signs of Turner syndrome, which is usually associated with an XO karyotype. Aortic coarctation occurs in about 15% to 20% of those with this disorder. Down syndrome is most commonly associated with endocardial cushion defects or VSD. Marfan syndrome (mutation 15q21.1) is associated with dilatation of the aorta and mitral and aortic regurgitation. Ellis-van Creveld syndrome (defect 4p16) is associated with ASD.