A 14-year-old Guyanese girl of East Indian heritage was admitted to the hospital with a 1-month history of neck pain on exertion and substernal chest pain when walking. Results of a physical examination disclosed a comfortable, well-developed adolescent girl with bilateral corneal arcus and multiple xanthomas. Vital signs were normal except for a blood pressure of 140/70 mm Hg. Cardiological examination revealed a normal S1 and S2, with a 2/6 systolic ejection murmur at the right base. Systolic bruits were present over both carotid arteries.
The electrocardiogram showed no ST-T wave changes or abnormal Q waves. Results of creatinine kinase, lactate dehydrogenase, and serum glutamicoxalacetic transaminase measurements were all within normal limits. An echocardiogram demonstrated normal ventricular size and function, and no regional wall motion abnormalities were present. An area of increased echo density was noted superior to the aortic valve (Figure 1). No significant Doppler gradient was