A 4-year-old boy with a history of mental retardation and seizures

A 4-year-old boy with a history of mental retardation and seizures is brought to the physician with a 3-month history of worsening shortness of breath. During physical examination, the physician notices numerous acnelike papules on the patient’s face. Echocardiography shows significant left ventricular outflow obstruction. Which of the following is the most likely diagnosis for this patient’s heart condition?

(A) Coronary artery disease
(B) Dilated cardiomyopathy
© Myxoma
(D) Rhabdomyoma
(E) Transposition of the great vessels