A 25-year-old man presents after experiencing pronounced shortness of breath while at the gym. You cannot obtain satisfying information from him during the interview, and you think that he may have an intellectual disability disorder. On examination, he appears short for his age and you notice webbed neck, dental malocclusion, antimongoloid slanting of the eyes, and hypogonadism. Auscultation reveals high-pitched systolic ejection murmur maximal in the second left interspace with radiation to the left shoulder and ejection click that decreases with inspiration. His second heart sound (P2) is delayed and soft. The impulse of right ventricle is increased, and you palpate a thrill at second left intercostal space. Question
What will be your best next diagnostic step?
1 Intellectual disability assessment
2 Echocardiography/Doppler
3 Cardiac catheterization
4 Cardiac MRI
5 Karyotyping