Aortic root dilatation and mitral valve prolapse are cardiac findings sometimes seen in disorders of connective tissue, most often in the Marfan syndrome. This report describes an infant with these cardiac anomalies and a specific chromosomal abnormality, partial trisomy of chromosome 7 associated with partial monosomy of chromosome 22. This association may have significance with respect to the etiology of cardiac disease in connective tissue disorders such as Marfan syndrome.