Major and minor anomalies in Japanese children with Down's syndrome.

Abstract

Fifty-five percent of 106 Japanese patients between 2 days and 5 years of age with Down's syndrome were found to have major congenital cardiac defects. Autopsy was performed on 18 cases. Of these, 11 had major congenital heart defects. In addition, all 18 autopsied cases revealed many minor cardiac abnormalities, such as nodular or diffuse hypertrophic valves, parachute formation of atrioventricular valves, hypoplastic papillary muscles, and abnormal attachment of chorda tendineae. It is postulated that minor cardiac abnormalities are secondary to abnormal endocardial and bulbar cushion formation.