Sir A. E. Garrod, congenital heart disease in Down syndrome, and the doctrine of fetal endocarditis.

Archibald Garrod was apparently the first to document congenital heart disease as a component of Down syndrome. This arose from his interest in fetal endocarditis, a theoretical cause of cardiac malformations, in vogue roughly from 1840-1940, that drew its strength from analogies with rheumatic heart disease in adults. Garrod's discovery sheds light not only on nineteenth century ideas about teratology, but also on his methodology, genius, and approaches that, in many ways, foreshadowed the techniques that guided his later work on inborn errors.