Epidemiology is the study of the distribution of a disease in a population and of the factors influencing this distribution. As a chronic disease with presumably many causes, mongolism (Down's syndrome) admirably lends itself to an epidemiologic critique. The Epidemiology of Mongolism is a provocative attempt to arrange the known factors of mongolism into statistical significant form from which to suggest research areas and etiologic hypotheses.
From the prolific literature of mongolism and within the early pages of this book, mongolism appears with such wide intragroup variability of physical and developmental characteristics that comparison of reports is often meaningless. The inconsistency of diagnostic criteria, record keeping, maternal characteristics, and chromosomal analysis leads to confusion. Dr. Lilienfeld counsels that allusive data can be consolidated when mongols are expressed in terms of their chromosomal type: nondisjunction, translocation, mosaic. He contemplates that variability in form is a differential effect of distinct etiologic agents