What struck Archibald Garrod as black urine on a baby's diaper led to his book on inborn errors of metabolism (1909), viewed then as a small work on "obscure metabolic abnormalities."1,2 More ignored, however, was his idea on disease predisposition and person-to-person variation in biochemical traits, or "chemical individuality" (1931): "[I]n every case of every malady there are two sets of factors at work in the formation of the morbid picture, namely internal or constitutional factors, inherent in the sufferer and usually inherited from his forebears, and external ones which fire the train."3
See also p 1494.
Therefore, Garrod probably would have been pleased to see the article on N-acetyltransferase 2 (NAT2, or acetylator) enzymes, smoking, and breast cancer by Ambrosone et al4 in this week's issue of The Journal, because it follows his way of thinking about disease predisposition. The article suggests that defective acetylator
Lin HJ. Smokers and Breast Cancer'Chemical Individuality' and Cancer Predisposition. JAMA. 1996;276(18):1511-1512. doi:10.1001/jama.1996.03540180067035