FAMILIAL INCIDENCE OF RHEUMATOID ARTHRITIS AND ACUTE RHEUMATISM IN 100 RHEUMATOID ARTHRITICS BY

It is comparatively rare in clinical medicine to encounter a condition which can be shown to be inherited as a simple Mendelian gene. As Crew (1947) pointed out, the human subject is by no means satisfactory to study from a genetic point of view; his mate is not chosen for him, he matures slowly, he has few offspring, his chromosomes are numerous, and his mutation rate cannot be speeded up with x rays. The best we can hope to do, in most diseases, is to show whether or not an heredito-familial tendency is involved. The final picture is modified partly by the powers of penetration of a gene or the modifying influence of other genes, but chiefly by the incalculable effect of environment factors. In those conditions where such a tendency can be shown to exist it is important to establish it and, conversely, to disprove it where absent. This will assist us in our understanding of the aetiology, diagnosis, and prognosis. Our knowledge of the aetiology of rheumatoid arthritis remains imperfect. The report by the Scientific Advisory Committee of the Empire Rheumatis