Medicine and books: Genetics of Common Diseases
Authors: Andrew Read
Journal: BMJ (1998)

Ed INM Day, SE Humphries 

Bios Scientific Publishers, £65, pp 344 

ISBN 1 85996 041 3 

Everybody agrees that the major impact of genetics on health is through genes that influence susceptibility to heart attacks, diabetes, schizophrenia, and other common diseases. Until recently, attempts to identify these genes failed. In retrospect we can see that the tools available were inadequate for the task. The methods that had led so successfully to understanding simply inherited diseases (such as cystic fibrosis and Huntington’s chorea) broke down when applied to diseases to which susceptibility depends on several (possibly many) genes together with environmental factors. Now new laboratory and statistical tools have been developed for fresh assaults on these complex diseases. This book, based on talks given at the University College London Molecular Pathology symposium in December 1996 and aimed at scientifically literate non-specialists, is a fine introduction to the methods, achievements, and hopes of the investigators. 

So far, it has to be said, we live mainly in hope. Progress has been made with diseases in which a subset shows simple inheritance, like breast cancer, and with those in which much of the susceptibility is governed at a single locus, like Alzheimer’s disease, but repeated assaults on schizophrenia, multiple sclerosis, autism, and many other prime targets have yet to show much result. One always hopes for a clever idea that will suddenly make everything plain, but the problem may be just one of low statistical power, requiring us to expand studies by one or two orders of magnitude before we get answers. When we have answers, prevention, diagnosis, and treatment should all benefit—the second half of the book deals with these aspects. But what about the implications for employment, insurance, and civil liberties? 

Much depends on whether the susceptibility factors prove predictive for individuals. My guess is that most won’t. People expect and fear far too much of genetics. Somehow common sense seems to fly out of the window when gene technology comes in. Look at Dolly: half a million human clones walk the streets of Britain, yet the media go ballistic over one cloned sheep. Actually, your granny had a very sound understanding of susceptibility. She called it “constitution.” She understood that your constitution might predispose you to disease or moral turpitude, but it doesn’t predestine you. Those favourite bogeymen, the insurers, show little real interest in predictive factors (and we should be grateful for that). They worry about being denied access to genetic test results, yet they insure Methodist ministers and Glasgow bus drivers on the same terms. In short, while we must remain ready to resist abuses, we should not be frightened about identifying susceptibility genes. Patients, physicians, and drug companies should all benefit. 

I recommend this book as a good introduction to this exciting area—and I hope that your copy, unlike mine, is bound the right way up between its covers. Pity your reviewer, reading through a mirror while standing on his head.