Inappropriate Use of Genetic Terminology in Medical Research: A Public Health Issue

INAPPROPRIATE USE OF GENETIC TERMINOLOGY IN MEDICAL RESEARCH: A PUBLIC HEALTH ISSUE GORDONJ. EDUN* Approximately 3,500 Mendelian or single-gene defects have been identified in the human genome by virtue of an observable disease or defect in individuals [I]. Prior to 1973, only 64 structural genes had been mapped to a particular human chromosome, but by 1983 the number had increased to 554, largely as a result of modern recombinant DNA and cell-culture techniques. Despite the large number of monogenic human disorders that have been identified, most human diseases and abnormal behaviors with a genetic component are determined by a large number of unidentified genes and an even larger number of unknown environmental factors. Such diseases and defects are, therefore, usually referred to as polygenic-multifactorial disorders. The number of genes involved in polygenic disorders could be of the order oftens, or even hundreds, ifone wants to include genes coding for the formation and functions of the brain and nervous system. However, no actual genes, gene products, chromosomal abnormalities, or Mendelian patterns of inheritance have been demonstrated for polygenic disorders . Mathematical models of inheritance have been developed that are consistent with some ofthe observed patterns ofpolygenic disorders, but as has been pointed out, "It remains a challenge to develop polygenic models that are both analytically tractable and biologically believable" [2, S]. Despite the absence of identifiable genes, more emphasis is generally placed by medical researchers on the hereditary (genetic) components of heart disease, cancer, schizophrenia, and a host ofother diseases than on the environmental factors that may contribute to the initiation and progression of these diseases. This is evidenced by the frequent use in research articles of such terms as "genetic vulnerability," "genetic factors ," "genetic basis," "genetic predisposition," and "genetic tendency" ?Department of Genetics, University of California, Davis, California 95616.© 1987 by The University of Chicago. AU rights reserved. 0031-5982/88/3101-0565$01.00 Perspectives in Biology and Medicine, 31, 1 · Autumn 1987 \ 47 that are commonly used to describe the etiology of many disorders, diseases, and behaviors. The following quotes represent a sampling from recent research articles and demonstrate what I believe is an inappropriate "geneticizing" of human disorders of possible polygenic-multifactorial origin based on scant or no genetic evidence. A number of studies using the adoption strategy have been conducted over the past 20 years in Denmark, the United States, Sweden and Belgium. The results of these indicate the operation of genetic factors to a significant extent in schizophrenia, sociopathy, alcoholism, affective disorders, and suicide. [4] In summary, whereas epidemiologic surveys and initial histocompatibility surveys suggest that genetic factors have a role in inflammatory bowel disease, probably in association with actions of an external agent or agents and altered immunologic and other host defense mechanisms, more definitive studies are needed. [5] It is apparent that in a relatively short time a good deal of work has been carried out providing strong evidence for some genetic predisposition to alcoholism . [6, 7] In summary, there is no doubt that the tendency to become allergic is inherited . Studies on this inheritance have revealed several different types ofcontrols. [8] Recent studies of twins suggest that human obesity and fatness are highly heritable. [9] If we look for biochemical correlates of suicide, we find a number of studies suggesting biochemical processes which may be an expression of the genetic trait predisposing to suicide. [10] The psychiatrists began to realize that here was a subgroup of panic-disorder patients who were also social phobies. All that pointed to the theory that social phobia may be a form of panic disorder, and may have biological or genetic roots. [11] I will argue in what follows that the strong emphasis on genes and heredity in disorders such as allergies [8], sociopathy [4, 12], suicide [10], alcoholism [6, 7], depression [13], obesity [9], and others is both scientifically unjustified and ethically questionable. Moreover, the increased overemphasis on "genetic factors" and "genetic tendencies" in human disorders has serious consequences in allocating federal research funds and in formulating public health policies. I cannot offer a blanket refutation of all of the research that supposedly establishes a genetic basis for most human disorders, but several...