Moments of Truth in Genetic Medicine

Chapter 2: Babies' Blood: Phenylketonuria and the Rise of Public Health Genetics

chapter 2 B A B I E S ’ B L O O D Phenylketonuria and the Rise of Public Health Genetics One of the great success stories in the history of genetic disease was engineered not by geneticists, physicians, or biochemists but primarily by advocates for children with mental retardation. Over the ten years from 1953 to 1963, an obscure and extremely rare metabolic disorder became the focus of major public health programs in the United States and other industrialized nations. It emerged from the “medical ghetto” (Yoxen 1982) of genetic disease to become the center of a network of information, technology, social management, and legislation. Phenylketonuria (PKU), a disorder of phenylalanine metabolism present in about one in fifteen thousand neonates in the United States, attracted funding from national organizations devoted to children’s health. It was the focus of dozens of scientific papers. A field trial of a new diagnostic test was sponsored by the U.S. Children’s Bureau, and by September 1965 neonatal screening for PKU was established public health policy in thirty-two states. In twenty-five of these states, the screening was mandatory.1 Thus, in a short period, a rare genetic disease came to be embedded in a dispersed system of medical and political management. Explanations of why this happened have appeared in retrospectives by participants, in scientific reviews, and in scholarly studies by ethicists, po- litical scientists, and historians (Paul and Edelson 1998; Scriver 1995; Faden, Holtzman, and Chwalow 1982; Bessman and Swazey 1971). Perhaps the simplest narrative portrays the rise of PKU screening as the consequence of new knowledge. Scientists began to understand how to intervene in PKU through dietary controls: infants with the biochemical disorder could avoid mental retardation if the amino acid phenylalanine (normally essential to development) were virtually eliminated from their diet. This new knowledge led naturally to a legislative and public health program. PKU screening was therefore the simple consequence of new technical and therapeutic capabilities (Scriver 1995; Centerwall and Centerwall 1965; Guthrie and Whitney 1964). A more complicated story appeared in a 1975 National Academy of Sciences report that was critical of the new screening programs. In this report, PKU screening programs were the product of “fragmented, uneducated and hurried decision-making.” State legislators were swayed by pleas from parents of children with mental retardation, and these parental appeals led lawmakers to approve public health programs with uncertain consequences, based on “unfounded claims” about the efficacy of a low-phenylalanine diet. “There was very little recognition of the implications for public policy, or for the impact on individuals who were screened, of the fact that PKU is a genetic disease” (Committee for the Study of Inborn Errors of Metabolism 1975, 92–93; emphasis in original). From a rather different analytical perspective, the historian Diane Paul tells an ironic story of uncertainty, conflicting agendas, and ideological utility in the rise of PKU testing and dietary therapy. Many physicians were skeptical of the testing programs, which they interpreted as inappropriate state intervention into medicine. The dietary therapy was boring for the patient , expensive for the family, and difficult to manage and assess. And the screening tests were sometimes inaccurate. Yet PKU testing has been idealized , Paul notes, by those on both sides of the long-running nature-nurture debate. For critics emphasizing the power of the environment to determine human health, the dietary control of PKU is a prime exemplar of the idea that biology is not destiny. And for those promoting the power of genetic medicine and the importance of genetic disease, the success of PKU screening programs suggests the many benefits to be expected from genetic screening more generally (Paul 1999b). These accounts explaining how PKU became a public health priority are B A B I E S ’ B L O O D 2 9 compelling ways of situating a genetic disease that has had an unusually high historical and political profile. From one perspective, the disease became politically relevant because of technical knowledge. From another, political relevance was driven by responses to the problems of children with mental retardation and the social experiences of family members who testi fied before lawmakers. From still a third, it reflected complex ideological commitments to the power of genetic medicine or to the potential of environmental intervention. Certainly there seem to have been many kinds of knowledge and many stakes...