Neonatal screening part 3: controversial issues.

This series of three articles examines different aspects of neonatal screening. In the first article, the author discussed general principles, including criteria for test selection, sensitivity and specificity of tests, cost-benefit analyses, laboratory factors in screening, and the role of neonatal screening in the spectrum of diagnostic techniques for genetic disease. The second article described the status of screening in Canada, the diseases for which screening is now applied, and the benefits of screening and treatment. In this, the final article of this series, the author describes the controversial topics that represent the possible future of screening. He examines four diseases (cystic fibrosis, hypercholesterolemia, sickle cell disease, and muscular dystrophy) for which we can screen, but currently do not screen in Canada.