title: Determination of human teratogenicity by the astute clinician method: review of illustrative agents and a proposal of guidelines.
abstract: BACKGROUND
  The determination that an exposure is a human teratogen is a complex process involving the application of the principles of teratology, epidemiology, biology, and clinical medicine. Shepard suggested that the "rare exposure/rare defect" or "case report method", the astute clinician model, was one approach for establishing teratogenicity. The purpose of this article is to review selected exposures with the goal of identifying principles that lead to a working proposal for the application of this approach.
  
  
  METHODS
  We selected three known exposures--penicillamine, fluconazole and mycophenolate mofetil--for detailed review. These agents were chosen because their evidence for causation arises mostly from clinical observations in the context of biologic plausibility.
  
  
  RESULTS
  All three agents were originally detected based on astute observations by clinicians reporting on individual cases of a distinctive pattern of malformation or, in the case of penicillamine distinctive phenotype, after the rare exposure. All three have varying degrees of biologic evidence that support the hypothesis that each represents a human teratogen. All three meet Shepard's criteria for "proof."
  
  
  CONCLUSIONS
  The basic premise of this approach depends on the rarity of both the exposure and the outcome. We propose guidelines for utilization of this approach in the determination of human teratogenicity.
authors.affiliation: Department of Pediatrics, Division of Medical Genetics, University of Utah Health Sciences Center, Salt Lake City, Utah, USA. john.carey@hsc.utah.edu
authors.forename: John C
authors.initials: JC
authors.lastname: Carey
authors.forename: Lynn
authors.initials: L
authors.lastname: Martinez
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Balken
authors.forename: Marsha
authors.initials: M
authors.lastname: Leen-Mitchell
authors.forename: Julia
authors.initials: J
authors.lastname: Robertson
mesh_terms: D000014:Abnormalities, Drug-Induced / Q000209:etiology*; D000935:Antifungal Agents / Q000633:toxicity; D018501:Antirheumatic Agents / Q000633:toxicity; D000013:Congenital Abnormalities / Q000209:etiology*; D019317:Evidence-Based Medicine; D005260:Female; D005333:Fetus / Q000187:drug effects; D015725:Fluconazole / Q000633:toxicity; D006801:Humans; D007166:Immunosuppressive Agents / Q000633:toxicity; D007231:Infant, Newborn; D009173:Mycophenolic Acid / Q000031:analogs & derivatives / Q000633:toxicity; D010396:Penicillamine / Q000633:toxicity; D017410:Practice Guidelines as Topic; D011247:Pregnancy; D013723:Teratogens / Q000633:toxicity*
chemical_list: D000935:Antifungal Agents; D018501:Antirheumatic Agents; D007166:Immunosuppressive Agents; D013723:Teratogens; D015725:Fluconazole; D010396:Penicillamine; D009173:Mycophenolic Acid