Pedigree parables.

Pedigrees are a foundation of genetic counseling and human genetic research. To protect patient/subject and family privacy and confidentiality it is not unusual to find published pedigrees that have been masked (i.e. a pedigree that has been changed in ways that are obvious to the reader such as diamonds to mask gender) or altered (i.e. changing pedigree information in ways that are not obvious to the reader such as changing gender and birth order or deleting unaffected siblings from the pedigree). Failure to report pedigree data (e.g. omitting ages, ethnicity, etc.) is another measure used to protect subject and family confidentiality. At what point do such practices hinder the recognition of genetic processes? Is there evidence that harm has occurred to subjects who have appeared in published pedigrees? How does the researcher or clinician determine which information is essential to record on the pedigree? The author uses a historical perspective and case examples to illustrate the issues of balancing protection of the genetic subject's privacy with the reporting of unaltered family data. The author presents several critical questions for peer reviewers and investigators to consider when a pedigree is included in a manuscript, or for researchers involved in family studies.